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Kholssi R, Lougraimzi H, Moreno-Garrido I. Effects of global environmental change on microalgal photosynthesis, growth and their distribution. MARINE ENVIRONMENTAL RESEARCH 2023; 184:105877. [PMID: 36640723 DOI: 10.1016/j.marenvres.2023.105877] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 01/06/2023] [Accepted: 01/08/2023] [Indexed: 06/17/2023]
Abstract
Global climate change (GCC) constitutes a complex challenge posing a serious threat to biodiversity and ecosystems in the next decades. There are several recent studies dealing with the potential effect of increased temperature, decrease of pH or shifts in salinity, as well as cascading events of GCC and their impact on human-environment systems. Microalgae as primary producers are a sensitive compartment of the marine ecosystems to all those changes. However, the potential consequences of these changes for marine microalgae have received relatively little attention and they are still not well understood. Thus, there is an urgent need to explore and understand the effects generated by multiple climatic changes on marine microalgae growth and biodiversity. Therefore, this review aimed to compare and contrast mechanisms that marine microalgae exhibit to directly respond to harsh conditions associated with GCC and the potential consequences of those changes in marine microalgal populations. Literature shows that microalgae responses to environmental stressors such as temperature were affected differently. A stress caused by salinity might slow down cell division, reduces size, ceases motility, and triggers palmelloid formation in microalgae community, but some of these changes are strongly species-specific. UV irradiance can potentially lead to an oxidative stress in microalgae, promoting the production of reactive oxygen species (ROS) or induce direct physical damage on microalgae, then inhibiting the growth of microalgae. Moreover, pH could impact many groups of microalgae being more tolerant of certain pH shifts, while others were sensitive to changes of just small units (such as coccolithophorids) and subsequently affect the species at a higher trophic level, but also total vertical carbon transport in oceans. Overall, this review highlights the importance of examining effects of multiple stressors, considering multiple responses to understand the complexity behind stressor interactions.
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Affiliation(s)
- Rajaa Kholssi
- Composting Research Group, Faculty of Sciences, University of Burgos, Burgos, Spain; Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain.
| | - Hanane Lougraimzi
- Laboratory of Plant, Animal and Agro-Industry Productions, Faculty of Sciences, Ibn Tofail University, BP: 242, 14000, Kenitra, Morocco
| | - Ignacio Moreno-Garrido
- Ecology and Coastal Management, Institute of Marine Sciences of Andalusia (ICMAN-CSIC), Campus Río San Pedro, 11510, Puerto Real, Cádiz, Spain
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2
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Li W, Wang T, Campbell DA, Gao K. Light history modulates growth and photosynthetic responses of a diatom to ocean acidification and UV radiation. MARINE LIFE SCIENCE & TECHNOLOGY 2023; 5:116-125. [PMID: 37073326 PMCID: PMC10077217 DOI: 10.1007/s42995-022-00138-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/08/2022] [Indexed: 05/03/2023]
Abstract
To examine the synergetic effects of ocean acidification (OA) and light intensity on the photosynthetic performance of marine diatoms, the marine centric diatom Thalassiosira weissflogii was cultured under ambient low CO2 (LC, 390 μatm) and elevated high CO2 (HC, 1000 μatm) levels under low-light (LL, 60 μmol m-2 s-1) or high-light (HL, 220 μmol m-2 s-1) conditions for over 20 generations. HL stimulated the growth rate by 128 and 99% but decreased cell size by 9 and 7% under LC and HC conditions, respectively. However, HC did not change the growth rate under LL but decreased it by 9% under HL. LL combined with HC decreased both maximum quantum yield (F V/F M) and effective quantum yield (Φ PSII), measured under either low or high actinic light. When exposed to UV radiation (UVR), LL-grown cells were more prone to UVA exposure, with higher UVA and UVR inducing inhibition of Φ PSII compared with HL-grown cells. Light use efficiency (α) and maximum relative electron transport rate (rETRmax) were inhibited more in the HC-grown cells when UVR (UVA and UVB) was present, particularly under LL. Our results indicate that the growth light history influences the cell growth and photosynthetic responses to OA and UVR. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00138-x.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Science, Xiamen University, Xiamen, 361005 China
- College of Life and Environmental Sciences, Huangshan University, Huangshan, 245041 China
| | - Tifeng Wang
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Science, Xiamen University, Xiamen, 361005 China
| | | | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science & College of Ocean and Earth Science, Xiamen University, Xiamen, 361005 China
- Co-innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, 222005 China
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3
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Extracellular carbonic anhydrase activity promotes a carbon concentration mechanism in metazoan calcifying cells. Proc Natl Acad Sci U S A 2022; 119:e2203904119. [PMID: 36161891 DOI: 10.1073/pnas.2203904119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many calcifying organisms utilize metabolic CO2 to generate CaCO3 minerals to harden their shells and skeletons. Carbonic anhydrases are evolutionary ancient enzymes that have been proposed to play a key role in the calcification process, with the underlying mechanisms being little understood. Here, we used the calcifying primary mesenchyme cells (PMCs) of sea urchin larva to study the role of cytosolic (iCAs) and extracellular carbonic anhydrases (eCAs) in the cellular carbon concentration mechanism (CCM). Molecular analyses identified iCAs and eCAs in PMCs and highlight the prominent expression of a glycosylphosphatidylinositol-anchored membrane-bound CA (Cara7). Intracellular pH recordings in combination with CO2 pulse experiments demonstrated iCA activity in PMCs. iCA activity measurements, together with pharmacological approaches, revealed an opposing contribution of iCAs and eCAs on the CCM. H+-selective electrodes were used to demonstrate eCA-catalyzed CO2 hydration rates at the cell surface. Knockdown of Cara7 reduced extracellular CO2 hydration rates accompanied by impaired formation of specific skeletal segments. Finally, reduced pHi regulatory capacities during inhibition and knockdown of Cara7 underscore a role of this eCA in cellular HCO3- uptake. This work reveals the function of CAs in the cellular CCM of a marine calcifying animal. Extracellular hydration of metabolic CO2 by Cara7 coupled to HCO3- uptake mechanisms mitigates the loss of carbon and reduces the cellular proton load during the mineralization process. The findings of this work provide insights into the cellular mechanisms of an ancient biological process that is capable of utilizing CO2 to generate a versatile construction material.
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Vázquez V, León P, Gordillo FJL, Jiménez C, Concepción I, Mackenzie K, Bresnan E, Segovia M. High-CO 2 Levels Rather than Acidification Restrict Emiliania huxleyi Growth and Performance. MICROBIAL ECOLOGY 2022:10.1007/s00248-022-02035-3. [PMID: 35624343 DOI: 10.1007/s00248-022-02035-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 05/05/2022] [Indexed: 06/15/2023]
Abstract
The coccolithophore Emiliania huxleyi shows a variety of responses to ocean acidification (OA) and to high-CO2 concentrations, but there is still controversy on differentiating between these two factors when using different strains and culture methods. A heavily calcified type A strain isolated from the Norwegian Sea was selected and batch cultured in order to understand whether acclimation to OA was mediated mainly by CO2 or H+, and how it impacted cell growth performance, calcification, and physiological stress management. Emiliania huxleyi responded differently to each acidification method. CO2-enriched aeration (1200 µatm, pH 7.62) induced a negative effect on the cells when compared to acidification caused by decreasing pH alone (pH 7.60). The growth rates of the coccolithophore were more negatively affected by high pCO2 than by low pH without CO2 enrichment with respect to the control (400 µatm, pH 8.1). High CO2 also affected cell viability and promoted the accumulation of reactive oxygen species (ROS), which was not observed under low pH. This suggests a possible metabolic imbalance induced by high CO2 alone. In contrast, the affinity for carbon uptake was negatively affected by both low pH and high CO2. Photochemistry was only marginally affected by either acidification method when analysed by PAM fluorometry. The POC and PIC cellular quotas and the PIC:POC ratio shifted along the different phases of the cultures; consequently, calcification did not follow the same pattern observed in cell stress and growth performance. Specifically, acidification by HCl addition caused a higher proportion of severely deformed coccoliths, than CO2 enrichment. These results highlight the capacity of CO2 rather than acidification itself to generate metabolic stress, not reducing calcification.
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Affiliation(s)
- Víctor Vázquez
- Department of Ecology, Faculty of Sciences, University of Málaga, Boulevard Louis Pasteur S/N, 29071, Málaga, Spain.
| | - Pablo León
- Marine Laboratory, Marine Scotland Science, 375 Victoria Road, Aberdeen, AB11 9DB, UK
| | - Francisco J L Gordillo
- Department of Ecology, Faculty of Sciences, University of Málaga, Boulevard Louis Pasteur S/N, 29071, Málaga, Spain
| | - Carlos Jiménez
- Department of Ecology, Faculty of Sciences, University of Málaga, Boulevard Louis Pasteur S/N, 29071, Málaga, Spain
| | - Iñiguez Concepción
- Department of Ecology, Faculty of Sciences, University of Málaga, Boulevard Louis Pasteur S/N, 29071, Málaga, Spain
| | - Kevin Mackenzie
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Eileen Bresnan
- Marine Laboratory, Marine Scotland Science, 375 Victoria Road, Aberdeen, AB11 9DB, UK
| | - María Segovia
- Department of Ecology, Faculty of Sciences, University of Málaga, Boulevard Louis Pasteur S/N, 29071, Málaga, Spain
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Reduced H + channel activity disrupts pH homeostasis and calcification in coccolithophores at low ocean pH. Proc Natl Acad Sci U S A 2022; 119:e2118009119. [PMID: 35522711 PMCID: PMC9171652 DOI: 10.1073/pnas.2118009119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coccolithophore calcification is a major ocean biogeochemical process. While this process is likely to be sensitive to acidification-driven changes in ocean carbonate chemistry, incomplete understanding of the underlying mechanisms and constraints is a major bottleneck in predicting ocean acidification effects on calcification. We report severe disruption of pH homeostasis linked to a loss of H+ channel function in the coccolithophore Coccolithus braarudii acclimated to seawater pH values that are likely to be encountered currently in localized regions and more widely in future oceans. This disruption leads to specific defects in coccolith morphology. These findings provide mechanistic insight into how calcification in different coccolithophores is affected by changes in seawater carbonate chemistry. Coccolithophores are major producers of ocean biogenic calcite, but this process is predicted to be negatively affected by future ocean acidification scenarios. Since coccolithophores calcify intracellularly, the mechanisms through which changes in seawater carbonate chemistry affect calcification remain unclear. Here we show that voltage-gated H+ channels in the plasma membrane of Coccolithus braarudii serve to regulate pH and maintain calcification under normal conditions but have greatly reduced activity in cells acclimated to low pH. This disrupts intracellular pH homeostasis and impairs the ability of C. braarudii to remove H+ generated by the calcification process, leading to specific coccolith malformations. These coccolith malformations can be reproduced by pharmacological inhibition of H+ channels. Heavily calcified coccolithophore species such as C. braarudii, which make the major contribution to carbonate export to the deep ocean, have a large intracellular H+ load and are likely to be most vulnerable to future decreases in ocean pH.
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Xu D, Tong S, Wang B, Zhang X, Wang W, Zhang X, Fan X, Wang Y, Sun K, Ye N. Ocean acidification stimulation of phytoplankton growth depends on the extent of departure from the optimal growth temperature. MARINE POLLUTION BULLETIN 2022; 177:113510. [PMID: 35299145 DOI: 10.1016/j.marpolbul.2022.113510] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 01/23/2022] [Accepted: 02/25/2022] [Indexed: 06/14/2023]
Abstract
Ocean acidification and warming are two major environmental stressors; however, the generality of how warming will alter growth responses of phytoplankton to ocean acidification is less known. Here, enhancement of growth by high CO2 (HC) in Phaeodactylum tricornutum and Thalassiosira weissflogii was most prominent at optimum temperature. The extent to which growth rates in HC cultures were raised compared to low CO2 (LC) cultures tended to decrease with increasing or decreasing temperature, compared to the optimum. Further mechanistic studies in P. tricornutum revealed that cellular carbon and nitrogen content, superoxide dismutase activity, and respiration were generally higher in HC than those in LC at high and low temperatures, whereas PSII photochemical parameters were generally lower in HC than in LC at high and low temperatures. These results indicate that HC-grown cells needed to invest more energy and materials to maintain intracellular homeostasis and repair damage induced by the unsuitable temperatures.
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Affiliation(s)
- Dong Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Shanying Tong
- College of Life Science, Ludong University, Yantai, China
| | - Bingkun Wang
- School of Environment, Harbin Institute of Technology, Harbin, China
| | - Xiansheng Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Wei Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiaowen Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiao Fan
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yitao Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Ke Sun
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Naihao Ye
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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7
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Zhang J, Yang Q, Liu Q, Liu S, Zhu Y, Yao J, Wang H, Guan W. The responses of harmful dinoflagellate Karenia mikimotoi to simulated ocean acidification at the transcriptional level. HARMFUL ALGAE 2022; 111:102167. [PMID: 35016771 DOI: 10.1016/j.hal.2021.102167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 12/06/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
The HAB-forming, toxic dinoflagellate Karenia mikimotoi, previously found to benefit from ocean acidification (OA), was cultivated to investigate its transcriptional response to simulated OA for 30 generations. Batch cultures were grown under two CO2 concentrations, 450 (control) and 1100 (simulated OA) μatm, and physiological parameters [growth, pigments, catalase (CAT), glutathione reductase (GR), and superoxide dismutase (SOD) activity], as well as transcriptomes (obtained via RNA-seq), were compared. Chlorophyll a (Chl a) and carotenoid (Caro) contents, as well as CAT and GR activities, were significantly increased under OA conditions. Transcriptomic analysis revealed 2,490 differentially expressed unigenes in response to OA, which comprised 1.54% of all unigenes. A total of 1,121 unigenes were upregulated, and 1,369 unigenes were downregulated in OA compared to control conditions. The downregulated expression of bicarbonate transporter and carbonic anhydrase genes was a landmark of OA acclimation. Key genes involved in energy metabolism, e.g., photosynthesis, tricarboxylic acid cycle, oxidative phosphorylation, and nitrogen metabolism, were highly upregulated under OA, contributing to increases in the Chl a (55.05%) and Caro (28.37%). The enhanced antioxidant enzyme activities (i.e. CAT, GR) and upregulated genes (i.e. glutathione peroxidase, ascorbate peroxidase, heat shock protein, 20S proteasome, aldehyde dehydrogenase, and apolipoprotein) benefit cells against the potential lower pH stress condition under OA. In addition, the downregulation of four genes associated with motility suggested that the preserved energy could further boost growth. In conclusion, the present study suggests that K. mikimotoi exhibits efficient gene expression regulation for the utilization of energy and resistance to OA-induced stress. Taken together, K. mikimotoi appeared as a tolerant species in response to OA. Thus, more extensive algal blooms that threaten marine organisms are likely in the future. These findings expand current knowledge on the gene expression of HAB-forming species in response to future OA.
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Affiliation(s)
- Jiazhu Zhang
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Qiongying Yang
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Qianlou Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Shuqi Liu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Yue Zhu
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Jiang Yao
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China
| | - Hong Wang
- Department of Medical Laboratory Technology, Xinyang Vocational and Technical College, Xinyang, Henan 464000, China
| | - Wanchun Guan
- Wenzhou Key Laboratory of Sanitary Microbiology, School of Laboratory Medicine and Life Sciences, Wenzhou Medical University, Wenzhou, Zhejiang 325035, China.
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Meng R, Zhang L, Zhou C, Liao K, Xiao P, Luo Q, Xu J, Cui Y, Hu X, Yan X. Genome Sequence of Chrysotila roscoffensis, a Coccolithphore Contributed to Global Biogeochemical Cycles. Genes (Basel) 2021; 13:genes13010040. [PMID: 35052381 PMCID: PMC8775090 DOI: 10.3390/genes13010040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/16/2021] [Accepted: 12/21/2021] [Indexed: 01/18/2023] Open
Abstract
Chrysotila is a genus of coccolithophores. Together with Emiliania, it is one of the representative genera in the Haptophyta which have been extensively studied. They are photosynthetic unicellular marine algae sharing the common characteristic of the production of CaCO3 platelets (coccoliths) on the surface of their cells and are crucial contributors to global biogeochemical cycles. Here, we report the genome assembly of Chrysotila roscoffensis. The assembled genome size was ~636 Mb distributed across 769 scaffolds with N50 of 1.63 Mb, and maximum contig length of ~2.6 Mb. Repetitive elements accounted for approximately 59% of the genome. A total of 23,341 genes were predicted from C. roscoffensis genome. The divergence time between C. roscoffensis and Emiliania huxleyi was estimated to be around 537.6 Mya. Gene families related to cytoskeleton, cellular motility and morphology, and ion transport were expanded. The genome of C. roscoffensis will provide a foundation for understanding the genetic and phenotypic diversification and calcification mechanisms of coccolithophores.
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Affiliation(s)
- Ran Meng
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China; (R.M.); (C.Z.)
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Lin Zhang
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Chengxu Zhou
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China; (R.M.); (C.Z.)
- Li Dak Sum Yip Yio Chin Kenneth Li Marine Biopharmaceutical Research Center, Ningbo University, Ningbo 315211, China
| | - Kai Liao
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Peng Xiao
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Qijun Luo
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Jilin Xu
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
| | - Yanze Cui
- Novogene Bioinformatics Institute, Beijing 100083, China;
| | - Xiaodi Hu
- Novogene Bioinformatics Institute, Beijing 100083, China;
- Correspondence: (X.H.); (X.Y.); Tel.: +86-0574-87600458 (X.Y.); +86-0574-87600738 (X.H.)
| | - Xiaojun Yan
- School of Marine Science, Ningbo University, Ningbo 315211, China; (L.Z.); (K.L.); (P.X.); (Q.L.); (J.X.)
- School of Marine Science, Zhejiang Ocean University, Zhoushan 316022, China
- Correspondence: (X.H.); (X.Y.); Tel.: +86-0574-87600458 (X.Y.); +86-0574-87600738 (X.H.)
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Xie E, Xu K, Li Z, Li W, Yi X, Li H, Han Y, Zhang H, Zhang Y. Disentangling the Effects of Ocean Carbonation and Acidification on Elemental Contents and Macromolecules of the Coccolithophore Emiliania huxleyi. Front Microbiol 2021; 12:737454. [PMID: 34745039 PMCID: PMC8564145 DOI: 10.3389/fmicb.2021.737454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 09/29/2021] [Indexed: 11/21/2022] Open
Abstract
Elemental contents change with shifts in macromolecular composition of marine phytoplankton. Recent studies focus on the responses of elemental contents of coccolithophores, a major calcifying phytoplankton group, to changing carbonate chemistry, caused by the dissolution of anthropogenically derived CO2 into the surface ocean. However, the effects of changing carbonate chemistry on biomacromolecules, such as protein and carbohydrate of coccolithophores, are less documented. Here, we disentangled the effects of elevated dissolved inorganic carbon (DIC) concentration (900 to 4,930μmolkg−1) and reduced pH value (8.04 to 7.70) on physiological rates, elemental contents, and macromolecules of the coccolithophore Emiliania huxleyi. Compared to present DIC concentration and pH value, combinations of high DIC concentration and low pH value (ocean acidification) significantly increased pigments content, particulate organic carbon (POC), and carbohydrate content and had less impact on growth rate, maximal relative electron transport rate (rETRmax), particulate organic nitrogen (PON), and protein content. In high pH treatments, elevated DIC concentration significantly increased growth rate, pigments content, rETRmax, POC, particulate inorganic carbon (PIC), protein, and carbohydrate contents. In low pH treatments, the extents of the increase in growth rate, pigments and carbohydrate content were reduced. Compared to high pH value, under low DIC concentration, low pH value significantly increased POC and PON contents and showed less impact on protein and carbohydrate contents; however, under high DIC concentration, low pH value significantly reduced POC, PON, protein, and carbohydrate contents. These results showed that reduced pH counteracted the positive effects of elevated DIC concentration on growth rate, rETRmax, POC, PON, carbohydrate, and protein contents. Elevated DIC concentration and reduced pH acted synergistically to increase the contribution of carbohydrate–carbon to POC, and antagonistically to affect the contribution of protein–nitrogen to PON, which further shifted the carbon/nitrogen ratio of E. huxleyi.
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Affiliation(s)
- Emei Xie
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control and Resource Recycling, Fujian Normal University, Fuzhou, China
| | - Kui Xu
- Hubei Key Laboratory of Edible Wild Plants Conservation and Utilization, Hubei Engineering Research Center of Special Wild Vegetables Breeding and Comprehensive Utilization Technology, College of Life Sciences, Hubei Normal University, Huangshi, China
| | - Zhengke Li
- School of Food and Biological Engineering, Shanxi University of Science and Technology, Xi'an, China
| | - Wei Li
- College of Life and Environmental Sciences, Huangshan University, Huangshan, China
| | - Xiangqi Yi
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Hongzhou Li
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control and Resource Recycling, Fujian Normal University, Fuzhou, China
| | - Yonghe Han
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control and Resource Recycling, Fujian Normal University, Fuzhou, China
| | - Hong Zhang
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control and Resource Recycling, Fujian Normal University, Fuzhou, China
| | - Yong Zhang
- College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control and Resource Recycling, Fujian Normal University, Fuzhou, China
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Zhong J, Guo Y, Liang Z, Huang Q, Lu H, Pan J, Li P, Jin P, Xia J. Adaptation of a marine diatom to ocean acidification and warming reveals constraints and trade-offs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 771:145167. [PMID: 33736151 DOI: 10.1016/j.scitotenv.2021.145167] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Revised: 01/04/2021] [Accepted: 01/10/2021] [Indexed: 06/12/2023]
Abstract
Ocean acidification and warming are recognized as two major anthropogenic perturbations of the modern ocean. However, little is known about the adaptive response of phytoplankton to them. Here we examine the adaptation of a marine diatom Thalassiosira weissflogii to ocean acidification in combination with ocean warming. Our results show that ocean warming have a greater effect than acidification on the growth of T. weissflogii over the long-term selection experiment (~380 generations), as well as many temperature response traits (e.g., optimum temperatures for photosynthesis, maximal net photosynthetic oxygen evolution rates, activation energy) in thermal reaction norm. These results suggest that ocean warming is the main driver for the evolution of the marine diatom T. weissflogii, rather than oceanacidification. However, the evolution resulting from warming can be constrained by ocean acidification, where ocean warming did not impose any effects at high CO2 level. Furthermore, adaptations to ocean warming alone or to the combination of ocean acidification and warming come with trade-offs by inhibiting photochemical performances. The constrains and trade-offs associated with the adaptation to ocean acidification and warming demonstrated in this study, should be considered for parameterizing evolutionary responses in eco-evolutionary models of phytoplankton dynamics in a future ocean.
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Affiliation(s)
- Jiahui Zhong
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Yingyan Guo
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Zhe Liang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Quanting Huang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Hua Lu
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Jinmei Pan
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Peiyuan Li
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
| | - Peng Jin
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China.
| | - Jianrong Xia
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou 510006, China
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11
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Peled-Zehavi H, Gal A. Exploring Intracellular Ion Pools in Coccolithophores Using Live-Cell Imaging. Adv Biol (Weinh) 2021; 5:e2000296. [PMID: 33852773 DOI: 10.1002/adbi.202000296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 02/08/2021] [Indexed: 11/06/2022]
Abstract
Some microorganisms, such as coccolithophores, produce an intricate exoskeleton made of inorganic solids. Coccoliths, the calcium carbonate scales of coccolithophores, are examples of the precise bioproduction of such complex 3D structures. However, the understanding of the cellular mechanisms that control mineral formation inside the cell, specifically the ability of these microalgae to transport high fluxes of inorganic building blocks, is still limited. Recently, using cryo-electron and X-ray microscopy, several intracellular compartments are shown to store high concentrations of calcium and phosphorous and are suggested to have a dominant role in the intracellular mineralization pathway. Here, live-cell confocal microscopy and fluorescent markers are used to examine the dynamics of ion stores in coccolithophores. Using calcein and 4',6-diamidino-2-phenylindole (DAPI) as fluorescent proxies for calcium and polyphosphates, the experiments reveal an unexpected plethora of organelles with distinct fluorescent signatures over a wide range of strains and conditions. Surprisingly, the fluorescent labeling does not show changes along the calcification process and is similar between calcifying and noncalcifying cells, suggesting that these ion pools may not be a dynamic avenue for calcium transport. In such a case, the enigma behind the ability of coccolithophores to sustain intracellular calcification still awaits comprehensive elucidation.
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Affiliation(s)
- Hadas Peled-Zehavi
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Assaf Gal
- Department of Plant and Environmental Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
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12
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Tong S, Xu D, Wang Y, Zhang X, Li Y, Wu H, Ye N. Influence of ocean acidification on thermal reaction norms of carbon metabolism in the marine diatom Phaeodactylum tricornutum. MARINE ENVIRONMENTAL RESEARCH 2021; 164:105233. [PMID: 33310685 DOI: 10.1016/j.marenvres.2020.105233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 11/26/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Under the present CO2 condition, the efficiency of biological pump mediating carbon sequestration is predicted to decline in the future because respiration tends to be more sensitive to rising temperature than is photosynthesis. However, it remains unknown whether the impacts of global warming on metabolic rates of phytoplankton can be modulated by elevated CO2 induced ocean acidification. Here we show that in the model diatom species Phaeodactylum tricornutum, Ea (activation energy) of photosynthesis (~0.5 eV) was significantly lower than that of respiration (1.8 eV), while CO2 concentration had no effect on the Ea value. Eh (deactivation energy) of respiration was increased to 2.5 eV, that was equivalent to Eh of photosynthesis in high CO2-grown cells and 28.4% higher than that in low CO2-grown ones. The respiration to photosynthesis ratio (R/P) was consistently higher in high CO2 condition, which increased with temperature at the beginning and subsequently decreased in both CO2 conditions. The ratio of R/P in high CO2 to R/P in low CO2 gradually increased with temperature above the optimal temperature. Our results imply that ocean acidification will aggravate the negative impacts or offset the alleviating effects of warming on the R/P ratio depending on the temperature range in Phaeodactylum tricornutum.
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Affiliation(s)
- Shanying Tong
- School of Life Sciences, Ludong University, Yantai, China
| | - Dong Xu
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Yitao Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xiansheng Zhang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yan Li
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Hongyan Wu
- School of Life Sciences, Ludong University, Yantai, China.
| | - Naihao Ye
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China; Function Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China.
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13
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Physiological and Molecular Responses to Main Environmental Stressors of Microalgae and Bacteria in Polar Marine Environments. Microorganisms 2020; 8:microorganisms8121957. [PMID: 33317109 PMCID: PMC7764121 DOI: 10.3390/microorganisms8121957] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 12/18/2022] Open
Abstract
The Arctic and Antarctic regions constitute 14% of the total biosphere. Although they differ in their physiographic characteristics, both are strongly affected by snow and ice cover changes, extreme photoperiods and low temperatures, and are still largely unexplored compared to more accessible sites. This review focuses on microalgae and bacteria from polar marine environments and, in particular, on their physiological and molecular responses to harsh environmental conditions. The data reported in this manuscript show that exposure to cold, increase in CO2 concentration and salinity, high/low light, and/or combination of stressors induce variations in species abundance and distribution for both polar bacteria and microalgae, as well as changes in growth rate and increase in cryoprotective compounds. The use of -omics techniques also allowed to identify specific gene losses and gains which could have contributed to polar environmental adaptation, and metabolic shifts, especially related to lipid metabolism and defence systems, such as the up-regulation of ice binding proteins, chaperones and antioxidant enzymes. However, this review also provides evidence that -omics resources for polar species are still few and several sequences still have unknown functions, highlighting the need to further explore polar environments, the biology and ecology of the inhabiting bacteria and microalgae, and their interactions.
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14
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Feng Y, Roleda MY, Armstrong E, Summerfield TC, Law CS, Hurd CL, Boyd PW. Effects of multiple drivers of ocean global change on the physiology and functional gene expression of the coccolithophore Emiliania huxleyi. GLOBAL CHANGE BIOLOGY 2020; 26:5630-5645. [PMID: 32597547 DOI: 10.1111/gcb.15259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/04/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
Ongoing ocean global change due to anthropogenic activities is causing multiple chemical and physical seawater properties to change simultaneously, which may affect the physiology of marine phytoplankton. The coccolithophore Emiliania huxleyi is a model species often employed in the study of the marine carbon cycle. The effect of ocean acidification (OA) on coccolithophore calcification has been extensively studied; however, physiological responses to multiple environmental drivers are still largely unknown. Here we examined two-way and multiple driver effects of OA and other key environmental drivers-nitrate, phosphate, irradiance, and temperature-on the growth, photosynthetic, and calcification rates, and the elemental composition of E. huxleyi. In addition, changes in functional gene expression were examined to understand the molecular mechanisms underpinning the physiological responses. The single driver manipulation experiments suggest decreased nitrate supply being the most important driver regulating E. huxleyi physiology, by significantly reducing the growth, photosynthetic, and calcification rates. In addition, the interaction of OA and decreased nitrate supply (projected for year 2100) had more negative synergistic effects on E. huxleyi physiology than all other two-way factorial manipulations, suggesting a linkage between the single dominant driver (nitrate) effects and interactive effects with other drivers. Simultaneous manipulation of all five environmental drivers to the conditions of the projected year 2100 had the largest negative effects on most of the physiological metrics. Furthermore, functional genes associated with inorganic carbon acquisition (RubisCO, AEL1, and δCA) and calcification (CAX3, AEL1, PATP, and NhaA2) were most downregulated by the multiple driver manipulation, revealing linkages between responses of functional gene expression and associated physiological metrics. These findings together indicate that for more holistic projections of coccolithophore responses to future ocean global change, it is necessary to understand the relative importance of environmental drivers both individually (i.e., mechanistic understanding) and interactively (i.e., cumulative effect) on coccolithophore physiology.
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Affiliation(s)
- Yuanyuan Feng
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin, China
- Department of Botany, University of Otago, Dunedin, New Zealand
| | - Michael Y Roleda
- Department of Botany, University of Otago, Dunedin, New Zealand
- The Marine Science Institute, University of the Philippines, Quezon City, Philippines
| | - Evelyn Armstrong
- NIWA/University of Otago Research Centre for Oceanography, Department of Chemistry, University of Otago, Dunedin, New Zealand
| | | | - Cliff S Law
- NIWA/University of Otago Research Centre for Oceanography, Department of Chemistry, University of Otago, Dunedin, New Zealand
- National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
| | - Catriona L Hurd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
| | - Philip W Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, Hobart, Tas., Australia
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15
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Hu MY, Petersen I, Chang WW, Blurton C, Stumpp M. Cellular bicarbonate accumulation and vesicular proton transport promote calcification in the sea urchin larva. Proc Biol Sci 2020; 287:20201506. [PMID: 32900308 PMCID: PMC7542784 DOI: 10.1098/rspb.2020.1506] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 08/07/2020] [Indexed: 12/12/2022] Open
Abstract
The sea urchin embryo develops a calcitic endoskeleton through intracellular formation of amorphous calcium carbonate (ACC). Intracellular precipitation of ACC, requires [Formula: see text] concentrating as well as proton export mechanisms to promote calcification. These processes are of fundamental importance in biological mineralization, but remain largely unexplored. Here, we demonstrate that the calcifying primary mesenchyme cells (PMCs) use Na+/H+-exchange (NHE) mechanisms to control cellular pH homeostasis during maintenance of the skeleton. During skeleton re-calcification, pHi of PMCs is increased accompanied by substantial elevation in intracellular [Formula: see text] mediated by the [Formula: see text] cotransporter Sp_Slc4a10. However, PMCs lower their pHi regulatory capacities associated with a reduction in NHE activity. Live-cell imaging using green fluorescent protein reporter constructs in combination with intravesicular pH measurements demonstrated alkaline and acidic populations of vesicles in PMCs and extensive trafficking of large V-type H+-ATPase (VHA)-rich acidic vesicles in blastocoelar filopodial cells. Pharmacological and gene expression analyses underline a central role of the VHA isoforms Sp_ATP6V0a1, Sp_ATP6V01_1 and Sp_ATPa1-4 for the process of skeleton re-calcification. These results highlight novel pH regulatory strategies in calcifying cells of a marine species with important implications for our understanding of the mineralization process in times of rapid changes in oceanic pH.
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Affiliation(s)
- Marian Y. Hu
- Institute of Physiology, Christian-Albrechts-University Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
| | - Inga Petersen
- Institute of Physiology, Christian-Albrechts-University Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
| | - William Weijen Chang
- Institute of Physiology, Christian-Albrechts-University Kiel, Hermann-Rodewaldstraße 5, 24118 Kiel, Germany
| | - Christine Blurton
- Institute of Immunobiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Meike Stumpp
- Institute of Immunobiology, Christian-Albrechts-University Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
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16
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The Biotechnological Potential of the Marine Diatom Skeletonema dohrnii to the Elevated Temperature and pCO 2 Concentration. Mar Drugs 2020; 18:md18050259. [PMID: 32429035 PMCID: PMC7281586 DOI: 10.3390/md18050259] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/07/2020] [Accepted: 05/12/2020] [Indexed: 11/17/2022] Open
Abstract
Marine diatoms are promising candidates for biotechnological applications, since they contain high-value compounds, naturally. To facilitate the production of these compounds, stress conditions are often preferable; however, challenges remain with respect to maximizing a metabolic potential for the large-scale cultivation. Here, we sequenced the transcriptome of diatom Skeletonema dohrnii under the actual (21 °C, 400 ppm) and elevated (25 °C, 1000 ppm) temperature and pCO2 condition. Results indicated that cells grown at higher temperature and pCO2 showed increasing growth rate, pigment composition, and biochemical productivity as did the expression of chlorophyll, carotenoid and bioactive compound related genes or transcripts. Furthermore, performing de novo transcriptome, we identified 32,884 transcript clusters and found 10,974 of them were differentially expressed between these two conditions. Analyzing the functions of differentially expressed transcripts, we found many of them involved in core metabolic and biosynthesis pathways, including chlorophyll metabolism, carotenoid, phenylpropanoid, phenylalanine and tyrosine, and flavonoid biosynthesis was upregulated. Moreover, we here demonstrated that utilizing a unique bio-fixation ability, S. dohrnii is capable of suppressing central carbon metabolism to promote lipid productivity, fatty acid contents and other bioactive compounds under high temperature and pCO2 treatment. Our study suggests that this S. dohrnii species could be a potential candidate for wide-scale biotechnological applications under elevated temperature and CO2 conditions.
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17
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Tan YH, Lim PE, Beardall J, Poong SW, Phang SM. A metabolomic approach to investigate effects of ocean acidification on a polar microalga Chlorella sp. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2019; 217:105349. [PMID: 31734626 DOI: 10.1016/j.aquatox.2019.105349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/18/2019] [Accepted: 10/27/2019] [Indexed: 06/10/2023]
Abstract
Ocean acidification, due to increased levels of anthropogenic carbon dioxide, is known to affect the physiology and growth of marine phytoplankton, especially in polar regions. However, the effect of acidification or carbonation on cellular metabolism in polar marine phytoplankton still remains an open question. There is some evidence that small chlorophytes may benefit more than other taxa of phytoplankton. To understand further how green polar picoplankton could acclimate to high oceanic CO2, studies were conducted on an Antarctic Chlorella sp. Chlorella sp. maintained its growth rate (∼0.180 d-1), photosynthetic quantum yield (Fv/Fm = ∼0.69) and chlorophyll a (0.145 fg cell-1) and carotenoid (0.06 fg cell-1) contents under high CO2, while maximum rates of electron transport decreased and non-photochemical quenching increased under elevated CO2. GCMS-based metabolomic analysis reveal that this polar Chlorella strain modulated the levels of metabolites associated with energy, amino acid, fatty acid and carbohydrate production, which could favour its survival in an increasingly acidified ocean.
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Affiliation(s)
- Yong-Hao Tan
- Institute of Advanced Studies, University of Malaya, 50603 Kuala Lumpur, Malaysia; Institute of Ocean & Earth Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Phaik-Eem Lim
- Institute of Ocean & Earth Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia.
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Australia
| | - Sze-Wan Poong
- Institute of Ocean & Earth Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Siew-Moi Phang
- Institute of Ocean & Earth Sciences, University of Malaya, 50603 Kuala Lumpur, Malaysia
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18
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A coastal coccolithophore maintains pH homeostasis and switches carbon sources in response to ocean acidification. Nat Commun 2018; 9:2857. [PMID: 30030435 PMCID: PMC6054640 DOI: 10.1038/s41467-018-04463-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 04/27/2018] [Indexed: 12/30/2022] Open
Abstract
Ocean acidification will potentially inhibit calcification by marine organisms; however, the response of the most prolific ocean calcifiers, coccolithophores, to this perturbation remains under characterized. Here we report novel chemical constraints on the response of the widespread coccolithophore species Ochrosphaera neapolitana (O. neapolitana) to changing-CO2 conditions. We cultured this algae under three pCO2-controlled seawater pH conditions (8.05, 8.22, and 8.33). Boron isotopes within the algae's extracellular calcite plates show that this species maintains a constant pH at the calcification site, regardless of CO2-induced changes in pH of the surrounding seawater. Carbon and oxygen isotopes in the algae's calcite plates and carbon isotopes in the algae's organic matter suggest that O. neapolitana utilize carbon from a single internal dissolved inorganic carbon (DIC) pool for both calcification and photosynthesis, and that a greater proportion of dissolved CO2 relative to HCO3- enters the internal DIC pool under acidified conditions. These two observations may explain how O. neapolitana continues calcifying and photosynthesizing at a constant rate under different atmospheric-pCO2 conditions.
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19
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Tong S, Gao K, Hutchins DA. Adaptive evolution in the coccolithophore Gephyrocapsa oceanica following 1,000 generations of selection under elevated CO 2. GLOBAL CHANGE BIOLOGY 2018; 24:3055-3064. [PMID: 29356310 DOI: 10.1111/gcb.14065] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 12/05/2017] [Accepted: 01/12/2018] [Indexed: 06/07/2023]
Abstract
Coccolithophores are important oceanic primary producers not only in terms of photosynthesis but also because they produce calcite plates called coccoliths. Ongoing ocean acidification associated with changing seawater carbonate chemistry may impair calcification and other metabolic functions in coccolithophores. While short-term ocean acidification effects on calcification and other properties have been examined in a variety of coccolithophore species, long-term adaptive responses have scarcely been documented, other than for the single species Emiliania huxleyi. Here, we investigated the effects of ocean acidification on another ecologically important coccolithophore species, Gephyrocapsa oceanica, following 1,000 generations of growth under elevated CO2 conditions (1,000 μatm). High CO2 -selected populations exhibited reduced growth rates and enhanced particulate organic carbon (POC) and nitrogen (PON) production, relative to populations selected under ambient CO2 (400 μatm). Particulate inorganic carbon (PIC) and PIC/POC ratios decreased progressively throughout the selection period in high CO2 -selected cell lines. All of these trait changes persisted when high CO2 -grown populations were moved back to ambient CO2 conditions for about 10 generations. The results suggest that the calcification of some coccolithophores may be more heavily impaired by ocean acidification than previously predicted based on short-term studies, with potentially large implications for the ocean's carbon cycle under accelerating anthropogenic influences.
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Affiliation(s)
- Shanying Tong
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science, College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - David A Hutchins
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
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20
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Müller MN, Krabbenhöft A, Vollstaedt H, Brandini FP, Eisenhauer A. Stable isotope fractionation of strontium in coccolithophore calcite: Influence of temperature and carbonate chemistry. GEOBIOLOGY 2018; 16:297-306. [PMID: 29431278 DOI: 10.1111/gbi.12276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
Marine calcifying eukaryotic phytoplankton (coccolithophores) is a major contributor to the pelagic production of CaCO3 and plays an important role in the biogeochemical cycles of C, Ca and other divalent cations present in the crystal structure of calcite. The geochemical signature of coccolithophore calcite is used as palaeoproxy to reconstruct past environmental conditions and to understand the underlying physiological mechanisms (vital effects) and precipitation kinetics. Here, we present the stable Sr isotope fractionation between seawater and calcite (Δ88/86 Sr) of laboratory cultured coccolithophores in individual dependence of temperature and seawater carbonate chemistry. Coccolithophores were cultured within a temperature and a pCO2 range from 10 to 25°C and from 175 to 1,240 μatm, respectively. Both environmental drivers induced a significant linear increase in coccolith stable Sr isotope fractionation. The temperature correlation at constant pCO2 for Emiliania huxleyi and Coccolithus braarudii is expressed as Δ88/86 Sr = -7.611 × 10-3 T + 0.0061. The relation of Δ88/86 Sr to pCO2 was tested in Emiliania huxleyi at 10 and 20°C and resulted in Δ88/86 Sr = -5.394 × 10-5 pCO2 - 0.0920 and Δ88/86 Sr = -5.742 × 10-5 pCO2 - 0.1351, respectively. No consistent relationship was found between coccolith Δ88/86 Sr and cellular physiology impeding a direct application of fossil coccolith Δ88/86 Sr as coccolithophore productivity proxy. An overall significant correlation was detected between the elemental distribution coefficient (DSr ) and Δ88/86 Sr similar to inorganic calcite with a physiologically induced offset. Our observations indicate (i) that temperature and pCO2 induce specific effects on coccolith Δ88/86 Sr values and (ii) that strontium elemental ratios and stable isotope fractionation are mainly controlled by precipitation kinetics when embedded into the crystal lattice and subject to vital effects during the transmembrane transport from seawater to the site of calcification. These results provide an important step to develop a coccolith Δ88/86 Sr palaeoproxy complementing the existing toolbox of palaeoceanography.
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Affiliation(s)
- M N Müller
- Department of Oceanography, Federal University of Recife, Cidade Universitária, Recife, PE, Brazil
- Oceanographic Institute at the University of São Paulo, São Paulo, SP, Brazil
| | - A Krabbenhöft
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - H Vollstaedt
- Institute of Geological Science, University of Bern, Bern, Switzerland
| | - F P Brandini
- Oceanographic Institute at the University of São Paulo, São Paulo, SP, Brazil
| | - A Eisenhauer
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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21
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Miao H, Beardall J, Gao K. Calcification Moderates the Increased Susceptibility to UV Radiation of the Coccolithophorid Gephryocapsa oceanica Grown under Elevated CO 2 Concentration: Evidence Based on Calcified and Non-calcified Cells. Photochem Photobiol 2018; 94:994-1002. [PMID: 29701244 DOI: 10.1111/php.12928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 04/07/2018] [Indexed: 01/31/2023]
Abstract
The physiological performance of calcified and non-calcified cells of Gephyrocapsa oceanica (NIES-1318) and their short-term responses to UV radiation were compared for cultures grown under present-day (LC, 400 μatm) and high pCO2 (HC, 1000 μatm) conditions. Similar growth rates and Fv /Fm values were observed in both types of cell under LC conditions, indicating that the loss of calcification in the non-calcified cells did not lead to a competitive disadvantage under such conditions. Detrimental effects of elevated pCO2 were observed in both cell types, with the growth rate of non-calcified cells decreasing more markedly, which might reflect a negative impact of higher cytoplasmic H+ . When exposed to short-term UV radiation, similar trends in effective quantum yield were observed in both cell types acclimated to LC conditions. Elevated pCO2 and associated seawater chemical changes strongly reduced effective quantum yield in non-calcified cells but no significant influence was observed in calcified cells. Based on these findings and comparisons with previous studies, we suggest that the negative impact of elevated cytoplasmic H+ would exacerbate the detrimental effects of UV radiation while the possession of calcification attenuated this influence.
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Affiliation(s)
- Hangbin Miao
- State Key Laboratory of Marine Environmental Science/College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - John Beardall
- State Key Laboratory of Marine Environmental Science/College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.,School of Biological Sciences, Monash University, Clayton, Vic, Australia
| | - Kunshan Gao
- State Key Laboratory of Marine Environmental Science/College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.,Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
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22
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Yin X, Ziegler A, Kelm K, Hoffmann R, Watermeyer P, Alexa P, Villinger C, Rupp U, Schlüter L, Reusch TBH, Griesshaber E, Walther P, Schmahl WW. Formation and mosaicity of coccolith segment calcite of the marine algae Emiliania huxleyi. JOURNAL OF PHYCOLOGY 2018; 54:85-104. [PMID: 29092105 DOI: 10.1111/jpy.12604] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 10/14/2017] [Indexed: 06/07/2023]
Abstract
Coccolithophores belong to the most abundant calcium carbonate mineralizing organisms. Coccolithophore biomineralization is a complex and highly regulated process, resulting in a product that strongly differs in its intricate morphology from the abiogenically produced mineral equivalent. Moreover, unlike extracellularly formed biological carbonate hard tissues, coccolith calcite is neither a hybrid composite, nor is it distinguished by a hierarchical microstructure. This is remarkable as the key to optimizing crystalline biomaterials for mechanical strength and toughness lies in the composite nature of the biological hard tissue and the utilization of specific microstructures. To obtain insight into the pathway of biomineralization of Emiliania huxleyi coccoliths, we examine intracrystalline nanostructural features of the coccolith calcite in combination with cell ultrastructural observations related to the formation of the calcite in the coccolith vesicle within the cell. With TEM diffraction and annular dark-field imaging, we prove the presence of planar imperfections in the calcite crystals such as planar mosaic block boundaries. As only minor misorientations occur, we attribute them to dislocation networks creating small-angle boundaries. Intracrystalline occluded biopolymers are not observed. Hence, in E. huxleyi calcite mosaicity is not caused by occluded biopolymers, as it is the case in extracellularly formed hard tissues of marine invertebrates, but by planar defects and dislocations which are typical for crystals formed by classical ion-by-ion growth mechanisms. Using cryo-preparation techniques for SEM and TEM, we found that the membrane of the coccolith vesicle and the outer membrane of the nuclear envelope are in tight proximity, with a well-controlled constant gap of ~4 nm between them. We describe this conspicuous connection as a not yet described interorganelle junction, the "nuclear envelope junction". The narrow gap of this junction likely facilitates transport of Ca2+ ions from the nuclear envelope to the coccolith vesicle. On the basis of our observations, we propose that formation of the coccolith utilizes the nuclear envelope-endoplasmic reticulum Ca2+ -store of the cell for the transport of Ca2+ ions from the external medium to the coccolith vesicle and that E. huxleyi calcite forms by ion-by-ion growth rather than by a nanoparticle accretion mechanism.
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Affiliation(s)
- Xiaofei Yin
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany
| | - Andreas Ziegler
- Central Facility for Electron Microscopy, University of Ulm, Ulm, 89081, Germany
| | - Klemens Kelm
- Institute of Materials Research, German Aerospace Center (DLR), Cologne, 51147, Germany
| | - Ramona Hoffmann
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany
| | - Philipp Watermeyer
- Institute of Materials Research, German Aerospace Center (DLR), Cologne, 51147, Germany
| | - Patrick Alexa
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany
| | - Clarissa Villinger
- Central Facility for Electron Microscopy, University of Ulm, Ulm, 89081, Germany
- Institute of Virology, University Medical Center Ulm, Ulm, 89081, Germany
| | - Ulrich Rupp
- Central Facility for Electron Microscopy, University of Ulm, Ulm, 89081, Germany
| | - Lothar Schlüter
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Marine Ecology - Evolutionary Ecology, Kiel, 24105, Germany
| | - Thorsten B H Reusch
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Marine Ecology - Evolutionary Ecology, Kiel, 24105, Germany
| | - Erika Griesshaber
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany
| | - Paul Walther
- Central Facility for Electron Microscopy, University of Ulm, Ulm, 89081, Germany
| | - Wolfgang W Schmahl
- Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München, Munich, 80333, Germany
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23
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Xu K, Chen H, Wang W, Xu Y, Ji D, Chen C, Xie C. Responses of photosynthesis and CO 2 concentrating mechanisms of marine crop Pyropia haitanensis thalli to large pH variations at different time scales. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.10.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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24
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Pang M, Xu J, Qu P, Mao X, Wu Z, Xin M, Sun P, Wang Z, Zhang X, Chen H. Effect of CO 2 on growth and toxicity of Alexandrium tamarense from the East China Sea, a major producer of paralytic shellfish toxins. HARMFUL ALGAE 2017; 68:240-247. [PMID: 28962984 DOI: 10.1016/j.hal.2017.08.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/17/2017] [Accepted: 08/31/2017] [Indexed: 06/07/2023]
Abstract
In recent decades, the frequency and intensity of harmful algal blooms (HABs), as well as a profusion of toxic phytoplankton species, have significantly increased in coastal regions of China. Researchers attribute this to environmental changes such as rising atmospheric CO2 levels. Such addition of carbon into the ocean ecosystem can lead to increased growth, enhanced metabolism, and altered toxicity of toxic phytoplankton communities resulting in serious human health concerns. In this study, the effects of elevated partial pressure of CO2 (pCO2) on the growth and toxicity of a strain of Alexandrium tamarense (ATDH) widespread in the East and South China Seas were investigated. Results of these studies showed a higher specific growth rate (0.31±0.05day-1) when exposed to 1000μatm CO2, (experimental), with a corresponding density of (2.02±0.19)×107cellsL-1, that was significantly larger than cells under 395μatm CO2(control). These data also revealed that elevated pCO2 primarily affected the photosynthetic properties of cells in the exponential growth phase. Interestingly, measurement of the total toxin content per cell was reduced by half under elevated CO2 conditions. The following individual toxins were measured in this study: C1, C2, GTX1, GTX2, GTX3, GTX4, GTX5, STX, dcGTX2, dcGTX3, and dcSTX. Cells grown in 1000μatm CO2 showed an overall decrease in the cellular concentrations of C1, C2, GTX2, GTX3, GTX5, STX, dcGTX2, dcGTX3, and dcSTX, but an increase in GTX1 and GTX4. Total cellular toxicity per cell was measured revealing an increase of nearly 60% toxicity in the presence of elevated CO2 compared to controls. This unusual result was attributed to a significant increase in the cellular concentrations of the more toxic derivatives, GTX1 and GTX4.Taken together; these findings indicate that the A. tamarense strain ATDH isolated from the East China Sea significantly increased in growth and cellular toxicity under elevated pCO2 levels. These data may provide vital information regarding future HABs and the corresponding harmful effects as a result of increasing atmospheric CO2.
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Affiliation(s)
- Min Pang
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200,China
| | - Jintao Xu
- Qinhuangdao Marine Environmental Monitoring Central Station of SOA, Qinhuangdao 066000, China
| | - Pei Qu
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China
| | - Xuewei Mao
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China
| | - Zhenxing Wu
- Shandong Entry-Exit Inspection and Quarantine Bureau, Qingdao 266002, China
| | - Ming Xin
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200,China
| | - Ping Sun
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China
| | - Zongxing Wang
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China
| | - Xuelei Zhang
- Key Laboratory of Marine Ecology and Environmental Science and Engineering, First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200,China
| | - Hongju Chen
- The Key Laboratory of Marine Environment and Ecology, Ministry of Education, Ocean University of China, Qingdao 266100, China; Laboratory of Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200,China.
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25
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Taylor AR, Brownlee C, Wheeler G. Coccolithophore Cell Biology: Chalking Up Progress. ANNUAL REVIEW OF MARINE SCIENCE 2017; 9:283-310. [PMID: 27814031 DOI: 10.1146/annurev-marine-122414-034032] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Coccolithophores occupy a special position within the marine phytoplankton because of their production of intricate calcite scales, or coccoliths. Coccolithophores are major contributors to global ocean calcification and long-term carbon fluxes. The intracellular production of coccoliths requires modifications to cellular ultrastructure and metabolism that are surveyed here. In addition to calcification, which appears to have evolved with a diverse range of functions, several other remarkable features that likely underpin the ecological and evolutionary success of coccolithophores have recently been uncovered. These include complex and varied life cycle strategies related to abiotic and biotic interactions as well as a range of novel metabolic pathways and nutritional strategies. Together with knowledge of coccolithophore genetic and physiological variability, these findings are beginning to shed new light on species diversity, distribution, and ecological adaptation. Further advances in genetics and functional characterization at the cellular level will likely to lead to a rapid increase in this understanding.
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Affiliation(s)
- Alison R Taylor
- Department of Biology and Marine Biology, University of North Carolina Wilmington, Wilmington, North Carolina 28403;
| | - Colin Brownlee
- Marine Biological Association, Plymouth PL1 2PB, United Kingdom; ,
- School of Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton SO14 3ZH, United Kingdom
| | - Glen Wheeler
- Marine Biological Association, Plymouth PL1 2PB, United Kingdom; ,
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26
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Torstensson A, Hedblom M, Mattsdotter Björk M, Chierici M, Wulff A. Long-term acclimation to elevated pCO2 alters carbon metabolism and reduces growth in the Antarctic diatom Nitzschia lecointei. Proc Biol Sci 2016; 282:rspb.2015.1513. [PMID: 26354939 DOI: 10.1098/rspb.2015.1513] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Increasing atmospheric CO2 levels are driving changes in the seawater carbonate system, resulting in higher pCO2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to increased pCO2, and few on slow-growing polar organisms with a relative low adaptation potential. In order to recognize the consequences of climate change in biological systems, acclimation and adaptation to new environments are crucial to address. In this study, physiological responses to long-term acclimation (194 days, approx. 60 asexual generations) of three pCO2 levels (280, 390 and 960 µatm) were investigated in the psychrophilic sea ice diatom Nitzschia lecointei. After 147 days, a small reduction in growth was detected at 960 µatm pCO2. Previous short-term experiments have failed to detect altered growth in N. lecointei at high pCO2, which illustrates the importance of experimental duration in studies of climate change. In addition, carbon metabolism was significantly affected by the long-term treatments, resulting in higher cellular release of dissolved organic carbon (DOC). In turn, the release of labile organic carbon stimulated bacterial productivity in this system. We conclude that long-term acclimation to ocean acidification is important for N. lecointei and that carbon overconsumption and DOC exudation may increase in a high-CO2 world.
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Affiliation(s)
- Anders Torstensson
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Mikael Hedblom
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - My Mattsdotter Björk
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden
| | - Melissa Chierici
- Department of Chemistry and Molecular Biology, University of Gothenburg, Göteborg, Sweden Institute of Marine Research, Tromsø, Norway
| | - Angela Wulff
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
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27
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Schlüter L, Lohbeck KT, Gröger JP, Riebesell U, Reusch TBH. Long-term dynamics of adaptive evolution in a globally important phytoplankton species to ocean acidification. SCIENCE ADVANCES 2016; 2:e1501660. [PMID: 27419227 PMCID: PMC4942326 DOI: 10.1126/sciadv.1501660] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 06/15/2016] [Indexed: 05/12/2023]
Abstract
Marine phytoplankton may adapt to ocean change, such as acidification or warming, because of their large population sizes and short generation times. Long-term adaptation to novel environments is a dynamic process, and phenotypic change can take place thousands of generations after exposure to novel conditions. We conducted a long-term evolution experiment (4 years = 2100 generations), starting with a single clone of the abundant and widespread coccolithophore Emiliania huxleyi exposed to three different CO2 levels simulating ocean acidification (OA). Growth rates as a proxy for Darwinian fitness increased only moderately under both levels of OA [+3.4% and +4.8%, respectively, at 1100 and 2200 μatm partial pressure of CO2 (Pco2)] relative to control treatments (ambient CO2, 400 μatm). Long-term adaptation to OA was complex, and initial phenotypic responses of ecologically important traits were later reverted. The biogeochemically important trait of calcification, in particular, that had initially been restored within the first year of evolution was later reduced to levels lower than the performance of nonadapted populations under OA. Calcification was not constitutively lost but returned to control treatment levels when high CO2-adapted isolates were transferred back to present-day control CO2 conditions. Selection under elevated CO2 exacerbated a general decrease of cell sizes under long-term laboratory evolution. Our results show that phytoplankton may evolve complex phenotypic plasticity that can affect biogeochemically important traits, such as calcification. Adaptive evolution may play out over longer time scales (>1 year) in an unforeseen way under future ocean conditions that cannot be predicted from initial adaptation responses.
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Affiliation(s)
- Lothar Schlüter
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Kai T. Lohbeck
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Joachim P. Gröger
- Living Marine Resources Research Unit, Thünen-Institute of Sea Fisheries, Palmaille 9, 22767 Hamburg, Germany
| | - Ulf Riebesell
- Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Thorsten B. H. Reusch
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
- Corresponding author.
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28
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Kottmeier DM, Rokitta SD, Rost B. Acidification, not carbonation, is the major regulator of carbon fluxes in the coccolithophore Emiliania huxleyi. THE NEW PHYTOLOGIST 2016; 211:126-37. [PMID: 26918275 PMCID: PMC5069628 DOI: 10.1111/nph.13885] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/06/2016] [Indexed: 05/11/2023]
Abstract
A combined increase in seawater [CO2 ] and [H(+) ] was recently shown to induce a shift from photosynthetic HCO3 (-) to CO2 uptake in Emiliania huxleyi. This shift occurred within minutes, whereas acclimation to ocean acidification (OA) did not affect the carbon source. To identify the driver of this shift, we exposed low- and high-light acclimated E. huxleyi to a matrix of two levels of dissolved inorganic carbon (1400, 2800 μmol kg(-1) ) and pH (8.15, 7.85) and directly measured cellular O2 , CO2 and HCO3 (-) fluxes under these conditions. Exposure to increased [CO2 ] had little effect on the photosynthetic fluxes, whereas increased [H(+) ] led to a significant decline in HCO3 (-) uptake. Low-light acclimated cells overcompensated for the inhibition of HCO3 (-) uptake by increasing CO2 uptake. High-light acclimated cells, relying on higher proportions of HCO3 (-) uptake, could not increase CO2 uptake and photosynthetic O2 evolution consequently became carbon-limited. These regulations indicate that OA responses in photosynthesis are caused by [H(+) ] rather than by [CO2 ]. The impaired HCO3 (-) uptake also provides a mechanistic explanation for lowered calcification under OA. Moreover, it explains the OA-dependent decrease in photosynthesis observed in high-light grown phytoplankton.
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Affiliation(s)
- Dorothee M. Kottmeier
- Alfred Wegener InstituteHelmholtz Centre for Polar and Marine ResearchAm Handelshafen 1227570BremerhavenGermany
| | - Sebastian D. Rokitta
- Alfred Wegener InstituteHelmholtz Centre for Polar and Marine ResearchAm Handelshafen 1227570BremerhavenGermany
| | - Björn Rost
- Alfred Wegener InstituteHelmholtz Centre for Polar and Marine ResearchAm Handelshafen 1227570BremerhavenGermany
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29
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Monteiro FM, Bach LT, Brownlee C, Bown P, Rickaby REM, Poulton AJ, Tyrrell T, Beaufort L, Dutkiewicz S, Gibbs S, Gutowska MA, Lee R, Riebesell U, Young J, Ridgwell A. Why marine phytoplankton calcify. SCIENCE ADVANCES 2016; 2:e1501822. [PMID: 27453937 PMCID: PMC4956192 DOI: 10.1126/sciadv.1501822] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 06/16/2016] [Indexed: 05/23/2023]
Abstract
Calcifying marine phytoplankton-coccolithophores- are some of the most successful yet enigmatic organisms in the ocean and are at risk from global change. To better understand how they will be affected, we need to know "why" coccolithophores calcify. We review coccolithophorid evolutionary history and cell biology as well as insights from recent experiments to provide a critical assessment of the costs and benefits of calcification. We conclude that calcification has high energy demands and that coccolithophores might have calcified initially to reduce grazing pressure but that additional benefits such as protection from photodamage and viral/bacterial attack further explain their high diversity and broad spectrum ecology. The cost-benefit aspect of these traits is illustrated by novel ecosystem modeling, although conclusive observations remain limited. In the future ocean, the trade-off between changing ecological and physiological costs of calcification and their benefits will ultimately decide how this important group is affected by ocean acidification and global warming.
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Affiliation(s)
- Fanny M. Monteiro
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - Lennart T. Bach
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Colin Brownlee
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Paul Bown
- Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK
| | - Rosalind E. M. Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Alex J. Poulton
- Ocean Biogeochemistry and Ecosystems, National Oceanography Centre, Southampton SO14 3ZH, UK
| | - Toby Tyrrell
- Ocean and Earth Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Luc Beaufort
- Aix-Marseille University/CNRS, Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement (CEREGE), 13545 Aix-en-Provence, France
| | - Stephanie Dutkiewicz
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Samantha Gibbs
- Ocean and Earth Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Magdalena A. Gutowska
- Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss Landing, CA 95039, USA
| | - Renee Lee
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Ulf Riebesell
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Jeremy Young
- Museum of Natural History, Cromwell Road, London SW7 5BD, UK
| | - Andy Ridgwell
- School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
- Department of Earth Sciences, University of California, Riverside, Riverside, CA 92521, USA
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30
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Flynn KJ, Clark DR, Wheeler G. The role of coccolithophore calcification in bioengineering their environment. Proc Biol Sci 2016; 283:rspb.2016.1099. [PMID: 27358373 PMCID: PMC4936047 DOI: 10.1098/rspb.2016.1099] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 06/08/2016] [Indexed: 11/12/2022] Open
Abstract
Coccolithophorids are enigmatic plankton that produce calcium carbonate coccoliths, which over geological time have buried atmospheric CO2 into limestone, changing both the atmosphere and geology of the Earth. However, the role of coccoliths for the proliferation of these organisms remains unclear; suggestions include roles in anti-predation, enhanced photosynthesis and sun-screening. Here we test the hypothesis that calcification stabilizes the pH of the seawater proximate to the organisms, providing a level of acidification countering the detrimental basification that occurs during net photosynthesis. Such bioengineering provides a more stable pH environment for growth and fits the empirical evidence for changes in rates of calcification under different environmental conditions. Under this scenario, simulations suggest that the optimal production ratio of inorganic to organic particulate C (PIC : POCprod) will be lower (by approx. 20%) with ocean acidification and that overproduction of coccoliths in a future acidified ocean, where pH buffering is weaker, presents a risk to calcifying cells.
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Affiliation(s)
- Kevin J Flynn
- College of Science, Swansea University, Swansea SA2 8PP, UK
| | - Darren R Clark
- Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK
| | - Glen Wheeler
- Marine Biological Association, Citadel Hill, Plymouth, PL1 2PB, UK
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31
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Brownlee C, Wheeler GL, Taylor AR. Coccolithophore biomineralization: New questions, new answers. Semin Cell Dev Biol 2015; 46:11-6. [DOI: 10.1016/j.semcdb.2015.10.027] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 10/16/2015] [Accepted: 10/16/2015] [Indexed: 11/28/2022]
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32
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Bermúdez R, Feng Y, Roleda MY, Tatters AO, Hutchins DA, Larsen T, Boyd PW, Hurd CL, Riebesell U, Winder M. Long-Term Conditioning to Elevated pCO2 and Warming Influences the Fatty and Amino Acid Composition of the Diatom Cylindrotheca fusiformis. PLoS One 2015; 10:e0123945. [PMID: 25970340 PMCID: PMC4430207 DOI: 10.1371/journal.pone.0123945] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2014] [Accepted: 03/09/2015] [Indexed: 11/18/2022] Open
Abstract
The unabated rise in anthropogenic CO₂ emissions is predicted to strongly influence the ocean's environment, increasing the mean sea-surface temperature by 4°C and causing a pH decline of 0.3 units by the year 2100. These changes are likely to affect the nutritional value of marine food sources since temperature and CO₂ can influence the fatty (FA) and amino acid (AA) composition of marine primary producers. Here, essential amino (EA) and polyunsaturated fatty (PUFA) acids are of particular importance due to their nutritional value to higher trophic levels. In order to determine the interactive effects of CO₂ and temperature on the nutritional quality of a primary producer, we analyzed the relative PUFA and EA composition of the diatom Cylindrotheca fusiformis cultured under a factorial matrix of 2 temperatures (14 and 19°C) and 3 partial pressures of CO₂ (180, 380, 750 μatm) for >250 generations. Our results show a decay of ~3% and ~6% in PUFA and EA content in algae kept at a pCO₂ of 750 μatm (high) compared to the 380 μatm (intermediate) CO₂ treatments at 14°C. Cultures kept at 19°C displayed a ~3% lower PUFA content under high compared to intermediate pCO₂, while EA did not show differences between treatments. Algae grown at a pCO₂ of 180 μatm (low) had a lower PUFA and AA content in relation to those at intermediate and high CO₂ levels at 14°C, but there were no differences in EA at 19°C for any CO₂ treatment. This study is the first to report adverse effects of warming and acidification on the EA of a primary producer, and corroborates previous observations of negative effects of these stressors on PUFA. Considering that only ~20% of essential biomolecules such as PUFA (and possibly EA) are incorporated into new biomass at the next trophic level, the potential impacts of adverse effects of ocean warming and acidification at the base of the food web may be amplified towards higher trophic levels, which rely on them as source of essential biomolecules.
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Affiliation(s)
- Rafael Bermúdez
- GEOMAR | Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Facultad de Ingeniería Marítima, Ciencias Biológicas, Oceánicas y Recursos Naturales, Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
- * E-mail:
| | - Yuanyuan Feng
- Department of Botany, University of Otago, Dunedin, New Zealand
| | - Michael Y. Roleda
- Department of Botany, University of Otago, Dunedin, New Zealand
- Bioforsk Norwegian Institute for Agricultural and Environmental Research, Bodø, Norway
| | - Avery O. Tatters
- Marine and Environmental Biology, University of Southern California, Los Angeles, California, United States of America
| | - David A. Hutchins
- Marine and Environmental Biology, University of Southern California, Los Angeles, California, United States of America
| | - Thomas Larsen
- Leibniz-Laboratory for Radiometric Dating and Stable Isotope Research, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
| | - Philip W. Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Catriona L. Hurd
- Department of Botany, University of Otago, Dunedin, New Zealand
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
| | - Ulf Riebesell
- GEOMAR | Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Monika Winder
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
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33
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Rautenberger R, Fernández PA, Strittmatter M, Heesch S, Cornwall CE, Hurd CL, Roleda MY. Saturating light and not increased carbon dioxide under ocean acidification drives photosynthesis and growth in Ulva rigida (Chlorophyta). Ecol Evol 2015; 5:874-88. [PMID: 25750714 PMCID: PMC4338970 DOI: 10.1002/ece3.1382] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/10/2014] [Accepted: 12/12/2014] [Indexed: 11/28/2022] Open
Abstract
Carbon physiology of a genetically identified Ulva rigida was investigated under different CO2(aq) and light levels. The study was designed to answer whether (1) light or exogenous inorganic carbon (Ci) pool is driving growth; and (2) elevated CO2(aq) concentration under ocean acidification (OA) will downregulate CAext-mediated [Formula: see text] dehydration and alter the stable carbon isotope (δ (13)C) signatures toward more CO2 use to support higher growth rate. At pHT 9.0 where CO2(aq) is <1 μmol L(-1), inhibition of the known [Formula: see text] use mechanisms, that is, direct [Formula: see text] uptake through the AE port and CAext-mediated [Formula: see text] dehydration decreased net photosynthesis (NPS) by only 56-83%, leaving the carbon uptake mechanism for the remaining 17-44% of the NPS unaccounted. An in silico search for carbon-concentrating mechanism elements in expressed sequence tag libraries of Ulva found putative light-dependent [Formula: see text] transporters to which the remaining NPS can be attributed. The shift in δ (13)C signatures from -22‰ toward -10‰ under saturating light but not under elevated CO2(aq) suggest preference and substantial [Formula: see text] use to support photosynthesis and growth. U. rigida is Ci saturated, and growth was primarily controlled by light. Therefore, increased levels of CO2(aq) predicted for the future will not, in isolation, stimulate Ulva blooms.
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Affiliation(s)
- Ralf Rautenberger
- Department of Botany, University of OtagoP.O. Box 56, Dunedin, 9054, New Zealand
| | - Pamela A Fernández
- Department of Botany, University of OtagoP.O. Box 56, Dunedin, 9054, New Zealand
| | - Martina Strittmatter
- The Scottish Association for Marine Science, Scottish Marine InstituteOban, Argyll, PA37 1QA, Scotland
| | - Svenja Heesch
- Irish Seaweed Research Group, Ryan Institute for Environmental, Marine and Energy Research, National University of IrelandGalway (NUIG), University Road, Galway, Ireland
| | - Christopher E Cornwall
- Department of Botany, University of OtagoP.O. Box 56, Dunedin, 9054, New Zealand
- Institute for Marine and Antarctic Studies, University of TasmaniaHobart, Tasmania, 7001, Australia
| | - Catriona L Hurd
- Department of Botany, University of OtagoP.O. Box 56, Dunedin, 9054, New Zealand
- Institute for Marine and Antarctic Studies, University of TasmaniaHobart, Tasmania, 7001, Australia
| | - Michael Y Roleda
- Department of Botany, University of OtagoP.O. Box 56, Dunedin, 9054, New Zealand
- Bioforsk Norwegian Institute for Agricultural and Environmental ResearchKudalsveien 6, 8049, Bodø, Norway
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34
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Lohbeck KT, Riebesell U, Reusch TBH. Gene expression changes in the coccolithophore Emiliania huxleyi after 500 generations of selection to ocean acidification. Proc Biol Sci 2015; 281:rspb.2014.0003. [PMID: 24827439 DOI: 10.1098/rspb.2014.0003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Coccolithophores are unicellular marine algae that produce biogenic calcite scales and substantially contribute to marine primary production and carbon export to the deep ocean. Ongoing ocean acidification particularly impairs calcifying organisms, mostly resulting in decreased growth and calcification. Recent studies revealed that the immediate physiological response in the coccolithophore Emiliania huxleyi to ocean acidification may be partially compensated by evolutionary adaptation, yet the underlying molecular mechanisms are currently unknown. Here, we report on the expression levels of 10 candidate genes putatively relevant to pH regulation, carbon transport, calcification and photosynthesis in E. huxleyi populations short-term exposed to ocean acidification conditions after acclimation (physiological response) and after 500 generations of high CO2 adaptation (adaptive response). The physiological response revealed downregulation of candidate genes, well reflecting the concomitant decrease of growth and calcification. In the adaptive response, putative pH regulation and carbon transport genes were up-regulated, matching partial restoration of growth and calcification in high CO2-adapted populations. Adaptation to ocean acidification in E. huxleyi likely involved improved cellular pH regulation, presumably indirectly affecting calcification. Adaptive evolution may thus have the potential to partially restore cellular pH regulatory capacity and thereby mitigate adverse effects of ocean acidification.
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Affiliation(s)
- Kai T Lohbeck
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Ulf Riebesell
- Biological Oceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
| | - Thorsten B H Reusch
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany
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Hattenrath-Lehmann TK, Smith JL, Wallace RB, Merlo L, Koch F, Mittelsdorf H, Goleski JA, Anderson DM, Gobler CJ. The effects of elevated CO 2 on the growth and toxicity of field populations and cultures of the saxitoxin-producing dinoflagellate, Alexandrium fundyense. LIMNOLOGY AND OCEANOGRAPHY 2015; 60:198-214. [PMID: 27721521 PMCID: PMC5055070 DOI: 10.1002/lno.10012] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The effects of coastal acidification on the growth and toxicity of the saxitoxin-producing dinoflagellate Alexandrium fundyense were examined in culture and ecosystem studies. In culture experiments, Alexandrium strains isolated from Northport Bay NY, USA, and the Bay of Fundy, Canada, grew significantly faster (16 -190%; p<0.05) when exposed to elevated levels of pCO2 (~ 800- 1900μatm) compared to lower levels (~390μatm). Exposure to higher levels of pCO2 also resulted in significant increases (71 - 81%) in total cellular toxicity (fg STX eq. cell-1) in the Northport Bay strain, while no changes in toxicity were detected in the Bay of Fundy strain. The positive relationship between pCO2 enhancement and elevated growth was reproducible using natural populations from Northport; Alexandrium densities were significantly and consistently enhanced when natural populations were incubated at 1500 μatm pCO2, a value at the upper range of those recorded in Northport Bay, 390 - 1500 µatm. During natural Alexandrium blooms in Northport Bay, pCO2 concentrations increased over the course of a bloom to more than 1700μatm and were highest in regions with the greatest Alexandrium abundances, suggesting Alexandrium may be further exacerbating acidification or be especially adapted to these extreme, acidified conditions. The co-occurrence of Alexandrium blooms and elevated pCO2 represents a previously unrecognized, compounding environmental threat to coastal ecosystems. The ability of elevated pCO2 to enhance the growth and toxicity of Alexandrium indicates that acidification promoted by eutrophication or climate change can intensify these, and perhaps other, harmful algal blooms.
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Affiliation(s)
| | | | - Ryan B. Wallace
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
| | - Lucas Merlo
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
| | - Florian Koch
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
| | - Heidi Mittelsdorf
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
| | - Jennifer A. Goleski
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
| | | | - Christopher J. Gobler
- Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA
- Corresponding author,
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36
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Fernández PA, Hurd CL, Roleda MY. Bicarbonate uptake via an anion exchange protein is the main mechanism of inorganic carbon acquisition by the giant kelp Macrocystis pyrifera (Laminariales, Phaeophyceae) under variable pH. JOURNAL OF PHYCOLOGY 2014; 50:998-1008. [PMID: 26988782 DOI: 10.1111/jpy.12247] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 08/28/2014] [Indexed: 06/05/2023]
Abstract
Macrocystis pyrifera is a widely distributed, highly productive, seaweed. It is known to use bicarbonate (HCO3 (-) ) from seawater in photosynthesis and the main mechanism of utilization is attributed to the external catalyzed dehydration of HCO3 (-) by the surface-bound enzyme carbonic anhydrase (CAext ). Here, we examined other putative HCO3 (-) uptake mechanisms in M. pyrifera under pHT 9.00 (HCO3 (-) : CO2 = 940:1) and pHT 7.65 (HCO3 (-) : CO2 = 51:1). Rates of photosynthesis, and internal CA (CAint ) and CAext activity were measured following the application of AZ which inhibits CAext , and DIDS which inhibits a different HCO3 (-) uptake system, via an anion exchange (AE) protein. We found that the main mechanism of HCO3 (-) uptake by M. pyrifera is via an AE protein, regardless of the HCO3 (-) : CO2 ratio, with CAext making little contribution. Inhibiting the AE protein led to a 55%-65% decrease in photosynthetic rates. Inhibiting both the AE protein and CAext at pHT 9.00 led to 80%-100% inhibition of photosynthesis, whereas at pHT 7.65, passive CO2 diffusion supported 33% of photosynthesis. CAint was active at pHT 7.65 and 9.00, and activity was always higher than CAext , because of its role in dehydrating HCO3 (-) to supply CO2 to RuBisCO. Interestingly, the main mechanism of HCO3 (-) uptake in M. pyrifera was different than that in other Laminariales studied (CAext -catalyzed reaction) and we suggest that species-specific knowledge of carbon uptake mechanisms is required in order to elucidate how seaweeds might respond to future changes in HCO3 (-) :CO2 due to ocean acidification.
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Affiliation(s)
- Pamela A Fernández
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
| | - Catriona L Hurd
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Private Bag 129, Sandy Bay, Hobart, Tasmania, 7001, Australia
| | - Michael Y Roleda
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
- Bioforsk Norwegian Institute for Agricultural and Environmental Research, Kudalsveien 6, Bodø, 8049, Norway
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Kottmeier DM, Rokitta SD, Tortell PD, Rost B. Strong shift from HCO3 (-) to CO 2 uptake in Emiliania huxleyi with acidification: new approach unravels acclimation versus short-term pH effects. PHOTOSYNTHESIS RESEARCH 2014; 121:265-75. [PMID: 24563097 PMCID: PMC4077253 DOI: 10.1007/s11120-014-9984-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 02/10/2014] [Indexed: 05/07/2023]
Abstract
Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 μatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values ≤ 8.1, cells preferentially used CO2 (≥ 90 % CO2), whereas at pH values ≥ 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.
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Affiliation(s)
- Dorothee M Kottmeier
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany,
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38
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Isensee K, Erez J, Stoll HM. Detection of a variable intracellular acid-labile carbon pool in Thalassiosira weissflogii (Heterokontophyta) and Emiliania huxleyi (Haptophyta) in response to changes in the seawater carbon system. PHYSIOLOGIA PLANTARUM 2014; 150:321-338. [PMID: 23992373 DOI: 10.1111/ppl.12096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/30/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
Accumulation of an intracellular pool of carbon (C(i) pool) is one strategy by which marine algae overcome the low abundance of dissolved CO2 (CO2 (aq) ) in modern seawater. To identify the environmental conditions under which algae accumulate an acid-labile C(i) pool, we applied a (14) C pulse-chase method, used originally in dinoflagellates, to two new classes of algae, coccolithophorids and diatoms. This method measures the carbon accumulation inside the cells without altering the medium carbon chemistry or culture cell density. We found that the diatom Thalassiosira weissflogii [(Grunow) G. Fryxell & Hasle] and a calcifying strain of the coccolithophorid Emiliania huxleyi [(Lohmann) W. W. Hay & H. P. Mohler] develop significant acid-labile C(i) pools. C(i) pools are measureable in cells cultured in media with 2-30 µmol l(-1) CO2 (aq), corresponding to a medium pH of 8.6-7.9. The absolute C(i) pool was greater for the larger celled diatoms. For both algal classes, the C(i) pool became a negligible contributor to photosynthesis once CO2 (aq) exceeded 30 µmol l(-1) . Combining the (14) C pulse-chase method and (14) C disequilibrium method enabled us to assess whether E. huxleyi and T. weissflogii exhibited thresholds for foregoing accumulation of DIC or reduced the reliance on bicarbonate uptake with increasing CO2 (aq) . We showed that the C(i) pool decreases with higher CO2 :HCO3 (-) uptake rates.
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Affiliation(s)
- Kirsten Isensee
- Departmento de Geologia, Universidad Oviedo, 33006 Oviedo, Asturias, Spain
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39
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McMinn A, Müller MN, Martin A, Ryan KG. The response of Antarctic sea ice algae to changes in pH and CO2. PLoS One 2014; 9:e86984. [PMID: 24489821 PMCID: PMC3904983 DOI: 10.1371/journal.pone.0086984] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Accepted: 12/19/2013] [Indexed: 11/18/2022] Open
Abstract
Ocean acidification substantially alters ocean carbon chemistry and hence pH but the effects on sea ice formation and the CO2 concentration in the enclosed brine channels are unknown. Microbial communities inhabiting sea ice ecosystems currently contribute 10-50% of the annual primary production of polar seas, supporting overwintering zooplankton species, especially Antarctic krill, and seeding spring phytoplankton blooms. Ocean acidification is occurring in all surface waters but the strongest effects will be experienced in polar ecosystems with significant effects on all trophic levels. Brine algae collected from McMurdo Sound (Antarctica) sea ice was incubated in situ under various carbonate chemistry conditions. The carbon chemistry was manipulated with acid, bicarbonate and bases to produce a pCO2 and pH range from 238 to 6066 µatm and 7.19 to 8.66, respectively. Elevated pCO2 positively affected the growth rate of the brine algal community, dominated by the unique ice dinoflagellate, Polarella glacialis. Growth rates were significantly reduced when pH dropped below 7.6. However, when the pH was held constant and the pCO2 increased, growth rates of the brine algae increased by more than 20% and showed no decline at pCO2 values more than five times current ambient levels. We suggest that projected increases in seawater pCO2, associated with OA, will not adversely impact brine algal communities.
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Affiliation(s)
- Andrew McMinn
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
- * E-mail:
| | - Marius N. Müller
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Andrew Martin
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Ken G. Ryan
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
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40
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Bach LT, Mackinder LCM, Schulz KG, Wheeler G, Schroeder DC, Brownlee C, Riebesell U. Dissecting the impact of CO2 and pH on the mechanisms of photosynthesis and calcification in the coccolithophore Emiliania huxleyi. THE NEW PHYTOLOGIST 2013; 199:121-134. [PMID: 23496417 DOI: 10.1111/nph.12225] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 02/08/2013] [Indexed: 05/15/2023]
Abstract
Coccolithophores are important calcifying phytoplankton predicted to be impacted by changes in ocean carbonate chemistry caused by the absorption of anthropogenic CO2 . However, it is difficult to disentangle the effects of the simultaneously changing carbonate system parameters (CO2 , bicarbonate, carbonate and protons) on the physiological responses to elevated CO2 . Here, we adopted a multifactorial approach at constant pH or CO2 whilst varying dissolved inorganic carbon (DIC) to determine physiological and transcriptional responses to individual carbonate system parameters. We show that Emiliania huxleyi is sensitive to low CO2 (growth and photosynthesis) and low bicarbonate (calcification) as well as low pH beyond a limited tolerance range, but is much less sensitive to elevated CO2 and bicarbonate. Multiple up-regulated genes at low DIC bear the hallmarks of a carbon-concentrating mechanism (CCM) that is responsive to CO2 and bicarbonate but not to pH. Emiliania huxleyi appears to have evolved mechanisms to respond to limiting rather than elevated CO2 . Calcification does not function as a CCM, but is inhibited at low DIC to allow the redistribution of DIC from calcification to photosynthesis. The presented data provides a significant step in understanding how E. huxleyi will respond to changing carbonate chemistry at a cellular level.
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Affiliation(s)
- Lennart T Bach
- Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), D-24105, Kiel, Germany
| | - Luke C M Mackinder
- Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), D-24105, Kiel, Germany
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Kai G Schulz
- Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), D-24105, Kiel, Germany
| | - Glen Wheeler
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
- Plymouth Marine Laboratory, Prospect Place, Plymouth, PL1 3DH, UK
| | - Declan C Schroeder
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Colin Brownlee
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
| | - Ulf Riebesell
- Helmholtz-Zentrum für Ozeanforschung Kiel (GEOMAR), D-24105, Kiel, Germany
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41
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Rokitta SD, John U, Rost B. Ocean acidification affects redox-balance and ion-homeostasis in the life-cycle stages of Emiliania huxleyi. PLoS One 2012; 7:e52212. [PMID: 23300616 PMCID: PMC3530605 DOI: 10.1371/journal.pone.0052212] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 11/09/2012] [Indexed: 12/25/2022] Open
Abstract
Ocean Acidification (OA) has been shown to affect photosynthesis and calcification in the coccolithophore Emiliania huxleyi, a cosmopolitan calcifier that significantly contributes to the regulation of the biological carbon pumps. Its non-calcifying, haploid life-cycle stage was found to be relatively unaffected by OA with respect to biomass production. Deeper insights into physiological key processes and their dependence on environmental factors are lacking, but are required to understand and possibly estimate the dynamics of carbon cycling in present and future oceans. Therefore, calcifying diploid and non-calcifying haploid cells were acclimated to present and future CO(2) partial pressures (pCO(2); 38.5 Pa vs. 101.3 Pa CO(2)) under low and high light (50 vs. 300 µmol photons m(-2) s(-1)). Comparative microarray-based transcriptome profiling was used to screen for the underlying cellular processes and allowed to follow up interpretations derived from physiological data. In the diplont, the observed increases in biomass production under OA are likely caused by stimulated production of glycoconjugates and lipids. The observed lowered calcification under OA can be attributed to impaired signal-transduction and ion-transport. The haplont utilizes distinct genes and metabolic pathways, reflecting the stage-specific usage of certain portions of the genome. With respect to functionality and energy-dependence, however, the transcriptomic OA-responses resemble those of the diplont. In both life-cycle stages, OA affects the cellular redox-state as a master regulator and thereby causes a metabolic shift from oxidative towards reductive pathways, which involves a reconstellation of carbon flux networks within and across compartments. Whereas signal transduction and ion-homeostasis appear equally OA-sensitive under both light intensities, the effects on carbon metabolism and light physiology are clearly modulated by light availability. These interactive effects can be attributed to the influence of OA and light on the redox equilibria of NAD and NADP, which function as major sensors for energization and stress. This generic mode of action of OA may therefore provoke similar cell-physiological responses in other protists.
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Affiliation(s)
- Sebastian D Rokitta
- Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany.
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Drescher B, Dillaman RM, Taylor AR. Coccolithogenesis In Scyphosphaera apsteinii (Prymnesiophyceae). JOURNAL OF PHYCOLOGY 2012; 48:1343-61. [PMID: 27009987 DOI: 10.1111/j.1529-8817.2012.01227.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Accepted: 05/06/2012] [Indexed: 05/24/2023]
Abstract
Coccolithophores are the most significant producers of marine biogenic calcite, although the intracellular calcification process is poorly understood. In the case of Scyphosphaera apsteinii Lohmann 1902, flat ovoid muroliths and bulky, vase-shaped lopadoliths with a range of intermediate morphologies may be produced by a single cell. This polymorphic species is within the Zygodiscales, a group that remains understudied with respect to ultrastructure and coccolith ontogeny. We therefore undertook an analysis of cell ultrastructure, morphology, and coccolithogenesis. The cell ultrastructure showed many typical haptophyte features, with calcification following a similar pattern to that described for other heterococcolith bearing species including Emiliania huxleyi. Of particular significance was the reticular body role in governing fine-scale morphology, specifically the central pore formation of the coccolith. Our observations also highlighted the essential role of the inter- and intracrystalline organic matrix in growth and arrangement of the coccolith calcite. S. apsteinii secreted mature coccoliths that attached to the plasma membrane via fibrillar material. Time-lapse light microscopy demonstrated secretion of lopadoliths occurred base first before being actively repositioned at the cell surface. Significantly, growth irradiance influenced the coccosphere composition with fewer lopadoliths being formed relative to muroliths at higher light intensities. Overall, our observations support dynamic metabolic (i.e., in response to growth irradiance), sensory and cytoskeletal control over the morphology and secretion of polymorphic heterococcoliths. With a basic understanding of calcification established, S. apsteinii could be a valuable model to further study coccolithophore calcification and cell physiological responses to ocean acidification.
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Affiliation(s)
- Brandon Drescher
- Biology Department, University of North Carolina Wilmington, 601 S. College Road, Wilmington, North Carolina, 28403, USA
| | - Richard M Dillaman
- Biology Department, University of North Carolina Wilmington, 601 S. College Road, Wilmington, North Carolina, 28403, USA
| | - Alison R Taylor
- Biology Department, University of North Carolina Wilmington, 601 S. College Road, Wilmington, North Carolina, 28403, USA
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth, PL1 2PB, UK
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Taylor AR, Brownlee C, Wheeler GL. Proton channels in algae: reasons to be excited. TRENDS IN PLANT SCIENCE 2012; 17:675-84. [PMID: 22819465 DOI: 10.1016/j.tplants.2012.06.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 06/14/2012] [Accepted: 06/18/2012] [Indexed: 05/08/2023]
Abstract
A fundamental requirement of all eukaryotes is the ability to translocate protons across membranes. This is critical in bioenergetics, for compartmentalized metabolism, and to regulate intracellular pH (pH(i)) within a range that is compatible with cellular metabolism. Plants, animals, and algae utilize specialized transport machinery for membrane energization and pH homeostasis that reflects the prevailing ionic conditions in which they evolved. The recent characterization of H(+)-permeable channels in marine and freshwater algae has led to the discovery of novel functions for these transport proteins in both cellular pH homeostasis and sensory biology. Here we review the potential implications for understanding the origins and evolution of membrane excitability and the phytoplankton-based marine ecosystem responses to ocean acidification.
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Affiliation(s)
- Alison R Taylor
- Department of Biology and Marine Biology, University of North Carolina Wilmington, 601 South College Road, Wilmington, NC 28409, USA.
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Stumpp M, Hu MY, Melzner F, Gutowska MA, Dorey N, Himmerkus N, Holtmann WC, Dupont ST, Thorndyke MC, Bleich M. Acidified seawater impacts sea urchin larvae pH regulatory systems relevant for calcification. Proc Natl Acad Sci U S A 2012; 109:18192-7. [PMID: 23077257 PMCID: PMC3497771 DOI: 10.1073/pnas.1209174109] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Calcifying echinoid larvae respond to changes in seawater carbonate chemistry with reduced growth and developmental delay. To date, no information exists on how ocean acidification acts on pH homeostasis in echinoderm larvae. Understanding acid-base regulatory capacities is important because intracellular formation and maintenance of the calcium carbonate skeleton is dependent on pH homeostasis. Using H(+)-selective microelectrodes and the pH-sensitive fluorescent dye BCECF, we conducted in vivo measurements of extracellular and intracellular pH (pH(e) and pH(i)) in echinoderm larvae. We exposed pluteus larvae to a range of seawater CO(2) conditions and demonstrated that the extracellular compartment surrounding the calcifying primary mesenchyme cells (PMCs) conforms to the surrounding seawater with respect to pH during exposure to elevated seawater pCO(2). Using FITC dextran conjugates, we demonstrate that sea urchin larvae have a leaky integument. PMCs and spicules are therefore directly exposed to strong changes in pH(e) whenever seawater pH changes. However, measurements of pH(i) demonstrated that PMCs are able to fully compensate an induced intracellular acidosis. This was highly dependent on Na(+) and HCO(3)(-), suggesting a bicarbonate buffer mechanism involving secondary active Na(+)-dependent membrane transport proteins. We suggest that, under ocean acidification, maintained pH(i) enables calcification to proceed despite decreased pH(e). However, this probably causes enhanced costs. Increased costs for calcification or cellular homeostasis can be one of the main factors leading to modifications in energy partitioning, which then impacts growth and, ultimately, results in increased mortality of echinoid larvae during the pelagic life stage.
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Affiliation(s)
- Meike Stumpp
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), 24105 Kiel, Germany; and
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Science, University of Gothenburg, Kristineberg, 45178 Fiskebäckskil, Sweden
| | - Marian Y. Hu
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), 24105 Kiel, Germany; and
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Science, University of Gothenburg, Kristineberg, 45178 Fiskebäckskil, Sweden
| | - Frank Melzner
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), 24105 Kiel, Germany; and
| | - Magdalena A. Gutowska
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), 24105 Kiel, Germany; and
| | - Narimane Dorey
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Science, University of Gothenburg, Kristineberg, 45178 Fiskebäckskil, Sweden
| | - Nina Himmerkus
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
| | - Wiebke C. Holtmann
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
| | - Sam T. Dupont
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Science, University of Gothenburg, Kristineberg, 45178 Fiskebäckskil, Sweden
| | - Michael C. Thorndyke
- Department of Biological and Environmental Sciences, The Sven Lovén Centre for Marine Science, University of Gothenburg, Kristineberg, 45178 Fiskebäckskil, Sweden
| | - Markus Bleich
- Institute of Physiology, Christian Albrechts University Kiel, 24098 Kiel, Germany
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45
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Raven JA, Hurd CL. Ecophysiology of photosynthesis in macroalgae. PHOTOSYNTHESIS RESEARCH 2012; 113:105-25. [PMID: 22843100 DOI: 10.1007/s11120-012-9768-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 07/04/2012] [Indexed: 05/07/2023]
Abstract
Macroalgae occur in the marine benthos from the upper intertidal to depths of more than 200 m, contributing up to 1 Pg C per year to global primary productivity. Freshwater macroalgae are mainly green (Chlorophyta) with some red (Rhodophyta) and a small contribution of brown (Phaeophyceae) algae, while in the ocean all three higher taxa are important. Attempts to relate the depth distribution of three higher taxa of marine macroalgae to their photosynthetic light use through their pigmentation in relation to variations in spectral quality of photosynthetically active radiation (PAR) with depth (complementary chromatic adaptation) and optical thickness (package effect) have been relatively unsuccessful. The presence (Chlorophyta, Phaeophyceae) or absence (Rhodophyta) of a xanthophyll cycle is also not well correlated with depth distribution of marine algae. The relative absence of freshwater brown algae does not seem to be related to their photosynthetic light use. Photosynthetic inorganic carbon acquisition in some red and a few green macroalgae involves entry of CO(2) by diffusion. Other red and green macroalgae, and brown macroalgae, have CO(2) concentrating mechanisms; these frequently involve acid and alkaline zones on the surface of the alga with CO(2) (produced from HCO(3) (-)) entering in the acid zones, while some macroalgae have CCMs based on active influx of HCO(3) (-). These various mechanisms of carbon acquisition have different responses to the thickness of the diffusion boundary layer, which is determined by macroalgal morphology and water velocity. Energetic predictions that macroalgae growing at or near the lower limit of PAR for growth should rely on diffusive CO(2) entry without acid and alkaline zones, and on NH(4) (+) rather than NO(3) (-) as nitrogen source, are only partially borne out by observation. The impact of global environmental change on marine macroalgae mainly relates to ocean acidification and warming with shoaling of the thermocline and decreased nutrient flux to the upper mixed layer. Predictions of the impact on macroalgae requires further experiments on interactions among increased inorganic carbon, increased temperature and decreased nitrogen and phosphorus supply, and, when possible, studies of genetic adaptation to environmental change.
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Affiliation(s)
- John A Raven
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland, UK.
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Rossoll D, Bermúdez R, Hauss H, Schulz KG, Riebesell U, Sommer U, Winder M. Ocean acidification-induced food quality deterioration constrains trophic transfer. PLoS One 2012; 7:e34737. [PMID: 22509351 PMCID: PMC3324536 DOI: 10.1371/journal.pone.0034737] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 03/09/2012] [Indexed: 11/18/2022] Open
Abstract
Our present understanding of ocean acidification (OA) impacts on marine organisms caused by rapidly rising atmospheric carbon dioxide (CO2) concentration is almost entirely limited to single species responses. OA consequences for food web interactions are, however, still unknown. Indirect OA effects can be expected for consumers by changing the nutritional quality of their prey. We used a laboratory experiment to test potential OA effects on algal fatty acid (FA) composition and resulting copepod growth. We show that elevated CO2 significantly changed the FA concentration and composition of the diatom Thalassiosira pseudonana, which constrained growth and reproduction of the copepod Acartia tonsa. A significant decline in both total FAs (28.1 to 17.4 fg cell−1) and the ratio of long-chain polyunsaturated to saturated fatty acids (PUFA:SFA) of food algae cultured under elevated (750 µatm) compared to present day (380 µatm) pCO2 was directly translated to copepods. The proportion of total essential FAs declined almost tenfold in copepods and the contribution of saturated fatty acids (SFAs) tripled at high CO2. This rapid and reversible CO2-dependent shift in FA concentration and composition caused a decrease in both copepod somatic growth and egg production from 34 to 5 eggs female−1 day−1. Because the diatom-copepod link supports some of the most productive ecosystems in the world, our study demonstrates that OA can have far-reaching consequences for ocean food webs by changing the nutritional quality of essential macromolecules in primary producers that cascade up the food web.
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Affiliation(s)
- Dennis Rossoll
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Rafael Bermúdez
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Helena Hauss
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Kai G. Schulz
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Ulf Riebesell
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Ulrich Sommer
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
| | - Monika Winder
- Helmholtz Centre for Ocean Research Kiel (GEOMAR), Kiel, Germany
- Department of Systems Ecology, Stockholm University, Stockholm, Sweden
- * E-mail:
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Mackinder L, Wheeler G, Schroeder D, von Dassow P, Riebesell U, Brownlee C. Expression of biomineralization-related ion transport genes in Emiliania huxleyi. Environ Microbiol 2011; 13:3250-65. [PMID: 21902794 DOI: 10.1111/j.1462-2920.2011.02561.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biomineralization in the marine phytoplankton Emiliania huxleyi is a stringently controlled intracellular process. The molecular basis of coccolith production is still relatively unknown although its importance in global biogeochemical cycles and varying sensitivity to increased pCO₂ levels has been well documented. This study looks into the role of several candidate Ca²⁺, H⁺ and inorganic carbon transport genes in E. huxleyi, using quantitative reverse transcriptase PCR. Differential gene expression analysis was investigated in two isogenic pairs of calcifying and non-calcifying strains of E. huxleyi and cultures grown at various Ca²⁺ concentrations to alter calcite production. We show that calcification correlated to the consistent upregulation of a putative HCO₃⁻ transporter belonging to the solute carrier 4 (SLC4) family, a Ca²⁺/H⁺ exchanger belonging to the CAX family of exchangers and a vacuolar H⁺-ATPase. We also show that the coccolith-associated protein, GPA is downregulated in calcifying cells. The data provide strong evidence that these genes play key roles in E. huxleyi biomineralization. Based on the gene expression data and the current literature a working model for biomineralization-related ion transport in coccolithophores is presented.
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Affiliation(s)
- Luke Mackinder
- The Laboratory, Marine Biological Association of the UK, Citadel Hill, Plymouth PL1 2PB, UK.
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