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Shang Y, He J, Qiu J, Hu S, Wang X, Zhang T, Wang W, Yuan X, Xu J, Li F. The tolerance of two marine diatoms to diurnal pH fluctuation under dynamic light condition and ocean acidification scenario. MARINE ENVIRONMENTAL RESEARCH 2024; 196:106425. [PMID: 38442592 DOI: 10.1016/j.marenvres.2024.106425] [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: 10/23/2023] [Revised: 01/29/2024] [Accepted: 02/25/2024] [Indexed: 03/07/2024]
Abstract
Coastal waters undergo dynamic changes in seawater carbonate chemistry due to natural and anthropogenic factors. Despite this, our current understanding of how coastal phytoplankton respond to fluctuating pH is limited. In the present study, we investigated the physiological responses of two coastal diatoms Thalassiosira pseudonana and Thalassiosira weissflogii to seawater acidification and diurnally fluctuating pH under natural solar irradiance. Seawater acidification did not significantly impact the growth, maximum and effective quantum yield of PSII, and photosynthetic rates of the two species. However, it did increase the maximum relative electron transport rate of T. weissflogii by 11%. Overall, fluctuating pH had neutral or positive effects on both species. It enhanced the light-saturated photosynthetic rate of T. weissflogii by 20% compared to cells grown under seawater acidification condition. Results from the short-term pH exposure experiment revealed that the photosynthetic rates of both species remained unaffected by acute pH changes, indicating their tolerance to varying pH. Nevertheless, it is crucial to consider dynamic pH when predicting changes in primary production in coastal waters, given the interplay of various environmental drivers.
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Affiliation(s)
- Yu Shang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Jie He
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Jingmin Qiu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Siyu Hu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Xin Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Tianzhi Zhang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Weili Wang
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Xiaoyue Yuan
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Juntian Xu
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China
| | - Futian Li
- Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, Lianyungang, China; Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, Lianyungang, China; Marine Resources Development Institute of Jiangsu, Jiangsu Ocean University, Lianyungang, China.
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2
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Choi SW, Graf L, Choi JW, Jo J, Boo GH, Kawai H, Choi CG, Xiao S, Knoll AH, Andersen RA, Yoon HS. Ordovician origin and subsequent diversification of the brown algae. Curr Biol 2024; 34:740-754.e4. [PMID: 38262417 DOI: 10.1016/j.cub.2023.12.069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/08/2023] [Accepted: 12/20/2023] [Indexed: 01/25/2024]
Abstract
Brown algae are the only group of heterokont protists exhibiting complex multicellularity. Since their origin, brown algae have adapted to various marine habitats, evolving diverse thallus morphologies and gamete types. However, the evolutionary processes behind these transitions remain unclear due to a lack of a robust phylogenetic framework and problems with time estimation. To address these issues, we employed plastid genome data from 138 species, including heterokont algae, red algae, and other red-derived algae. Based on a robust phylogeny and new interpretations of algal fossils, we estimated the geological times for brown algal origin and diversification. The results reveal that brown algae first evolved true multicellularity, with plasmodesmata and reproductive cell differentiation, during the late Ordovician Period (ca. 450 Ma), coinciding with a major diversification of marine fauna (the Great Ordovician Biodiversification Event) and a proliferation of multicellular green algae. Despite its early Paleozoic origin, the diversification of major orders within this brown algal clade accelerated only during the Mesozoic Era, coincident with both Pangea rifting and the diversification of other heterokont algae (e.g., diatoms), coccolithophores, and dinoflagellates, with their red algal-derived plastids. The transition from ancestral isogamy to oogamy was followed by three simultaneous reappearances of isogamy during the Cretaceous Period. These are concordant with a positive character correlation between parthenogenesis and isogamy. Our new brown algal timeline, combined with a knowledge of past environmental conditions, shed new light on brown algal diversification and the intertwined evolution of multicellularity and sexual reproduction.
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Affiliation(s)
- Seok-Wan Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Louis Graf
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea; Institut de Biologie de l'École Normale Supérieure, Université Paris Sciences et Lettres, Paris 75005, France
| | - Ji Won Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jihoon Jo
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea; Honam National Institute of Biological Resources, Mokpo 58762, Republic of Korea
| | - Ga Hun Boo
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hiroshi Kawai
- Kobe University Research Center for Inland Seas, Rokkodai, Nadaku, Kobe 657-8501, Japan
| | - Chang Geun Choi
- Department of Ecological Engineering, College of Environmental and Marine Technology, Pukyong National University, Busan 48513, Republic of Korea
| | - Shuhai Xiao
- Department of Geosciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Andrew H Knoll
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Robert A Andersen
- Friday Harbor Laboratories, University of Washington, Seattle, WA 98250, USA
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea.
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3
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Min KH, Kim DH, Youn S, Pack SP. Biomimetic Diatom Biosilica and Its Potential for Biomedical Applications and Prospects: A Review. Int J Mol Sci 2024; 25:2023. [PMID: 38396701 PMCID: PMC10889112 DOI: 10.3390/ijms25042023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 01/28/2024] [Accepted: 02/05/2024] [Indexed: 02/25/2024] Open
Abstract
Diatom biosilica is an important natural source of porous silica, with three-dimensional ordered and nanopatterned structures referred to as frustules. The unique features of diatom frustules, such as their high specific surface area, thermal stability, biocompatibility, and adaptable surface chemistry, render diatoms valuable materials for high value-added applications. These attributes make diatoms an exceptional cost-effective raw material for industrial use. The functionalization of diatom biosilica surface improves its biophysical properties and increases the potential applications. This review focuses on the potential uses of diatom biosilica including traditional approaches and recent progress in biomedical applications. Not only well-studied drug delivery systems but also promising uses on bone regeneration and wound healing are covered. Furthermore, considerable aspects and possible future directions for the use of diatom biosilica materials are proposed to develop biomedical applications and merit further exploration.
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Affiliation(s)
- Ki Ha Min
- Institution of Industrial Technology, Korea University, Sejong 30019, Republic of Korea;
| | - Dong Hyun Kim
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea; (D.H.K.); (S.Y.)
| | - Sol Youn
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea; (D.H.K.); (S.Y.)
| | - Seung Pil Pack
- Department of Biotechnology and Bioinformatics, Korea University, Sejong 30019, Republic of Korea; (D.H.K.); (S.Y.)
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4
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Santin A, Russo MT, de Los Ríos LM, Chiurazzi M, d'Alcalà MR, Lacombe B, Ferrante MI, Rogato A. The tonoplast localized protein PtNPF1 participates in the regulation of nitrogen response in diatoms. THE NEW PHYTOLOGIST 2024; 241:1592-1604. [PMID: 38084038 DOI: 10.1111/nph.19461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 11/21/2023] [Indexed: 01/26/2024]
Abstract
Diatoms are a highly successful group of phytoplankton, well adapted also to oligotrophic environments and capable of handling nutrient fluctuations in the ocean, particularly nitrate. The presence of a large vacuole is an important trait contributing to their adaptive features. It confers diatoms the ability to accumulate and store nutrients, such as nitrate, when they are abundant outside and then to reallocate them into the cytosol to meet deficiencies, in a process called luxury uptake. The molecular mechanisms that regulate these nitrate fluxes are still not known in diatoms. In this work, we provide new insights into the function of Phaeodactylum tricornutum NPF1, a putative low-affinity nitrate transporter. To accomplish this, we generated overexpressing strains and CRISPR/Cas9 loss-of-function mutants. Microscopy observations confirmed predictions that PtNPF1 is localized on the vacuole membrane. Furthermore, functional characterizations performed on knock-out mutants revealed a transient growth delay phenotype linked to altered nitrate uptake. Together, these results allowed us to hypothesize that PtNPF1 is presumably involved in modulating intracellular nitrogen fluxes, managing intracellular nutrient availability. This ability might allow diatoms to fine-tune the assimilation, storage and reallocation of nitrate, conferring them a strong advantage in oligotrophic environments.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
| | | | - Laura Morales de Los Ríos
- Institute for Plant Science of Montpellier (IPSiM), University of Montpellier, CNRS, INRAE, Montpellier SupAgro, Place Pierre Viala 2, Montpellier, 34060, France
| | - Maurizio Chiurazzi
- Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, Naples, 80131, Italy
| | | | - Benoît Lacombe
- Institute for Plant Science of Montpellier (IPSiM), University of Montpellier, CNRS, INRAE, Montpellier SupAgro, Place Pierre Viala 2, Montpellier, 34060, France
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
- National Institute of Oceanography and Applied Geophysics, Trieste, 34010, Italy
| | - Alessandra Rogato
- Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
- Institute of Biosciences and BioResources, CNR, Via P. Castellino 111, Naples, 80131, Italy
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5
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Behrenfeld MJ, Bisson KM. Neutral Theory and Plankton Biodiversity. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:283-305. [PMID: 37368954 DOI: 10.1146/annurev-marine-112122-105229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/29/2023]
Abstract
The biodiversity of the plankton has been interpreted largely through the monocle of competition. The spatial distancing of phytoplankton in nature is so large that cell boundary layers rarely overlap, undermining opportunities for resource-based competitive exclusion. Neutral theory accounts for biodiversity patterns based purely on random birth, death, immigration, and speciation events and has commonly served as a null hypothesis in terrestrial ecology but has received comparatively little attention in aquatic ecology. This review summarizes basic elements of neutral theory and explores its stand-alone utility for understanding phytoplankton diversity. A theoretical framework is described entailing a very nonneutral trophic exclusion principle melded with the concept of ecologically defined neutral niches. This perspective permits all phytoplankton size classes to coexist at any limiting resource level, predicts greater diversity than anticipated from readily identifiable environmental niches but less diversity than expected from pure neutral theory, and functions effectively in populations of distantly spaced individuals.
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Affiliation(s)
- Michael J Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA; ,
| | - Kelsey M Bisson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA; ,
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6
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Limoges A, Ribeiro S, Van Nieuwenhove N, Jackson R, Juggins S, Crosta X, Weckström K. Marine diatoms record Late Holocene regime shifts in the Pikialasorsuaq ecosystem. GLOBAL CHANGE BIOLOGY 2023; 29:6503-6516. [PMID: 37772765 DOI: 10.1111/gcb.16958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 08/10/2023] [Accepted: 09/12/2023] [Indexed: 09/30/2023]
Abstract
The Pikialasorsuaq (North Water polynya) is an area of local and global cultural and ecological significance. However, over the last decades, the region has been subject to rapid warming, and in some recent years, the seasonal ice arch that has historically defined the polynya's northern boundary has failed to form. Both factors are deemed to alter the polynya's ecosystem functioning. To understand how climate-induced changes to the Pikialasorsuaq impact the basis of the marine food web, we explored diatom community-level responses to changing conditions, from a sediment core spanning the last 3800 years. Four metrics were used: total diatom concentrations, taxonomic composition, mean size, and diversity. Generalized additive model statistics highlight significant changes at ca. 2400, 2050, 1550, 1200, and 130 cal years BP, all coeval with known transitions between colder and warmer intervals of the Late Holocene, and regime shifts in the Pikialasorsuaq. Notably, a weaker/contracted polynya during the Roman Warm Period and Medieval Climate Anomaly caused the diatom community to reorganize via shifts in species composition, with the presence of larger taxa but lower diversity, and significantly reduced export production. This study underlines the high sensitivity of primary producers to changes in the polynya dynamics and illustrates that the strong pulse of early spring cryopelagic diatoms that makes the Pikialasorsuaq exceptionally productive may be jeopardized by rapid warming and associated Nares Strait ice arch destabilization. Future alterations to the phenology of primary producers may disproportionately impact higher trophic levels and keystone species in this region, with implications for Indigenous Peoples and global diversity.
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Affiliation(s)
- Audrey Limoges
- Department of Earth Sciences, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Sofia Ribeiro
- Department of Glaciology and Climate, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
| | - Nicolas Van Nieuwenhove
- Department of Earth Sciences, University of New Brunswick, Fredericton, New Brunswick, Canada
| | - Rebecca Jackson
- Department of Glaciology and Climate, Geological Survey of Denmark and Greenland, Copenhagen, Denmark
- Globe Institute, Copenhagen University, Copenhagen, Denmark
| | - Stephen Juggins
- School of Geography, Politics and Sociology, Newcastle University, Newcastle upon Tyne, UK
| | - Xavier Crosta
- CNRS, EPHE, UMR 5805 EPOC, Université de Bordeaux, Pessac Cedex, France
| | - Kaarina Weckström
- Ecosystems and Environment Research Programme (ECRU), University of Helsinki, Helsinki, Finland
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7
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Garza EA, Bielinski VA, Espinoza JL, Orlandi K, Alfaro JR, Bolt TM, Beeri K, Weyman PD, Dupont CL. Validating a Promoter Library for Application in Plasmid-Based Diatom Genetic Engineering. ACS Synth Biol 2023; 12:3215-3228. [PMID: 37857380 PMCID: PMC10661051 DOI: 10.1021/acssynbio.3c00163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Indexed: 10/21/2023]
Abstract
While diatoms are promising synthetic biology platforms, there currently exists a limited number of validated genetic regulatory parts available for genetic engineering. The standard method for diatom transformation, nonspecific introduction of DNA into chromosomes via biolistic particle bombardment, is low throughput and suffers from clonal variability and epigenetic effects. Recent developments in diatom engineering have demonstrated that autonomously replicating episomal plasmids serve as stable expression platforms for diverse gene expression technologies. These plasmids are delivered via bacterial conjugation and, when combined with modular DNA assembly technologies, provide a flexibility and speed not possible with biolistic-mediated strain generation. In order to expand the current toolbox for plasmid-based engineering in the diatom Phaeodactylum tricornutum, a conjugation-based forward genetics screen for promoter discovery was developed, and application to a diatom genomic DNA library defined 252 P. tricornutum promoter elements. From this library, 40 promoter/terminator pairs were delivered via conjugation on episomal plasmids, characterized in vivo, and ranked across 4 orders of magnitude difference in reporter gene expression levels.
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Affiliation(s)
- Erin A. Garza
- J. Craig Venter Institute, La Jolla, California 92037, United States
| | | | - Josh L. Espinoza
- J. Craig Venter Institute, La Jolla, California 92037, United States
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8
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Stenow R, Robertson EK, Whitehouse MJ, Ploug H. Single cell dynamics and nitrogen transformations in the chain forming diatom Chaetoceros affinis. THE ISME JOURNAL 2023; 17:2070-2078. [PMID: 37723340 PMCID: PMC10579250 DOI: 10.1038/s41396-023-01511-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/20/2023]
Abstract
Colony formation in phytoplankton is often considered a disadvantage during nutrient limitation in aquatic systems. Using stable isotopic tracers combined with secondary ion mass spectrometry (SIMS), we unravel cell-specific activities of a chain-forming diatom and interactions with attached bacteria. The uptake of 13C-bicarbonate and15N-nitrate or 15N-ammonium was studied in Chaetoceros affinis during the stationary growth phase. Low cell-to-cell variance of 13C-bicarbonate and 15N-nitrate assimilation within diatom chains prevailed during the early stationary phase. Up to 5% of freshly assimilated 13C and 15N was detected in attached bacteria within 12 h and supported bacterial C- and N-growth rates up to 0.026 h-1. During the mid-stationary phase, diatom chain-length decreased and 13C and 15N-nitrate assimilation was significantly higher in solitary cells as compared to that in chain cells. During the late stationary phase, nitrate assimilation ceased and ammonium assimilation balanced C fixation. At this stage, we observed highly active cells neighboring inactive cells within the same chain. In N-limited regimes, bacterial remineralization of N and the short diffusion distance between neighbors in chains may support surviving cells. This combination of "microbial gardening" and nutrient transfer within diatom chains represents a strategy which challenges current paradigms of nutrient fluxes in plankton communities.
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Affiliation(s)
- Rickard Stenow
- Department of Marine Sciences, University of Gothenburg, Box 461, SE, 405 30, Gothenburg, Sweden.
| | - Elizabeth K Robertson
- Department of Marine Sciences, University of Gothenburg, Box 461, SE, 405 30, Gothenburg, Sweden
| | - Martin J Whitehouse
- Swedish Museum of Natural History, Box 50 007, SE, 104 05, Stockholm, Sweden
| | - Helle Ploug
- Department of Marine Sciences, University of Gothenburg, Box 461, SE, 405 30, Gothenburg, Sweden
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9
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Walworth NG, Espinoza JL, Argyle PA, Hinners J, Levine NM, Doblin MA, Dupont CL, Collins S. Genus-Wide Transcriptional Landscapes Reveal Correlated Gene Networks Underlying Microevolutionary Divergence in Diatoms. Mol Biol Evol 2023; 40:msad218. [PMID: 37874344 PMCID: PMC10595192 DOI: 10.1093/molbev/msad218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/24/2023] [Accepted: 09/21/2023] [Indexed: 10/25/2023] Open
Abstract
Marine microbes like diatoms make up the base of marine food webs and drive global nutrient cycles. Despite their key roles in ecology, biogeochemistry, and biotechnology, we have limited empirical data on how forces other than adaptation may drive diatom diversification, especially in the absence of environmental change. One key feature of diatom populations is frequent extreme reductions in population size, which can occur both in situ and ex situ as part of bloom-and-bust growth dynamics. This can drive divergence between closely related lineages, even in the absence of environmental differences. Here, we combine experimental evolution and transcriptome landscapes (t-scapes) to reveal repeated evolutionary divergence within several species of diatoms in a constant environment. We show that most of the transcriptional divergence can be captured on a reduced set of axes, and that repeatable evolution can occur along a single major axis of variation defined by core ortholog expression comprising common metabolic pathways. Previous work has associated specific transcriptional changes in gene networks with environmental factors. Here, we find that these same gene networks diverge in the absence of environmental change, suggesting these pathways may be central in generating phenotypic diversity as a result of both selective and random evolutionary forces. If this is the case, these genes and the functions they encode may represent universal axes of variation. Such axes that capture suites of interacting transcriptional changes during diversification improve our understanding of both global patterns in local adaptation and microdiversity, as well as evolutionary forces shaping algal cultivation.
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Affiliation(s)
- Nathan G Walworth
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0371, USA
- J.Craig Venter Institute, La Jolla, CA 92037, USA
| | | | - Phoebe A Argyle
- Climate Change Cluster, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | - Jana Hinners
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
- Helmholtz-Zentrum Hereon, 21502 Geesthacht, Germany
| | - Naomi M Levine
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089-0371, USA
| | - Martina A Doblin
- Climate Change Cluster, University of Technology Sydney, Sydney, New South Wales 2007, Australia
| | | | - Sinéad Collins
- School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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10
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Ban H, Sato S, Yoshikawa S, Yamada K, Nakamura Y, Ichinomiya M, Sato N, Blanc-Mathieu R, Endo H, Kuwata A, Ogata H. Genome analysis of Parmales, the sister group of diatoms, reveals the evolutionary specialization of diatoms from phago-mixotrophs to photoautotrophs. Commun Biol 2023; 6:697. [PMID: 37420035 PMCID: PMC10328945 DOI: 10.1038/s42003-023-05002-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 05/31/2023] [Indexed: 07/09/2023] Open
Abstract
The order Parmales (class Bolidophyceae) is a minor group of pico-sized eukaryotic marine phytoplankton that contains species with cells surrounded by silica plates. Previous studies revealed that Parmales is a member of ochrophytes and sister to diatoms (phylum Bacillariophyta), the most successful phytoplankton group in the modern ocean. Therefore, parmalean genomes can serve as a reference to elucidate both the evolutionary events that differentiated these two lineages and the genomic basis for the ecological success of diatoms vs. the more cryptic lifestyle of parmaleans. Here, we compare the genomes of eight parmaleans and five diatoms to explore their physiological and evolutionary differences. Parmaleans are predicted to be phago-mixotrophs. By contrast, diatoms have lost genes related to phagocytosis, indicating the ecological specialization from phago-mixotrophy to photoautotrophy in their early evolution. Furthermore, diatoms show significant enrichment in gene sets involved in nutrient uptake and metabolism, including iron and silica, in comparison with parmaleans. Overall, our results suggest a strong evolutionary link between the loss of phago-mixotrophy and specialization to a silicified photoautotrophic life stage early in diatom evolution after diverging from the Parmales lineage.
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Affiliation(s)
- Hiroki Ban
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Shinya Sato
- Department of Marine Science and Technology, Fukui Prefectural University, 1-1 Gakuen-cho, Obama City, Fukui, 917-0003, Japan
| | - Shinya Yoshikawa
- Department of Marine Science and Technology, Fukui Prefectural University, 1-1 Gakuen-cho, Obama City, Fukui, 917-0003, Japan
| | - Kazumasa Yamada
- Department of Marine Science and Technology, Fukui Prefectural University, 1-1 Gakuen-cho, Obama City, Fukui, 917-0003, Japan
| | - Yoji Nakamura
- Bioinformatics and Biosciences Division, Fisheries Stock Assessment Center, Fisheries Resources Institute, Japan Fisheries Research and Education Agency, 2-12-4 Fuku-ura, Kanazawa, Yokohama, Kanagawa, 236-8648, Japan
| | - Mutsuo Ichinomiya
- Prefectural University of Kumamoto, 3-1-100 Tsukide, Kumamoto, 862-8502, Japan
| | - Naoki Sato
- Graduate School of Arts and Sciences, University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Romain Blanc-Mathieu
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
- Laboratoire de Physiologie Cellulaire & Végétale, CEA, Univ. Grenoble Alpes, CNRS, INRA, IRIG, Grenoble, France
| | - Hisashi Endo
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan
| | - Akira Kuwata
- Shiogama field station, Fisheries Resources Institute, Japan Fisheries Research and Education Agency, 3-27-5 Shinhama-cho, Shiogama, Miyagi, Japan.
| | - Hiroyuki Ogata
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan.
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11
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Inomura K, Pierella Karlusich JJ, Dutkiewicz S, Deutsch C, Harrison PJ, Bowler C. High Growth Rate of Diatoms Explained by Reduced Carbon Requirement and Low Energy Cost of Silica Deposition. Microbiol Spectr 2023; 11:e0331122. [PMID: 37010412 PMCID: PMC10269801 DOI: 10.1128/spectrum.03311-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Accepted: 03/02/2023] [Indexed: 04/04/2023] Open
Abstract
The rapid growth of diatoms makes them one of the most pervasive and productive types of plankton in the world's ocean, but the physiological basis for their high growth rates remains poorly understood. Here, we evaluate the factors that elevate diatom growth rates, relative to other plankton, using a steady-state metabolic flux model that computes the photosynthetic C source from intracellular light attenuation and the carbon cost of growth from empirical cell C quotas, across a wide range of cell sizes. For both diatoms and other phytoplankton, growth rates decline with increased cell volume, consistent with observations, because the C cost of division increases with size faster than photosynthesis. However, the model predicts overall higher growth rates for diatoms due to reduced C requirements and the low energetic cost of Si deposition. The C savings from the silica frustule are supported by metatranscriptomic data from Tara Oceans, which show that the abundance of transcripts for cytoskeleton components in diatoms is lower than in other phytoplankton. Our results highlight the importance of understanding the origins of phylogenetic differences in cellular C quotas, and suggest that the evolution of silica frustules may play a critical role in the global dominance of marine diatoms. IMPORTANCE This study addresses a longstanding issue regarding diatoms, namely, their fast growth. Diatoms, which broadly are phytoplankton with silica frustules, are the world's most productive microorganisms and dominate in polar and upwelling regions. Their dominance is largely supported by their high growth rate, but the physiological reasoning behind that characteristic has been obscure. In this study, we combine a quantitative model and metatranscriptomic approaches and show that diatoms' low carbon requirements and low energy costs for silica frustule production are the key factors supporting their fast growth. Our study suggests that the effective use of energy-efficient silica as a cellular structure, instead of carbon, enables diatoms to be the most productive organisms in the global ocean.
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Affiliation(s)
- Keisuke Inomura
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA
| | - Juan José Pierella Karlusich
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres, Paris, France
- Faculty of Arts and Sciences, Division of Science, Harvard University, Cambridge, Massachusetts, USA
| | - Stephanie Dutkiewicz
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Curtis Deutsch
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA
| | - Paul J. Harrison
- Department of Earth, Ocean, and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris Bowler
- Institut de Biologie de l'Ecole Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres, Paris, France
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12
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Ouaissa S, Gómez-Jakobsen F, Yebra L, Ferrera I, Moreno-Ostos E, Belando MD, Ruiz JM, Mercado JM. Phytoplankton dynamics in the Mar Menor, a Mediterranean coastal lagoon strongly impacted by eutrophication. MARINE POLLUTION BULLETIN 2023; 192:115074. [PMID: 37236094 DOI: 10.1016/j.marpolbul.2023.115074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 04/30/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023]
Abstract
The Mar Menor hypersaline coastal lagoon has suffered serious degradation in the last three decades attributable to nutrient pollution. In 2015, the lagoon experienced an intensive bloom of cyanobacteria that triggered a drastic change of its ecosystem. Our analyses indicate that phytoplankton in 2016-2021 did not present a seasonal variability pattern; the community was mainly dominated by diatoms and punctually reached abundance peaks above 107 cell L-1 along with chlorophyll a concentrations exceeding 20 μg L-1. The predominant diatom genera during these blooms were different as well as the nutrient conditions under which they were produced. These high diatom abundances are unprecedented in the lagoon; in fact, our data indicate that the taxonomic composition, time variation patterns and cell abundance of phytoplankton in 2016-2021 differ notably in comparison to the data published before 2015. Consequently, our results support the finding that the trophic status of the lagoon has changed profoundly.
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Affiliation(s)
- Sophia Ouaissa
- Programa de Doctorado Diversidad Biológica y Medioambiente, Facultad de Ciencias, Universidad de Málaga, Campus de Teatinos, 29071 Málaga, Spain
| | - Francisco Gómez-Jakobsen
- Centro Oceanográfico de Málaga (IEO-CSIC), Puerto Pesquero s/n, 29640 Fuengirola (Málaga), Spain
| | - Lidia Yebra
- Centro Oceanográfico de Málaga (IEO-CSIC), Puerto Pesquero s/n, 29640 Fuengirola (Málaga), Spain
| | - Isabel Ferrera
- Centro Oceanográfico de Málaga (IEO-CSIC), Puerto Pesquero s/n, 29640 Fuengirola (Málaga), Spain
| | - Enrique Moreno-Ostos
- Department of Ecology and Geology, Marine Ecology and Limnology Research Group, Universidad de Málaga, Málaga, Spain
| | - María Dolores Belando
- Centro Oceanográfico de Murcia (IEO-CSIC), Varadero 1. Apdo. 22, 30740 San Pedro del Pinatar (Murcia), Spain
| | - Juan M Ruiz
- Centro Oceanográfico de Murcia (IEO-CSIC), Varadero 1. Apdo. 22, 30740 San Pedro del Pinatar (Murcia), Spain
| | - Jesús M Mercado
- Centro Oceanográfico de Málaga (IEO-CSIC), Puerto Pesquero s/n, 29640 Fuengirola (Málaga), Spain.
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13
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Diaz BP, Zelzion E, Halsey K, Gaube P, Behrenfeld M, Bidle KD. Marine phytoplankton downregulate core photosynthesis and carbon storage genes upon rapid mixed layer shallowing. THE ISME JOURNAL 2023:10.1038/s41396-023-01416-x. [PMID: 37156837 DOI: 10.1038/s41396-023-01416-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 04/03/2023] [Accepted: 04/13/2023] [Indexed: 05/10/2023]
Abstract
Marine phytoplankton are a diverse group of photoautotrophic organisms and key mediators in the global carbon cycle. Phytoplankton physiology and biomass accumulation are closely tied to mixed layer depth, but the intracellular metabolic pathways activated in response to changes in mixed layer depth remain less explored. Here, metatranscriptomics was used to characterize the phytoplankton community response to a mixed layer shallowing (from 233 to 5 m) over the course of two days during the late spring in the Northwest Atlantic. Most phytoplankton genera downregulated core photosynthesis, carbon storage, and carbon fixation genes as the system transitioned from a deep to a shallow mixed layer and shifted towards catabolism of stored carbon supportive of rapid cell growth. In contrast, phytoplankton genera exhibited divergent transcriptional patterns for photosystem light harvesting complex genes during this transition. Active virus infection, taken as the ratio of virus to host transcripts, increased in the Bacillariophyta (diatom) phylum and decreased in the Chlorophyta (green algae) phylum upon mixed layer shallowing. A conceptual model is proposed to provide ecophysiological context for our findings, in which integrated light limitation and lower division rates during transient deep mixing are hypothesized to disrupt resource-driven, oscillating transcript levels related to photosynthesis, carbon fixation, and carbon storage. Our findings highlight shared and unique transcriptional response strategies within phytoplankton communities acclimating to the dynamic light environment associated with transient deep mixing and shallowing events during the annual North Atlantic bloom.
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Affiliation(s)
- Ben P Diaz
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, 08901, USA
- Biotechnology & Bioengineering, Sandia National Laboratories, 7011 East Avenue, Livermore, CA, 94550, USA
| | - Ehud Zelzion
- Office of Advanced Research Computing, Rutgers University, Piscataway, NJ, 08854, USA
| | - Kimberly Halsey
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA
| | - Peter Gaube
- Applied Physics Laboratory, University of Washington, Seattle, WA, 98105, USA
| | - Michael Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Kay D Bidle
- Department of Marine and Coastal Science, Rutgers University, New Brunswick, NJ, 08901, USA.
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14
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Sansone C, Pistelli L, Calabrone L, Del Mondo A, Fontana A, Festa M, Noonan DM, Albini A, Brunet C. The Carotenoid Diatoxanthin Modulates Inflammatory and Angiogenesis Pathways In Vitro in Prostate Cancer Cells. Antioxidants (Basel) 2023; 12:antiox12020359. [PMID: 36829917 PMCID: PMC9952135 DOI: 10.3390/antiox12020359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/23/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023] Open
Abstract
Xanthophylls, a group of carotenoids, have attracted attention as human health benefit compounds thanks to their functionality and bioavailability. The great antioxidant and anti-inflammatory abilities of diatoxanthin (Dt), a photoprotective xanthophyll synthetized by diatoms, were recently documented. This study investigates the capacity of Dt to intercept prostate cancer progression in vitro on different human cell lines, exploring its role against cancer proliferation and angiogenesis. Our results highlighted the chemopreventive role of Dt already at low concentration (44.1 pM) and suggest that the Dt-induced cancer cell death occurred through oxidative stress mechanisms. This hypothesis was supported by variations on the expression of key genes and proteins. Oxidative stress cell deaths (e.g., ferroptosis) are recently described types of cell death that are closely related to the pathophysiological processes of many diseases, such as tumors. Nonetheless, the interest of Dt was further strengthened by its ability to inhibit angiogenesis. The results are discussed considering the actual progress and requirements in cancer therapy, notably for prostate cancer.
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Affiliation(s)
- Clementina Sansone
- Stazione Zoologica Anton Dohrn, Sede Molosiglio Marina Acton, 80133 Napoli, Italy
- Laboratory of Vascular Biology and Angiogenesis, IRCCS MultiMedica, 20138 Milan, Italy
- Correspondence: (C.S.); (C.B.)
| | - Luigi Pistelli
- Stazione Zoologica Anton Dohrn, Sede Molosiglio Marina Acton, 80133 Napoli, Italy
| | - Luana Calabrone
- Laboratory of Vascular Biology and Angiogenesis, IRCCS MultiMedica, 20138 Milan, Italy
| | - Angelo Del Mondo
- Stazione Zoologica Anton Dohrn, Sede Molosiglio Marina Acton, 80133 Napoli, Italy
| | - Angelo Fontana
- Institute of Biomolecular Chemistry, Italian National Research Council (CNR), 80078 Pozzuoli, Italy
| | - Marco Festa
- Laboratory of Vascular Biology and Angiogenesis, IRCCS MultiMedica, 20138 Milan, Italy
| | - Douglas M. Noonan
- Department of Biotechnology and Life Sciences, University of Insubria, 21100 Varese, Italy
- Unit of Molecular Pathology, Biochemistry and Immunology, IRCCS MultiMedica, 20138 Milan, Italy
| | - Adriana Albini
- IRCSS European Institute of Oncology (IEO), 20141 Milan, Italy
| | - Christophe Brunet
- Stazione Zoologica Anton Dohrn, Sede Molosiglio Marina Acton, 80133 Napoli, Italy
- Correspondence: (C.S.); (C.B.)
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15
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Henderikx-Freitas F, Allen JG, Lansdorp BM, White AE. Diel variations in the estimated refractive index of bulk oceanic particles. OPTICS EXPRESS 2022; 30:44141-44159. [PMID: 36523096 DOI: 10.1364/oe.469565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 10/27/2022] [Indexed: 06/17/2023]
Abstract
The index of refraction (n) of particles is an important parameter in optical models that aims to extract particle size and carbon concentrations from light scattering measurements. An inadequate choice of n can critically affect the characterization and interpretation of optically-derived parameters, including those from satellite-based models which provide the current view of how biogeochemical processes vary over the global ocean. Yet, little is known about how n varies over time and space to inform such models. Particularly, in situ estimates of n for bulk water samples and at diel-resolving time scales are rare. Here, we demonstrate a method to estimate n using simultaneously and independently collected particulate beam attenuation coefficients, particle size distribution data, and a Mie theory model. We apply this method to surface waters of the North Pacific Subtropical Gyre (NPSG) at hourly resolution. Clear diel cycles in n were observed, marked by minima around local sunrise and maxima around sunset, qualitatively consistent with several laboratory-based estimates of n for specific phytoplankton species. A sensitivity analysis showed that the daily oscillation in n amplitude was somewhat insensitive to broad variations in method assumptions, ranging from 11.3 ± 4.3% to 16.9 ± 2.9%. Such estimates are crucial for improvement of algorithms that extract the particle size and production from bulk optical measurements, and could potentially help establish a link between n variations and changes in cellular composition of in situ particles.
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16
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Broddrick JT, Ware MA, Jallet D, Palsson BO, Peers G. Integration of physiologically relevant photosynthetic energy flows into whole genome models of light-driven metabolism. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:603-621. [PMID: 36053127 PMCID: PMC9826171 DOI: 10.1111/tpj.15965] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 08/25/2022] [Accepted: 08/31/2022] [Indexed: 06/01/2023]
Abstract
Characterizing photosynthetic productivity is necessary to understand the ecological contributions and biotechnology potential of plants, algae, and cyanobacteria. Light capture efficiency and photophysiology have long been characterized by measurements of chlorophyll fluorescence dynamics. However, these investigations typically do not consider the metabolic network downstream of light harvesting. By contrast, genome-scale metabolic models capture species-specific metabolic capabilities but have yet to incorporate the rapid regulation of the light harvesting apparatus. Here, we combine chlorophyll fluorescence parameters defining photosynthetic and non-photosynthetic yield of absorbed light energy with a metabolic model of the pennate diatom Phaeodactylum tricornutum. This integration increases the model predictive accuracy regarding growth rate, intracellular oxygen production and consumption, and metabolic pathway usage. Through the quantification of excess electron transport, we uncover the sequential activation of non-radiative energy dissipation processes, cross-compartment electron shuttling, and non-photochemical quenching as the rapid photoacclimation strategy in P. tricornutum. Interestingly, the photon absorption thresholds that trigger the transition between these mechanisms were consistent at low and high incident photon fluxes. We use this understanding to explore engineering strategies for rerouting cellular resources and excess light energy towards bioproducts in silico. Overall, we present a methodology for incorporating a common, informative data type into computational models of light-driven metabolism and show its utilization within the design-build-test-learn cycle for engineering of photosynthetic organisms.
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Affiliation(s)
- Jared T. Broddrick
- Division of Biological SciencesUniversity of California, San DiegoLa JollaCA92093USA
- Department of BioengineeringUniversity of California, San DiegoLa JollaCA92093USA
- Space Biosciences Research BranchNASA Ames Research CenterMoffett FieldCA94035USA
| | - Maxwell A. Ware
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
| | - Denis Jallet
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
| | - Bernhard O. Palsson
- Department of BioengineeringUniversity of California, San DiegoLa JollaCA92093USA
| | - Graham Peers
- Department of BiologyColorado State UniversityFort CollinsCO80524USA
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17
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Behrenfeld MJ, Bisson KM, Boss E, Gaube P, Karp-Boss L. Phytoplankton community structuring in the absence of resource-based competitive exclusion. PLoS One 2022; 17:e0274183. [PMID: 36112595 PMCID: PMC9481051 DOI: 10.1371/journal.pone.0274183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/23/2022] [Indexed: 11/23/2022] Open
Abstract
Under most natural marine conditions, phytoplankton cells suspended in the water column are too distantly spaced for direct competition for resources (i.e., overlapping cell boundary layers) to be a routine occurrence. Accordingly, resource-based competitive exclusion should be rare. In contrast, contemporary ecosystem models typically predict an exclusion of larger phytoplankton size classes under low-nutrient conditions, an outcome interpreted as reflecting the competitive advantage of small cells having much higher nutrient ‘affinities’ than larger cells. Here, we develop mechanistically-focused expressions for steady-state, nutrient-limited phytoplankton growth that are consistent with the discrete, distantly-spaced cells of natural populations. These expressions, when encompassed in a phytoplankton-zooplankton model, yield sustained diversity across all size classes over the full range in nutrient concentrations observed in the ocean. In other words, our model does not exhibit resource-based competitive exclusion between size classes previously associated with size-dependent differences in nutrient ‘affinities’.
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Affiliation(s)
- Michael J. Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States of America
- * E-mail:
| | - Kelsey M. Bisson
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States of America
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, ME, United States of America
| | - Peter Gaube
- Applied Physics Laboratory, University of Washington, Seattle, Washington, United States of America
| | - Lee Karp-Boss
- School of Marine Sciences, University of Maine, Orono, ME, United States of America
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18
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Modeling the elemental stoichiometry and silica accumulation in diatoms. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100164. [DOI: 10.1016/j.crmicr.2022.100164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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Facey JA, Michie LE, King JJ, Hitchcock JN, Apte SC, Mitrovic SM. Severe cyanobacterial blooms in an Australian lake; causes and factors controlling succession patterns. HARMFUL ALGAE 2022; 117:102284. [PMID: 35944962 DOI: 10.1016/j.hal.2022.102284] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 05/24/2022] [Accepted: 06/28/2022] [Indexed: 06/15/2023]
Abstract
Cyanobacterial blooms have major impacts on the ecological integrity and anthropogenic value of freshwater systems. Chrysosporum ovalisporum, a potentially toxic cyanobacteria has been rare in Australian waters until recently when is has bloomed in a number of lake and river systems. The aim of this study was to determine drivers of its growth and growing dominance. We performed regular monitoring of Mannus Lake, a small freshwater reservoir in South-Eastern Australia that has recently undergone extremely dense bloom events. Blooms of the diazotrophic Chrysosporum ovalisporum occurred in both summers of the 19 month study during periods of persistent thermal stratification. Following the C. ovalisporum blooms, non-diazotrophic taxa (Microcystis aeruginosa and Woronichinia sp.) dominated the phytoplankton community under less stratified conditions. Thermal stratification and nitrogen availability appeared to be the primary drivers of changes in cyanobacterial community structure. We propose that the observed transition from C. ovalisporum to M. aeruginosa and/or Woronichinia sp. may be a result of nitrogen limitation in early summer, which combined with persistent thermal stratification led to an ecological advantage for the nitrogen-fixing C. ovalisporum. Mixing events caused the senescence of the C. ovalisporum bloom, likely supplementing the nutrient budget of the lake with atmospherically derived N and alleviating N limitation to non-diazotrophic taxa. Non-diazotrophic cyanobacterial growth then increased, albeit at much lower biovolumes compared to the initial bloom. Overall, the results demonstrate the role of thermal stratification and nutrient cycling in structuring the cyanobacterial community and provide insights into the environmental factors driving the proliferation of the relatively new, potentially toxic cyanobacterium C. ovalisporum in Australian waters.
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Affiliation(s)
- Jordan A Facey
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia.
| | - Laura E Michie
- NSW Department of Primary Industries, Narrandera Fisheries Centre, PO Box 182, Narrandera, New South Wales, 2700, Australia
| | - Josh J King
- CSIRO Land and Water, Lucas Heights, 2234, Australia
| | - James N Hitchcock
- Centre for Applied Water Science, Institute for Applied Ecology, University of Canberra, Australia
| | - Simon C Apte
- CSIRO Land and Water, Lucas Heights, 2234, Australia
| | - Simon M Mitrovic
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia
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20
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Chase AP, Boss ES, Haëntjens N, Culhane E, Roesler C, Karp‐Boss L. Plankton Imagery Data Inform Satellite-Based Estimates of Diatom Carbon. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL098076. [PMID: 36245955 PMCID: PMC9541314 DOI: 10.1029/2022gl098076] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 06/01/2022] [Accepted: 06/03/2022] [Indexed: 06/16/2023]
Abstract
Estimating the biomass of phytoplankton communities via remote sensing is a key requirement for understanding global ocean ecosystems. Of particular interest is the carbon associated with diatoms given their unequivocal ecological and biogeochemical roles. Satellite-based algorithms often rely on accessory pigment proxies to define diatom biomass, despite a lack of validation against independent diatom biomass measurements. We used imaging-in-flow cytometry to quantify diatom carbon in the western North Atlantic, and compared results to those obtained from accessory pigment-based approximations. Based on this analysis, we offer a new empirical formula to estimate diatom carbon concentrations from chlorophyll a. Additionally, we developed a neural network model in which we integrated chlorophyll a and environmental information to estimate diatom carbon distributions in the western North Atlantic. The potential for improving satellite-based diatom carbon estimates by integrating environmental information into a model, compared to models that are based solely on chlorophyll a, is discussed.
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Affiliation(s)
- A. P. Chase
- Applied Physics LaboratoryUniversity of WashingtonSeattleWAUSA
| | - E. S. Boss
- School of Marine SciencesUniversity of MaineOronoMEUSA
| | - N. Haëntjens
- School of Marine SciencesUniversity of MaineOronoMEUSA
| | - E. Culhane
- Woods Hole Oceanographic InstitutionWoods HoleMAUSA
| | - C. Roesler
- Department of Earth and Oceanographic ScienceBowdoin CollegeBrunswickMEUSA
| | - L. Karp‐Boss
- School of Marine SciencesUniversity of MaineOronoMEUSA
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21
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Gill RL, Collins S, Argyle PA, Larsson ME, Fleck R, Doblin MA. Predictability of thermal fluctuations influences functional traits of a cosmopolitan marine diatom. Proc Biol Sci 2022; 289:20212581. [PMID: 35473374 PMCID: PMC9043731 DOI: 10.1098/rspb.2021.2581] [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: 02/02/2023] Open
Abstract
Evolutionary theory predicts that organismal plasticity should evolve in environments that fluctuate regularly. However, in environments that fluctuate less predictably, plasticity may be constrained because environmental cues become less reliable for expressing the optimum phenotype. Here, we examine how the predictability of +5°C temperature fluctuations impacts the phenotype of the marine diatom Thalassiosira pseudonana. Thermal regimes were informed by temperatures experienced by microbes in an ocean simulation and featured regular or irregular temporal sequences of fluctuations that induced mild physiological stress. Physiological traits (growth, cell size, complexity and pigmentation) were quantified at the individual cell level using flow cytometry. Changes in cellular complexity emerged as the first impact of predictability after only 8–11 days, followed by deleterious impacts on growth on days 13–16. Specifically, cells with a history of irregular fluctuation exposure exhibited a 50% reduction in growth compared with the stable reference environment, while growth was 3–18 times higher when fluctuations were regular. We observed no evidence of heat hardening (increasingly positive growth) with recurrent fluctuations. This study demonstrates that unpredictable temperature fluctuations impact this cosmopolitan diatom under ecologically relevant time frames, suggesting shifts in environmental stochasticity under a changing climate could have widespread consequences among ocean primary producers.
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Affiliation(s)
- Raissa L Gill
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Sinead Collins
- Institute for Evolutionary Biology, University of Edinburgh, EH8 9YL, UK
| | - Phoebe A Argyle
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Michaela E Larsson
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Robert Fleck
- School of Life Sciences, Faculty of Science, University of Technology Sydney, NSW, Australia
| | - Martina A Doblin
- Climate Change Cluster, Faculty of Science, University of Technology Sydney, NSW, Australia.,Sydney Institute of Marine Science, Mosman, NSW, Australia
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22
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Sharma D, Biswas H, Bandyopadhyay D. Simulated ocean acidification altered community composition and growth of a coastal phytoplankton assemblage (South West coast of India, eastern Arabian Sea). ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:19244-19261. [PMID: 34714479 DOI: 10.1007/s11356-021-17141-x] [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: 05/13/2021] [Accepted: 10/15/2021] [Indexed: 06/13/2023]
Abstract
Marine phytoplankton can be highly sensitive to ocean acidification; however, their responses are diverse and therefore, phytoplankton response study on the regional scale is of high research priority. The present study documented the community shift and growth responses of a natural phytoplankton assemblage from the South West coastal water of India (South Eastern Arabian Sea) under ambient CO2 (A-CO2 ≈ 400 µatm) and high CO2 (H-CO2 ≈ 830 µatm) levels in microcosms during the winter monsoon. A doubling of pCO2 resulted in increased cell density, particulate organic carbon and nitrogen (POC, PON) contents, and C:N ratios. The depleted values of δ13CPOC in the H-CO2-incubated cells indicated a higher diffusive CO2 influx. HPLC marker pigment analysis revealed that the community was microphytoplankton dominated (mostly diatoms); nanoplanktonic prymnesiophytic algae and picoplanktonic cyanobacteria showed insignificant response to the simulated ocean acidification. A high CO2-induced increased growth rate was noticed in 6 diatoms (Leptocylindrus danicus; Rhizosolenia setigera; Navicula sp., Asterionella glacialis, Dactyliosolen fragilissimus, and Thalassiosira sp.). The cell volumes of Thalassionema frauenfeldii, Asterionella glacialis, and Cylindrotheca closterium increased significantly, whereas Rhizosolenia setigera and Thalassiosira sp. showed decreased cell volume at the elevated CO2 levels. These changes in growth rate, cell volume, and elemental stoichiometry could be related to CO2 acquisition and the nutritional status of the cells. Some phytoplankton genera from this region are probably acclimatized to pCO2 fluctuations and are likely to benefit from the future increase in CO2 levels. Higher POC production and increased C:N ratio along with variable cell volume may impact the trophic transfer and cycling of organic carbon in this coastal water. However, a multi-stressor approach in a longer experimental exposure should be considered in future research.
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Affiliation(s)
- Diksha Sharma
- Biological Oceanography Division, CSIR National Institute of Oceanography, Dona Paula, Goa, 403 004, India
| | - Haimanti Biswas
- Biological Oceanography Division, CSIR National Institute of Oceanography, Dona Paula, Goa, 403 004, India.
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23
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Duncan RJ, Nielsen DA, Sheehan CE, Deppeler S, Hancock AM, Schulz KG, Davidson AT, Petrou K. Ocean acidification alters the nutritional value of Antarctic diatoms. THE NEW PHYTOLOGIST 2022; 233:1813-1827. [PMID: 34988987 DOI: 10.1111/nph.17868] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 11/07/2021] [Indexed: 06/14/2023]
Abstract
Primary production in the Southern Ocean is dominated by diatom-rich phytoplankton assemblages, whose individual physiological characteristics and community composition are strongly shaped by the environment, yet knowledge on how diatoms allocate cellular energy in response to ocean acidification (OA) is limited. Understanding such changes in allocation is integral to determining the nutritional quality of diatoms and the subsequent impacts on the trophic transfer of energy and nutrients. Using synchrotron-based Fourier transform infrared microspectroscopy, we analysed the macromolecular content of selected individual diatom taxa from a natural Antarctic phytoplankton community exposed to a gradient of fCO2 levels (288-1263 µatm). Strong species-specific differences in macromolecular partitioning were observed under OA. Large taxa showed preferential energy allocation towards proteins, while smaller taxa increased both lipid and protein stores at high fCO2 . If these changes are representative of future Antarctic diatom physiology, we may expect a shift away from lipid-rich large diatoms towards a community dominated by smaller taxa, but with higher lipid and protein stores than their present-day contemporaries, a response that could have cascading effects on food web dynamics in the Antarctic marine ecosystem.
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Affiliation(s)
- Rebecca J Duncan
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
- Department of Arctic Biology, The University Centre in Svalbard, Longyearbyen, 9171, Norway
| | - Daniel A Nielsen
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Cristin E Sheehan
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Stacy Deppeler
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., 7001, Australia
- National Institute of Water and Atmospheric Research, Wellington, 6021, New Zealand
| | - Alyce M Hancock
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tas., 7001, Australia
- Antarctic Gateway Partnership, Battery Point, Tas., 7004, Australia
- Antarctic Climate and Ecosystems Cooperative Research Centre, Hobart, Tas., 7001, Australia
| | - Kai G Schulz
- Centre for Coastal Biogeochemistry, Southern Cross University, East Lismore, NSW, 2480, Australia
| | - Andrew T Davidson
- Antarctic Climate and Ecosystems Cooperative Research Centre, Hobart, Tas., 7001, Australia
- Australian Antarctic Division, Department of the Environment and Energy, Hobart, Tas., 7050, Australia
| | - Katherina Petrou
- School of Life Sciences, University of Technology Sydney, Sydney, NSW, 2007, Australia
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Buck JM, Kroth PG, Lepetit B. Identification of sequence motifs in Lhcx proteins that confer qE-based photoprotection in the diatom Phaeodactylum tricornutum. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1721-1734. [PMID: 34651379 DOI: 10.1111/tpj.15539] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 08/11/2021] [Indexed: 05/08/2023]
Abstract
Photosynthetic organisms in nature often experience light fluctuations. While low light conditions limit the energy uptake by algae, light absorption exceeding the maximal rate of photosynthesis may go along with enhanced formation of potentially toxic reactive oxygen species. To preempt high light-induced photodamage, photosynthetic organisms evolved numerous photoprotective mechanisms. Among these, energy-dependent fluorescence quenching (qE) provides a rapid mechanism to dissipate thermally the excessively absorbed energy. Diatoms thrive in all aquatic environments and thus belong to the most important primary producers on earth. qE in diatoms is provided by a concerted action of Lhcx proteins and the xanthophyll cycle pigment diatoxanthin. While the exact Lhcx activation mechanism of diatom qE is unknown, two lumen-exposed acidic amino acids within Lhcx proteins were proposed to function as regulatory switches upon light-induced lumenal acidification. By introducing a modified Lhcx1 lacking these amino acids into a Phaeodactylum tricornutum Lhcx1-null qE knockout line, we demonstrate that qE is unaffected by these two amino acids. Based on sequence comparisons with Lhcx4, being incapable of providing qE, we perform domain swap experiments of Lhcx4 with Lhcx1 and identify two peptide motifs involved in conferring qE. Within one of these motifs, we identify a tryptophan residue with a major influence on qE establishment. This tryptophan residue is located in close proximity to the diadinoxanthin/diatoxanthin-binding site based on the recently revealed diatom Lhc crystal structure. Our findings provide a structural explanation for the intimate link of Lhcx and diatoxanthin in providing qE in diatoms.
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Affiliation(s)
- Jochen M Buck
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| | - Peter G Kroth
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| | - Bernard Lepetit
- Plant Ecophysiology, Department of Biology, University of Konstanz, Konstanz, 78457, Germany
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25
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Behrenfeld MJ, O'Malley R, Boss E, Karp-Boss L, Mundt C. Phytoplankton biodiversity and the inverted paradox. ISME COMMUNICATIONS 2021; 1:52. [PMID: 36750580 PMCID: PMC9723737 DOI: 10.1038/s43705-021-00056-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 11/08/2022]
Abstract
Earth's aquatic food webs are overwhelmingly supported by planktonic microalgae that live in the sunlit water column where only a minimum number of physical niches are readily identifiable. Despite this paucity of environmental differentiation, these "phytoplankton" populations exhibit a rich biodiversity, an observation not easily reconciled with broadly accepted rules of resource-based competitive exclusion. This conundrum is referred to as the "Paradox of the Plankton". Consideration of physical distancing between nutrient depletion zones around individual phytoplankton, however, suggests a competition-neutral resource landscape. Application of neutral theory to the sheer number of phytoplankton in physically-mixed water masses yields a prediction of astronomical biodiversity, suggesting the inverted paradox: Why are there so few phytoplankton species? Here, we introduce a trophic constraint on phytoplankton that, when combined with stochastic principals of ecological drift, predicts only modest levels of diversity in an otherwise competition-neutral landscape. Our "trophic exclusion" principle predicts diversity to be independent of population size and yields a species richness across cell-size classes that is consistent with broad oceanographic survey observations.
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Affiliation(s)
- Michael J Behrenfeld
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
| | - Robert O'Malley
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Emmanuel Boss
- School of Marine Sciences, University of Maine, Orono, ME, USA
| | - Lee Karp-Boss
- School of Marine Sciences, University of Maine, Orono, ME, USA
| | - Christopher Mundt
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
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