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Sheward RM, Liefer JD, Irwin AJ, Finkel ZV. Elemental stoichiometry of the key calcifying marine phytoplankton Emiliania huxleyi under ocean climate change: A meta-analysis. GLOBAL CHANGE BIOLOGY 2023; 29:4259-4278. [PMID: 37279257 DOI: 10.1111/gcb.16807] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 05/16/2023] [Accepted: 05/17/2023] [Indexed: 06/08/2023]
Abstract
The elemental composition of marine microorganisms (their C:N:P ratio, or stoichiometry) is central to understanding the biotic and biogeochemical processes underlying key marine ecosystem functions. Phytoplankton C:N:P is species specific and flexible to changing environmental conditions. However, bulk or fixed phytoplankton stoichiometry is usually assumed in biogeochemical and ecological models because more realistic, environmentally responsive C:N:P ratios have yet to be defined for key functional groups. Here, a comprehensive meta-analysis of experimental laboratory data reveals the variable C:N:P stoichiometry of Emiliania huxleyi, a globally significant calcifying phytoplankton species. Mean C:N:P of E. huxleyi is 124C:16N:1P under control conditions (i.e. growth not limited by one or more environmental stressors) and shows a range of responses to changes in nutrient and light availability, temperature and pCO2 . Macronutrient limitation caused strong shifts in stoichiometry, increasing N:P and C:P under P deficiency (by 305% and 493% respectively) and doubling C:N under N deficiency. Responses to light, temperature and pCO2 were mixed but typically shifted cellular elemental content and C:N:P stoichiometry by ca. 30% or less. Besides these independent effects, the interactive effects of multiple environmental changes on E. huxleyi stoichiometry under future ocean conditions could be additive, synergistic or antagonistic. To synthesise our meta-analysis results, we explored how the cellular elemental content and C:N:P stoichiometry of E. huxleyi may respond to two hypothetical future ocean scenarios (increased temperature, irradiance and pCO2 combined with either N deficiency or P deficiency) if an additive effect is assumed. Both future scenarios indicate decreased calcification (which is predominantly sensitive to elevated pCO2 ), increased C:N, and up to fourfold shifts in C:P and N:P. Our results strongly suggest that climate change will significantly alter the role of E. huxleyi (and potentially other calcifying phytoplankton species) in marine biogeochemical processes.
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Affiliation(s)
- Rosie M Sheward
- Institute of Geosciences, Goethe-University Frankfurt, Frankfurt am Main, Germany
- Department of Geography and Environment, Mount Allison University, Sackville, New Brunswick, Canada
| | - Justin D Liefer
- Department of Biology/Geography and Environment, Mount Allison University, Sackville, New Brunswick, Canada
| | - Andrew J Irwin
- Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Zoe V Finkel
- Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
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Villiot N, Poulton AJ, Butcher ET, Daniels LR, Coggins A. Allometry of carbon and nitrogen content and growth rate in a diverse range of coccolithophores. JOURNAL OF PLANKTON RESEARCH 2021; 43:511-526. [PMID: 34326702 PMCID: PMC8315238 DOI: 10.1093/plankt/fbab038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/26/2021] [Accepted: 05/01/2021] [Indexed: 05/26/2023]
Abstract
As both photoautotrophs and calcifiers, coccolithophores play important roles in ecosystems and biogeochemical cycles. Though some species form blooms in high-latitude waters, low-latitude communities exhibit high diversity and niche diversification. Despite such diversity, our understanding of the clade relies on knowledge of Emiliana huxleyi. To address this, we examine carbon (C) and nitrogen (N) content of strains (n = 9) from the main families of the calcifying Haptophyceae, as well as allometry and cell size frequency across extant species. Coccolithophore cell size is constrained, with ~71% of 159 species smaller than 10 μm in diameter. Growth rates scale with cell biovolume (μ = 1.83 × cell volume-0.19), with an exponent close to metabolic theory. Organic carbon (C) per cell is lower than for other phytoplankton, providing a coccolithophore-specific relationship between cell organic C content and biovolume (pg C cell-1 = 0.30 × cell volume0.70). Organic C to N ratios (~8.3 mol:mol) are similar to other phytoplankton, implying little additional N cost for calcification and efficient retention and recycling of cell N. Our results support observations that coccolithophores are efficient competitors in low-nutrient conditions, able to photosynthesize, calcify and run the routine metabolic machinery necessary without any additional need for N relative to noncalcifying algae.
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Affiliation(s)
- Naomi Villiot
- The Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University, Research Avenue South, Edinburgh, EH14 4AS, UK
| | - Alex J Poulton
- The Lyell Centre for Earth and Marine Science and Technology, Heriot-Watt University, Research Avenue South, Edinburgh, EH14 4AS, UK
| | - Elizabeth T Butcher
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, Southampton, SO18 3ZH, UK
| | - Lucie R Daniels
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, Southampton, SO18 3ZH, UK
| | - Aimee Coggins
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, Southampton, SO18 3ZH, UK
- Atmospheric and Ocean Sciences, College of Life and Environmental Sciences, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK
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Müller MN, Brandini FP, Trull TW, Hallegraeff GM. Coccolith volume of the Southern Ocean coccolithophore Emiliania huxleyi as a possible indicator for palaeo-cell volume. GEOBIOLOGY 2021; 19:63-74. [PMID: 32931664 DOI: 10.1111/gbi.12414] [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: 03/28/2020] [Accepted: 08/23/2020] [Indexed: 06/11/2023]
Abstract
Coccolithophores are a key functional phytoplankton group and produce minute calcite plates (coccoliths) in the sunlit layer of the pelagic ocean. Coccoliths significantly contribute to the sediment record since the Triassic and their geometry have been subject to palaeoceanographic and biological studies to retrieve information on past environmental conditions. Here, we present a comprehensive analysis of coccolith, coccosphere and cell volume data of the Southern Ocean Emiliania huxleyi ecotype A, subject to gradients of temperature, irradiance, carbonate chemistry and macronutrient limitation. All tested environmental drivers significantly affect coccosphere, coccolith and cell volume with driver-specific sensitivities. However, a highly significant correlation emerged between cell and coccolith volume with Vcoccolith = 0.012 ± 0.001 * Vcell + 0.234 ± 0.066 (n = 23, r2 = .85, p < .0001, σest = 0.127), indicating a primary control of coccolith volume by physiological modulated changes in cell volume. We discuss the possible application of fossil coccolith volume as an indicator for cell volume/size and growth rate and, additionally, illustrate that macronutrient limitation of phosphorus and nitrogen has the predominant influence on coccolith volume in respect to other environmental drivers. Our results provide a solid basis for the application of coccolith volume and geometry as a palaeo-proxy and shed light on the underlying physiological reasons, offering a valuable tool to investigate the fossil record of the coccolithophore E. huxleyi.
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Affiliation(s)
- Marius N Müller
- Department of Oceanography, Federal University of Pernambuco (UFPE), Recife, PE, Brazil
| | - Frederico P Brandini
- Oceanographic Institute at the University of São Paulo (IO-USP), São Paulo, SP, Brazil
| | - Thomas W Trull
- Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania, and CSIRO Oceans and Atmosphere, Hobart, Australia
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Langley B, Halloran PR, Power A, Rickaby REM, Chana P, Diver P, Thornalley D, Hacker C, Love J. A new method for isolating and analysing coccospheres within sediment. Sci Rep 2020; 10:20727. [PMID: 33244023 PMCID: PMC7692543 DOI: 10.1038/s41598-020-77473-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 11/06/2020] [Indexed: 11/25/2022] Open
Abstract
Size is a fundamental cellular trait that is important in determining phytoplankton physiological and ecological processes. Fossil coccospheres, the external calcite structure produced by the excretion of interlocking plates by the phytoplankton coccolithophores, can provide a rare window into cell size in the past. Coccospheres are delicate however and are therefore poorly preserved in sediment. We demonstrate a novel technique combining imaging flow cytometry and cross-polarised light (ISX+PL) to rapidly and reliably visually isolate and quantify the morphological characteristics of coccospheres from marine sediment by exploiting their unique optical and morphological properties. Imaging flow cytometry combines the morphological information provided by microscopy with high sample numbers associated with flow cytometry. High throughput imaging overcomes the constraints of labour-intensive manual microscopy and allows statistically robust analysis of morphological features and coccosphere concentration despite low coccosphere concentrations in sediments. Applying this technique to the fine-fraction of sediments, hundreds of coccospheres can be visually isolated quickly with minimal sample preparation. This approach has the potential to enable rapid processing of down-core sediment records and/or high spatial coverage from surface sediments and may prove valuable in investigating the interplay between climate change and coccolithophore physiological/ecological response.
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Affiliation(s)
- Beth Langley
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK
| | - Paul R Halloran
- Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4RJ, UK.
| | - Ann Power
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Rosalind E M Rickaby
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
| | - Prabhjoat Chana
- Luminex B.V., Het Zuiderkruis 1, 5215 MV, 's-Hertogenbosch, The Netherlands
| | - Poppy Diver
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK
| | - David Thornalley
- Department of Geography, University College London, London, WC1H 9LG, UK
| | - Christian Hacker
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - John Love
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
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Toward an Improved Understanding of the Marine Barium Cycle and the Application of Marine Barite as a Paleoproductivity Proxy. MINERALS 2020. [DOI: 10.3390/min10050421] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Marine barite (BaSO4) is a relatively ubiquitous, though minor, component of ocean sediments. Modern studies of the accumulation of barite in ocean sediments have demonstrated a robust correlation between barite accumulation rates and carbon export to the deep ocean. This correlation has been used to develop quantitative relationships between barite accumulation rates and export production and is used to reconstruct export production in the geologic past, particularly during times of dynamic changes in the carbon cycle. We review the processes that affect the formation and preservation of marine barite, as well as those controlling the relationship between the barium (Ba) and carbon biogeochemical cycles. Additionally, we take a new approach to modeling the marine Ba cycle as a two-box model, specifically evaluating Ba utilization in the surface ocean and refining the equation describing the relationship between export production and barite formation. We compare these new results with past modeling efforts. The new model demonstrates that increases in export production can lead to sustained increases in barite accumulation in marine sediments without resulting in complete surface water Ba depletion, which is distinctly different from previous modeling results.
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Alvarez SA, Gibbs SJ, Bown PR, Kim H, Sheward RM, Ridgwell A. Diversity decoupled from ecosystem function and resilience during mass extinction recovery. Nature 2019; 574:242-245. [DOI: 10.1038/s41586-019-1590-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 08/27/2019] [Indexed: 11/09/2022]
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Foster GL, Hull P, Lunt DJ, Zachos JC. Placing our current 'hyperthermal' in the context of rapid climate change in our geological past. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2018; 376:rsta.2017.0086. [PMID: 30177567 PMCID: PMC6127387 DOI: 10.1098/rsta.2017.0086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/07/2018] [Indexed: 05/22/2023]
Abstract
'…there are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know.' Donald Rumsfeld 12th February 2002.This article is part of a discussion meeting issue 'Hyperthermals: rapid and extreme global warming in our geological past'.
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Affiliation(s)
- Gavin L Foster
- School of Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, SO14 3ZH, UK
| | - Pincelli Hull
- Department of Geology and Geophysics, Yale University, Box 208109, New Haven, CT 06520-8109, USA
| | - Daniel J Lunt
- School of Geographical Sciences, University of Bristol, University Road, Clifton, Bristol BS8 1SS, UK
| | - James C Zachos
- Department of Earth and Planetary Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
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