CO2 effects on diatoms: A Synthesis of more than a decade of ocean acidification experiments with natural communities.

Bach, Lennart T. and Taucher, Jan (2019) CO2 effects on diatoms: A Synthesis of more than a decade of ocean acidification experiments with natural communities. Open Access Ocean Science, 15 . pp. 1159-1175. DOI 10.5194/os-15-1159-2019.

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Diatoms account for 40 % of marine primary production and are considered to be key players in the biological carbon pump. Ocean acidification (OA) is expected to affect diatoms primarily by changing the availability of CO2 as a substrate for photosynthesis or through altered ecological interactions within the marine food web. Yet, there is little consensus how entire diatom communities will respond to increasing CO2. To address this question, we synthesized the literature from over a decade of OA-experiments with natural diatom communities to uncover: 1) if and how bulk diatom communities respond to elevated CO2; 2) if shifts within the diatom communities could be expected and how they are expressed with respect to taxonomic affiliation and size structure. We found that diatom communities responded to high CO2 in ~60 % of the experiments and in this case more often positively (56 %) than negatively (32 %; 12 % did not report the direction of change). Shifts among different diatom species were observed in 65 % of the experiments. Our synthesis supports the hypothesis that high CO2 particularly favors larger species as 12 out of 13 experiments which investigated cell size found a shift towards larger species. Unraveling winners and losers with respect to taxonomic affiliation was difficult due to a limited database, but there is evidence that the genus Pseudo-nitzschia could be among the losers. We conclude that OA-induced changes in diatom competitiveness and assemblage structure must be classified as a “risk for ecosystem services” due to the pivotal role diatoms play in trophic transfer and biogeochemical cycles.

Document Type: Article
Keywords: Ocean acidification, climate change, mesocosm, literature review, food web, phytoplankton, Bacillariophyceae
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BM Biogeochemical Modeling
OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-BI Biological Oceanography
Corresponding Author:
Corresponding Author Name
Bach, Lennart T.
Bach, Lennart T. (Bach, Lennart)
FB2-BI Biological Oceanography
Refereed: Yes
Open Access Journal?: Yes
Publisher: Copernicus Publications (EGU)
Projects: BIOACID
Date Deposited: 17 May 2019 07:43
Last Modified: 06 Apr 2022 13:56

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