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Ocean acidification reduces growth and grazing impact of Antarctic heterotrophic nanoflagellates

Citation

Deppeler, S and Schulz, KG and Hancock, A and Pascoe, P and McKinlay, J and Davidson, A, Ocean acidification reduces growth and grazing impact of Antarctic heterotrophic nanoflagellates, Biogeosciences, 17, (16) pp. 4153-4171. ISSN 1726-4170 (2020) [Refereed Article]


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DOI: doi:10.5194/bg-17-4153-2020

Abstract

High-latitude oceans have been identified as particularly vulnerable to ocean acidification if anthropogenic CO2 emissions continue. Marine microbes are an essential part of the marine food web and are a critical link in biogeochemical processes in the ocean, such as the cycling of nutrients and carbon. Despite this, the response of Antarctic marine microbial communities to ocean acidification is poorly understood. We investigated the effect of increasing fCO2 on the growth of heterotrophic nanoflagellates (HNFs), nano- and picophytoplankton, and prokaryotes (heterotrophic Bacteria and Archaea) in a natural coastal Antarctic marine microbial community from Prydz Bay, East Antarctica. At CO2 levels ≥634µatm, HNF abundance was reduced, coinciding with increased abundance of picophytoplankton and prokaryotes. This increase in picophytoplankton and prokaryote abundance was likely due to a reduction in top-down control of grazing HNFs. Nanophytoplankton abundance was elevated in the 634 µatm treatment, suggesting that moderate increases in CO2 may stimulate growth. The taxonomic and morphological differences in CO2 tolerance we observed are likely to favour dominance of microbial communities by prokaryotes, nanophytoplankton, and picophytoplankton. Such changes in predator–prey interactions with ocean acidification could have a significant effect on the food web and biogeochemistry in the Southern Ocean, intensifying organic-matter recycling in surface waters; reducing vertical carbon flux; and reducing the quality, quantity, and availability of food for higher trophic levels.

Item Details

Item Type:Refereed Article
Keywords:ocean acidification, heterotrophs, nanoplankton, Antarctica
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Marine and estuarine ecology (incl. marine ichthyology)
Objective Division:Environmental Management
Objective Group:Management of Antarctic and Southern Ocean environments
Objective Field:Assessment and management of Antarctic and Southern Ocean ecosystems
UTAS Author:Deppeler, S (Ms Stacy Deppeler)
UTAS Author:Hancock, A (Miss Alyce Hancock)
UTAS Author:Pascoe, P (Ms Penelope Pascoe)
UTAS Author:Davidson, A (Dr Andrew Davidson)
ID Code:142934
Year Published:2020
Deposited By:Ecology and Biodiversity
Deposited On:2021-02-17
Last Modified:2021-02-17
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