Shift from carbon flow through the microbial loop to the viral shunt in coastal Antarctic waters during austral summer.

Claire Evans, Joost Brandsma, Michael Meredith, David Neville Thomas, Hugh Venables, David Pond, Corina Brussaard

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Sammanfattning

The relative flow of carbon through the viral shunt and the microbial loop is a pivotal factor controlling the contribution of secondary production to the food web and to rates of nutrient remineralization and respiration. The current study examines the significance of these processes in the coastal waters of the Antarctic during the productive austral summer months. Throughout the study a general trend towards lower bacterioplankton and heterotrophic nanoflagellate (HNF) abundances was observed, whereas virioplankton concentration increased. A corresponding decline of HNF grazing rates and shift towards viral production, indicative of viral infection, was measured. Carbon flow mediated by HNF grazing decreased by more than half from 5.7 μg C L−1day−1 on average in December and January to 2.4 μg C L−1 day−1 in February. Conversely, carbon flow through the viral shunt increased substantially over the study from on average 0.9 μg C L−1day−1 in December to 7.6 μg C L−1 day−1 in February. This study shows that functioning of the coastal Antarctic microbial community varied considerably over the productive summer months. In early summer, the system favors transfer of matter and energy to higher trophic levels via the microbial loop, however towards the end of summer carbon flow is redirected towards the viral shunt, causing a switch towards more recycling and therefore increased respiration and regeneration.
Originalspråkengelska
Artikelnummer460
TidskriftMicroorganisms
Volym9
Utgåva2
Antal sidor12
ISSN2076-2607
DOI
StatusPublicerad - 23 feb 2021
MoE-publikationstypA1 Tidskriftsartikel-refererad

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  • 1181 Ekologi, evolutionsbiologi

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