Carbon transfer in herbivore- and microbial loop-dominated pelagic food webs in the southern Barents Sea during spring and summer

We compared carbon budgets between a herbivore - domina led and a microbial loop-dominated food web and examined the implications of food web structure for fish production. We used the southern Barents Sea as a case study and inverse modelling as an analysis method. In spring, when the system was do...

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Bibliographic Details
Published in:Marine Ecology Progress Series
Main Authors: De Laender, Frederik, Van Oevelen, Dick, Middelburg, Jack, Soetaert, Karline
Format: Article in Journal/Newspaper
Language:English
Published: 2010
Subjects:
Biology and Life Sciences
Microbial loop
Food web
Protozoa
Copepods
Gadus morhua
DISSOLVED ORGANIC-CARBON
NORTHEAST ARCTIC COD
MARGINAL ICE-ZONE
GADUS-MORHUA L
POPULATION-DYNAMICS
SEASONAL-VARIATION
ATLANTIC COD
HETEROTROPHIC BACTERIAL
ZOOPLANKTON COMMUNITY
CALANUS-FINMARCHICUS
Arctic
Barents Sea
Arctic cod
atlantic cod
Calanus finmarchicus
Northeast Arctic cod
Phytoplankton
Zooplankton
Online Access:https://biblio.ugent.be/publication/1191654
http://hdl.handle.net/1854/LU-1191654
https://doi.org/10.3354/meps08335
https://biblio.ugent.be/publication/1191654/file/1191658
Description
Summary:We compared carbon budgets between a herbivore - domina led and a microbial loop-dominated food web and examined the implications of food web structure for fish production. We used the southern Barents Sea as a case study and inverse modelling as an analysis method. In spring, when the system was dominated by the herbivorous web, the diet of protozoa consisted of similar amounts of bacteria and phytoplankton. Copepods showed no clear preference for protozoa. Cod Gadus morhua, a predatory fish preying on copepods and on copepod-feeding capelin Mallotus villosus in spring, moderately depended on the microbial loop in spring, as only 20 to 60% of its food passed through the microbial loop. In summer, when the food web was dominated by the microbial loop, protozoa ingested 4 times more bacteria than phytoplankton and protozoa formed 80 to 90%, of the copepod diet. Because of this strong link between the microbial loop and copepods (the young cod's main prey item) young cod (< 3 yr) depended more on the microbial loop than on any other food web compartment, as > 60% of its food passed through the microbial loop in summer. Adult cod (<= 3 yr) relied far less on the microbial loop than young cod as it preyed on strictly herbivorous krill in summer. Food web efficiency for fish production was comparable between seasons (similar to 5 x 10(-4)) and 2 times higher in summer (5 x 10(-2)) than in spring for copepod production.

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