The paradox high zooplankton biomass-low vegetal particulate organic matter in high turbidity zones : What way for energy transfer?

摘要: Abstract Estuarine ecosystems are characterized by high zooplanktonic biomasses, essentially constituted copepods and mysids whose nutritional requirements mainly provided phytoplankton, an easily available carbon form. The Gironde estuary is turbidities which limit light penetration in the water column therefore primary production. Consequently, production low its availability for higher trophic level very limited. main goal of this study was to characterize total vegetal particulate organic matter (POM) turbidity zones during summer (a critical period heterotrophic bacterial degradation biomasses) analyse utilization zooplankton, using prey/predator experiments biomarkers (fatty acids). specific goals were define (i) how POM exploited different groups (protozoa, mysids) (ii) alternative preys could be used when not sufficient ensure their requirements. Chlorophyll biomass MTZ 2002 (0.48 ± 0.03 mg m − 3 ). Total zooplankton grazing (19% d − 1 ) probably due a large contribution detritus originating from terrestrial plants compared phytoplankton. highest pressure exercised mysid Mesopodopsis slabberi abundances almost entirely herbivorous diet (phytoplankton small detritus). Grazing rates (19.7 ± 4.2 9.6 μgC cop juveniles adults, respectively) seemed satisfy daily requirement. rate copepod Eurytemora affinis (139 ngC insufficient cover needed complete great part protozoa. Neomysis integer (24.7 ± 0.01 20.89 ± 8.45 than those M. feeding only on However, other introduced environment, N. fed E. with preference nauplii. revealed importance protozoa bacteria transfers between summer, despite (3.1%). detritic food chain implies various little direct relationships zooplankton.