|d13C and d15N composition of suspended particular organic matter (SPOM) and zooplankton in the eutrophic Scheldt estuary (Belgium) (poster)|
|De Brabandere, L.; Dehairs, F.A. (2002). d13C and d15N composition of suspended particular organic matter (SPOM) and zooplankton in the eutrophic Scheldt estuary (Belgium) (poster), in: Mees, J. et al. (Ed.) (2002). VLIZ Young Scientists' Day, Brugge, Belgium 13 March 2002: book of abstracts. VLIZ Special Publication, 7: pp. 32|
|In: Mees, J.; Seys, J. (Ed.) (2002). VLIZ Young Scientists' Day, Brugge, Belgium 13 March 2002: book of abstracts. VLIZ Special Publication, 7. Vlaams Instituut voor de Zee: Oostende. VI, 57 pp., more|
|In: VLIZ Special Publication. Vlaams Instituut voor de Zee (VLIZ): Oostende. ISSN 1377-0950, more|
d13C and d15N were used to study food sources of zooplankton in the Scheldt Estuary. The SPOM carried by the river is a mixture of antropogenic and terrestrial detritus with associated bacteria and locally produced autotrophic organic matter.
Samples of SPOM and zooplankton were taken monthly from June 1999 to April 2000 at four stations located along a salinity gradient (0-14 ppt). We investigated the relative importance of detritus, heterotrophic and autotrophic organic matter in the diet of zooplankton.
Both d15NSPOM and d13CSPOM varied seasonally, paralleling the change in biomass of autotrophic organisms. Generally, phytoplankton bloom periods were characterised by high d15NSPOM (maximum +12.9‰) and low d13CSPOM values (minimum -31.1‰). Winter d15NSPOM and d13CSPOM values were characteristic for pure antropogenic/terrestrial detritus (d15N = +2.5‰; d13C = -26.8‰). The summer increase of d15NSPOM was attributed to autotrophic consumption of NH4+ strongly enriched in 15N due to intense nitrification. However, the seasonal pattern between the stations differed reflecting differences in the timing, duration and intensity of the phytoplankton bloom.
d13Czooplankton and d15Nzooplankton co-varied with d13CSPOM and d15NSPOM. The high deviation from the original d13CSPOM and d15NSPOM suggested selective feeding on specific components of the SPOM.