Assessment of the pelagic food web structure of the Scheldt estuary from C and N stable isotope ratios
De Brabandere, L.; Dehairs, F.A.; Baeyens, W.F.J. (2002). Assessment of the pelagic food web structure of the Scheldt estuary from C and N stable isotope ratios, in: ECSA Local Meeting: ecological structures and functions in the Scheldt Estuary: from past to future, Antwerp, Belgium October 7-10, 2002: abstract book. pp. 37 In: (2002). ECSA Local Meeting: Ecological structures and functions in the Scheldt Estuary: from past to future, Antwerp, Belgium October 7-10, 2002: abstract book. University of Antwerp: Antwerp. 73 + 1 cd-rom pp., more |
| Available in | Authors | | Document type: Conference paper
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| Keywords | Chemical elements > Nonmetals > Atmospheric gases > Nitrogen > Organic nitrogen > Dissolved organic matter > Dissolved organic nitrogen
Chemical reactions > Denitrification
Chemical reactions > Nitrification
Food webs
Food webs > Food chains
Inorganic matter
Inorganic matter > Carbon > Inorganic carbon
Materials > Isotropic materials
Spatial variations
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| Authors | | Top | - De Brabandere, L., more
- Dehairs, F.A., more
- Baeyens, W.F.J., more
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| Abstract | It is well known that the d 13C and d 15N signatures of the inorganic/organic substrates at the basis of the food web set the isotopic signatures of the higher trophic levels. For the Scheldt system, seasonality of the (high) input of nutrients and organic matter and intensive reprocessing of this material in the river and estuary induce temporally and spatially variable isotopic compositions at the food web base, complicating the understanding of interdependencies at the higher trophic levels. Reprocessing of nutrients includes carbon fixation, heterotrophic respiration, uptake, excretion, ammonification, nitrification, denitrification. For C the most likely processes influencing d 13C of dissolved inorganic carbon are heterotrophic respiration and carbon fixation. For N, the processes influencing d 15N of dissolved inorganic nitrogen are organic matter mineralisation, nitrification, denitrification and autotrophic and heterotrophic uptake. The spatial and temporal variations in stable C and N isotopic composition of the suspended microbial biomass, including primary producers, reflect the seasonality of nutrient reprocessing and differential functioning between river and estuary. The impact of this seasonality and spatial variability is transferred up the food chain. |
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