Organic matter processing in tidal estuaries
Middelburg, J.J.; Herman, P.M.J. (2007). Organic matter processing in tidal estuaries, in: Goldberg, E.D. (Ed.) (1974). Marine chemistry. The sea: ideas and observations on progress in the study of the seas, 5: pp. 127-147. http://dx.doi.org/10.1016/j.marchem.2006.02.007
|
| Keywords |
ANE, British Isles, England, Thames Estuary [Marine Regions]; ANE, France, Gironde Estuary [Marine Regions]; ANE, France, Pays de Loire, Loire Estuary [Marine Regions]; ANE, Germany, Elbe Estuary [Marine Regions]; ANE, Germany, Ems Estuary [Marine Regions]; ANE, Netherlands, Rhine estuary [Marine Regions]; ANE, Netherlands, Westerschelde [Marine Regions]; ANE, Portugal, Sado Estuary [Marine Regions]
Marine/Coastal; Brackish water; Fresh water |
| Abstract |
Processing of organic matter in tidal estuaries modifies its transfer from the river to the sea. We examined the distribution and the elemental and isotopic composition of organic matter in nine tidal estuaries along the Atlantic coast of Europe (Elbe, Ems, Thames, Rhine, Scheldt, Loire, Gironde, Douro and Sado). Short-residence time estuaries such as the Douro and Rhine estuaries have low suspended matter (SPM) contents with variable organic carbon (OC) concentrations, but rather uniform d15N values and C/N ratios. Carbon isotope ratios vary from -20 to -22‰ in the marine end-member to -26 to -30‰ in the river end-member with conservative mixing in between. Tidal-dominated estuaries have high SPM contents, rather uniform OC contents and C/N ratios, and uniform and intermediate d13C values (-24 to -26‰). Organic matter in these intermediate to long residence time estuaries is extensively modified such that d15N values may show enrichments up to 20‰ due to (heterotrophic) processing. Pools of dissolved and particulate organic matter appear to be involved in dynamic exchange reactions with their partitioning mainly governed by SPM concentration. The interaction of tidally induced cycles of deposition and erosion with this repartitioning of organic matter between dissolved and particulate pools due to changes in SPM concentration can be viewed as a chemical reactor with optimal solid-liquid exchange. As a consequence, riverine organic matter is extensively modified in tidal estuaries before it is transferred to the sea. |
| Dataset |
- Middelburg J. 1998: Publication data from Jack Middelburg for BIOGEST (particulate del13C, del15N, POC, PON, DOC, N2O and nitrogen uptake data). Netherlands Institute of Ecology; Centre for Estuarine and Marine Ecology, Netherlands. Metadata available at http://mda.nioo.knaw.nl/imis.php?module=dataset&dasid=1811, more
|
|
