|Very low salinity regions of estuaries: important sites for chemical and biological reactions|
Morris, A.W.; Mantoura, R.F.C.; Bale, A.J.; Howland, R.J.M. (1978). Very low salinity regions of estuaries: important sites for chemical and biological reactions. Nature (Lond.) 274(5672): 678-680
In: Nature: International Weekly Journal of Science. Nature Publishing Group: London. ISSN 0028-0836, more
Bacteria; Biochemical cycles; Chemical reactions; Dissolved oxygen; Ecosystems; Estuaries; Geochemistry; Organic matter; Physicochemical properties; Salinity; Salinity effects; Water mixing; British Isles, England, Tamar R. [Marine Regions]; Brackish water
|Authors|| || Top |
- Morris, A.W.
- Mantoura, R.F.C.
- Bale, A.J.
- Howland, R.J.M.
Data derived from detailed investigations of the immediate mixing of the fresh and brackish water in the Tamar Estuary, SW England, are presented for 11 determinands which point to the freshwater-seawater interphase (FSI) as being an important site for chemical and biological processes in estuaries. Estuarine profiles (plotted against log10 salinity) have been constructed for dissolved oxygen, pH, relative chlorophyll fluorescence, temperature and the concentrations of dissolves organic carbon (DOC), conservative DOC profile, nitrate NO3- , nitrite NO2- , manganese, zinc and copper. Examination of these parameters at the FSI leads to the following conclusions: (1) the drop in oxygen appears to be triggered by seasonal biological activity; (2) the DOC peak and chlorophyll minimum point to a common mechanism at the FSI; possibly a sequence of mass mortality of freshwater halophobes, leading to plasmolysis and a localised proliferation of oxygen-utilising bacteria. Other data support this 'osmotic hypothesis'. (3) Anomalies in chemical parameters derive variously from perturbations in pH, salinity, redox and adsorption equilibria, and kinetic barriers at the FSI.