ABSTRACT
Estuaries serve as a filter of trace metals, and sedimentological processes, together with hydrodynamic and chemical factors, control basic fluxes of the metal content. The actual pathway of accumulation of trace metals in estuarine organisms is confounded by several factors, most notably the chemical behavior of the element, the feeding type of the organism, the composition of food ingested, and the chemical properties of the water. Redox potential, pH, permeability, water content, calcium concentrations, bioturbation, and physical mixing appear to be the most important factors controlling the adsorption-desorption reactions of phosphorus in estuarine sediments. In estuarine waters, physical-chemical factors, especially those affecting gaseous solubility, primarily determine the concentration and distribution of dissolved gases other than oxygen and carbon dioxide, which are strongly influenced by biological activity. Seasonal changes in oxygen concentrations depend on long-term variations in physical and biological factors.
