The use of benthic metabolic processes as indicators for environmental quality assessment in coastal lagoons

The review highlights the various methods used for assessing environmental quality in Mediterranean coastal lagoons, with emphasis on benthic parameters and processes. The application of indices based on benthic macrofauna, extensively used in coastal areas, may fail in discerning between natural and anthropogenic pressures over naturally stressed coastal lagoons. Sediment can play an important regulatory role over the overlying water composition through the storage capacity for organic matter and pollutants, regeneration of nutrients or its buffering capacity. Descriptive classical measurements like sedimentary organic matter, Chlorophyll α and nutrient content are commonly included in monitoring efforts. However, other more complex indicators like primary production, sediment-water solute fluxes, solute sorption dynamics or microbial reaction rate determinations, have not been fully implemented for environmental quality assessment in coastal lagoons. These could offer crucial information on current and projected anthropogenic influence on ecosystem functioning. Irruption of novel techniques in benthic biogeochemistry like Excitation-Emission-Matrix (EEM) fluorescence for the study of dissolved organic matter dynamics shows high potential in combination with biological quality elements and other metabolic measurements for the evaluation of the environmental quality in coastal lagoons.