Application of taxonomic and morpho-functional properties of phytoplankton communities to water quality assessment for artificial lakes in the Mediterranean Ecoregion

Abstract

Starting in September 2010, a monitoring program was developed for evaluating the water quality in six artificial lakes (reservoirs) of the Apulia Region (Southern Italy). Lake ecological status was evaluated according to the requirements of the 2000/60/EC Water Framework Directive. Phytoplankton taxonomic composition, biovolume and chlorophyll a data were used in an application of the Italian methods (Italian Phytoplankton Assessment Method or New Italian Method) for water quality assessment of artificial lakes. Even though all the reservoirs were classified as being in good ecological status, the phytoplankton communities of the six reservoirs were different and characterized by highly site-specific components and by distinctive dominant taxa. The influences of environmental variables on the phytoplankton communities were analyzed. Results of Constrained Coordinate Analysis (CCA) indicated strong influences of the trophic gradient and water depth on the phytoplankton assemblages, but significant factors are also the surrounding landscape and the origin and the history of the lakes. A functional traits-based analysis was carried out to support the water quality assessment tools. Twenty-one morpho-functional groups were identified. Most of them were common in all six lakes, so functional properties clearly recur among different phytoplankton species.