Multiannual phytoplankton trends in relation to environmental changes across aquatic domains: a case study from Sardinia (Mediterranean Sea)

We investigated multiannual trends in phytoplankton in relation to several environmental drivers. We analyzed ecological data collected during the last two decades from three aquatic sites: an artificial lake, a coastal lagoon, and a marine coastal area. Hydrographic-, nutrient-, and phytoplankton- data were statistically analyzed to detect trends and interactions. In all ecosystems, the chlorophyll <i>a</i> concentration decreased with increasing abundance of small-sized phytoplankton. Phytoplankton dynamics were related to decreased nutrient concentrations in the lake, to dynamics of phosphorus and decreased salinity in the lagoon, and probably to combined top-down and bottom-up processes in the marine gulf.