Changes in phytoplankton composition in a M editerranean coastal lagoon in the C ullera E stany ( C omunitat V alenciana, S pain)

The C ullera E stany is a coastal lagoon located in a highly intensified agriculture and tourist area in V alencia. This coastal lagoon has connections with the sea that produce marine intrusion and generate a freshwater interface. Four sampling campaigns were carried out during 2010 in order to analyse the phytoplankton composition and its relation to nutrient content through a R edundancy A nalysis. Temperature, dissolved oxygen, nitrite and salinity are the main factors controlling the dynamics of phytoplankton community. During J uly and O ctober, there is water column stratification; meanwhile in M arch, there is a well‐mixed water column. In addition, in M ay and J uly campaigns, hypoxia/anoxia conditions are detected at the bottom. The most abundant phytoplankton groups are D iatoms and C ryptophyceae. D iatoms and C yanophyceae respond positively to temperature while C ryptophyceae, P rasinophyceae and D inophyceae respond to high salinity and dissolved oxygen values. Furthermore, picoplankton is correlated inversely with nutrient concentrations.