Annual cycle of phytoplankton community through the water column: Study applied to the implementation of bivalve offshore aquaculture in the southeastern Bay of Biscay

摘要: Abstract This study describes, for the first time, annual variability of phytoplankton community in different layers water column open waters off Basque coast (southeastern Bay Biscay). Phytoplankton composition, abundance and biomass, together with size-fractionated chlorophyll a, nutrients, optical hydrographic conditions were measured an experimental bivalve culture area from May 2014 to June 2015. Water showed typical dynamics previously described temperate areas, characterised by winter homogeneity summer stratification. temporal was studied at depths 3, 17 33 m, found be related those processes. In particular, temperature nutrients (mostly nitrate silicate) environmental variables which significantly explained most concentration, whereas river flow main driver variability. Total generally low (0.6 µg L−1 on average). Of 194 registered taxa, 47.4% belonged dinoflagellates 35.1% diatoms. addition, diatoms highest biomass values, haptophytes represented greatest contribution cell-abundance. fact, despite values indicating could favour mussel growth given high fatty acid content reported haptophytes.