Phytoplankton and environmental drivers at a long-term offshore station in the northern Adriatic Sea (1988-2018)
Francesca Neri; Tiziana Romagnoli; Stefano Accoroni; *; Alessandra Campanelli; Mauro Marini; Federica Grilli; Cecilia Totti;
A long term (1988-2018) data set of phytoplankton and physico-chemical parameters was analyzed for the first
time in an offshore station of the LTER Senigallia-Susak transect (northern Adriatic Sea) not directly affected by
the coastal nutrient input. The mean annual cycle of phytoplankton markedly differed from that observed in the
coastal areas, showing the maximum in June and the minimum in November. The main component of phytoplankton
community was represented by phytoflagellates, whose trend paralleled that of total phytoplankton.
On average, diatoms peaked in July, dinoflagellates in June and coccolithophores in April. The phytoplankton
maximum in summer is explained mainly by the allochthonous input of DIN and PO4 carried by the low salinity
waters expanding eastward, during the stratification of water column. Resuspension processes seem to be less effective
for PO4 than for DIN. The most representative phytoplankton taxa for each season as indicated by the Ind-
Val analysis were identified and were only in part similar to those observed in the coastal area. The interannual
anomaly trend showed a significant increase of temperature, DIN and phosphates. Although no significant
changes were found for the total phytoplankton, a reduction of winter dinoflagellate and coccolithophore abundances
was observed.
2022 - Journal article
Continental shelf research (2022). doi:10.1016/j.csr.2022.104746
Keywords: PhytoplanktonInterannual variability, LTER-Long-term ecosystem research, Biological oceanography, Biodiversity