Phytoplankton samples (n= 2,217) from the Gulf of Riga, Gulf of Finland and Archipelago Sea have been analyzed to investigate whether the presence/absence of species or genera changes could be related to nutrient levels. A total of 76 phytoplankton taxonomic units (identification on either species or genus level), being present in at least 5% of all samples, were examined and the presence of species/genera was modeled by means of response surfaces describing the probability of a specific species/genus being present in a sample as function of the month of sampling, salinity and TN, TP or N/P ratio. Specific response surfaces and seasonal patterns for each of the investigated taxonomical units are given below.
The method and results are described in detail in Carstensen & Heiskanen (in press) “Screening method for phytoplankton indicator species of nutrient status: application to the Baltic Sea ”. Marine Ecology Progress Series. For use of the species-specific graphs please make reference to the article in MEPS.