A COMPARISON OF PHYTOPLANKTON BIOMASS ESTIMATORS AND THEIR ENVIRONMENTAL CORRELATES IN THE MALI-STON BAY (SOUTHERN ADRIATIC)

Phytoplankton biomass estimators - total cell number (CN), total cell volume (CV), chlorophyll a (Chl a), phytoplankton organic carbon (PC), and their response to environmental variables, with a special emphasi s on the vertical variability in the structure of the water column - w ere examined in the Mall Ston Bay (Southern Adriatic). Correlations am ong biomass estimators as well as with physical-chemical parameters va ried according to hydrodynamic characteristics of the water column. Th e amount of Chl a per cell ranged from 0.28-0.6.10(-6) mu g during str atification to 0.7-2.0.10(-6)mu g during the mixing period. Most frequ ent values for PC/Chl a ratios and for Chl a/CV in mixed natural phyto plankton populations were 20-25 and 1-2, respectively.