STUDIES ON TRANSPARENT EXOPOLYMER PARTICLES (TEP)-PRODUCED IN THE ROSS SEA (ANTARCTICA) AND BY PHAEOCYSTIS-ANTARCTICA (PRYMNESIOPHYCEAE)

The distribution and production of transparent exopolymer particles (T EPs) were studied quantitatively both in cultures of Phaeocystis antar ctica Karsten (Prymnesiophyceae) and in natural phytoplankton assembla ges in the Ross Sea, Antarctica. TEP production in culture was a funct ion of growth rate and photosynthetic activity and was strongly influe nced by photon flux density. The concentrations of TEP measured during a bloom, dominated by P. antarctica, were higher than those produced by coastal diatom blooms and were correlated with chlorophyll a (Chl a ), being low at Chl a levels below 3 mu g.L-1 but increasing rapidly a t greater Chl a concentrations. Because higher chlorophyll levels are dominated by larger P. antarctica colonies, this relationship suggests that TEP was produced primarily by sloughing and disintegration of th e colonial matrix. TEP concentrations (both absolute and relative to C hl a) increased as the bloom's biomass increased. Vertical distributio ns of TEP and Chl a showed TEP: chlorophyll maxima at the bottom of th e water column at most stations. Because TEP and floc formation are ti ghtly coupled, we suggest that mucous flocs derived from TEP, rather t han intact P. antarctica colonies, are the dominant component of aggre gates and subsequent organic carbon vertical flux.