Manganese accumulation in the high pH microenvironment of Phaeocystis sp. (Haptophyceae) colonies from the North Sea

Colonies of Pharocjstis sp. (Ilaptophyceae] isolated from the North Sea accumulated manganese during ~ncubati.on of 15 d in a culture med~um w ~t h near-natural (0 45 ~rmol l ' 1:ln) conccntratlon When maximum cell density was reached, u p to 75'1L of the manganese originally prcsrnt in the medium was found in the colonies; the amount of manganese in the single cells remained at a constant level of about 7 '%B. Bio-accun~ulation of manganese in the mucous colonies appeared to be an indirect process: photosynthesis induced a pH above 9 inside the colonieshigh enough for the transition of soluble ~n ' ' to insoluble Mn-oxides. The role of Phaeocystis colon~cs in the qcling and transport of manganese in the North Sea can be expected to be important in view of their dominance in the phytoplankton, especially during spring.