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

Abstract

Colonies of Pharocjstis sp. (Ilaptophyceae] isolated from the North Sea accumulated manganese during incubation of 15 d in a culture medium with near-natural (0 45 Umol l' 1:ln) conccntratlon When maximum cell density was reached, up to 75'1L of the manganese originally present in the medium was found in the colonies; the amount of manganese in the single cells remained at a constant level of about 7% Bio-accumulation of manganese in the mucous colonies appeared to be an indirect process: photosynthesis induced a pH above 9 inside the colonies - high enough for the transition of soluble Mn2 to insoluble Mn-oxides. The role of Phaeocystis colonies in the cycling 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.