PHYTOPLANKTON CELL-SIZE AND THE DEVELOPMENT OF MICROENVIRONMENTS

The effect of cell size on the development of extracellular microenvir onments of pH produced by individual photosynthesizing phytoplankton c ells was investigated. The presence of pH microenvironments was determ ined by detection of a chemical reaction known to occur in microenviro nments of high pH produced by algal photosynthesis, specifically the e xtracellular oxidation of Mn(II) to MnOx. The dye leukoberbelin blue w as used to detect the reaction. It was experimentally determined that individual algal cells larger than 20 mu m (length and/or width) produ ced microenvironments, while smaller cells did not unless present as c ell aggregates larger than 20 mu m. A mathematical model is presented and discussed.