WHITING EVENTS - BIOGENIC ORIGIN DUE TO THE PHOTOSYNTHETIC ACTIVITY OF CYANOBACTERIAL PICOPLANKTON

An annual whiting event occurs each year in late May to early June in Fayetteville Green Lake, New York. The initiation of this event correl ates with exponential growth of the Synechococcus population within th e lake. Synechococcus is the dominant (by similar to 4 orders of magni tude) autotrophic organism owing to the oligotrophic condition of the lake. The delta(13)C values of the dissolved inorganic C range seasona lly from -9.5 parts per thousand in winter to -6.2 parts per thousand in summer due to photosynthetic activity. Calcite precipitates princip ally in the microenvironment surrounding Synechococcus because of a ph otosynthetically driven alkalization process and the availability of t he cells as nucleation sites. This calcite has a heavier delta(13)C va lue (>4 parts per thousand) than does the dissolved inorganic C of the lake water owing to the cells preferential uptake of C-12. A conceptu al model suggests that photosynthetic activity and cell surface chemis try, together with the substantial surface area that arises from the g reat abundance of micron-sized cells, allow Synechococcus to dominate the annual whiting events in Fayetteville Green Lake.