THE ROLE OF PLANKTONIC BACTERIA IN PHOSPHORUS CYCLING IN LAKES - SINKAND LINK

Due to their high P content (approximately 10 times that of the algae) , the bacteria in Lake Nesjovatn were responsible for 80% of the net u ptake of this element in summer. Thus, the heterotrophic bacteria acte d as a sink and competed for inorganic phosphate with the algae, but t he bacteria were unable to achieve physiological P saturation. Heterot rophic flagellates feeding on P-rich bacteria regenerated two-thirds o f the P released by grazers. Therefore the role of bacteria is not as mineralizers but as net consumers of phosphate, and, because of their high requirement for P, they are a key factor in regulating the P flux in lakes. The main importance of bacteria in regeneration of P is as P-rich food particles.