The dynamics of bacterioplankton versus resources of organic carbon in the heated Konin lakes

Abstract

This study demonstrates the significant effect of the thermal regime of the Konin lakes on the structure of bacterioplankton and the concentration of heteromorphic organic matter. Seasonal differentiation in the maximum concentrations of POC and DOC should be considered the most typical trait of the lakes examined. The dynamics of POC were characterized by the occurrence of maximum concentrations in the fall period of temperature decrease. Intensive lysis of dead hydrobionts was the main factor determining this phenomenon. The substantial decline in the DOC pool, occurring in the same period, was determined by the intensive course of microbiological processes of biotransformation. In contrast, the spring maximum of DOC was mainly linked with the occurrence of mass alga blooms and inflows of allochthonous matter. The response of bacterioplankton to changes in the thermal regime of waters was characterized by a high dependency between the number and temperature and the morphological structure and concentration of DOC. High correlation coefficients were obtained in both cases.

CORRESPONDING AUTHOR:

Aleksander Świątecki, Uniwersytet Warmińsko-Mazurski, Zakład Mikrobiologii, ul. Oczapowskiego 1A, 10-957 Olsztyn; Tel./Fax: +48 89 5234428; e-mail: aswiat@uwm.edu.pl