Carbon dynamics in a heated water system (Wielkopolsko-Kujawskie Lake District, Poland)

Abstract

The aim of the study was to examine the spatial and seasonal variability, and the dynamics of organic carbon compared to the hydrochemical parameters, and subsequently, to determine the productivity of the waters included in the cooling system of two power plants. The results of the study revealed obvious differences in the content of dissolved (DOC) and particulate (POC) fractions of organic carbon in the whole system of heated waters. The dominant form was DOC (mean 6.7 mg C l-1) comprising 67% of TOC. Intensive primary production occurred as early as spring, which was shown by the high amount of easily available organic matter (high DOC concentrations and simultaneously low SUVA260 values), and by the statistically significant relationship between POC and organic phosphorus, and BOD5 and seston. In spring, the process was additionally favored by elevated water temperature and the enzymatic activity of the bacterioplankton, shown by the significant relationship between total bacterial count (TBC), DOC, and SUVA260. In summer, the dynamics of organic carbon were lower compared to those in spring; the cooling system waters were abundant in organic matter unavailable to bacteria, as shown by the high value of SUVA260. The amount and quality of organic matter in the cooling system waters were also determined by abiotic factors. The phenomenon of simultaneous precipitation of phosphate and iron on the humic complexes was observed in the near-bottom waters of Lake Licheńskie.

CORRESPONDING AUTHOR:

Julita Dunalska, Uniwersytet Warmińsko-Mazurski, Katedra Inżynierii Ochrony Środowiska, ul. Prawocheńskiego 1, 10-957 Olsztyn, Tel./Fax: +48 89 5234259, e-mail: julitad@uwm.edu.pl