Chemical composition of the top-layer bottom deposits from underneath assemblages of the subtropical species Vallisneria spiralis L. in the phytolittoral zone of two heated lakes [SHORT COMMUNICATION]

Abstract

The chemical composition of the top-layer bottom deposits in littoral was determined in areas of the phytolittoral zone dominated by Vallisneria spiralis L. in Lakes Licheńskie and the Ślesińskie, two heated lakes in central Poland. The lakes differ in terms of water temperature and seasonal patterns in water temperature. The chemical composition of leaves of V. spiralis and the periphytic algae growing on them was also determined. The main component of the littoral sediments was silica, comprising from 80.9 to 93.7% SiO₂ d.w. from Lake Licheńskie, and 89.3 to 93.8% SiO₂ d.w. from Lake Ślesińskie, calcium content ranged from 3.0 to 8.1% d.w., and from 1.5 to 3.7% d.w., respectively. Organic matter content was low and ranged from 0.6 to 4.2% d.w. in sediments from Lake Licheńskie, and from 0.6 to 2.5% in sediments from Lake Ślesińskie. Chemical analysis of leaves of V. spiralis revealed that the leaves and the algae growing on them were far more encrusted with calcium carbonate at Lake Licheńskie than in Lake Ślesińskie. The calcium carbonate encrusting the leaves of V. spiralis in Lake Licheńskie was deposited as the result of biological decalcification, in which the periphytic flora plays a key role.

CORRESPONDING AUTHOR:

Andrzej Hutorowicz, Instytut Rybactwa Śródlądowego, Zakład Hydrobiologii, ul. Oczapowskiego 10, 10-719 Olsztyn, Poland; Tel./Fax +48 89 5240171 +48 89 5240505; e-mail: ahut@infish.com.pl