Author/Editor		Muri, Gregor; Simčič, Tatjana
Title		Respiratory activity in sediments of three mountain lakes in Julian Alps and in subalpine lake Bled (Slovenia): effects of altitude and anthropic influence
Type		članek
Source		Aquat Microb Ecol
Vol. and No.		Letnik 34
Publication year		2004
Volume		str. 291-9
Language		eng
Abstract		Respiratory activity in sediments was studied in 3 Siovenian mountain lakes and 1 subalpine Iake. Electron transport system (ETS) activity was measured in the sediments to assess the potential mineralisation of organic matter (OM), while oxygen consumption rate (R), induced under laboratory conditions, was used to asses the actual mineralisation of OM in these sedimenis. The Lakes are situated at different altitudes, with different water temperatures. They also have different trophic status. It was found that higher lake water temperatures and more productive lakes, having higher contents of labile autochthonous OM, caused higher microbial respiratory activity, reflected in higher ETS activities and R. Subsurface peak values of ETS activity and R were observed in lhe mountain lakes, most probably indicating slower degradation of OM; in particular, the more refractory terrestrial OM, and the presence of anaerobic microorganisms. In the case of ihe lowland eutrophic Lake Bled, no such distribution was observed. In this Iake, OM is effectively degraded in the water column and surface sedimenis due to high lake water temperatures and high content of autochthonous OM. A high correlation between ETS activity and R was observed in ail the sediments, while correlations between ETS activity and organic carbon (OC) concentration, and between R and OC concentration were lower.
Descriptors		FRESH WATER ELECTRON TRANSPORT OXYGEN CONSUMPTION TEMPERATURE EUTROPHICATION CARBON