Experimental Approach to a Lake Ecosystem Assessment in the Great Lota, Turkey

Experimentally selected from the benthic communities the cells of diatoms at one station of the karstic Great Lota
Lake were used for assessment of the lake ecosystem dynamic in 2000-2001. Each in vitro experiment was about 15
days after the monthly sampling. A total of 48 diatoms taxa were identified in 19 samples, and used for ecological
analysis by statistic methods. Bio-indication groups of temperature, habitat preferences, oxygenation, organic
pollution (according to Sládeček and Watanabe’s saprobity system), N-uptake metabolism, and trophic states were
evaluated. The saprobity indices and new integral aquatic ecosystem state index (WESI) were calculated. As a result,
experimentally selected diatoms from the lake benthos reflects temperate, low-saline, and alkaline water. The
saprobity is oligo- and betamesosaprobic when the trophic state is eutrophic according to Van Dam’s system. Living
diatom communities with prevailing of moving cells of Mastogloia species are formed two major groups – winter
and summer, which depend on climatic or anthropogenic environmental conditions. Mastogloia species can be used
as special indicator for sulfates in arid lakes monitoring. Experimental assessment was compared with the same
assessment on the base of whole benthic diatoms, and show preference to the living cells communities assessment
for following monitoring.