Investigations on the phytoplankton composition and trophic status of Lake Karagöl (Dikili-İzmir-Türkiye)
Diğer yayınlar > Diğer · 2024
Yazarlar: Sömek, Haşim, Esat Tarık TOPKARA
Diğer, Uluslararası, 2024,
Özet
The phytoplankton composition, TN:TP ratios as the limiting factor on phytoplankton and the trophic Status of Lake Karagöl, a small volcanic-originated lake, were first investigated in this study. Additionally, the physicochemical parameters of the lake were measured. As a result of the investigations, 21 dominant taxa from four divisions among phytoplanktonic organisms were identified in Karagöl. Three taxa belonged to Cyanobacteria, eleven to Chlorophyta, six to Ochrophyta (only Bacillariophycea), and to one to Myzozoa. The average depth of the lake was calculated as 8.7 m. In line with the atmospheric temperatures brought by the Mediterranean climate prevailing in the region, surface water temperatures of the lake fluctuated between 23.0 °C (summer) and 6.5 °C (winter). Conductivity ranged from 780 to 423 µS and dissolved oxygen ranged from 15.3 to 7.3 mg l-1. The average scores of TSI (SD), TSI (Chl-a), TSI (TN) and TSI (TP) were calculated as 68.0, 55.1, 62.1 and 86.4 respectively. These TSI scores indicated that Lake Karagöl was at eutrophic or hypereutrophic levels. TN:TP ratio of the lake ranged from 9.8 to 7.2 and in this case, the Lake Karagöl food chain is nitrogen-limited because of the low TN:TP ratios. Dolichospermum flosaquae (N2-fixing heterocystous Cyanobacteria) was the dominant species in Lake Karagöl phytoplankton during the summer months when the high-water temperature. As a result of this study, based on phytoplankton composition, dominant algae groups (especially Cyanobacteria) and TSI scores, it was evaluated that Lake Karagöl (Dikili) has suitable environmental conditions for many algae species found in mesotrophic and eutrophic lakes and is in a very rapidly progressing hypertrophication process.