Investigating Summer Dynamics of the Nutrients in Lake Aktas (Ardahan) Surface Water, Using Geographic Information Systems

Abstract

Lake Aktas is a tectonic lake with a total surface area of 25.5 km(2) (11.7 km(2) in Ardahan, Turkey; 13.8 km2 in Georgia). This study investigated water quality of the lake, a crucial element in protecting the ecological characteristics of a lake, and ensuring its sustainable use. The study involved use of Geographical Information Systems software to analyze the temporal and spatial changes in nutrient element concentrations that may deteriorate water quality and ecological characteristics of the lake. In the framework of the study, surface water samples were collected on the Lake Aktas in June, July, and August 2014 from nine stations selected at intervals in accordance with spatial analysis. The collected samples were measured for temperature, pH, dissolved oxygen, ammonium nitrogen, nitrate nitrogen, nitrite nitrogen, and orthophosphate. The obtained results were compared with the concentrations specified in Surface Water Quality Management Regulation published by the T. R. Ministry of Agriculture and Forestry. According to the findings, surface water classification and distribution for Lake Aktas included the following categories class I ( WS-I/natural) in terms of oxygen, ammonium, and nitrate nitrogen, and class II (WS-II/undeveloped) in terms of nitrite. It was found that ammonium and phosphate levels have considerably increased in the last ten years, based on the comparisons made with the study sampled in Aktas Lake during 2004-2005 (Ozbay and Kilinc 2008).