Speaker
Description
This study examines the organic matter content of bottom sediments collected from five selected locations along the Struga shoreline of Lake Ohrid, with the objective of identifying its potential sources. Organic matter in lake sediments is an important indicator of ecosystem productivity, sedimentary processes, and anthropogenic influence1,2. Each sampling location comprised five sampling points situated at distances of 5, 10, 15, 20, and 25 m from the shoreline. Total organic matter content was determined using the loss-on-ignition (LOI) method through gravimetric analysis, with sediment samples combusted at 600°C for 1 hour. In parallel, sediment moisture content was measured to assess the primary medium associated with organic matter accumulation. The results revealed substantial spatial variability in organic matter content, ranging from 5.54% to 16.17% across all samples. Comparison of moisture and organic matter data suggests that organic matter is predominantly associated with the water-rich fraction of the sediment, while a smaller proportion is adsorbed onto mineral particles. Elevated organic matter concentrations were observed at sites exposed to pronounced anthropogenic influence or to a combination of natural and anthropogenic factors.
The highest values were recorded near the mouth of the Sateska River, indicating that the river is a significant source of organic matter entering Lake Ohrid. This pattern is most likely related to the transport of organic pollutants and other anthropogenic inputs originating from the Sateska River catchment.
Keywords: Organic matter, lake sediment, Lake Ohrid, anthropogenic impact
References:
- Robert G. Wetzel (2001). Limnology: Lake and River Ecosystems (3rd ed.). Academic Press.
- Philip A. Meyers & Ryo Ishiwatari (1993). Lacustrine organic geochemistry—an overview of indicators of organic matter sources and diagenesis in lake sediments. Organic Geochemistry, 20(7), 867–900.