The numerical and proportional distributions of benthic macroinvertebrates in Tunca (Tundja, Tundzha) River (Edirne/Turkey) were determined from July 2002 to June 2003 at monthly intervals at four different stations. It was found that the benthic macrofauna consisted of 63% Oligochaeta, 24% Chironomidae larvae, and 13% Varia by numbers. According to the Shannon-Wiener index, Tunca River had a diversity of 1.36; station 2 and September were found to have the highest diversity while station 4 and December to have the poorest. According to Bray-Curtis similarity index, stations 2 and 3 and April and May were found to be the most similar to each other while stations 1 and 4 and August and January were found to be the most different from each other for the dynamics of the benthic macrofauna. Also some physicochemical parameters of the water (water temperature, electrical conductivity, pH, dissolved oxygen, chloride, total hardness, NO 3 --N, NO 2 --N, sulfate, phosphate, biochemical and chemical oxygen demands) were analyzed. Pearson correlation index supported the relationships between the dynamics of organisms and physicochemical variables. The relation between the number of macroinvertebrates and pH (r = +0.57, P a 0.05) was direct proportional while the relation between the number of macroinvertebrates and NO 3 --N (r = -0.99, P a 0.05) was inverse proportional. Furthermore, the Chironomidae larvae of Bryophaenocladius muscicola and Mesosmittia flexuella were new records for Turkish Thrace region. High pH and supersaturated oxygen levels, hard water quality, second quality levels of NO 3 --N, BOD, COD and fourth quality levels of NO 2 --N as well as the density of 490 individuals m -2 for 124 taxa and the diversity of 1.36 showed that similar studies should be repeated periodically in Tunca to determine the future of the river.

In order to determine the relationships between the dynamics of benthic macroinvertebrates (both species number and individual number) and environmental variables, sampling was made at four different stations at monthly intervals during a year between March 2004 and January 2005 of Lake Gala which is a part of an important wetland and a national park in European part of Turkey (Enez/Edirne). Altogether, a total of 49 zoobenthic taxa which were grouped as "Oligochaeta", "Chironomidae", and "Varia", comprised of 1,628 individuals in per m 2 at average were recognised in the sampling stations of the Lake. The present study showed that larval chironomids comprising 57% abundance of the total specimens are the biggest part of benthic macroinvertebrates. It is followed by oligochaetes and the group varia comprising 34% and 9% abundance, respectively. Also, it was seen changing that the composition of zoobenthic group dominancy in the Lake as time passes.Furthermore, according to Shannon-Weaner index, species diversity for zoobenthic macroinvertebrate fauna of the lake was found as H'=1.21 at average. Also, similarities of the sampling stations and months, both the dynamics of benthic macroinvertebrates and physicochemical features were evaluated by using Bray-Curtis similarity index.According to Spearman correlation index, relationship between the number of individuals and some physicochemical variables such as temperature, turbidity (light permeability), and depth of the lake was determined statistically significant.

It is generally thought that the seasonal succession of phytoplankton is minimized during winter months. However, some studies have indicated that there is also diversity in phytoplankton communities in winter. The main purpose of this study was to determine the phytoplankton community structure and species composition of a lake during winter, when covered with ice. Phytoplankton samples from the lake were taken in the winter seasons of 2015 and 2016, during the period from the appearance of the ice cover on the lake until it completely melted, and phytoplankton composition in the lake and some physicochemical properties of the lake water were measured. The phytoplankton community was found to be dominated by Cyclotella meneghiniana, which is a centric diatom, followed by the flagellates, especially Synura uvella, small cryptophytes (Cryptomonas paramecium), dinoflagellates (Peridinium aciculiferum and Gymnodinium sp.), and nonfilamentous greens (Pediastrum duplex, Scenedesmus spp., and Monoraphidium spp.). Phytoplankton development under ice-cover is largely related to temperature, but the development of phytoplankton composition is random. A low correlation was determined between the dominant organisms and ice thickness. Species biodiversity was low, but the dominant species started to be represented with different taxonomic groups after midwinter .

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Larval chironomids feed on algae, diatomae, detritus, decaying plant and animal fragments. The larvae in turn are food for other carnivore and omnivore animals. Thus, larval chironomids have a very important role in the aquatic food cycle. In this study, the algal flora in the stomachs of Tanypus punctipennis, which is known as a very common species in Turkish Thrace, was examined in terms of qualitative and quantitative factors. It was found that Bacillariophyta was the dominant group with 42 taxa in the stomach of T. punctipennis. It was followed by Cyanophyta with 3 taxa, Euglenophyta with 6 taxa, Chlorophyta with 4 taxa, Carophyta with 2 taxa, and Rhodophyta with 1 taxa.