Seasonal Variations of Water Quality Parameters and Algal Flora of Tundzha(Tunca)River(Edirne,Turkey)

In this study which was performed in order to determine the seasonal variations of water quality parameters and algal flora of Tundzha River, samplings were made monthly from 5 different stations along the river. A total of 138 taxa from Chlorophyceae (65 taxa), Bacillariophyceae (46 taxa), Euglenophyta (13 taxa) and Cyanophyta and Charophyta (7 taxa) were found to represent the algal flora of the river. Diatoms were recorded to be the dominant group throughout the year in terms of biovolume. Station I was the richest station during the whole study in terms of species diversity and composition. The maximum abundance of phytoplanktonic community within this station was 3,459,313 cells.L-1, and Station IV was found to be richest station in terms of biovolume, with 2028.8 μg.L-1. The water quality of the river was found to be close to the 2nd and 3rd quality levels. 2nd and 3rd, and 1st and 3rd stations were found to be most similar to each other in terms of floristic compositions biovolume, respectively.

Compound-specific δD and its hydrological and environmental implication in the lakes on the Tibetan Plateau

The hydrogen isotopic composition(δD) of n-alkanes in lacustrine sediments is widely used in palaeoenvironmental studies, but the heterogeneous origins and relative contributions of these lipids provide challenges for the interpretation of the increasing dataset as an environment and climatic proxy. We systematically investigated n-alkane δD values from 51 submerged plants(39 Potamogeton, 1 Myriophyllum, and 11 Ruppia), 13 algae(5 Chara, 3 Cladophora, and 5 Spirogyra) and 20 terrestrial plants(10 grasses and 10 shrubs) in and around 15 lakes on the Tibetan Plateau. Our results demonstrate that δD values of C_(29) nalkane are correlated significantly with the lake water δD values both for algae(R^2=0.85, p<0.01, n=9) and submerged plants(R^2=0.90, p<0.01, n=25), indicating that δD values of these algae and submerged plants reflect the δD variation of lake water. We find that apparent hydrogen isotope fractionation factors between individual n-alkanes and water(εa/w) are not constant among different algae and submerged plants, as well as in a single genus under different liminological conditions, indicating that the biosynthesis or environmental conditions(e.g. salinity) may affect their δD values. The δD values of submerged plant Ruppia in the Xiligou Lake(a closed lake) are significant enriched in D than those of terrestrial grasses around the lake(one-way ANOVA,p<0.01), but the algae Chara in the Keluke Lake(an open lake) display similar δD values with grasses around the lake(one-way ANOVA, p=0.826>0.05), suggesting that the n-alkane δD values of the algae and submerged plants record the signal of D enrichment in lake water relative to precipitation only in closed lakes in arid and semi-arid area. For each algae and submerged plant sample, we find uniformed δD values of different chain length n-alkanes, implying that, in combination with other proxies such as Paq and Average Chain Length, the offset between the δD values of different chain length n-alkanes can help determine the source of sedimentary n-alkanes as well as inferring the hydrological characteristics of an ancient lake basin(open vs closed lake).