DETERMINATION OF TOTAL ORGANIC CARBON AND TOTAL NITROGEN FROM SOIL SEDIMENTS FROM HORIA LAKE, TULCEA
ADINA POPESCU, MIRELA CRETU, ANGELICA DOCAN University of "Dunarea de Jos" Galati, Faculty of Food Science and Engineering, Department of Food Science, Food Engineering, Biotechnology and Aquaculture, e-mail: adina.popescu@ugal.ro; mirela.cretu@ugal.ro; adocan@ugal.ro
Carbon and Nitrogen have an important role in maintaining trophic levels in lake ecosystems and can be used us pollution indices, soil quality and productivity indicators. In this context, the aim of this research was to determine the total organic carbon (TOC), total nitrogen (TN) and the carbon - nitrogen ratio (C/N) from the sediment samples collected from lake Horia, Tulcea county, Romania. The lake is located in the area of Horia, being limited to the north, west and south by the agricultural field, and the eastern limit is represented by the intercounty road 222 A. The surface of the lake is 230 ha, and the depth varies between 0.5 - 1 m in summer time in the foot rope zone; the maximum depth is 3.962 m in the dam area. The incline of the ground permits the accumulation of the waters from the versants adjacent to the lake, with suspension contributions, fertilizers and herbicides used for the adjacent corn crop. The samples were collected in the autumn season, from six stations of the lake and the sediment TOC and TN contents were measured using PrimacsSLC and PrimacsSNC Analyzer, from the laboratory of Romanian Center for Modelling Recirculating Aquaculture Systems, University Dunărea de Jos, Galaţi. The higher values of TOC and TN were registered at station 3 (TOC = 2.53 ± 0.18%; TN= 0.67 ± 0.02%). The C/N ratio registered values between (3 - 9) indicating a source of protein rich, lignin poor organic matter sourced from phytoplankton (lake sourced algae).
