Aquatic macrophytes of Sapanca Lake and their relationships with water quality

Aquatic macrophytes, one of the most important components of the lake littoral zones, have an important role in a healthy aquatic ecosystem affecting water quality directly and indirectly. Aquatic macrophytes are the ideal biological monitoring tools thanks to their long life span and abundances. Sapanca Lake, which is used as drinking water source for Adapazarı and Kocaeli provinces, is also used for socio-economic purposes such as irrigation water source in agriculture, sports and commercial fishing, recreation and irrigation area. The aim of this study, carried out in the coastal areas of Sapanca Lake between February 2017 and November 2017, was to identify underwater macrophytes and to reveal the relationship with water quality parameters. During the study period, seasonal variations of species composition, density, distribution, species diversity and richness of submerged macrophytes were determined and their relationships with the main environmental parameters were investigated. In this study, seven species of the submerged macrophytes; Myriophyllum spicatum, Ceratophyllum demersum, Elodea canadensis, Najas minor, Chara sp., Potamogeton perfoliatus and Potamogeton lucens were found in the Lake. The presence of E. canadensis in Sapanca Lake as an alien and invasive species was reported firstly. The presences of the identified species were different according to the seasons and stations through the study. There are no records of aquatic submerged macrophyes in the winter season. Water temperature is determined as a primary and effective factor in the seasonal differences of the macrophytes development in this study and also water temperature showed a strong positive relation with the macrophytes abundance. Seasonal biomass of the macrophytes in Sapanca Lake were increased in the spring season (3568 g/m2) as parallel to the water temperature incensement and reached its maximum (5335 g/m2) in the summer season. Macrophyte abundance was recorded as 2733 g/m2 in the autumn period. P. lucens was determined as the dominant species in three seasons and constituted 66 % of the total biomass. In general, species diversity was recorded as low values (<1); these values are due to the dominancy of the Potamogeton (66 %) mostly and Chara (15 %) sometimes.