Determination of nutrient status of çardak lagoon (Lapseki, Çanakkale, Turkey) phytoplankton through an analysis of seasonal changes in C: N: p ratios

The ratios of the main elements such as carbon (C), nitrogen (N) and phosphorus (P) in the biomass differs among various organisms and may lead to the potential limitation of biological production in ecosystems. All organisms have a set of nutritional requirements for their metabolism and growth. A balanced and optimum diet determines growth efficiency and the diets are said to be more balanced when their composition is close to the composition of the consumer. The position of phytoplankton at the base of aquatic food webs makes the cellular elemental composition of phytoplankton important for the food web efficiency of aquatic ecosystems. While the variation in the concentrations of dissolved nutrients in water may cause algal blooms and associated changes in the environment a deficiency in the amount of concentrations or in the proportion of them may limit primary production. In this completed Msc project on nutrient status of phytoplankton community of Çardak Lagoon (Lapseki, Çanakkale), which is an important shelfish and fin fish area and also has been given ?highly protected area? status by Edirne District Cultural and Natural Heritage Protection Body, was investigated through analysis of amounts and ratios of dissolved nutrients and particulate C, N and P in phytoplankton biomass over a seasonal cycle. The results showed that lagoon was enriched with nitrogen but phosphorus was in short supply in both dissolved and particulate fractions in respect of phytoplankton growth requirements. Thus analysis of nutritional status of phytoplankton revealed that phosphorus was the limiting nutrient on phytoplankton growth and phytoplanton constitutes a low quality food resource in terms of phosphorus content for consumers at the upper trophic levels of the food web of the Çardak Lagoon.