Nutrient composition and physicochemical characteristics in the destination sites of migratory water birds: a case study at the selected locations of seashores and lakes in southern India

The biodiversity in aquatic systems are indirectly controlled by their nutrient dynamics. The abundance of phytoplanktons and zooplanktons depends on the availability of nutrients such as nitrates, phosphates and silicates since these are the building blocks for their further growth. The phytoplanktons act as prey for the next higher trophic level including various fishes and other small organisms. One of the factors that enchant the migratory birds at some particular locations is the availability of the species of organisms that they prey on. In this paper a preliminary analysis is done to explore the nutrient dynamics of selected tropical aquatic systems in order to correlate the arrival of migratory birds at those locations. Water samples are collected from coastal region of Aleppey, Purakkad and Koonthankulam Bird Sancturay. The latter two sites are the important destination of many migratory water birds including Pallus Gull, Heuglins Gull, Bar-headed goose, Comb Duck and Spot Billed Pelican. The samples are analyzed chemically to trace the nutrient compositions and the related chemical parameters such as temperature, pH, conductivity, primary productivity, chloride, salinity, turbidity, nitrate, phosphate, dissolved oxygen and biochemical oxygen demand. Remarkable differences are observed mainly in the composition of phosphate, organic matter content and salinity. Finally, an attempt has been done to correlate the biodiversity of these locations with the chemical parameters and the prevailing nutrient compositions.