Caspian Sea

The salinity of the Caspian Sea is one of its [blank] intriguing aspects, with levels significantly lower than that of the world's oceans, averaging about one-third the salinity of seawater. This reduced salinity is due to the large volume of fresh water it receives from rivers, particularly the Volga, which [blank] contributes about 80% of the incoming water. However, the Caspian Sea's salinity is not [blank] throughout; it varies from north to south, being lower in the northern parts due to the greater influx of river water and higher in the southern parts due to higher evaporation rates. These differences in salinity [blank] the distribution of marine life and the ecological balance of the Caspian basin, making it a unique environment for researchers studying the impacts of salinity on aquatic ecosystems.