What does salinity refer to in aquatic ecosystems?

Salinity refers to the concentration of dissolved salts in water, which is a critical factor in aquatic ecosystems. It influences various biological and chemical processes, including the types of organisms that can inhabit a particular environment. For example, organisms in freshwater systems, like rivers and lakes, are adapted to lower salinity levels, while those in marine environments, such as oceans and seas, thrive in higher salinity conditions.

Salinity affects the density of water, impacting buoyancy and circulation patterns, which can further influence the distribution of nutrients and organisms within an aquatic ecosystem. Understanding salinity is essential in environmental science, especially when studying habitats, species distributions, and the impacts of human activities on water quality. This central concept is vital in both freshwater and marine contexts, shaping the ecological dynamics of these environments.