How does water density affect plankton?

Water density affects plankton by influencing their buoyancy and vertical positioning in the water column. Denser water can create stratification, leading to distinct layers where certain plankton species thrive, as they may be better adapted to specific densities. Additionally, changes in water density due to temperature or salinity can impact nutrient availability and light penetration, further affecting plankton distribution and productivity. This, in turn, has implications for the entire aquatic food web, as plankton are foundational to marine and freshwater ecosystems.