What term defines a habitat where freshwater meets saltwater?

The term that defines a habitat where freshwater meets saltwater is an estuary. Estuaries are dynamic environments typically found at the mouths of rivers, where the influx of freshwater from the river mixes with the saltwater from the ocean. This mixing creates unique ecological conditions that support a diverse range of plant and animal species adapted to fluctuating salinity levels.

Estuaries play a crucial role in the lifecycle of many marine species, providing essential nursery habitats for fish and other aquatic organisms. They also serve important functions for human communities, including filtering pollutants, acting as buffers against storms, and providing recreational opportunities. The combination of nutrients from freshwater and the salinity from the ocean leads to high productivity, making estuaries some of the most biologically rich ecosystems on Earth.

Understanding the significance of estuaries is vital in oceanography and conservation, as they face threats from pollution, habitat destruction, and climate change.