The biome that contains both freshwater and saltwater is known as an estuary.
Estuaries are unique ecosystems where rivers meet the ocean, creating a brackish water environment that is a mix of fresh and saltwater. This blending occurs at the mouth of rivers, where freshwater from rivers and streams flows into the ocean’s saltwater. This transitional zone is incredibly productive and supports a diverse range of plant and animal life.
In an estuary, the salinity levels can vary significantly due to tides, weather conditions, and the amount of freshwater flowing into the system. The varying salinity creates a unique habitat that is home to various species such as fish, birds, and plants adapted to this unique environment.
Additionally, estuaries serve as crucial nurseries for many marine species, providing safe havens for young fish and invertebrates. They also play an essential role in filtering pollutants, protecting coastal areas from erosion, and providing recreational and economic opportunities for nearby communities.