Brackish water is a mixture of fresh water and salt water, typically found in areas where rivers meet the sea, such as estuaries. This type of water has a higher salinity than fresh water but lower salinity than seawater. Brackish environments support unique ecosystems and are home to various species of plants and animals that can tolerate these varying salinity levels. Common examples of brackish water habitats include mangroves, salt marshes, and estuaries. These areas are crucial for biodiversity, serving as nurseries for many marine species, including fish and crustaceans. Brackish water is also important for human activities, such as aquaculture and recreational fishing.