The answers were provided by U.S. Navy oceangraphers.
Estuaries provide a habitat where numerous fish and crustaceans breed.
Estuaries act as a filtration system for impurities from the inland waters before they reach the ocean. Life at these depths utilize the chemicals produced at the vents for their source of nutrition. The animals are all blind because sight is not necessary. They rely on other senses. However, scientists across the world have categorized over 25,000 species of fish alone.