Eventually the water from Lake Okeechobee and The Big Cypress makes its way to the ocean. Mangrove trees are well adapted to the transitional zone of brackish water where fresh and salt water meet.[72] The estuarine ecosystem of the Ten Thousand Islands, which is comprised almost completely of mangrove forests, covers almost 200,000 acres (810 km2).[73] In the wet season fresh water pours out into Florida Bay, and sawgrass begins to grow closer to the coastline. In the dry season, and particularly in extended periods of drought, the salt water creeps inland into the coastal prairie, an ecosystem that buffers the freshwater marshes by absorbing sea water. Mangrove trees begin to grow in fresh water ecosystems when the salt water goes far enough inland.[74]