The place where the Great Bitter Lake is located used to be a dry salt valley. This still influences the salinity of the lake. Starting with the Six-Day War (1967), the Suez Canal was closed for eight years. During this time, the salinity of the lake increased a lot. It depends on how much seawater flows into it from the Red and the Mediterranean seas. Even when the canal is open, the Great Bitter Lake has a salinity level "more than twice" the level of the sea. While this makes it difficult for plant life to exist there, many species (of crabs, for example) migrate from the Red Sea through the area.