Past sea level has varied by somewhat more than a hundred metres. This is primarily due to the growth and decay of ice sheets (mostly in the northern hemisphere) with water evaporated from the sea. The Mediterranean Basin's gradual growth as the Neotethys basin, begun in the Jurassic, did not suddenly affect ocean levels. While the Mediterranean was forming during the past 100 million years, the average ocean level was generally 200 metres above current levels. However, the largest known example of marine flooding was when the Atlantic breached the Strait of Gibraltar at the end of the Messinian Salinity Crisis about 5.2
Deep sea fish to some degree. Most fish that have evolved in this harsh environment are not capable of surviving in laboratory conditions, and attempts to keep them in captivity have led to their deaths. Deep-sea organisms contain gas-filled spaces (vacuoles). Gas is compressed under high pressure and expands under low pressure. Because of this, these organisms have been known to blow up if they come to the surface. The fish of the deep-sea are among the strangest and most elusive creatures on Earth. In this deep, dark unknown lie many unusual creatures that have yet to be studied. Since many of these