Alien Benthic Algae and Seagrasses in the Mediterranean Sea and Their Connection to Global Warming

Abstract

Nearly 140 alien benthic-algae taxa and one seagrass invader species were reported found in the Mediterranean Sea since the beginning of the twentieth century. Some caused major changes in the community structure and function of marine flora and fauna. Most non-indigenous species reached the Mediterranean due to anthropogenic activities. The opening of the Suez Canal, along with the increase of marine transportation and mariculture, enabled alien invasion from the Atlantic, Indian, and Pacific Oceans. Alien algae from the Atlantic Ocean probably invade the Mediterranean via the Straits of Gibraltar through cargo ships (through ballast water or attached to the hulls). Shellfish transfer is the most important vector for introducing alien seaweed from the Far East into the western Mediterranean. Global warming raised the surface water temperature, especially in the eastern Mediterranean Basin; therefore, it plays an important role in facilitating settlement establishment and the spread of alien algae and seagrasses from the tropical Atlantic, Indian, and Pacific Oceans in the Mediterranean. The control and reduction of marine invasions are also discussed.