International Day of Biological Diversity: Marine Biodiversity
In 2000, the United Nations declared 22nd May as International Day of Biological Diversity (IDB). This year, the focus is on marine biodiversity. There’s a day for most things/themes nowadays so, one may ask, ‘why another “Day”?’ According to the US Geological Survey, about 70% of the Earth is covered by water, about 97% of this attributed to oceans. So, it is fitting that marine biodiversity be finally given its ‘Day’.
‘Biodiversity’, a term coined in 1985, is actually a contraction of ‘biological diversity’. It refers to the variety of all forms of life, whether we focus at the level of genes, species or ecosystems. Marine biodiversity takes account of life both at the coast and in the open ocean. This includes plant life, such as red mangroves (Rhizophora mangle) seen lining some of Antigua and Barbuda’s coastlines. Many species of seagrasses, including turtle grass (Thalassia testudinum), are commonly found in Antigua/Barbuda’s waters. Also included is coral, composed of thousands of polyps (some have developed a hard outer covering) sometimes in a mutualistic relationship with photosynthetic algae called zooxanthellae; the polyps provide shelter to the algae which, in turn, provide nutrients for the polyps. (These algae impart vivid colours to some coral.)
Coral reef ecosystems are called the “rainforests of the ocean” because of their vastly rich biodiversity; a third of all marine species are found there.
In the open ocean, a plethora of species contribute to marine biodiversity. These include fish, sea turtles, and marine mammals.
The range of marine biodiversity is fascinating but is it worth losing sleep over? Without life in the ocean, there would be no life on land! Half of the Earth’s oxygen is produced by phytoplankton as a product of their photosynthesis. These microscopic organisms form the base of the ocean’s food web so the fish we enjoy depend directly or indirectly on phytoplankton for life. Coral reefs and mangroves buffer the coastline from the effects of waves and storm winds, helping to prevent coastal erosion. In addition, mangroves trap sediment from the land, helping to purify water running off into the ocean. Gums from seaweed are commonly used as thickeners in many foods, skin care products, toothpaste and paint. The ocean is also a vast resource for health-related products such as omega-3 fatty acids, some anti-cancer drugs and pain killers and it has been suggested that many future medicines will be derived from the sea.
Humans play a significant role in reducing the richness of the ocean. Due to over-fishing, many fishermen lament decreasing catch and smaller fish and lobster. Bottom trawling, reportedly at Deep Bay, not only harvests unwanted species but it severely disrupts habitats, such as seagrass beds. Inappropriate use of fertilisers and untreated sewage can run-off and lead to poisoning of marine life and eutrophication where resulting decreased oxygen levels eventually lead to suffocation of some sea life; some fish-kills at McKinnon’s Pond have similar causes. Trash, including plastic, entering the ocean can be mistaken for food by some birds and sea turtles, accumulating in these animals and eventually contributing to their death.
How can we help preserve marine biodiversity? Properly dispose of trash and chemicals to reduce killing of endangered sea turtles and reduce ocean acidification that can lead to coral bleaching and their subsequent death. Use fishing methods that do not target unwanted species or destroy habitats. Environmental legislation and subsequent law enforcement is needed. A draft Environmental Protection and Management Bill has been languishing for years in the halls of government. As we celebrate IDB 2012, we urge our policy makers to dust off this document and make its revision and passage a priority. Our marine biodiversity depends