what kinds of coral are in the great barrier reef
Great Barrier Reef There are at least 330 species of ascidians on the reef system with the diameter of 1–10 cm (0.4–4 in). Between 300–500 species of bryozoans live on the reef.[40] Four hundred coral species, both hard corals and soft corals inhabit the reef.[32] The majority of these spawn gametes, breeding in mass spawning events that are triggered by the rising sea temperatures of spring and summer, the lunar cycle, and the diurnal cycle. Reefs in the inner Great Barrier Reef spawn during the week after the full moon in October, while the outer reefs spawn in November and December.[44] Its common soft corals belong to 36 genera.[45] Five hundred species of marine algae or seaweed live on the reef,[32] including thirteen species of genus Halimeda, which deposit calcareous mounds up to 100 metres (110 yd) wide, creating mini-ecosystems on their surface which have been compared to rainforest cover.[20]:185
Environmental threats to the Great Barrier Reef According to the 2014 report of the Australian Government's Great Barrier Reef Marine Park Authority (GBRMPA), says that climate change is the most significant environmental threat to the Great Barrier Reef,[5] while the other major environmental pressures are listed as decreased water quality from land-based runoff, impacts from coastal development and some persistent impacts from fishing activities. The reef is also threatened by storms, coral bleaching and ocean acidification.[6][7][8] The 2014 report also shows that, while numerous marine life species have recovered after previous declines, the strength of the dugong population is continuing to decline.[9] Terry Hughes, Federation Fellow, ARC Centre of Excellence for Coral Reef Studies at James Cook University, wrote in a 14 August 2014 Conversation piece that harmful government policies and ongoing conflicts of interest over mining royalties are risks of an equivalent magnitude.[10]