Great Barrier Reef may decline to 10 percent due to warming

Great Barrier Reef may decline to 10 percent

Current and future environmental scenarios could cause the Great Barrier Reef to decline to less than 10% due to ocean warming according to a new study.

An international team of researchers conducted a study at the National Institute for Mathematical and Biological Synthesis aimed at exploring the short-term and long-term consequences of environmental changes to the reef, as well as projecting the composition of the Great Barrier Reef in the future.

Using a multivariate statistical model and quantitative surveys of 46 reef habitats over 10 years of data from 1996 to 2006, the researchers found out that in the short term, increasing temperatures coupled with man-made threats such as coastal development, pollution, and over-fishing among others could cause an explosion of seaweed population that would eventually over-run and suffocate coral populations

Competition and dominance would also characterize future interactions among reef organisms, with groups such as sponges and gorgonians dominating the entire reef habitat.

The long term impact is a high probability of coral cover decline to less than 10% due to a moderate warming 1-2 degrees Celsius.

“The model indicated that warming of an additional 1-2 degrees Celsius would more than likely lead large declines in coral cover and overall changes to the community structure,
said lead author Jennifer K. Cooper, a graduate student in marine biology at James Cook University. “If our model is correct the Great Barrier Reef will begin to look very different as ocean temperatures increase.”

The Great Barrier Reef stretches along most of the coastline of Queensland, Australia. It is about the size of Japan and it is home to the largest collection of coral reefs, 400 types of corals, 1,500 species of fish, and 4,000 types of mollusks.

During the last 27 years, the reef has lost half of its coral cover due to pressing environmental problems leading to ocean acidification and manmade reef destructions. The United Nations has named the Great Barrier Reef as a World Heritage Site in 1981. However, with the current rate of destruction, the reef is likely to be included on the List of World Heritage in Danger.

“Losing the GBR and other reefs would be a massive blow to marine biodiversity and to the people that depend on healthy reefs for food, tourism, and protection from storms,” said co-author John Bruno, a marine ecologist from the University of North Carolina, Chapel Hill.

The results of the study are published in the article “Stochastic dynamics of a warmer Great Barrier Reef” that appeared in the journal Ecology.

Photo credit: Catlin Seaview Survey/Underwater Earth