The Marine Conservation Institute has two primary objectives: protecting marine ecosystems and advancing the science of Marine Conservation Biology. One of their focus areas is protection and conservation of deep-sea corals. Unlike shallow coral reefs, which are confined to the warm sunlit waters of tropical regions, deep sea corals have an almost global distribution, and have been found living at depths greater than 2500m. Our understanding of the extent, distribution and ecology of these vibrant and productive communities has increased greatly in recent years, but unfortunately it has also become clear that their depth and often-remote location has not protected deep-sea corals from severe human impact. Like their tropical counterparts, many species of deep-sea corals create complex three-dimensional structures that provide habitat and food for a diverse and abundant community of animals. Some of these reef-associated animals are also commercially valuable fisheries species, and in order to extract them from their refuge, heavy bottom trawling equipment is used to break the coral structure and harvest the fish. This kind of destructive fishing indiscriminately removes vast numbers of fish, and the corals will take many years to recover, if ever.

Although bottom trawling is causing the most immediate physical damage to deep-sea corals worldwide, the looming threat of changes in ocean chemistry may cause more widespread and possibly permanent damage in the future. The combustion of fossil fuels has released tons of carbon dioxide into the atmosphere, and much of this dissolves in the surface of the oceans, forming carbonic acid. The chemistry of the ocean is complex and can balance a large amount of CO2, but as this level increases, the oceans cannot compensate, and the water will become more acidic. The skeletons of animals such as corals, clams, sea urchins etc are made of a substance that dissolves in acid. Consequently, reducing the pH of ocean water will compromise the ability of these animals to produce their skeletons and shells. Since deep-water corals live far beneath the surface, it seems they should be safe from ocean acidification, but unfortunately this is not the case. The combined physical and chemical properties of deep water mean that these corals are also vulnerable to the effects of acidification.

Since deep-sea corals are under threat both within US waters and on the ‘high seas’ MCI is working with US federal resource management agencies, and international entities to identify vulnerable coral areas and then place them under protection from destructive human activities. MCI is also creating models to predict the occurrence of deep corals in the US, Europe, New Zealand and on the high seas. Since deep sea exploration is so expensive and challenging, we know that we will never be able to survey the whole ocean floor; however we can use our knowledge of the deep sea environment and of deep sea coral ecology to predict where these ecosystems might be, and guide protective measures. We are also using the future predictions of changes in ocean acidification to predict which deep coral ecosystems are under the greatest threat, and which might provide the refuges for the future.

Header photos courtesy of the MCI.

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