Life in the depths of the ocean

Throughout the history of humankind, the deep ocean has often inspired both wonder and fear. It has often been seen as a dark, mystical and mysterious place entirely inhospitable for life or the home of legendary sea monsters that haunted the fevered imaginations of the ancient mariners.

The deep ocean is one of the last major frontiers of the planet. Research over the past decade has revealed remarkably high levels of biodiversity and endemism associated with many deep-sea ecosystems. Most marine biologists agree that the deep sea constitutes a major reservoir of the earth’s biodiversity. Estimates of the numbers of species inhabiting the deep sea range between 500,000 and 100 million.

I recently attended the First International Marine Protected Areas Congress, which was held in Geelong, Australia from Oct. 23 to 28, 2005. It was one of the most significant gatherings of marine protected areas where scientists, resource managers and policy-makers from all over the world attended to share ideas, knowledge, and experience for the protection of the marine environment.

A very important theme discussed throughout the Congress was the concept of having Marine Protected Areas in the High Seas. At present, most MPAs are in the EEZ, or the Exclusive Economic Zone of coastal countries.

High Seas Marine Protected Areas represent an opportunity for the global community to cooperate to provide a higher level of protection than prevailing levels, a structure for coordinated decision-making amongst a range of stakeholders, i.e., governments, international and regional organizations, fishing, shipping, marine conservation, and a basis for integrated and ecosystem-based oceans management.

The deep sea starts beyond the shallower continental shelf and includes the slope and rise of the continental margin, deep-ocean basins and plains, trenches, mid-ocean ridge systems, seamounts, plateaus and other underwater features rising from the deep ocean floor. Most of this area lies beyond the 200 nautical miles from shore and constitutes over 90 percent of the ocean bottom.

Deep-sea coral “reefs,” like their shallow water counterparts, have been found on seamounts and along the continental slope throughout the world’s oceans and are known to support rich and diverse assemblages of marine life.

It is now known that some of the continental slope coral systems or “reefs” are remarkably old. Carbon 14 dating has revealed that the cold water corals can be at least 5,000 years old, some have been dated to be as much as 8,500 years old.

In addition to the value of deep-water corals as areas of high biodiversity and as habitats to many fish and other marine life, deep-water corals and associated species are potential sources of medicine. Gorgonian corals, for example, produce antibiotics and some coral species contain the pain killing compounds known as pseudopterosians. Sea fans contain high concentrations of prostoglandins, compounds used to treat asthma and heart disease. Further research into coral and other deep-sea ecosystems over the coming years may well reveal many more such benefits from species as yet undiscovered by science.

Seamounts are increasingly recognized as being high in endemic species—isolated islands or island chains of biodiversity beneath the surface of the sea harboring concentrations of endemic species and providing the conditions for the evolution of new species. Endemics are species found at only one restricted location in the oceans.

Corals often form the basic structure of seamount ecosystems, together with other sessile species such as sea fans and sponges. Because of the slow growth and restricted distribution of many of the species associated with seamount ecosystems, they are considered particularly vulnerable to human impacts and the risk of extinction.

Recent estimates state that there may be up to 50,000 seamounts over 1,000 meters high in the Pacific Ocean and 100,000 seamounts altogether worldwide. Seamounts represent large pools of undiscovered biodiversity in the ocean.

In spite of their importance, deep-sea coral and seamount ecosystems throughout the world’s oceans are being threatened by bottom trawl fishing. Losses of up to 95-98 percent of the coral cover of seamounts as a result of deep-sea trawl fishing have been documented.

The conservation and management of fisheries and the protection of biodiversity within the 200 nautical miles of the Exclusive Economic Zone is largely the responsibility of coastal states. However, the international community as a whole has a collective responsibility to ensure the conservation of fish stocks on the high seas and the protection of biodiversity beyond national jurisdiction.

The U.N. General Assembly in 2002, recognizing the vulnerability of deep-sea biodiversity, called upon the international community to urgently consider the risks to the biodiversity associated with seamounts and other deep-sea areas. The General Assembly reiterated its concerns in 2003 and further called on relevant global and regional organizations “to investigate urgently how to better address, on a scientific basis, including the application of precaution, the threats and risks to vulnerable and threatened marine ecosystems and biodiversity in areas beyond national jurisdiction…”

The oceans of the world need to be protected urgently! The opportunity exists now for the international community, individually and collectively, to take preventive action to protect a major portion of the biodiversity on the high seas—the world’s global commons. Leading scientists have concluded that the threat posed by deep-sea bottom trawl fishing is real, the potential loss of marine biodiversity is significant, and have called upon the U.N. General Assembly to declare a moratorium of bottom trawl fishing on the high seas. We need to take action now as a world community, before we experience invaluable losses of biodiversity and possible extinctions of species yet unknown to us!

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Dr. Teny Topalian is a coral reef ecologist of the Pacific Islands Regional Office, National Oceanic and Atmospheric Administration.