International talks are under way to create a new legally binding instrument.

The high seas are critical to life on Earth. They constitute over 50 percent of the planet's area and over 90 percent of the habitable volume, with depths of 200 meters or more. Researchers continue to discover amazing life forms in the deep sea. But this rich biota faces a host of threats, from climate-change-related ocean acidification to pollution, deep-water trawling, and overfishing. Recently, scientists added to the list declining oxygen levels.

Coral communities, well known on warm coasts, also form in the deep seas in the cold-water environment, providing habitat and feeding grounds to many species of fish, sharks, cephalopods, and mollusks. Corals are being irreparably damaged by trawling. Photograph: National Oceanic and Atmospheric Administration OKEANOS Explorer Program, 2013 Northeast US Canyons Expedition.

Coral communities, well known on warm coasts, also form in the deep seas in the cold-water environment, providing habitat and feeding grounds to many species of fish, sharks, cephalopods, and mollusks. Corals are being irreparably damaged by trawling. Photograph: National Oceanic and Atmospheric Administration OKEANOS Explorer Program, 2013 Northeast US Canyons Expedition.

A February 2016 study published in Global Biogeochemical Cycles revealed an increasing number of oxygen-minimum zones, areas with significantly diminished marine life. Another 2016 paper that had been widely anticipated, published in Conservation Letters, called for expanding protected areas to a minimum of 30 percent of total ocean area.

Beyond the life it supports, the global ocean system plays a key role in mitigating climate change. The seas have an immense natural capacity to absorb heat and carbon. Some researchers also look to the oceans for potential geoengineering schemes, such as adding iron as a way to sequester carbon.

The high seas encompass the international area beyond the 200-mile-from-shore exclusive economic zones over which coastal nations have legal jurisdiction. Deciding how to conserve and sustainably manage high-seas biodiversity has long been a challenge. Researchers are hopeful that ongoing discussions aimed at adding a supplemental “biodiversity” treaty to the 1982 United Nations (UN) Convention on the Law of the Sea may provide an opening for protecting species and habitats in this critical area. A 2015 UN General Assembly resolution, 69/292, established a process for shaping an international legally binding instrument (ILBI) for protecting biodiversity in areas beyond national jurisdiction. The General Assembly resolution set up a preparatory committee (PrepCom), which will meet for 2 years to develop substantive recommendations for the General Assembly on such an instrument.

The fact that the UN is getting serious about a legal instrument reflects a growing awareness that the deep oceans’ biodiversity is being degraded, with many gaps in protection and with international bodies and stakeholders not working together. The first World Ocean Assessment, which the UN published in 2015, found that many global players focus on narrow sectoral interests rather than on cooperation. “Without a sound framework in which to work, [stakeholders] may well fail to take into account the ways in which their decisions and actions interact with those of others,” the assessment authors found.

The first PrepCom meeting, held in April, identified the central issues: how to manage environmental impact assessments, marine genetic resources, and high-seas marine protected areas in an international context, including the role of existing oceans authorities, such as regional fisheries-management organizations. The second PrepCom meeting takes place in September, with two more scheduled for 2017. Later next year, the PrepCom will make its recommendations to the UN General Assembly.

Deep-seas environments, such as at hydrothermal vents and seamounts, are home to many unique fish and other organisms, some of which depend on chemosynthetic microorganisms for sustenance. The fish here is in the genus Gaidropsaurus. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

Deep-seas environments, such as at hydrothermal vents and seamounts, are home to many unique fish and other organisms, some of which depend on chemosynthetic microorganisms for sustenance. The fish here is in the genus Gaidropsaurus. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

“What for me is exciting is the realization of a 10-plus-year path toward trying to raise awareness of the importance of these oceans issues—in the United Nations, the Convention on Biological Diversity, and the Food and Agriculture Organization—any place we could go,” says Kristina Gjerde, the senior high-seas advisor to the International Union for Conservation of Nature. “[High-seas biodiversity policy discussion] is centralized now; it is a fixture in the firmament of international law, and governments are taking it very seriously.”

If the PrepCom lays the proper groundwork in its report, she says, “the UN General Assembly can agree to launch an intergovernmental negotiating committee, which can then rapidly finish their work by 2018.” She and others fear, however, that the agreement may be so broad and compromised by competing interests that it will not be potent enough to protect high-seas biodiversity.

Black smokers are unique places of emission on the deep seafloor, often at the deep abyssal plane. The black emissions indicate the presence of sulfides, which are of mining interest. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

Black smokers are unique places of emission on the deep seafloor, often at the deep abyssal plane. The black emissions indicate the presence of sulfides, which are of mining interest. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

Threats to life in the deep

In the early days of deep-sea exploration, researchers thought that only a few species lived in a muddy, food-poor environment. “Especially in the last 40 years, we've discovered this profusion of different habitats, ecosystems, and species and many different ways that animals make a living down in the deep ocean,” explains Lisa Levin, a marine ecologist at the Scripps Oceanographic Institute and a director of the Deep Ocean Stewardship Initiative, a union of experts who advocate for and advise on deep oceans conservation and science.

Levin points out that modern technologies—such as remotely operated vehicles, autonomous underwater vehicles, human-operated vehicles, and sonar mapping—have shed light on seafloor structures, such as seamounts (steep underwater, mostly inactive volcanoes) and hydrothermal vents, and depressed features, such as canyons and basins. She adds that scientists now better appreciate that currents, surface winds, and the upwelling of the waters influence species adaptations and increase biodiversity. “What we have discovered is that this wealth of environmental heterogeneity promotes biodiversity in many different forms,” she says.

Litter, especially plastics, has been found in the farthest recesses of the deep seas, including in the Mariana Trench (not pictured here) in the Pacific Ocean, the deepest place on Earth. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

Litter, especially plastics, has been found in the farthest recesses of the deep seas, including in the Mariana Trench (not pictured here) in the Pacific Ocean, the deepest place on Earth. Photograph: Eva Ramirez-Llodra, BIOFUN/ICM-CSIC.

Seamounts, hydrothermal vents, midocean ridge environments, the abyssal plain, and cold-water coral and sponge fields are the high seas’ signature ecosystems, and their biota is shaped by food sources, water mass, salinity, and topography. Seamounts have “dense assemblages of filter feeding organisms, typically coral and sponges,” says Levin. Corals serve as critical habitat, hosting rich biodiversity. Thousands of seamounts are in the open ocean and deep national waters; some are flat topped, called guyots, with distinctive effects on ocean circulation, attracting long-maturing fish, such as orange roughy, that are commercially valuable.

Hydrothermal vents in the deep oceans are another critical habitat. Hydrothermal vents are home to chemosynthetic species, which use the chemicals emitted from the vents as an energy source, just as photosynthetic species use sunlight. For example, the famous and colorful tubeworms at Pacific Ocean hydrothermal vents do not have mouths or digestive systems and depend on their symbiotic chemosynthetic microorganisms for sustenance. Eva Ramirez-Llodra, a deep-seas marine biologist with the Research Centre for Coast and Ocean at the Norwegian Institute for Water Research, participated in the discovery of hydrothermal vents south of the Polar Front toward Antarctica and in the South Mid-Atlantic Ridge. She says that scientists have noticed some regional biotic differences with the vents: East Pacific vents are home to white clams and mussels, whereas the Atlantic vents have large shrimp and mussel populations, and the subpolar front vents have dense populations of yeti crabs. Ramirez-Llodra adds that “hydrothermal vents are like oases in the deep seas where there is very high biomass, with a lot of animals, and many large animals, but very little biodiversity because these are extreme environments.”

These amazing life forms are threatened, though, by human activities in the high seas. Orange roughy and other species are being devastated by overfishing. Trawling has degraded the biodiversity of seamounts and has damaged corals that take thousands of years to regenerate. In a recent study of the Mediterranean deep sea, Ramirez-Llodra and colleagues found that in samples in the eastern Mediterranean, the average weight of litter in the sea, most of it plastic, was more than the weight of fish, mollusks, and other animals.

Recent ocean-acidification science underscores the seas’ interconnectedness. The North Atlantic has severe ocean acidification, and these waters are transported through thermohaline circulation to other oceans depths and regions. “These changes that are being experienced at the surface are being communicated much more directly to the deep sea than we thought before,” says Levin. This means that deep cold-water corals and other species will be harmed, just as shallow water corals are.

Levin has also researched low-ocean-oxygen zones, beginning in 1988, when she used the famous submersible Alvin to explore “Volcano 7,” 200 miles off Acapulco. Levin recounts observing a profusion of life—including masses of brittle stars, sponges, and crabs—going up the volcano's slope. When she entered an oxygen-minimum zone, though, she saw gray stones and only a few traversing fish. “That was my first wake-up to the fact that oxygen is an incredibly powerful control on the biodiversity and structure of life on the seafloor,” Levin says. In fact, scientists believe that the East Pacific region is experiencing significantly expanding oxygen-minimum zones.

According to Levin, the deoxygenation is due to two ocean-warming factors. First, oxygen is less soluble in warmer water, and second, warmer water is more stratified with less upper oxygen-rich waters circulating into the deep, where organisms consume oxygen that is not replaced. “This affects the margins [in particular], but it is actually affecting the whole ocean,” Levin says, “There is already evidence that [deoxygenation] is affecting fish, big bill fish for example, with high oxygen demands, and they are experiencing habitat compression into shallower and shallow water.”

Scientists are exploring why sharks congregate in certain areas, such as the “Shark Café” in the Pacific Ocean. Sharks, top predators in high-seas environments, are being devastated by fishing. Photograph: Richard Brooks for the Pew Charitable Trusts.

Scientists are exploring why sharks congregate in certain areas, such as the “Shark Café” in the Pacific Ocean. Sharks, top predators in high-seas environments, are being devastated by fishing. Photograph: Richard Brooks for the Pew Charitable Trusts.

To date, there is no international policy for controlling ocean acidification and deoxygenation in the high seas.

An ILBI: Environmental impact assessments, marine genetic resources, and protected areas

The main focus of the PrepCom talks is on three issues: environmental impact assessments, marine genetic resources, and marine protected areas. Gjerde says the environmental impact assessments (EIAs) are the most promising for early progress. “There seems to be clear agreement for the need for prior assessment of activities having impact on marine biodiversity for areas beyond national jurisdiction,” she observes. She adds that the current work on EIAs for mining within the Law of the Sea's International Seabed Authority can offer guidance for the PrepCom discussions.

Kristina Gjerde, senior International Union for Conservation of Nature representative to United Nations (UN) deep-seas discussions, says an international legally binding instrument for high seas biodiversity would bring together disparate authorities who often do not communicate. Gjerde supports expanding the percentage of marine protected areas to beyond the current UN 10 percent goal. Photograph: Adam de Sola Pool.

Kristina Gjerde, senior International Union for Conservation of Nature representative to United Nations (UN) deep-seas discussions, says an international legally binding instrument for high seas biodiversity would bring together disparate authorities who often do not communicate. Gjerde supports expanding the percentage of marine protected areas to beyond the current UN 10 percent goal. Photograph: Adam de Sola Pool.

Her colleague, international environmental lawyer David Freestone, agrees. He points out that the Law of the Sea Convention has EIA provisions, but they are vague, lack reporting directives, and are not being used. “The Conference of the Parties [treaties’ recurrent gathering of national representatives] to this new instrument would be an ideal body to receive EIAs for new activities,” make decisions, and send out further directions. Freestone believes a strong EIA process could also address a major gap in international governance: how to control geoengineering activity that might be staged in the high seas, such as dumping iron into the oceans to see if it causes carbon sequestration or spreading chalk on the surface to simulate a reflecting albedo effect.

Marine genetic resources may be the most controversial of the agenda items. The genetic components of organisms can be extracted for various uses, such as pure taxonomic science, commercial research, and pharmaceuticals. Many living in developing countries want to share in the benefits of genetic-resource discoveries connected to the high seas, but some in developed countries are wary of a new system that might challenge established intellectual-property norms, such as patents.

There is also continuing disagreement about the concept known as the common heritage of mankind, which implies collective ownership, an obligation to conserve for future generations, and some sharing of rewards for the development of common heritage of mankind materials. The Law of the Sea Convention explicitly links the common heritage of mankind principle to high-seas seafloor resources, but there is ongoing debate as to whether this includes not only minerals but also biological resources. In the first PrepCom gathering, some developing countries advocated for a common heritage of mankind understanding for organisms’ genome components in the water column, too.

Gina Guillen-Grillo, legal adviser to the Costa Rica mission to the UN and representative to the talks, says open dialogue during the PrepCom process can lead to clarity on this issue. The delegates can use the PrepCom process to discuss terminology and elaborate the fairness, conservation, and development characteristics of a just, international regime for high-seas genetic resources. “We need to focus on what we want the common heritage for,” Guillen-Grillo says, adding that this would help bridge the differences about the common heritage of mankind principle.

The third main issue, marine protected areas, also generates disagreement. Globally, marine protected areas differ in which activities are allowed—some are no-take zones, although others are not. Many nations, including the United States, want marine protected areas in international waters to include fisheries protections, whereas a few fishing nations, prominently Russia, do not. Also, many participants expect that regional fisheries-management organizations will be wary of introducing fisheries management into a new agreement. At the same time, regional fisheries-management organizations will certainly play a role in enforcing the agreement, whether by means of their participating in crafting the instrument or by the member states’ directing these organizations to abide by the new UN instrument.

Elizabeth Wilson, director of international ocean policy at the Pew Charitable Trust, advocates within the PrepCom process for a strong marine protected areas program. “It became apparent there was this enormous gap in the inability to establish marine protected areas in the high seas and that these needed to be areas across fisheries and all the other activities that were occurring,” says Wilson. Guillen-Grillo says that the mandate of existing institutions should be respected but that an ILBI can set up standards for marine protected areas and get the different actors to work together. “The only way for us to really save the oceans is to set up this [marine protected areas] network,” she says.

Wilson hopes the PrepCom and ILBI process can lead to “a representative system of protected areas… to cover a variety of different habitats.” Pew is also working with University of York marine conservation scientist Callum Roberts, coauthor of the influential 2016 Conservation Letters article, on the science of high-seas marine protected areas. Roberts argues that managing fisheries has to be included in a marine protected areas program. “If fisheries [management] is not included, the major source of harm to the high seas is outside the box. It would be like having an agreement on forest protection that does not include logging companies,” he says. Any agreement, says Roberts, should protect species such as the Pacific bluefin tuna, which has declined by 97 percent of its historic abundance and is imperiled with extinction. Moreover, Roberts believes it is imperative not only to establish marine protected areas but also to reform the regional fisheries-management organizations, which have not properly managed fish stocks.

Effective high-seas marine protected areas will need to incorporate other cutting-edge science. Ramirez-Llodra is conducting related research on high-seas organisms’ population connectivity, reproduction cycles, and larval distribution. According to her, scientists need to understand whether larvae or juveniles at healthy sites can travel to impacted sites, such as where deep-seas mining has taken place. “If we are going to develop marine protected areas, we need to know how the network is connected genetically,” Ramirez-Llodra explains. “And one of the key criteria is if [an area is] a source for larvae or juveniles that can then populate other regions.”

Resilience and timeliness

This high-seas biodiversity discourse comes at a time when the recent Paris Accord on Climate Change has raised hopes for international efforts to address global environmental problems, especially climate change. Wilson says there is “a lot of momentum coming out of the Paris agreement” and that the talks on the high-seas biodiversity treaty are “an opportunity to further those developments.” Creating marine reserves on the high seas, she says, can “help build [ecological] resilience … in the light of climate change.”

Roberts agrees and has begun exploring with other scientists what marine protected areas can do for mitigating global environmental change impacts. High seas marine protected areas help increase wildlife populations, making them less prone to extinction, more resilient to shocks and catastrophes, and better able to cope with background stresses, Roberts says, “so if we have richer, more diverse, more abundant life, we are definitely going to be better off in terms of coping with the stresses of a changing planet.”

Conserving life in the Sargasso Sea.
 

Ten endemic species live in the Sargassum weed, according to ocean biologist Howard Roe. For many fish, the Sargassum serves as a nursery and a feeding area. The Sargasso Sea is also a major migration hub for several species of sharks and whales. Photograph: LookBermuda.

Ten endemic species live in the Sargassum weed, according to ocean biologist Howard Roe. For many fish, the Sargassum serves as a nursery and a feeding area. The Sargasso Sea is also a major migration hub for several species of sharks and whales. Photograph: LookBermuda.

 

This loggerhead sea turtle, hatched on Georgia's Blackbeard Island, is taking his time to adjust to his new surroundings and strengthen his muscles before his long journey to the Sargasso Sea. Photograph: United States Fish and Wildlife Service/Becky Skiba.

This loggerhead sea turtle, hatched on Georgia's Blackbeard Island, is taking his time to adjust to his new surroundings and strengthen his muscles before his long journey to the Sargasso Sea. Photograph: United States Fish and Wildlife Service/Becky Skiba.

The Sargasso Sea, named after its two prevalent seaweed species Sargassum natans and Sargassum fluitans, is home and refuge to many species in the subtropical North Atlantic Ocean. The Sargasso is actually a unique and naturally occurring ocean gyre system, says ocean biologist Howard Roe, chair of the Sargasso Sea Commission, a scientific and conservation organization supported by governments. The sea, encompassing roughly 4 million square miles, is “bounded by the Gulf Stream to the North and West, the Canary Current to the East, and the North Equatorial Current and Antilles Current to the South,” Roe explains. The Sargasso Sea is held up as an example of successful but arduous conservation efforts that could come easier with an international legally binding instrument (ILBI) for the high seas.

The Sargasso Sea has astounding biodiversity, including 26 species of seabirds; great white, basking, mako, tiger, and blue sharks; and humpback whales, according to Roe. It is also a hub for turtles at different life stages: Roe explains that green, loggerhead, hawksbill, and Kemp's ridley sea turtles “spend their ‘lost years’ in the Sargasso sea, sitting in mats of Sargassum weed, where they are protected.” Perhaps most iconic, the American eel and the European eel journey thousands of miles to spawn in the Sargasso Sea for reasons that are still unknown to scientists.

David Freestone, executive secretary of the Sargasso Sea Commission, says that getting the European eel listed as endangered in a Convention on Migratory Species annex shows how the commission works. The commission produced an eel study and received support from Monaco, which took the protection proposal to the Convention on Migratory Species for listing.

Kristina Gjerde, who works on the affiliated Sargasso Sea Project, says there have been important conservation achievements, as well as valuable lessons on which to draw. “The Sargasso Sea was both a place to try to get urgent protection for the measures you could [get] through existing agreements but also as an experiment [to learn] what you could not get through existing processes,” she says. She thinks an overarching high-seas instrument would establish the conservation principles and implementing force to improve and interconnect these existing processes.

Freestone agrees. Although going to the different sectoral bodies, such as the Convention on Migratory Species or the Northwest Atlantic Fisheries Organization, has produced successes, an overarching high-seas treaty would add consistent guidance and standards directed to the different authorities on what are the global norms for protecting the high seas. For example, Freestone says that as it stands now, there is no way to stop the potential harvesting of Sargassum. “A body which would pull it all together and have some holistic overarching agendas and viewpoints—again, that's another reason for having this [ILBI] instrument.”

Meanwhile, the Sargasso Sea conservation efforts continue with the means available. “The Sargasso Sea is an iconic place because of the combination of oceanography and biology,” Roe explains. He adds that its ecology influences the coupled atmosphere–oceans system. “In the Sargasso Sea, we can observe how the global ocean works and how it is changing. It is a special place.”

Guillen-Grillo also thinks the time is right for action. “This agreement is going to be, I think, the most important agreement since we adopted [the Convention on the Law of the Sea] because of the area it covers,” she says. The negotiators will have to be thorough and dedicated, given the many stakeholders to consider and the complex issues of who will be enforcing what. But, Guillen-Grillo asserts, “This is a moment in which we can really do something very, very important and we can be happy that this is happening on our watch.”

Further reading.

Long MC, Deutsch C, Ito T. 2016. Finding forced trends in oceanic oxygen. Global Biogeochemical Cycles 30: 381–397. doi:10.1002/2015GB005310

O'Leary BC, Winther-Janson M, Bainbridge J, Aitken J, Hawkins JP, Roberts C. 2016. Effective coverage targets for ocean protection. Conservation Letters. doi:10.1111/conl.12247

Ramirez-Llodra E, et al. 2011. Man and the last great wilderness: Human impact on the deep sea. PLOS ONE 6 (art. e22588). doi:10.1371/journal.pone.0022588

United Nations Division for Ocean Affairs and the Law of the Sea. 2016. First Global Integrated Marine Assessment (First World Ocean Assessment). United Nations Division for Ocean Affairs and the Law of the Sea. (13 July 2016; www.un.org/depts/los/global_reporting/WOA_RegProcess.htm)