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The next frontier of ecosystem restoration: the deep sea

The deep seas are truly Earth’s last frontier, faraway worlds of alien beauty of which only an infinitesimal fraction have been explored—and it’s time to start thinking about how to restore them.
October 9, 2019

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The deep seas are truly Earth’s last frontier, faraway worlds of alien beauty of which only an infinitesimal fraction have been explored—and it’s time to start thinking about how to restore them.

Just a few decades after their exploration began in earnest, deep-sea ecosystems are subject to ever-increasing impacts from human activity. Heavy metals will soon be mined from abyssal plains and submerged mountaintops and hydrothermal vents; declines in shallow-water trawl fisheries have sent vessels scouring deep-sea canyons and cold-water coral reefs. Seabed oil and gas exploration is yet another threat.

Given the slow growth rates and fragile nature of organisms living in those cold, lightless depths, damage caused by these activities promises to be considerable. Yet little attention has been given to how we might reverse them.

“Restoration actions in the deep sea will be increasingly required in the future,” write biologists led by Antonio Dell’Anno and Roberto Danovaro of Italy’s Polytechnic University of Marche in the journal Marine Policy. “If specific exploitation activities will be allowed, they should be strongly regulated,” with requirements that industries “provide specific environmental management plans that includes baseline assessment, monitoring and mitigation measures.”

A hodgepodge of international conventions and institutions presently govern these ecosystems; the institutions are not well-coordinated, say the researchers, and new regulations are needed to shape development. These should set guidelines for determining areas that merit complete protection and those that can be exploited—and, in the latter case, how to minimize their degradation.

On land, ecological restoration, or setting ecosystems on a trajectory to recover their pre-development biodiversity and abundance, is a common part of environmental management. “Similar approaches in the deep sea will face numerous challenges,” write the researchers, beginning with the fact that “for most deep-sea ecosystems, we lack information on ecosystem baselines to establish an appropriate reference for effective restoration.”

Less than 0.0001 percent of the deep ocean has been investigated to date. Much more research is still needed: on how those ecosystems function, the flora and fauna living there, how hotspots are connected to one another and are naturally colonized. And once that’s done, say the researchers, restoration will still be a challenge. In some cases ecosystems may recover on their own, but most will probably require assistance—but operating at depth is difficult, requiring autonomous and remote-operated vehicles. These are expensive, and restoration may take a very long time.

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Given the considerable expenses involved, securing restoration funding is an essential step. At present “activities like high seas fishing and oil extraction have free access to deep-sea resources and are not obliged to fun such programs,” note the researchers. They suggest a tax of 1 percent on revenues, which would “generate a big fund to support actions for deep-sea conservation in any form.”

That fund would indeed need to be big: because of the machinery involved, deep-sea restoration efforts are likely to be orders of magnitude more expensive than those in shallow waters and coastlines. One hypothetical estimate of restoring deep-sea sand mounds off the coast of Scotland put the cost at $75 million per hectare. Another estimate of restoring mine sites in waters around Papua New Guinea at $740 million per hectare. And whereas the human benefits of restoring storm-buffering mangrove forests or fish-nursery seagrass beds are obvious, a utilitarian case may be harder to make for the deep ocean.

“If the costs of restoration overtake the benefits obtained by exploiting activities,” write Dell’Anno and colleagues, “policy makers should consider carefully the convenience of such activities.” The same goes for consumers. If we don’t way to pay the true cost of using deep-sea resources, perhaps it’s better to leave them alone.

Source: Da Ros et al. “The deep sea: The new frontier for ecological restoration.Marine Policy, 2019.

Image: NOAA


About the author: Brandon Keim is a freelance journalist specializing in animals, nature and science, and the author of The Eye of the Sandpiper: Stories From the Living World. Connect with him on Twitter, Instagram and Facebook.

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