Researchers develop blueprint for protecting ocean biodiversity

March 17, 2021

A new study might have a fix for our ocean issues. (Pixabay/Public Domain Pictures)

A first-of-a-kind study maps and identifies marine areas that, if strictly protected from fishing and other habitat-damaging activities, could make significant progress toward tackling three of humanity's most pressing issues: climate change, loss of biodiversity and the global decrease of Earth's fishing supply.

The study, published Wednesday in Nature, is the result of a three-year endeavor and authored by an international team of 26 experts from a wide array of disciplines, including marine scientists, climate scientists, oceanographers, biogeochemists and fishery scientists. 

"We came together because there is an urgent need to do more to protect our ocean," Darcy Bradley, an author of the study and a director of the Environmental Market Solutions Lab and research faculty member at the University of California, Santa Barbara, told The Academic Times

"We are realizing that human impacts on the ocean are increasing. The ocean holds a huge amount of marine life and is home to huge proportions of our world's global carbon stocks," Bradley said. "It has a huge amount of ecosystem services from which humans benefit, so there is an urgent need to protect more ocean space."

The study comes ahead of the 15th Conference of the United Nations Convention on Biological Diversity, set for October in Kunming, China. The convention is an international treaty that has near-universal adoption, with 196 countries as signatories. 

The conference is expected to present, discuss and negotiate the 30x30 framework —  a global biodiversity plan that seeks to protect 30% of the oceans and 30% of land areas and inland waters by 2030. The goal is to prevent, halt and reverse the decline of Earth's species and the degradation of its ecosystems, allowing nature to nurture itself and replenish ecosystem services used by humans. 

Bradley and her colleagues developed a way to achieve this goal while also tackling climate change and seafood production, providing out-of-the-box utility for the international forces that are spearheading nature conservation efforts.

"The many researchers that came together for this study were interested in doing just that, but doing so in such a way that we could re-envision what conservation planning looks like, creating a framework where we could consider multiple potential objectives simultaneously," Bradley said. 

"Naturally, we think that closing areas of the ocean to certain human activities will result in losses for some user groups, particularly for fisheries" she added. "What we're showing here is that with informed conservation planning, that doesn't need to be the case."

In order to create this framework, the researchers first identified marine areas throughout Earth's oceans that are greatly threatened by anthropogenic harm that could be reduced by designating the area as a marine protected area, as defined by the International Union for the Conservation of Nature. Designating an area as a marine protected area may entail bans on or reductions in fishing, bans on oil and gas production and other bans on extractive practices that would result in habitat destruction, according to Bradley.

"A critical step in what we did that's quite different from a standard conservation planning approach is that our benefit function is explicitly considering places that stand to gain the most through protection; where threats can be abated by MPAs," Bradley said. 

The researchers identified new areas for protection by examining humanity's "business-as-usual" trajectory and comparing that to a trajectory where certain protection areas were established in order to examine how much benefit is achieved through a marine protection area. 

An algorithm they developed then helped them identify and map the marine locations whose protection provided the greatest benefit across the three overall objectives of the study — biodiversity protection, seafood production and climate mitigation.

While the overarching premise of this solution is single-pointed — protecting more of the Earth's oceans —  each of the three overall goals contains multifaceted findings and reveals distinct priority areas essential to achieving that particular goal. 

Priority areas for biodiversity are distributed throughout the ocean, with 90% of the top 10 priority areas contained within exclusive economic zones — nautical areas within 200 miles of individual coastal nations that claim sole rights to the resources found within them. Other regions include areas around seamount clusters, offshore plateaus and biogeographically unique areas such as the Antarctic Peninsula, the Mid-Atlantic Ridge, the Mascarene Plateau, the Nazca Ridge and the Southwest Indian Ridge.

The study found that through protection of these specific areas, the average protection of endangered species could increase from 1.5% to 82%, while critically endangered species protection could increase from 1.1% to 87%. 

Priority areas for climate mitigation are also mostly within exclusive economic zones. To identify these priority areas, Bradley said the researchers looked at carbon in the sediment of the ocean.

"We had to look at which human impacts are affecting ocean sediment — ocean carbon stocks," she said. "In this case, the one that we had the best data on was bottom trawling," a fishing practice where sea vessels drag nets across the ocean floor.

Bottom trawling is responsible for one gigaton of carbon emissions on average annually, which is equivalent to the emissions from worldwide aviation and greater than the annual emissions of all countries except China, the U.S., India, Russia and Japan, according to the researchers. 

These emissions occur because trawling disturbs and releases carbon in marine sediments. These sediments are the "largest pool of organic carbon on the planet, and if left undisturbed, organic carbon stored in marine sediments can remain there for millennia," according to the study, which is the first to calculate the carbon emission impact of the fishing practice.

"Bottom trawling directly disturbs the bottom sediment and releases carbon into the water column," Bradley said, adding that their algorithm identified and prioritized areas that, given the same two levels of sediment carbon, have more bottom trawling.

Eliminating 90% of the present risk of carbon disturbance due to bottom trawling would require protecting only 3.6% of the ocean. 

As for seafood production, the study found that highly protected areas that ban overfishing would boost the production of fish by 8.3 million metric tons compared to the industry's current trajectory. The researchers said the protection areas would only need to be placed across 28% of the ocean where overfishing is occurring in order to produce this result. 

A ban on overfishing and other habitat-damaging activities would increase the biomass of commercially targeted fishes, but would also have a spillover effect into other parts of the ocean, according to the study. 

For these efforts to achieve their objectives, though, researchers say a global, not a national, effort on protecting priority areas is quintessential. Global cooperation on placing marine protection areas could achieve 90% of the maximum possible biodiversity benefit with less than half as much area as a protection strategy based solely on national priorities.

Moreover, unprotected marine areas with the highest potential for triple benefits are found within exclusive economic zones, and thus protecting those areas is key, according to the study. 

"There is no one right solution," Bradley said. "There is an infinite number of solutions, but this framework we created can accommodate any number of different preferences and priorities." 

Bradley added that the framework provided by the study is a flexible one, allowing countries to decide which areas to protect depending on their national focus and priorities. 

"We want to encourage this type of thoughtful conservation planning where we identify places that stand to gain the most from being protected," Bradley said. "We felt it important that we provided a framework that can optimize multiple objectives, particularly those that were previously seen in conflict, and we can potentially resolve that conflict by considering these objectives simultaneously."

The study "Protecting the global ocean for biodiversity, food and climate," published in March 17 in Nature, was authored by Enric Sala, Pristine Seas, National Geographic Society; Juan Mayorga, Pristine Seas, National Geographic Society and University of California Santa Barbara; Darcy Bradley, Reniel B. Cabral, Christopher Costello, Steven D. Gaines and Benjamin S. Halpern, University of California Santa Barbara; Trisha B. Atwood and Audra Hinson, Utah State University; Arnaud Auber, Channel and North Sea Fisheries Unit, Boulogne-sur-Mer, France; William Cheung and Juliano Palacios-Abrantes, University of British Columbia, Vancouver; Francesco Ferretti, Virginia Polytechnic Institute and State University; Alan M. Friedlander and Whitney Goodell, Pristine Seas, National Geographic Society and Hawai'i Institute of Marine Biology; Cristina Garilao and Kristin Kaschner, Albert Ludwigs University; Kathleen Kesner-Reyes, Quantitative Aquatics, Los Baños, The Philippines; Fabien Leprieur, University of Montpellier; Jennifer McGowan, The Nature Conservancy, Arlington, Va.; Lance E. Morgan, Marine Conservation Institute, Seattle, Wash.; David Mouillot, University of Montpellier; Hugh P. Possingham, The University of Queensland Brisbane; Kristin D. Rechberger, Dynamic Planet, Washington, D.C.; Boris Worm, Dalhousie University; Jane Lubchenco, Oregon State University.

This story has been updated to reflect the changed date of the UN biodiversity conference in Kunming, China.

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