Scientists Expected This Underwater Mountain Range to Be Barren. They Found Life Instead

After about 40 years of federal protection, destroyed underwater mountain ecosystems are showing signs of life.

The Northwest Hawaiian Ridge and the Lower Emperor Seamount Chain are underwater mountain ranges located in the deep sea that are home to coral communities, vulnerable marine ecosystems that hosts many rare organisms. These mountain ranges were heavily fished in the 1960s through the 1980s, leaving scars, rubble, lost gear, and destroyed coral communities on these seamounts.

Based on the level of destruction, scientists didn’t expect to find any signs of recovery during a recent check-in. To their surprise, they found that these ravaged underwater mountain ranges are in the process of being revived.

Researchers from Florida State and Texas A&M took thousands of images of the surface of seven seamounts to catalog what organisms lived there, according to a study published on Wednesday in Science Advances. They found coral over trawl marks and reef-forming coral growing out of discarded trawl nets. They found sponges, sea stars, jellyfish. Though some slow-growing, rare corals were absent, the communities looked as if they were starting to recover.

“We expected to be writing a paper that said there was no recovery after 40 years,” lead author Amy Baco-Taylor said. “We’re really excited that that’s not the case.”

Scientists theorize that federal protection is to thank for the amazing recovery of these underwater mountains. In 1997, the US government created an exclusive economic zone that included four of the seamounts. The ordinance meant that no other country could fish there, and put those seamounts on the path to recovery. The other three are still trawled.

The protected seamounts are recovering the most, but there was some recovery even in those seamounts that are still trawled. Fishers move around, trawling different areas on the seamount, which allows some areas to start the recovery process, according to the researchers.

The two seamounts with the healthiest recovering communities—called Northeast and Southwest Hancock—were included in the 2016 expansion of the Papahānaumokuākea Marine National Monument, the largest conservation area on earth. This expansion, carried out under President Obama, is one of the many monument expansions that the Department of Interior is currently considering rolling back.

“Having long-term protection for those areas is allowing the recovery process,” Baco-Taylor said. “You see a lot of destruction, but it shows that protecting these areas can make a difference and recovery can happen.”

The deep sea is often depicted as a lifeless area, but scientists have recently begun to understand seamounts as important underwater communities. According to Baco-Taylor, they’re regions of high biodiversity, and their relative isolation makes them an important place for speciation.

The study draws a clear line between intensive land-use and poor ecosystem health, and shows how official protection can help ecosystems recover. At a time when environmental protections are under increasing attack, this study shows that federal protections work.