A deep-sea mission in the ocean around Bermuda confirms the existence of a new oceanic zone, Geographical reports.
"You almost pinch yourself and think you’re on some distant planet," explains Professor Alex Rogers as he reminisces about his dives into the deep ocean around Bermuda. For him, every trip in the Triton submarine, whose clear dome provides an unprecedented view of the ocean’s inhabitants, is magical. "There’s always something novel to see and the landscapes are fantastical. It’s a very humbling experience," he adds.
Rogers is a co-founder of Nekton, an organisation exploring the depths of the ocean for the benefit of humankind. In July 2016, Rogers and a team of marine scientists launched Nekton’s ‘Mission I’ to investigate the ocean around Bermuda, the Sargasso Sea and the northwest Atlantic. During the mission, dive teams, manned submarines and remote-controlled vehicles collected thousands of samples from the ocean’s surface down to 1,500 metres. Now, nearly two years later, the results of the mission have been processed and the team has announced some striking finds.
There was a great deal beneath the waves to excite the Nekton team, but the most important discovery of all was the existence of a new zone in the ocean, dubbed the ‘rariphotic’ (or ‘rare light’) zone. First mentioned by Dr Carole Baldwin from the Smithsonian Institute in March 2018, and now confirmed by the Nekton mission, the rariphotic zone extends from 130m to 300m and is the fourth zone confirmed in the top 3,000m of the ocean.
The rariphotic zone was identified by examining the unique biological communities that congregate at those depths. Each of the four ocean zones – altiphotic (0m to 40m), mesophotic (40m to 130m), rariphotic (130m to 300m) and bathyal (300m to 3,000m) – are characterised by these distinct groups of sea-life. For the Nekton researchers, understanding the zones and their different inhabitants is vital for improving understanding of ocean biodiversity and patterns of life.
At the moment, that understanding is limited. One impact of the mission’s results was to reveal just how much we still don’t know. Rogers and his team were amazed to discover over 100 new species around Bermuda, mostly in the rariphotic zone, including more than 40 new species of algae, a new black coral and at least 13 new crustaceans.
‘Given that Bermuda is such a well-studied area in general terms, we really weren’t expecting to find as many new species,’ says Rogers. ‘We found a new species of black coral. They looked like big forests of coiled bed springs. Discovering an animal that large and learning that it makes up a community that was not known to be around the islands of Bermuda was a really nice thing to find.’
Each discovery made bears its own wider significance and Nekton is currently preparing policy recommendations for the Bermudan government in light of the research. One of the most significant finds was a number of lionfish, an invasive species, as far down as 300 metres, the deepest recorded evidence of their troubling presence. Lionfish are capable of reducing populations of smaller fish on a reef by nearly 90 per cent in just five weeks. While policies to control them in shallow waters have had some success, their discovery in deeper water requires further action.