It spans half the planet and supports our oldest known lifeforms, but we still know so little about our planet’s deep ocean. Almost every time a voyage is made, scientists discover new species in the depths.
The scale of what we still have to learn is exemplified in a new study that focuses on one rather unassuming deep-sea dweller: the brittle star. Scientists from the German Center for Marine Biodiversity Research and Museums Victoria in Australia analyzed brittle stars that had been collected from within the Clarion Clipperton Fracture Zone (CCZ), a deep-sea region between Hawaii and Mexico in the eastern Pacific Ocean.
Using DNA sequencing, the scientists were able to map the invertebrates’ lineages very precisely, with impressive results: they discovered “unprecedented” levels of biodiversity. “There were whole lineages that we’d never come across before,” says Tim O’Hara, a senior curator at Museums Victoria and one of the report’s lead authors. “Some of them were as distant as 70 million years from any other species that we knew about.”
It’s the first time a study of this kind has taken place in the CCZ. “You see some spectacular things,” says O’Hara, “and I can imagine that’s going to be repeated in other groups, too.” The research was not, however, a simple exercise in scientific curiosity. Scientists and environmentalists are scrambling to chart species and pinpoint biologically-sensitive areas on the Pacific Ocean’s seabed ahead of a possible “gold rush” for minerals such as manganese, cobalt, and nickel.
These minerals are currently used to produce rechargeable lithium-ion batteries for products like portable electronics and electric cars, as well as for military and aerospace applications. As such, their value has skyrocketed in recent years, and ocean deposits have caught the attention of a number of companies.
But the environmental costs of scraping minerals off the seafloor are difficult to fathom. Mining would create a plume of dislodged sediment that would float in the water, “and this is an area that hasn’t had sedimentation like that for tens of millions of years,” says O’Hara. “That’s the real fear: that not only is it taking some substrate from the seafloor, but you might also smother a whole lot of other animals over a much greater area.”
Considering that Pacific Island countries often have few sources of income due to their isolation, limited natural resources and low populations, it’s easy to see why potential profits from licensing companies to mine the seabeds of their exclusive economic zones (EEZs) might be tempting.
But Pacific Islanders remain divided on whether or not it’s a good idea. At the Pacific Islands Forum in Tuvalu in August, Fijian Prime Minister Frank Bainimarama floated the idea of a 10-year moratorium on seabed mining across the entire Pacific Ocean to allow for sufficient research into the likely biodiversity impacts.
The bid was supported by Vanuatu and Papua New Guinea, but other countries opposed the move, including the Cook Islands, which has since begun mining exploration. Its seabed minerals authority said in a statement in October that “the Cooks are set to be the frontier of the new gold rush” and that the country could be ready to begin mining in under five years’ time. “I see us as taking the lead,” said deputy prime minister Mark Brown.
Within the Cook Islands, though, there is considerable opposition to the idea. The country made world headlines in 2017 when it created the world’s biggest mixed-use marine protected area (MPA), which spans its entire EEZ and is named Marae Moana (Sacred Ocean). But when Marae Moana’s co-founder and then-director, Jacqueline Evans, suggested to the government that they support the moratorium – in line with the MPA’s principles of sustainable use and biodiversity preservation – she was dismissed from her role.
The sacking caused public outcry and raised concerns about the country’s increasingly dictatorial style of government. “I was told that we live in a country where we have free speech,” said Evans in a statement; “I said it certainly doesn’t seem that way when I’m being sacked for expressing my opinion.”
The upcoming Conference of the Parties of the U.N. Framework Convention on Climate Change (COP 25) in Madrid aims to put the world’s oceans in the spotlight and encourage countries to include ocean-related initiatives and marine biodiversity protection in their nationally-determined contributions (NDCs) to the Paris Agreement on climate change mitigation.
“People dismiss the deep sea as being unimportant, but collectively, that abyssal fauna is hugely important in terms of biomass,” says O’Hara. “So it’s crucial to know what’s there – and that things there are special.”