This article originally appeared in Conservation News on October 29, 2020.
A team of researchers recently discovered three new species of black coral in the North Pacific — each more than 670 meters (2,221 feet) below the ocean’s surface.
While the lifespans of these particular species are not yet known, black corals are among some of the longest-living animals on the planet, thriving on the deep-sea floor, where conditions are typically as stable as the perpetual darkness.
But these conditions may not remain stable for long, according to Daniel Wagner, co-author of this research and a marine scientist at Conservation International.
Although active mining has not yet begun, mining companies have already started to prospect the deep sea for rare metals and minerals — which could put deep-sea coral and the species they support at risk.
Conservation News spoke to Wagner about how these new coral species could be affected by deep-sea mining — and what must be done to protect them.
Question: How did you find these new coral species?
Answer: Given that these black coral species were found hundreds of meters below “scuba diving level,” we needed the help of underwater robots to explore the deep-sea floor. Working with the National Oceanic and Atmospheric Administration, we used small robots equipped with cameras — known as remotely operated vehicles (ROVs) — to collect samples of coral and videos of the seafloor that were broadcasted on the internet in real time. Using the ROVs, we found a variety black coral species on underwater mountains and ridges across a range of deep-sea locations, including around the Hawaiian Islands, California and the high seas waters of the North Pacific.
Once we had the samples, we were able to determine if they were a new species or not. In birds, you can typically identify a species by the appearance of its feathers or its beak, but for coral, you need to look at their skeletons under a microscope. On the three new species that we found, tiny microscopic features on their skeletons allowed us to differentiate them from other species of coral.
Q: What makes these species interesting?
A: Some recent scientific studies have shown the black corals actually produce bioactive compounds that could potentially be used to fight diseases. In fact, remedies made out of black coral have been used in many cultures throughout China, Hawai‘i and Greece for centuries. Recent studies have found that many black corals harbor compounds that could help us find clues to fight cancer and other diseases.
Another interesting trait about black corals is their prolonged lifespan. Similar to trees, black corals form growth rings which can be used to determine their age. They are generally long-lived, with lifespans of different species ranging from centuries to millennia. In fact, one black coral species found in deep waters around the Hawaiian Islands has been found to live more than 4,250 years. The reason they can live so long is because they are slow-growing and inhabit environments that have remained stable over very long periods of time.
Q: What could disrupt their environment?
A: The biggest impending threat to deep-sea corals and other species inhabiting these environments is deep-sea mining. The three new species of black coral species that we discovered were found in the heart of the Prime Crust Zone — an area of the Pacific Ocean with some of the highest known concentrations of commercially valuable deep-sea minerals. The seafloor in this region is carpeted by a thick, black crust that contains manganese, iron, cobalt, copper, nickel, platinum and other trace metals — and many mining companies are eager to start prospecting it. The problem: Research indicates that deep-sea mining is likely going to have devastating impacts to marine biodiversity. In essence, deep-sea mining requires large machines to scrape the seafloor, killing any fish, coral or small creatures living there. And that is just the most immediate impact — there are more indirect impacts from the sediment plumes, light, toxins and noise generated by deep-sea mining that will negatively affect marine life far beyond actual mining sites. If deep-sea coral reefs and other species are affected by this process, it will take an extremely long time for them to recover — if they can recover at all.
Q: What can be done?
A: More time is needed to study the deep sea and increase our understanding of the risks associated with deep-sea mining. Currently, only 20 percent of the deep seafloor has been mapped, and even in that small area, we’ve found a wealth of marine life, including more than 116 coral reefs flourishing throughout the high seas. There are many other high-biodiversity areas throughout our ocean that have yet to be discovered. Before any deep-sea mining takes place, we need to understand where the most vulnerable and special ecosystems are located, so we can protect them.