An analysis by scientists from the Oceans Initiative in the US, the National Institute of Advanced Industrial Science and Technology (AIST) in Japan, Curtin University in Australia and the University of Hawaii, published in the journal Science, found that noise from a mine alone could to travel 500 kilometers (over 300 miles) in mild weather. Seventeen contractors with exploration licenses are considering the possibility of mining the Clarion-Clipperton Zone (CCZ), an area of 4.5 sq. m. The scientists estimated the noise impact if each of these mining companies launched a mine in the CCZ. They found that noise levels within a 4-6 kilometer radius of each mine could exceed limits set by the US National Marine Fisheries Service, above which there are risks of effects on the behavior of marine mammals. Marine mammal species known to be sensitive to noise are found throughout the CCZ, including endangered migratory whales and deep-diving toothed whales. Many deep-sea species – about which very little is known – are believed to use sound and vibrations to navigate, communicate and detect predators in the absence of sunlight. Underwater noise is likely to “disrupt ecosystems,” said the authors of the paper, which was funded by the Pew Charitable Trusts. “The deep sea is home to potentially millions of species that have yet to be identified, and the processes there enable life to exist on Earth,” said Travis Washburn, a deep-sea ecologist at AIST. While much work remained to be done on the effects of noise, he said, there was still an opportunity to understand and mitigate them before they occurred. The impact of noise pollution from deep-sea mining is “understudied and overlooked”, according to the report, whose findings have implications for mining regulations drawn up by the International Seabed Authority (ISA). The Pacific island of Nauru has said it plans to start deep-sea mining and invoked a UN rule two years ago that could force the ISA to finalize regulations allowing deep-sea mining by next July. The Science study follows widespread concerns from governments, companies and environmental organizations that the science and governance of deepwater mining remains insufficient to move the search forward. Proceeding without strict and transparent standards “would represent the beginning of a large-scale, uncontrolled experiment,” the report said. The authors urged the ISA to use the “precautionary principle” and, in the case of deep ocean exploitation, ensure that only one or two mines are operated at a time until the impact of noise pollution is fully understood. A beached whale on the Pacific coast of Mexico. Many marine mammals, known to be sensitive to noise, are found throughout the main mining zone. Photo: Guillermo Arias/AFP/Getty Their analysis used noise levels produced by existing industrial processes, such as dredging, oil and gas exploration, as proxies for deep-water mining. The findings suggest that if all 17 contractors were to operate one mine each, it would cause increased noise levels over an area of 5.5 square kilometers – much larger than the European Union. Craig Smith, co-author and emeritus professor of oceanography at the University of Hawaii, said: “If our modeling is correct, it could require a review of environmental regulations, including the number of mining operations allowed in the Clarion-Clipperton zone.” Companies are currently required to study areas where mining is proposed and compare them to control areas within their sites where no mining will take place. These are known as ‘conservation reference areas’. Each contractor has up to 75,000 sq.km. “Our models indicate that nowhere in … the entire 75,000 square kilometers is free of noise,” Smith said. “The regulations may need to be changed so that the control areas are further apart. “We weren’t able to do the studies, but if mining was going on at the same time, it could have a big impact on a whole bunch of organisms.” The authors, who were unable to find peer-reviewed data on the noise levels of the few deep-sea engines that have been tested, also called for transparency. “We urge contractors to make public information on the sound source characteristics of all bottom mining components in a timely manner,” they wrote in the report. Their findings are likely to underestimate noise levels, the scientists suggest, because the machines they modeled operate in shallower water. They were also likely to have missed the acoustic energy produced by heavier deep-sea machinery, as well as support ship pumps and other sound sources. The ISA is charged with protecting the marine environment from “serious harm” from seabed mining. While it has recommendations for assessing noise impacts, it has yet to define what constitutes serious harm, including unacceptable noise levels, according to the report. In a statement, the ISA said: “Effective protection of the marine environment is ensured through the requirements for environmental baseline studies and environmental impact assessments and monitoring as set out in the Exploration and Futures Exploitation Regulations.” Test mining and testing of mining components requires an environmental impact assessment, which includes measuring noise, he said, adding that the tests will provide “a better understanding of the potential impacts of noise” on the seabed and deep-sea biodiversity.
