According to scientists, projected deep-sea mining might cause noise pollution that would radiate through the ocean for hundreds of kilometers, generating a “cylinder of sound” that would go from the surface to the sea bed.
One mine’s noise alone could travel 500km (more than 300 miles) in calm weather, according to research 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 that was published in the journal Science.
There are a lot of mineral-rich lumps known as polymetallic nodules in the Clarion-Clipperton Zone (CCZ), an area spanning 4.5 million square kilometers between Mexico and Hawaii, and seventeen contractors with exploration licenses are considering the prospect of mining it.
If each of these mining corporations opened a mine in the CCZ, scientists calculated the noise impact. They discovered that noise levels in a 4-6 km radius around each mine could be higher than the US National Marine Fisheries Service’s standards, which raise the possibility of behavioral effects on marine mammals.
The CCZ is home to several marine animal species, including deep-diving toothed whales and endangered migratory baleen whales, which are known to be noise-sensitive. In the absence of sunshine, it is thought that many deep-sea organisms, about which very little is known, use sound and vibrations to navigate, communicate, and find predators. According to the authors of the report, which was supported by the Pew Charitable Trusts, underwater noise is likely to “alter ecosystems.”
Travis Washburn, a deep-sea ecologist at AIST, stated that the deep water “holds possibly millions of species that have yet to be identified, and processes there allow life on Earth to exist.” He claimed that even while there was still much to be done on the effects of noise, there was still time to comprehend them and take precautions against them.
The International Seabed Authority research, whose results have consequences for mining laws, claims that the impact of noise pollution from deep-sea mining is “understudied and underestimated” (ISA).
The island nation of Nauru in the Pacific Ocean has declared its intention to begin deep-sea mining and invoked a UN resolution from two years ago, which might compel the ISA to finish the rules allowing deep-sea mining by next July. The Science report comes in response to widespread worries from governments, businesses, and environmental organizations that deep-sea mining science and governance are still insufficient for prospecting to proceed.
The paper stated that moving forward without clear and strict rules in place “would mark the beginning of a large-scale, uncontrolled experiment.” The authors recommended the ISA to follow the “precautionary principle” and limit the number of deep-sea mining to one or two until the effects of noise pollution could be fully understood.
Deep-sea mining noise levels were substituted in their analysis for those produced by current industrial processes like dredging and oil and gas exploration. According to the research, operating one mine by each of the 17 companies would result in excessive noise levels throughout a 5.5 million square kilometer area, an area much greater than the European Union.
“If our modeling is true, it could demand reassessment of environmental restrictions, including the amount of mining operations authorized within the Clarion-Clipperton Zone,” said Craig Smith, co-author and professor emeritus of oceanography at the University of Hawaii.
Currently, businesses are expected to research the planned mining zones and contrast them with control areas on their locations where no mining would occur. “Preservation reference areas” are what these are called. Up to 75,000 sq km are available to any contractor.
Nowhere in the 75,000 km2 area, according to “our models, is free from noise impact,” Smith said. “The rules may need to be changed to move the control areas farther away.
“We haven’t been able to do the investigations, but if mining operations continued at the same time, it might have a significant influence on a number of organisms,” said the researcher.
The authors also demanded transparency because they were unable to locate peer-reviewed information on the noise levels of the few deep-sea equipment that have been tested. In the study, they urged “contractors to promptly submit information on sound-source characteristics of all seabed-mining components.”
The scientists assert that because the machines they modeled operate in shallower water, their results are likely to understate noise levels. Additionally, they might have missed the acoustic energy produced by louder deep-sea machinery, pumps, and other sound sources.
The ISA is in charge of guarding against “severe harm” from sea-bed mining to the marine ecosystem. The paper states that while it has guidelines for evaluating the effects of noise, it has not yet specified what constitutes substantial harm, such as unacceptable noise levels.
The ISA stated in a statement: “The procedures for environmental baseline investigations, environmental impact assessments, and monitoring, as laid out in exploration and future exploitation regulations, ensure adequate preservation of the marine environment.”
It added that testing will give a “greater knowledge of the possible impact of noise” on the deep sea bed and deep sea biodiversity. Test mining and testing of mining components require an environmental impact assessment, which includes noise monitoring.
Lead Image: A family of humpback whales in the National Marine Sanctuary off the coast of Maui, Hawaii. Cetaceans are highly sensitive to noise. Photograph: NOAA/Alamy. This article by Karen McVeigh was first published by The Guardian on 8 July 2022.
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