Bad effect of mining on whales
A team of experts believes that impact assessments of such activities have focused on seabed species rather than large animals passing through areas where mining is planned, and that research is urgently needed to understand the potential impact on cetaceans.
However, one mining company states that the potential impact of planned activities on cetaceans is being assessed by examining acoustic data collected during its recent mining test in the Clarion-Clipperton.
In a new article published on the Frontiers in Marine Science website , scientists from the University of Exeter, Greenpeace Research Laboratories and Oregon State University argue that proposed deep-sea mining operations would likely produce a range of noises with frequencies equal to those used by cetaceans to communicate, which can potentially lead to changes in these animals regarding their behavior.
The authors say that most assessments of the potential impact of deep-sea mining on biodiversity have focused on “bottom-bound species and not large, transient animals” such as whales and dolphins.
Small pod of dolphins. The potentially imminent start of international deep-sea mining activities could affect whales, dolphins and porpoises, notably through noise pollution. Image by Jeremy Bishop obtained via Pexels (Public domain).
Deep-sea mining activities could begin in the near future
As countries strive to reduce greenhouse gas emissions, there is growing demand for such materials for renewable energy technologies such as wind turbines, solar panels and electric car batteries . According to a 2021 report from the International Energy Agency, such minerals are currently mined on land but the quantity is lacking to achieve the energy transition.
Those in favor of deep-sea mining believe that such activities will enable a substantial and necessary supply of metals for the transition to climate-friendly energy sources. They add that seabed mining will be much less destructive than mining on land.
However, those against it believe that too little is known about deep-sea habitats and the species that live there to adequately assess the impact that deep-sea mining activities may have on the oceans. They also believe that, based on current knowledge, such extractive activities appear likely to cause irreparable damage to the ancient marine ecosystems that help support all life on the planet.
In June 2021, the Pacific island state of Nauru, favoring the operations of a subsidiary of the Canadian company The Metals Company (TMC), resorted to a “two-year rule” provided for in the United Nations Convention on the Law of sea (UNCLOS) to urge the ISA to allow deep-sea mining to begin within two years regardless of the rules in place at the end of that period.
Following Nauru's request, the ISA has scheduled a series of meetings so that the rules on mining activities are defined within two years and such activities can begin. While some ISA member states are in favor of doing so, others, including France, Chile, New Zealand and Palau, have called for a moratorium, a “preventive pause” or even a total ban on mining in deep waters. Many conservation scientists and companies such as Renault, Rivian, BMW and Samsung SDI also oppose deep-sea mining.
The ship is chartered by Global Sea Mineral Resources (GSR), a Belgian company that carries out research aimed at extractive activities in the deep waters of the Pacific. Image © Marten van Dijl/Greenpeace.
“Sensitive to noise”
According to the new paper, cetaceans “produce and detect sounds in some specific frequency ranges” for communicative purposes regarding feeding, social interactions and reproduction. The authors argue however that deep-sea mining activities could compromise such behaviors with the transmission of different anthropogenic sounds at various frequencies (from the equipment used for extraction, operation. Low-frequency sounds, such as noise from ships on the surface, could travel hundreds of kilometers into the ocean, potentially affecting cetaceans across a wide area. The authors believe it is “reasonable to expect” that commercial mining will take place 24 hours a day.
The report draws particular attention to the Clarion-Clipperton fracture zone, a 4.5 million square kilometer area in the Pacific Ocean designated for deep-sea mining, which provides habitat for 30 species of cetaceans, including sperm whales ( Physeter macrocephalus ), fin whales ( Balaenoptera physalus ) and critically endangered blue whales ( Balaenoptera musculus ).
The test was the subject of controversy after scientists tasked with monitoring its progress leaked a video showing sediment being dumped on the ocean surface, raising questions about the environmental impact of mining activities. A 2020 report suggested that dumping the material may be environmentally destructive due to the dispersion of sediment and dissolved metals . In a response published on its website, the TMC called the incident a “case of limited significance” that “could not cause damage to the marine habitat.”
Thompson, of the University of Exeter, believes it is important to ensure there are peer-reviewed scientific assessments of mining noise and its impact on cetaceans, but that such assessments have not yet been published.
“We know that noise pollution in the oceans is already a problem for cetaceans and starting a new type of activity that would last 24 hours a day, 7 days a week would inevitably create more anthropogenic noise if mining activities in deep waters were to continue,” says Thompson. “Despite the lack of information, it appears that industrial-scale mining may soon begin in one of the few untouched habitats on the planet.”
School of sperm whales. Image courtesy Amanda Cotton/ The Ocean Agency .
According to the report, noise is not the only aspect that could negatively affect cetaceans. The latter could also be affected by the sediment plumes generated by the means of extraction activities on the seabed, as well as by the discharge of sediments which could "make the water columns more turbid and cause the movement of contaminants".
In an email to Mongabay, Rose states that “the impact could also be considerable on cetaceans, as it has already been shown that species that periodically dive to such depths.
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