Deep-Sea Mining Tests Show Reduction in Seabed Animal Populations
A recent study has assessed the ecological impact of deep-sea mining machinery on seabed environments. Scientists reported a measured reduction in animal populations within areas affected by test mining operations. The research identified over 4,000 animal species in a remote Pacific Ocean region, with 90% previously unrecorded.
The deep ocean is estimated to contain substantial quantities of critical minerals, which are essential for green technologies. However, deep-sea mining in international waters is a subject of ongoing discussion, with operations currently not permitted pending further assessment of its environmental consequences.
Study Methodology and Findings
The study was conducted by scientists from the Natural History Museum in London, the UK National Oceanography Centre, and the University of Gothenburg. It was initiated at the request of The Metals Company. The researchers affirmed their independence, noting that the company had access to the results prior to publication but no authority to modify them.
The team compared biodiversity data collected two years before and two months after test mining activities. During these tests, machines traversed 80 kilometers of the seafloor. The investigation focused on macrofauna, animals ranging from 0.3mm to 2cm in size, including species such as worms, sea spiders, snails, and clams.
Findings indicated a 37% decrease in the number of animals and a 32% reduction in species diversity within the vehicle tracks. Lead author Eva Stewart, a PhD student at the Natural History Museum and the University of Southampton, stated that the machinery removes approximately the top five centimeters of sediment, which constitutes the primary habitat for most of these animals.
Dr. Guadalupe Bribiesca-Contreras from the National Oceanography Centre suggested that pollution from mining operations could affect less resilient species and raised questions about the potential for animal populations to recover post-disturbance. Conversely, in areas adjacent to the vehicle tracks where sediment clouds settled, no decrease in animal abundance was observed, though a shift in dominant species occurred, according to Dr. Adrian Glover, a research scientist at the Natural History Museum.
Industry and Expert Perspectives
A spokesperson for The Metals Company acknowledged the data, noting that the observed biodiversity impacts were confined to the directly mined areas.
Dr. Patrick Schröder, a senior research fellow at the Environment and Society Centre at Chatham House, commented that the study's findings suggest current harvesting technologies may be too damaging for large-scale commercial exploitation. He highlighted that even the tests demonstrated a measurable impact, implying a potentially greater impact if scaled commercially.
Broader Context and Future Considerations
The discussion surrounding deep-sea mining stems from the requirement for critical minerals to support renewable energy technologies, such as solar panels, wind turbines, and electric vehicles, which are essential for addressing climate change. The International Energy Agency forecasts a potential doubling of demand for these minerals by 2040.
The research area, the Clarion-Clipperton Zone in the Pacific Ocean, spans 6 million square kilometers and is estimated to contain over 21 billion tonnes of polymetallic nodules rich in nickel, cobalt, and copper.
However, scientific and environmental organizations express concerns regarding the potential for substantial ecological impact on the undiscovered deep ocean, an environment critical for planetary regulation and already susceptible to rising temperatures.