Deep-sea mining can catastrophically damage marine life and habitats after just two hours, reveals new research.
Long-term analysis of a seabed in the northwest Pacific Ocean following a short mining test in 2020 found that shrimp and fish populations nearly halved both at the mining site and in the surrounding areas.
The Japanese test was the first to successfully extract cobalt crusts from the top of deep-sea mountains to mine cobalt – an essential mineral in making electric car batteries.
But scientists found that not only did the mined areas become less habitable for ocean animals, but the harmful plume of sediment it led to also spread around the surrounding waters.
The study warns that even short mining sessions such as this could be impactful on ocean populations both in and around the mining zone, and may influence new regulations soon to be announced by the International Seabed Authority (ISA).
A team of scientists working with the Geological Survey of Japan collected and analyzed data from three of Japan’s visits to the Takuyo-Daigo seamount in the Pacific: a month before, a month after and a year after the mining tests.
Following a seven-day boat trip, a remotely operated vehicle was dispatched to the seafloor to collect video footage of the impacted areas.
The study did not observe any major changes in less-mobile ocean animals such as coral and sponges – though these would likely be impacted by longer-term mining operations.
But the scientists surprisingly discovered the small-scale mining test – which lasted a mere two hours – led to a 43 percent reduction in fish and shrimp density in areas directly impacted by sediment pollution.
However, the alarming data also indicated a drop of more than half (56%) in the density of fish and shrimp populations in the surrounding areas of the mining site.
The research team, though acknowledging there could be various explanations for this decline in fish populations, believes the short mining test may have been responsible for contaminating fish food sources.
Dr. Travis Washburn, a benthic ecologist and first author of the study – published in the journal Current Biology – admitted his surprise at how such a short-lived test could have such long-standing and widespread consequences.
“I had assumed we wouldn’t see any changes because the mining test was so small,” he explained.
“They drove the machine for two hours, and the sediment plume only traveled a few hundred meters – but it was actually enough to shift things.”
The ISA, which has authority over seafloor resources outside a given country’s jurisdiction, is soon to implement a fresh set of deep-sea mining regulations.
But for companies looking to mine the ocean’s floor for minerals such as cobalt, copper, and manganese, the ISA is required to either adopt a set of exploitation regulations or consider mining exploitation under existing international laws due to come into effect this month.
Though the study team admitted their research needed to be repeated several times to gain a more accurate understanding of how deep-sea mining impacts the ocean floor, Dr. Wasburn recognized this initial experiment’s importance.
“These data are really important to get out,” he said.
“A set of regulations is supposed to be finalized soon, so a lot of these decisions are happening now.
“We’re going to need more data regardless, but this study highlights one area that needs more focus.
“We’ll have to look at this issue on a wider scale because these results suggest the impact of deep-sea mining could be even bigger than we think.”
Produced in association with SWNS Talker
Edited by Saba Fatima and Asad Ali
