Sign In
International
Media release
From:
Ocean animals vacate areas both around and outside deep-sea mining operations
In 2020, Japan performed the first successful test extracting cobalt crusts from the top of deep-sea mountains to mine cobalt—a mineral used in electric vehicle batteries. Not only do directly mined areas become less habitable for ocean animals, but mining also creates a plume of sediment that can spread through the surrounding water. An investigation on the environmental impact of this first test, published July 14 in the journal Current Biology, reports a decrease in ocean animals both in and around the mining zone.
The International Seabed Authority (ISA), which has authority over seafloor resources outside a given country’s jurisdiction, has yet to finalize a set of deep-sea mining regulations. However, 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 starting July 9.
“These data are really important to get out,” says first author Travis Washburn, a benthic ecologist who works closely with the Geological Survey of Japan. “A set of regulations is supposed to be finalized soon, so a lot of these decisions are happening now.”
The team analyzed data from three of Japan’s visits to the Takuyo-Daigo seamount: one month before the mining test, one month after, and one year after. After taking a seven-day boat trip from port, a remotely operated vehicle went to the seafloor and collected video of the impacted areas. One year after the mining test, researchers observed a 43% drop in fish and shrimp density in the areas directly impacted by sediment pollution. However, they also noted a 56% drop in the fish and shrimp density of surrounding areas. While there are several possible explanations for this decrease in fish populations, the team thinks it may be due to the mining test contaminating fish food sources.
The study did not observe a major change in less mobile ocean animals, like coral and sponges. However, the researchers note that this was only after a two-hour test, and coral or sponges could still be impacted by long-term mining operations.
“I had assumed we wouldn’t see any changes because the mining test was so small. They drove the machine for two hours, and the sediment plume only traveled a few hundred meters,” says Washburn. “But it was actually enough to shift things.”
The researchers note that they will need to repeat this study several times to gain a more accurate understanding of how deep-sea mining impacts the ocean floor. Ideally, multiple years of data should be collected before a mining test occurs to account for any natural variation in ocean animal communities.
“We’re going to need more data regardless, but this study highlights one area that needs more focus,” says Washburn. “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.”
###
This work was supported by the Agency for Natural Resources and Energy of Japan, the Research Laboratory on Environmentally-Conscious Developments and Technologies, and the UK Natural Environment Research Council. The authors declare no conflicts of interest.
Expert Reaction
These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.
Professor James J. Bell, School of Biological Sciences, Victoria University of Wellington
Seamounts are important biodiversity hotspots in generally deeper water environments and there is increasing interest globally in mining seamounts for valuable minerals. However, such mining activities both physically disturb the seafloor, mechanically damaging organisms, and create sediment plumes that can be transported outside the immediately mined area and impact marine organisms far away from the mined site.
This paper is particularly interesting as most previous work has focused on how non-mobile animals, such as sponges and corals, might be impacted by sediment plumes, but this study also focused on mobile animals.
The link between the detrimental impacts of sediment plumes and non-mobile organisms is perhaps more obvious as these organisms can’t escape the plume and maybe smothered or have their feeding apparatus blocked. However, this study found this was not the case and in fact it was only the abundance of mobile fauna that were impacted by the mining, and these impacts persisted for more than a year after the mining took place.
Given that seabed mining is being considered by many states across world, including New Zealand, due to the increasing demand for consumer electronics and other commercial products, it is vitally important for us to understand the impacts of mining on seamount communities.
These results demonstrate just how susceptible the marine communities associated with seamounts might be to the impacts of mining and that these impacts could be long-lasting. Importantly, this study also shows that even very small scale mining activity can have lasting impacts. Until we have a full understanding of what the impacts of mining is on these ecosystems, we should take a very cautious approach.
Associate Professor Kat Bolstad, Department of Environmental Science, Auckland University of Technology
The deep sea is full of life. These habitats seem extreme to us, but life has survived, thrived, and diversified here for billions of years. Many of these lives are conducted across time scales that we have trouble imagining—some microbes may divide only once every thousand years. Some fish live for centuries. Abrupt disturbances are rare, and deep-sea life has evolved within these stable conditions.
Enter deep-sea mining: catastrophically destructive to the immediate seafloor, and producing noise, vibrations, clouds of sediment, and other impacts that we cannot yet fully predict. The effects of large-scale deep-sea mining are likely to be substantial, longer lasting, and more complex than we can anticipate.
This study is a great example; it shows that many mobile animals predicted to be ‘less impacted’ because they can move away from mining disturbances not only do so, but are then slow to return. This suggests that disruptions to the ecosystem last far beyond the immediate mining event.
There is widespread scientific agreement: We need a far greater understanding of deep-sea ecosystems before we can make responsible decisions. An increasing number of countries (including Aotearoa) and Indigenous groups are calling for a moratorium or outright ban on commercial-scale deep-sea mining. Authorities are under great pressure to determine the future of this proposed industry, but I hope we will not rush into this, and that future generations can look back at this moment and see that we acted in their—and our planet’s—best interests.
Multimedia
Attachments
Note: Not all attachments are visible to the general public. Research URLs will go live after the embargo ends.
