Deep-sea mining has larger-than-expected impacts on sea life, study says

The fast-growing practice of deep-sea mining poses significant threats to important sea creatures, such as fish, shrimp, corals, and sponges, according to a new study. 

Researchers say they found evidence that disturbances caused by deep-sea mining can slash populations of nearby ocean animals roughly in half and impact marine life across larger areas than scientists have previously thought.  

The study, published Friday in Current Biology, adds to evidence that mining the deep ocean for minerals used to make electric vehicles and renewable energy components has harmful ecological impacts that must be weighed against the climate benefits of transitioning away from fossil fuels. 

Although deep sea mining may be one way to meet the world’s growing demand for certain metals, “it also has the potential to greatly disrupt many deep-sea habitats,” the new paper states. 

“Is it worth it to get these [metals] and mess up the sea versus mess up somewhere else? I don’t know, but we have to use everything we have to make the right call,” said Travis Washburn, an ocean floor ecologist and author on the new study. 

Another study, released Tuesday, shows that deep-sea mining could interfere with tuna fisheries, as well. 

Calls for a moratorium 

The new research comes as multiple seafood industry groups are calling for a pause in deep-sea mining development, and nearly 20 nations have called for a moratorium or pause on the practice. Canada joined the group of opponents Monday, announcing that it supports a moratorium on seabed mining in international waters. “Seabed mining should take place only if effective protection of the marine environment is provided,” Canadian officials said in a statement.

The International Seabed Authority (ISA), an intergovernmental body established by the United Nations, meets in Kingston, Jamaica this week to discuss regulations on deep-sea mining. The ISA sets regulations for mining activities in international waters, and a mining license request to the ISA in July of 2021 triggered a clause that required the group to finalize its Mining Code before a two-year deadline which expired on Sunday. 

The Mining Code is meant to dictate where and how countries can mine the deep sea, but the ISA is reportedly far from finalizing the rules.

In May, scientists announced the discovery of more than 5,000 new species of marine organisms in an area of the Pacific Ocean regulated by the ISA. According to the National Oceanic and Atmospheric Administration, 16 mining contractors have been granted permits to explore the mining potential in 400,000 square miles of the Clarion-Clipperton Zone.

Research still emerging

Scientific knowledge about the impacts of deep sea mining on ocean life is still emerging, Washburn said, meaning the ISA must be cautious when determining how to regulate the industry.

The data that Washburn’s team gathered draws on imagery of an underwater cobalt mining site off the coast of Japan, where the Japanese government completed a short mining test by driving mining equipment over a length of the ocean floor.

The research team found that one year after that mining test, there was a 43% drop in fish and shrimp density in the areas directly impacted by sediment created from the mining test, and a 56% drop in the fish and shrimp density of nearby areas not directly impacted by sediment.

The study is one of the first to show that highly-mobile swimming species, such as fish and shrimp, may face negative effects from mining, in addition to sea stars, corals, and sponges, according to Washburn.

Another recent study of a mining test led by Washburn found that declines in animal populations at and around the deep-sea mining site persisted up to three years after the test.

Animals leave mining sites for multiple reasons, said Washburn. First, some mining directly removes rock from the surface of the ocean floor, destroying sea creatures’ habitat. Next, sediment created from mining operations enters the water and settles back on the ocean floor. Since the sediment originates deep within the rock, it doesn’t contain any organic material for fish and other marine animals to feed on, meaning that animals living where sediment settles are locked out of their food source.

The deep sea is the “life support system of the world,” said Washburn. “If you start messing up this large area, it’s gonna affect everything. People need to be aware of this to make educated decisions on what to do.”