Deep-Sea Mining and Warming Trigger Stress In

Helmet jellyfish in the North Pacific: A churning seabed causes Periphylla periphylla to produce more mucus than usual.

Extracting minerals from the seafloor could harm deep-sea inhabitants, according to a recent study. Researchers investigated for the first time how underwater mining affects animals living in the water column. Sediment stirred up by mining sites could stress creatures like jellyfish, as reported in the journal Nature Communications.

Minerals such as manganese, iron, and cobalt, in demand for various industries, are also present in the oceans. Plans are underway to extract them on a large scale for commercial purposes, with proponents arguing their necessity for manufacturing batteries for electric vehicles. However, scientists caution that too little is known about the consequences of seabed mining.

Previous research has primarily focused on benthic organisms. Still, this study explores the impact on swimming organisms, particularly deep-sea helmet jellyfish (Periphylla periphylla). Vanessa Stenvers and her team from the GEOMAR Helmholtz Centre for Ocean Research Kiel captured specimens from Norwegian fjords, placed them in test tanks on their research vessel, and simulated sediment clouds to observe the jellyfish’s response.

The researchers explained that mining activities, such as extracting manganese nodules from the seafloor, result in the stirring of fine rock particles, creating sediment clouds that can spread for tens to hundreds of kilometers. This can affect animals both on the seafloor and at depths ranging from 200 to 4000 meters. Since this zone typically has low sediment levels, the team suggests that animals in this area are highly sensitive to the sediment clouds caused by mining.

One notable result of the experiments was that jellyfish exhibited clear signs of stress when sediment levels exceeded 17 milligrams per liter. The researchers described how particles adhered to the jellyfish, leading to excessive mucus production, which is an unnecessary energy expenditure. The long-term impact of this stress could be detrimental to the jellyfish.

Deep-sea Mining Applications Can Already Be Submitted

While researchers are just beginning to understand the possible consequences, countries have already expressed interest in deep-sea mining. The International Seabed Authority (ISA) has already granted numerous licenses for the exploration of resources in an area exceeding 1.5 million square kilometers to individual states, including Germany.

However, initial discussions on opportunities, risks, and necessary regulations concluded in the summer without any binding decisions. During the ISA session, the 36 member states only agreed on the objective of adopting a regulatory framework by the year 2025.

No specific solution was decided upon for how to assess applications for deep-sea mining, which can now be submitted to the ISA for the first time. The Pacific state of Nauru had previously announced its intention to collaborate with the Canadian company The Metals Company (TMC) to extract manganese nodules from the seabed at depths ranging from 4000 to 6000 meters.

Featured Image: A helmet jellyfish (Periphylla periphylla), Vanessa Stenvers.