A unique study indicates that sediment disturbed by seabed mining can disrupt the metabolism of jellyfish and cause severe harm to the animals. Researchers say that sediment particles sticking to jellyfish bodies and producing excess mucus can lead to acute stress in the animals. If jellyfish are exposed to sediment for prolonged periods, it could be detrimental to their health. The researchers also note that jellyfish exposed to sediments have increased respiration rates, indicating that the animals require more energy than usual. If other gelatinous organisms in the deep sea respond in the same way, commercial seabed mining could reduce biodiversity and threaten critical vital functions of the ecosystem such as carbon storage and nutrient cycling.
Seabed Mining and Its Impact on Jellyfish
The first study on the effects of mining on animals living in the water column suggests that seabed mining may negatively affect deep-sea jellyfish. The study indicates that sediments displaced from mining sites can activate stress responses that inflict damage on jellyfish.
Potential Impacts of Mining on Deep Marine Environments
Commercial seabed mining may soon be greenlit to extract minerals like cobalt and manganese; proponents say it’s essential to support the electric car battery and other electronics industries. However, scientists warn that very little is known about its potential impacts on deep-sea ecosystems.
The First Study on the Effects of Mining on Jellyfish
So far, most research on mining has focused on its impacts on the seabed. Patricia A. Schubart, a marine scientist at the University of Aveiro in Portugal, says, “The water column is not a well-understood concept. So any studies coming from there are considered golden.”
Study Details
The study, led by Vanessa Steinfurth, a marine scientist at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, analyzed the deep-sea jellyfish (Periphylla periphylla) collected from several Norwegian fjords where the animals frequently aggregate. In test tanks aboard the research vessel, 43 jellyfish were exposed to five concentrations of sediments representing what the animals could encounter at a mining site, ranging from zero as a control to 333 milligrams per liter (mg/L).
At sediment concentrations above 17 mg/L, the jellyfish exhibited signs of acute stress. Sediment particles clung to the animals’ bodies, producing excess mucus – a common stress response in jellyfish. On average, more than 30% of the animals’ bodies were covered in mucus after exposure to the highest sediment concentrations for 24 hours. The production of mucus consumes a lot of energy, and this could be harmful to the health of jellyfish if they are exposed to sediments for extended periods, according to the researchers.
Steinfurth says, “Food in the deep sea is very scarce. If there isn’t extra energy coming in, it could really lead to starvation.” She and her colleagues also found that jellyfish increased their respiration rates at higher sediment concentrations, indicating that the animals require more energy than usual. Jellyfish that produced excess mucus also increased the expression of genes related to energy metabolism, wound repair, and the immune system.
If other gelatinous organisms in the deep ocean respond in the same way, commercial seabed mining could lead to a decrease in biodiversity and threaten critical vital functions of the ecosystem such as carbon storage and nutrient cycling.
References:
Stenvers, V. I. et al. Nature Commun. 14, 7352 (2023).
Source: https://www.nature.com/articles/d41586-023-03625-y
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