Deep sea miners want to explore faster than science can show how devastating mining for minerals on our last frontier can be. So science is working to pick up the pace so deep sea mining will not happen without a major shift in policy and research. The latest research to come out is that deep sea mining can harm jellyfish.
Mining of the ocean floor for minerals such as lithium for electric cars could harm deep-sea jellyfish by stressing them out with sediment, suggests the first study of how resource harvesting might affect animals living in the depths. But deep sea mining for concrete is also very problematic says this architect we feature.
Researchers collected helmet jellyfish (Periphylla periphylla) and exposed them to sediment at concentrations that could be churned up by mining. After a day, the animals had mucus covering much of their bodies, among other signs that they were really not happy. Being stressed uses a lot of energy, which could be harmful over extended periods, say the researchers.
The study, co-led by Vanessa Stenvers, a marine ecologist at the GEOMAR Helmholtz Centre for Ocean Research Kiel in Germany, analysed deep-sea helmet jellyfish collected from several Norwegian fjords where the animals regularly congregate. In testing tanks on board their research ship, Stenvers and her team exposed 43 jellyfish to five concentrations of sediment representative of what the animals could experience at a mining site, ranging from zero as a control up to 333 milligrams per litre (mg l−1).
At sediment concentrations above 17 mg l−1, the jellyfish showed signs of acute stress. Sediment particles stuck to the animals’ bodies, and they produced excessive amounts of mucus — a common stress response for cnidarians, the phylum to which jellyfish belong.
On average, more than 30% of the animals’ bodies were covered in mucus after being exposed to the two highest sediment concentrations for 24 hours. Producing mucus uses a lot of energy, which could be harmful for the health of jellyfish if they are exposed to sediment over extended periods, say the researchers.
“Food in the deep sea is very scarce. If there’s no extra energy coming in, this could potentially lead to starvation,” says Stenvers.
She and her colleagues also found that jellyfish doubled their respiration rate at the highest sediment concentrations, suggesting that the animals required more energy than they would otherwise need. Jellyfish that produced excessive mucus also overexpressed genes involved in energy metabolism, wound repair and the immune system.
If other gelatinous organisms in the deep ocean respond similarly, commercial harvesting of the sea floor could reduce biodiversity and threaten crucial functions of the ecosystem — such as carbon sequestration and nutrient cycling.
Let’s bookmark this research next time a lobby group springs up to support deep sea mining.
Keep reading these resources on deep sea mining.
