Helmet Jellyfish ‘Highly Sensitive’ to Plumes of Sediment From Seabed Mining [Study]

Seabed mining disturbs the marine creatures in the ocean. Among the affected animals are the jellyfish, which are sensitive to the plumes of sediments.

Seabed Mining Stresses Jellyfish

Unexpected effects on common jellyfish have been found in an experiment to investigate the potential impacts of seabed mining on deep-sea species. The extraction of valuable minerals from metallic "nodules" occurring naturally on the seafloor is gaining popularity.

However, marine biologists are worried about potential injury.

In a new study, they used dedicated tanks on a research vessel to replicate conditions brought about by mining activities. The researchers studied helmet jellyfish, and they worked at night because their subjects were highly light-sensitive. They took roughly 60 creatures and housed them in temperature-controlled tanks in the research ship's dark lab.

According to Vanessa Stenvers, a marine scientist at Kiel, Germany's Helmholtz Centre for Ocean Research, this mimicked the residue that would be stirred and released by submersible vehicles mining the sea floor for minerals.

"These are rotating tanks," she said. "Essentially re-creating a situation where sediment is disturbed and doesn't settle - it's circulating through the water."

The gelatinous organisms were discovered to be "highly sensitive" to sediment plumes, a condition designed to replicate how mining might agitate seabed deposits.

The European iAtlantic project experiment exposed the jellyfish to some peculiar effects - they secreted an excess of protective mucus when their bodies were covered with silt. According to the experts, the animals expended energy that they would have otherwise used for movement or food because doing that is energy-expensive.

The scientists also saw "acute stress" in the animal samples, such as the activation of genes linked to wound healing.

Stenvers noted that helmet jellyfish are not as fragile as worms and mollusks. Many animals living in the water column are fine being fragile because they are safe in their environment mid-water, but seabed mining would likely change their environment.

What Is Seabed Mining?

Seabed mining is a process used to remove minerals and metals from the seafloor. Although the former is usually called Deep Sea Mining (DSM), it can relate to shallower and deep sea mining processes.

The methods used to recover sand for public beaches or to create concrete are comparable to those used in seabed mining. However, in addition to digging up the bottom, seabed mining also includes discarding undesirable material back into the water, suffocating the surrounding environment with a cloud of silt.

Mining firms are searching increasingly for sand with unique and valuable features, as well as minerals and metals that may be turned into profitable products used in other industries. In doing so, the miners are targeting regions of the ocean rich in minerals and home to some of the planet's rarest and least understood wildlife.

The process involves extracting the sand from the ocean floor by a suction pump and sending it to a dredger above. Subsequently, the sand is frequently processed at sea, with the essential minerals or metals removed and shipped offshore and the remainder discarded into the water, creating a "sediment plume."

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