Deep sea mining might stress out jellyfish, starve them to death, warn scientists

The vast expanse of word's underwater communities remains incredibly unexplored and remarkably understudies. But a recent study published in the Nature Communications gives first insights into the stress response of a deep pelagic jellyfish to global warming and deep-sea mining induced mounds of sediments.

The study was conducted by GEOMAR Helmholtz Centre for Ocean Research Kiel.

Commercial mining remains top concern

Add WION as a Preferred Source

The study says that the biggest environmental stressor for deep sea organisms is the disturbance associated with the commercial mining for resources on the seafloor.

Also watch |WION Climate Tracker: U.S. storm brings jellyfish ashore

This is because mining operations pump up fine sediment off the seafloor, and thus generate suspended sediment 'clouds' along the seafloor.

Once on the ship, the collected sediment is discharged back into the water column. The sediment clouds can extend for tens to hundreds of kilometres throughout the water column.

"The midwater is crucial for the global ocean's capacity to store carbon, but also its inhabitants are the main food source for many fish, squid, and marine mammal species and therefore resemble a critical link in the marine food web. They have evolved under much more stable conditions compared to surface-dwelling animals, under a constant scarcity of food, and are therefore potentially more susceptible to changing conditions in their environment," Dr. Helena Hauss, co-first author of the study and Research Director of Marine Ecology at Norwegian Research Centre (NORCE), said in an official statement.

"Since determining 'stress' in a jellyfish is not a straightforward process, we investigated their response from multiple angles and combined insights gained from their physiology, gene expression and the microbial symbionts on the jellyfish's exterior," Vanessa Stenvers, co-first author of the study and doctoral candidate at GEOMAR and the Smithsonian Institution sad in an official statement.

Additionally, during the study, jellyfish showed expression of genes related to respiration, innate immunity, and wound repair in the highest sediment treatments, further indicating stress.

Sea temperatures will rise by one degree in the next 84 years, according to climate projections.

The authors of the study fear that jellyfish may suffer starvation since increased stresses due to human activity such as deep sea mining would result in increased energy expenditure, as they observed for the helmet jellyfish. This, they said, will have to be met with increased food intake. Since food in the deep sea is generally scarce, this could ultimately lead to starvation.

(With inputs from agencies)