Climate change is putting countless marine animals under pressure but jellyfish could actually benefit from warming ocean waters.
A study by researchers at Germany’s Alfred Wegener Institute (AWI) looked at eight different species of Arctic jellyfish. They exposed them to rising water temperatures, sea ice retreat and other changing environmental conditions through computer models.
Scientists found that by the second half of the century, seven of the eight species could expand their habitat polewards under these conditions. Simulations showed that the lion’s mane jellyfish - one of the biggest stinging jellyfish- in particular could nearly triple the size of its current habitat.
Just one species, Sminthea arctica, would experience a minor decrease in habitat since it would have to retreat to greater depths in order to find its optimal temperature range.
“These results clearly show how dramatically climate change could affect the ecosystems of the Arctic Ocean,” says Dmitrii Pantiukhin, a doctoral candidate in ARJEL (Arctic Jellies), a junior research group specialising in Arctic jellyfish at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).
“The projected expansion of the jellyfish habitats could have tremendous, cascading impacts on the entire food web.”
Despite their importance in the marine ecosystem, the transparent gelatinous organisms are often forgotten in ecological studies. This research closes an important gap in our knowledge.
Climate change could mean an ocean dominated by jellyfish
Researchers say that in the future, jellyfish and other gelatinous zooplankton may be some of the few organisms to benefit from climate change.
Studies have confirmed that marine organisms known as cnidarians, ctenophores and pelagic tunicates can thrive not only in rising water temperatures but also when there is nutrient contamination or overfishing.
When combined, all of these factors could mean a shift from a diverse marine ecosystem dominated by fish to an ocean full of jellyfish. Many researchers are already warning of impending ‘ocean jellification’.
“Jellyfish play an important part in the marine food web,” explains Pantiukhin.
“Now that climate change is putting more stress on marine organisms, it can often give the gelatinous zooplankton a leg up on their competitors for food, like fish.
“This in turn affects the entire food web and ultimately the fish themselves: many types of jellyfish feed on fish larvae and eggs, which can slow or prevent the recovery of fish populations already under pressure, which are often also heavily fished by humans.”
Pantiukhin adds that anyone interested in how fish - an important food source for many people - will develop in the future need to keep an eye on jellyfish.
