Climate Change Could Alter Global Distribution of Gelatinous Zooplankton; Jellyfish To Dominate Arctic Ocean in the Future

Climate change has driven environmental disruptions, which have disturbed natural habitats and biodiversity. It has altered terrestrial, marine, and freshwater ecosystems by causing species loss, which can lead to more widespread extinction.

While climate change exposes countless marine animals to environmental pressure, one organism could actually benefit from warming ocean waters.

The Rise of Jellyfish

Gelatinous zooplankton, like jellyfish and other nearly transparent organisms, play crucial roles in marine ecosystems. In a recent study, a team of scientists from the Alfred Wegener Institute investigated their fate in the Arctic Ocean which is one of the fastest warming oceans on our planet.

Led by Dmitrii Pantiukhin, the researchers combined 3D species distribution models with oceanographic variables from the Coupled Model Intercomparison Project Phase 6. This enabled them to determine species of gelatinous zooplankton with contracting or expanding habitat ranges as a response to climate change in the Arctic Ocean. The findings of their study are discussed in the paper "Pan-Arctic distribution modeling reveals climate-change-driven poleward shifts of major gelatinous zooplankton species."

The transparent gelatinous organisms are usually neglected or forgotten in ecological studies and model-based simulations. The recent study closes this crucial gap while concentrating on a hotspot for climate change. Not only is the Arctic Ocean warming the fastest, but roughly 10% of global fishing yields also come from this region, making it an ideal site for research.

In the computer models, the team exposed eight widespread Arctic jellyfish species to sea ice retreat, rising water temperatures, and other changing environmental conditions. It was found that by the second half of this century, all but one jellyfish species could expand their habitat toward the poles.

Negative Effects of Jellyfish Expansion

While jellyfish and other gelatinous zooplankton could benefit from climate change, this spread would not be good for other marine species. The predicted global expansion of jellyfish habitats can have great, cascading effects on the entire marine food web.

A particular species called the 'lion's mane jellyfish' could triple the size of its habitat, potentially affecting Arctic fish populations and the marine food web. Numerous studies have also confirmed that transparent cnidarians, pelagic tunicates, and ctenophores survive on rising ocean water temperatures but also on nutrient contamination and overfishing.

When combined together, these factors could lead to a major shift in the ocean, from a productive food web dominated by fish to a less productive one full of jellyfish. Because of this, many experts are already warning of an 'ocean jellification' which can happen in the future.

There is a puzzling question which has something to do with the way fish stocks in the Arctic would be affected by jellyfish expansion. Many types of jellyfish consume fish larvae and eggs, so ocean jellification can slow or prevent the recovery of fish populations which are already under pressure due to heavy fishing by humans. Because of this, the researchers suggest that anyone who studies the importance of fish as a food source should also keep an eye on the jellyfish.

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