Jellyfish May Dominate The Future Arctic Ocean – Eurasia Review

Climate change is putting pressure on countless marine species. But as researchers at the Alfred Wegener Institute have now successfully shown, jellyfish in oceans around the world may actually benefit from rising water temperatures, especially in the Arctic Ocean. There is sex. Researchers used computer models to expose eight widely distributed Arctic jellyfish species to rising temperatures, receding sea ice, and other environmental changes.

As a result, by the second half of this century, all but one of the species in question may significantly expand their range to the poles. The “lion’s mane jellyfish” could even triple the size of its habitat, potentially dramatically impacting marine food webs and Arctic fish populations. The study was just published in the journal Limnology and Oceanography.

In the future, jellyfish and other gelatinous zooplankton may become part of the few groups of organisms that benefit from climate change. As confirmed in many studies, transparent cnidarians, ctenophores, and pelagic tunicates thrive not only with increased water temperatures, but also with nutrient pollution and overfishing. The combination of these factors can lead to major changes in the ocean. A food web that is highly productive and dominated by fish could change to an ocean that is much less productive and populated by jellyfish. As a result, many researchers are already warning of an impending “ocean jellying” – a global increase in jellyfish populations.

“Jellyfish play an important role in marine food webs,” says Dr. A.D., from ARJEL (Arctic Jellies), a junior research group specializing in Arctic jellyfish at the Helmholtz Center for Polar and Marine Research (AWI) at the Alfred Wegener Institute. Researcher Dmitri Pantiukhin explains. ). “Currently, climate change is increasing stress on marine life, often giving gelatinous zooplankton an advantage over competitors for food such as fish. Many species of jellyfish feed on fish larvae and eggs, which can slow or prevent the recovery of fish populations already under pressure. These fish are often hunted in large numbers by humans, so anyone interested in how fish, an important food source for us, will develop in the future should pay attention to jellyfish. ”

Despite their importance to all marine life, transparent gelatinous organisms are often forgotten or ignored in ecological studies and model-based simulations. This study published by Dmitry Pantiukhin and his team fills an important gap in our knowledge, while also highlighting climate change hotspots. “Of all the oceans, the Arctic Ocean is warming the most rapidly,” said the study’s lead author. “Furthermore, about 10 percent of the world’s fish catches are obtained in the Arctic, so the High North is an ideal location for our research.”

Much is already known about jellyfish physiology, including the optimal temperature range for jellyfish growth. In the course of their research, the AWI team combined his three-dimensional species distribution model with the oceanographic component of the Max Planck Institute’s Earth System Model (MPI-ESM1.2). “Simulations of species distributions in the ocean are often two-dimensional and map-like,” says Dr. Charlotte Habermans, head of her ARJEL junior research group at AWI. “However, the distribution of jellyfish communities in particular is highly dependent on specific water depths. As a result, we have made our species models three-dimensional. When we combine these with MPI’s Earth System Model, we have identified eight major jellyfish We were able to calculate how the distribution of species will change from the reference period 1950-2014 to the second half of this century, 2050-2099. In other words, we applied a development path in which greenhouse gas emissions remain at a medium to high level. ”

The results speak for themselves. 7 out of 8 species including comb jellyfish (Beroe sp. / + 110%) and pelagic tunicates (Oikopleura Vanhefeni / + 102%) – From 2050 to 2099, habitats could expand to the polar regions, possibly on a large scale, and also benefit from the ongoing decline in sea ice .hair jelly Chianea capillataColloquially known as the “lion’s mane jellyfish,” this jellyfish has expanded particularly northward, where it can nearly triple (+ 180%) the size of its habitat. Only one of the species studied (Sumithea Arctica) has to retreat deeper to find its optimal temperature range, resulting in a slight decrease in habitat (-15%).

“These results clearly show how dramatically climate change can affect the Arctic ecosystem,” says AWI expert Dmitrii Pantiukhin. “The predicted expansion of jellyfish habitat could have significant cascading effects throughout the food web.”

One unanswered question is how Arctic fish stocks will be affected by jellyfish expansion. “There are many indications that key Arctic fish species, such as arctic cod, whose larvae and eggs are frequently eaten by jellyfish, will feel even more pressure,” says ARJEL group leader Charlotte Havermans. “Our study therefore provides an important basis for further research in this area. And management plans for the fisheries sector must avoid collapse of commercially exploited stocks and manage them sustainably.” This dynamic development needs to be kept in mind urgently.

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