More Jellyfish in Norway

Written by on November 22, 2012 in Jellyfish, Marine Life

Emily Tripp


Jellyfish. Photo credit: Tamíris Spinelli via photopin cc

The Baltic Sea, the North Sea, and Norway’s coastal waters and fjords may soon be filled with jellyfish.

The waters are getting darker, and researchers explain that this could be from overproduction of organic compounds–the perfect recipe for marine areas with fewer fish and more jellyfish.

Dag L. Aksnes, a marine biologist at the University of Bergen has been studying this process by which fresh water from rivers and lakes flows into the sea, mixing with coastal waters.

“This fresh water contains far more colored dissolved organic matter (CDOM) than marine water, so our coastal waters are darkening,” explained Professor Aksnes.

This has likely been occurring over many decades, but evidence suggests that climate change is causing it to accelerate.  One of the areas that Aksnes is studying, Lurefjorden, is already heavily populated with the jellyfish Periphylla periphylla.

Periphylla periphylla is a very light-sensitive jellyfish that thrives best in the world’s very deep marine waters,” Aksnes continued.  “But the water in Lurefjorden has now become so murky and dark that it probably is helping this jellyfish to thrive.  At the same time, the fjord has become less hospitable as a habitat for important fish species.”

Aksnes explained that another reason for the population shift is that the lower visibility makes it harder for the fish to find their prey.

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Copyright © 2012 by Marine Science Today, a publication of Marine Science Today LLC.

About the Author

About the Author: Emily Tripp is the Publisher and Editor of She holds marine science and biology degrees from the University of Miami's Rosenstiel School of Marine and Atmospheric Science and a Master of Advanced Studies degree in Marine Biodiversity and Conservation from Scripps Institution of Oceanography. When she's not writing about marine science, she's probably running around outside or playing with her dog. .


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