Jellyfish have played an important role in marine ecosystems for 500 million years. They are food for marine animals such as large fish and turtles, and they provide habitat for juvenile fish in areas where there aren't many places to hide.
But in large numbers, they can cause trouble — and not just because of their painful (and sometimes deadly) stings.
In recent years, swarms of jellyfish have caused power plants to shut down in the U.S., Israel, Sweden, Scotland, Japan and the Philippines. In Scotland, two nuclear reactors were shut down in 2011 when jellyfish clogged the power plant's seawater filter screens.
In Sweden in 2013 at the Oskarshamn nuclear power plant, operators couldn't get water from the Baltic Sea to cool its reactors because the water intake was clogged with jellyfish. The plant shut down operations as a precaution.
And just last month in Israel, swarming giant jellyfish clogged the seawater-intake cooling pipes at power plants up and down the coast, reports Haaretz. Even filters over the pipes didn't stop the jellyfish from shutting down the systems.
Now scientists are sharing their best guess as to why jellyfish swarms seem to be on the rise. A new study says offshore construction, such as wind farms and oil platforms, may be providing the perfect home for baby jellyfish (called polyps) to grow.
Many species of jellyfish — including moon jellies, the type responsible for many of the clogging issues — need to attach themselves to a surface in order to grow, which sometimes can be hard to find in nature. But construction platforms in the water provide an ideal location. Researchers found that the rise in population of moon jellyfish in the Adriatic Sea coincided with the rise of gas platforms there now.
Some experts suggest that moving platforms and wind farms away from major ocean currents, which can influence jellyfish numbers, may help control the population. But more research is needed to figure out how to prevent further damage to power plants.
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