An increasing number of stinging jellyfish are swarming European waters. Jellyfish have been seen close to the beaches of the Costa del Sol in southern Spain, a spot popular with holidaymakers. But, while they are a nuisance for swimmers, these creatures continue to mesmerize us.
The appearance of American Ctenophora in German waters had researchers scratching their heads. Using comparative DNA analysis, they determined that the invading jellyfish had come from North America. It's believed passing ships discharged ballast water near European coastlines, depositing a new population of these iridescent invaders.
Ctenophores are commonly called comb jellies. They use rows of hairlike cilia to propel themselves through the water and are especially resilient and adaptable. Foreign species can sometimes throw entire ecosystems out of balance. But scientists say the appearance of comb jellies in the North and Baltic Seas has had little effect on local wildlife.
The Lion's Mane jellyfish also lives in German waters. Here, an underwater view captures the billowing tentacles of this giant of the jelly world. Lion's mane jellyfish can grow to 2 meters (6 feet) in diameter. Their fiery red tentacles can deliver a painful and sometimes fatal sting.
Things get more dangerous beyond German waters. Box jellyfish live primarily in coastal waters off Northern Australia and throughout the Indo-Pacific region. Their venom is among the most deadly in the world - it contains toxins that attack the heart, nervous system, and skin cells.
Often mistaken for a jellyfish, the Portuguese man of war is actually a colony of organisms working together. Its tentacles extend more than 30 meters (98 feet) below the surface and are covered in venom used to kill fish. Their sting is excruciatingly painful for humans, but rarely deadly.
The sting of the compass jellyfish isn't quite as vicious as that of the box jellyfish or the man of war. But this ruthless underwater hunter likes to feed on other jellies, including the comb jellyfish.
Deadly assassins and ethereal beauties