• With bacteria they can form 'carbon dioxide factories' and destroy oceans
  
• Many jellies, like the 'zombie jelly,' can stave off death and re-grow
  
• Jellyfish beat out other species for food, can create 'killing fields'
  

By Daily Mail Reporter

PUBLISHED: 21:09 EST, 7 September 2013 | UPDATED: 21:19 EST, 7 September 2013

 Jellyfish, a common summertime nuisance, may be more dangerous than once thought. The sea creatures have been around for half a billion years - and new information alleges that they are growing in numbers, killing people and wreaking havoc in the oceans.

Lisa-ann Gershwin's book 'Stung! On Jellyfish and the Future of the Oceans,' describes the danger jellyfish pose and how they have overrun various ecosystems. Much of the species' success, she says is based on their life cycle.

'Hermaphroditism. Cloning. External fertilization. Self fertilization. Courtship and copulation. Fission. Fusion. Cannibalism. You name it, jellyfish [are] "doing it,"' she says. 

One jellyfish, the Mnemiopsis, is able to lay eggs when it is just 13 days old without needing a mate. It soon is able to lay 10,000 eggs per day. It also can eat over ten times its own body weight in food and can double in size each day.

Other jellyfish are extremely difficult to kill. When faced with death, some can 'de-grow' - which means that 'they reduce in size, but their bodies remain in proportion,' the New York Review of Books says. 

Another species, the zombie jelly, is seemingly immortal. When its particles disintegrate, cells escape and form an entirely new jelly. This period of growth happens within five days. 

Complex ecosystems, Gershwin says, at what have kept the jellyfish at bay. However, she claims that human involvement and manipulation have catapulted their growth and helped their numbers to explode.

Gershwin claims that overfishing anchovies, which compete with jellyfish for food, have created swarms of the sea creatures in South Africa. Jellyfish competitors quickly die out, leaving a 'stingy-slimy killing field,' she says.

Plastic bags and drift lines may also destroy the few natural jellyfish predators, like sea turtles. Jellyfish also use hard litter, like industrial waste, to form expansive nurseries. 

Rising acid and carbon dioxide levels have been noted to kill off many fish species. Jellyfish, however, reportedly thrive in these harsh environments. They release waste with high carbon levels -- which bacteria use to create 'carbon dioxide factories,' Gershwin says.

One example is the Gulf of Mexico -- in 2000, jellyfish took over an area of sixty square miles. They survived the damage wrought by Hurricane Katrina and the 2011 oil spill, when thousands of other species died.

These combined factors, she says, are what have allowed jellyfish to take over 'one bite at a time.'

'[There will be] no coral reefs teeming with life. No more mighty whales or wobbling penguins. No lobsters or oysters,' Gershwin says.

Jellyfish, like both the box jelly and Irukandji species, have taken dozens of lives. Box jellies can kill within two minutes, the New York Review of Books reports. Irukandji, which can cause extreme cramps, spasms, and vomiting, have taken countless victims. Many deaths are misdiagnosed as strokes and heart attacks.

In groups, jellyfish 'have an uncanny knack for getting stuck,' Gershwin writes. They can get sucked in and latch on to heavy structures.

In July 2006, jellyfish were sucked into the US Ronald Reagan, wiping out onboard capabilities. Japanese power plants have been 'under attack' from jellyfish since the 1960s, claims the New York Review of Books.

The damage may be permanent, Gershwin says. 'I think I underestimated how severely we have damaged our oceans and their inhabitants. I now think that we have pushed them too far [...] without us knowing the precise moment it all became irreversible.'