Sunday, June 05, 2011

The Jellyfish Ballet.

The Western Pacific island nation of Palau, 500 miles east of the Philippines, has an unique natural wonder. It's called Ongeim'l Tketau or Jellyfish Lake. It's a land locked saltwater lake which scientists think was formed when rising sea levels allowed seawater to fill the steep-sided marine lake. The lake is connected to the ocean only by fissures in the surrounding limestone. It keeps the lake isolated and the animals trapped. Mostly, the jellyfish named Mastigias which originally came from the ocean.



Mastigias jellyfish feed on small animal plankton, killing them with stinging cells on their long tentacles. But the magic is that the sting is not the powerful sting of other ocean jelly fish so humans can swim along with them as they migrate across the lake and back during the day.

Mastigias have evolved a symbiotic relationship with single-celled marine algae. Inside the tissues of Mastigias' frilly arms live millions of zooxanthellae, which use solar energy to convert carbon dioxide into carbohydrates that the jellyfish use for energy. Swimming back and forward across the lake during the day gives their zooxanthellae plenty of light and avoids the shadows that form at the lake edges where their predators, the bottom-living sea anemones, live.

At night they stop moving horizontally and swim vertically in the lake (away from the edges) and scientists think this is to provide nutrients for their symbiots which are only available in deep water.

There are five jellyfish lakes in Palau and even though the jellyfish all belong to the species Mastigias, they look different from each other and from Mastigias in the nearby ocean. It's also been proposed that the swimming could play a part in mixing stratified layers of water. So if you don't mind hiking up to the steep rim then hiking down to the lake for the pleasure of getting up close and personal with the locals then this is the holiday for you.





6 comments:

The Elephant's Child said...

They are beautiful but I'm not sure about swimming with them. Even without the sting I don't like the feel of jellyfish (or jelly if it comes to that).

River said...

I would love to go and see these jellyfish. I'd probably jump in for a swim if others were already in the water.
We have jellyfish here in the Port River, (at Port Adelaide) L and I used to walk there on Sundays from Semaphore and watch the jellyfish for a while before heading into the fisherman's market on Sundays.
It's a big flea market type thing n a huge old warehouse. We'd scrounge around in there for a couple of hours, get some hot fresh doughnuts for L,chips for us both, then walk home again.

JahTeh said...

EC, I remember picking up jellyfish on the beach, sort of a half moon shape but no stingers and it did feel funny.

River, start saving. I don't really like picking up fish, I'd rather watch them swim. But they're so nice to eat unless their eyes are still in, spooky.

R.H. said...

It's raining and it's your fault.

JahTeh said...

At least it's not snowing.

Middle Child said...

Where do you find all these photos - this is as with he volcanoes something else