Gliding globes of golden jellies. That’s what you’ll find in Ongeim’l Tketau. This tiny lake on a tiny island in the Pacific Ocean is known as "Jellyfish Central."
Over thousands of years, the jellies here have lost most of their sting. It's safe to swim here. But if you do, be prepared. You’ll have to keep up with the jellies’ busy schedule.
In the morning, the jellies float to the east side of the lake. In the afternoon, they bob back to the west side. At bedtime, they head toward the middle. Why? To follow the sunlight. Jellies get their energy from algae in their bodies—and the algae get their energy from the sun. Jellies avoid shadows along the shoreline. That's where their enemy, the anemone, lives.
Everyone likes nice warm water. But Boiling Lake on the island of Dominica, is extreme. It boils, like a pot of soup on a stove.
Dominica is built by volcanoes. And volcanoes often have fumaroles: searing hot holes where heat and gas escape. Boiling Lake fills a fumarole. No wonder it’s boiling. There’s hot magma underneath!
Getting there requires a tough hike. Tourists scramble up a slippery trail. They trek through a valley, where the air smells like rotten eggs. Finally, they reach a cliff overlooking Boiling Lake. Look, but don’t fall in!
These meltwater lakes formed on an iceberg in Greenland.
Down the Drain
It’s summer on Greenland’s vast ice sheet. Lakes of meltwater dot the frozen surface like blue jewels. The darker the blue, the deeper the lake.
Some of Greenland’s meltwater lakes play a game of now-you-see me, now-you-don’t. One, called North Lake, sometimes drains all at once. One year, all 45 billion liters (12 billion gallons) of it disappeared in two hours!
Scientists figured out what happens. As temperatures warm, the ice shifts. That opens huge cracks. The lakes drain down through the cracks. It's like someone pulled the plug on a bathtub. The water runs all the way to the base of the ice sheet. Then it flows toward the sea. Who knows? Maybe one day, Greenland’s whole ice sheet might slip away. Here today, gone tomorrow.