'Jellyfish Central'

Gliding globes of golden jellies. Gobs of them! That’s what you’ll find in Ongeim’l Tketau, on Eil Malk Island, Palau. This tiny lake on a tiny island in the Pacific Ocean is known around the world as "Jellyfish Central." In fact, many people don’t even know this lake’s real name.

Over thousands of years, the jellies here have lost most of their sting. Where else can you swim among clouds of jellies without getting stung? But here’s the kicker: 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 the commute? Sunlight is one reason. Tiny algae live in the jellies’ bodies. The algae get their energy from the sun, and the jellies get their energy from the algae. Scientists think the jellies are also avoiding shadows along the shoreline, where their archenemy, the anemone, lives.

What's Cooking?

Everyone likes nice warm water. But Boiling Lake, Dominica, is extreme. It boils, just like a pot of soup on a stove.

Dominica, like other islands in the Caribbean Sea, is a volcano. Where there are volcanoes, there are often 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 to Boiling Lake requires a tough hike through a muddy rainforest. Even so, the lake is a hot spot for adventurous tourists. They scramble up a slippery trail. They trek through the eerie Valley of Desolation, where the air is filled with steam and sulfur that smells like rotten eggs. Finally, they reach a cliff overlooking Boiling Lake. They peer through the mist, trying to get a look at the lake’s churning water, and they try hard not to fall in.

a view from above of Boiling Lake

Boiling Lake, Dominica

a meltwater lake in Greenland

These meltwater lakes formed on an iceberg in Greenland.

Down the Drain

It’s summer on Greenland’s vast, miles-thick ice sheet. Lakes, formed from melting water, dot the frozen surface. They sparkle like blue jewels. The darker the blue, the deeper the lake.

But some of Greenland’s meltwater lakes play a little 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! That’s about 18,000 times more water than an Olympic swimming pool.

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.

Scientists have figured out something else, too. The flowing water makes the ice above it move toward the sea faster. They are worried that if summers get too warm, Greenland’s whole ice sheet might eventually slip-slide away. Here today, gone tomorrow.

03/08/2021 12:53:02