Global warming is now taking its toll on the ancient Arctic ponds as well, according to new study by a researcher from Queen's University, Kingston, Canada.
These ponds, which lie atop bedrock, freeze solid in the winter and then melt for a few months each summer, becoming hot spots of activity in the forbidding Arctic terrain. Varying in size, with some reaching three feet (a meter) deep and around several hundred feet across, the ponds brim with moss, algae, fairy shrimp, and other organisms that need liquid water to live during the summer.
"If you fly over, you see them everywhere," said study leader John Smol.
But now these ponds are fast disappearing because of global warming caused by humans.
According to Smol, some of these ponds are going bone dry in the summer or shrinking to tiny puddles, while others are a fraction of their former size, said Smol.
The wetlands around some of the ponds are also disappearing, threatening the creatures that inhabit these areas, said Smol.
"They're so dry you can put a match to it and they'll burn," he said.
Smol, who together with Marianne Douglas at the University of Alberta in Edmonton, spent more than two decades tracking about 45 ponds on Canada's Ellsmere Island, which is located just off the northwest coast of Greenland, had found in earlier studies, that the ponds had been relatively stable for several thousand years-until the 1800s; but that new kinds of diatoms and mosses had taken over the ponds in recent years, the first signs of global warming.
During their study, the duo searched sediments in the ponds and dug out the shells of diatoms-microbes that grow protective mineral sheaths around themselves.
"In recent years there has actually been more rain and snow in this region than a couple of decades ago, but because of global warming, the summers are warmer, so the ponds are losing more water to evaporation-greater than the gain from the extra precipitation," said Smol.
"So like a pot of simmering stew, the ponds are becoming smaller and saltier. Of the 24 or so ponds that Smol and Douglas were tracking, all were drying and shrinking, and two or three went completely dry in the summers of 2005 and 2006," he said.
"We've seen, in our lifetime, in front of our eyes, some of these ponds dry up. It is quite striking," National Geographic quoted him as saying.
"In wetter years the now-dry ponds may again fill with water. But they won't be the same again, since many of the organisms that once lived in the ponds have probably died," he added.
The study appears in this week's Proceedings of the National Academy of Sciences (PNAS).