CRI听力:Lakes Faces Threat Affecting Their Ecosystem: Experts

A new study by NASA and the National Science Foundation has revealed that lakes around the world are rapidly being warmed due to climate change.

Based on temperature data from 235 lakes and analysis on temperature changes over 25 years, the study found that they are warming at an average of 0.34 degrees Celsius each decade.

Sam Hook, the Science Division Manager at NASA's Jet Propulsion Laboratory and co-author of the study, believes that the temperature changes have resulted from many factors.

"It could be a reflection of there being less cloud cover; it could be a consequence of more glacial melt water coming into the lake. All these different processes taking place and they integrate them and they warm more gradually but the consequences of that warming can be very serious."

Increase in lake temperatures can damage the ecosystems around the lakes, making it harder for fish to survive and for people to make use of the bodies of water.

One of the negative consequences is that the rising temperature could lead to algal blooms, which sometimes contain harmful toxins and therefore lower the water quality.

Meanwhile, Russian experts have discovered that endemic species in Lake Baikal in Siberia are facing a threat brought about by different toxic algae.

According to results tested from samples of water and flora from 4 meters deep, endemic sponge, a natural water purifier, is declining significantly.
Lyubov Chernogor, a researcher at the Laboratory of Bioorganic Chemistry, says such sponges play an important role in keeping the lake water clean.

"Sponge is a multicellular purifier organism. According to the different scientific datas, sponge is purifying around 20 liters of water per day. Can you imagine how much water it can clean? In other words sponge is banishing through itself and filtering all the water that is in the Baikal."

She added that it's impossible to find any visually healthy sponges, which they used to be able to find 6 years ago.

For his part, Igor Hanna, Team Leader of Diving and Underwater monitoring, says an up-to-date purification plans is required to alleviate the lake's situation, since none of existing purification plants are effective.

"After diving into the different parts of Lake Baikal I can say that we are seeing that the situation is deteriorating. Negative events that only exist in some parts of Baikal before we were witnessing is now spreading to the entire water area of Baikal."

Lake Baikal is listed as World Heritage Site and covers 20,000 square miles, holding a fifth of all the fresh water in the world.

For CRI, I'm Xie Cheng.