VOA慢速2019 美国科学家发现河蚌大量死亡（在线收听）

Scientists are investigating a massive die-off of mussels in a major river in the southeastern United States. They hope to learn the cause.

科学家正在研究美国东南部某主要河流的大规模贻贝死亡现象。他们希望能了解根本原因。

In 2016, fish and wildlife officials discovered a big drop in the mussel population in the Clinch River. The river flows about 480 kilometers through the states of Virginia and Tennessee. It is home to many different kinds of fish and 46 species of mussels.

2016年，鱼类和野生动物领域的工作人员发现克林奇河的贻贝族群数量出现了大幅下滑。这条河流流经弗吉尼亚州和田纳西州长达近480千米的距离。这里有许多不同种类的鱼和46类贻贝。

While freshwater mussels are small, they perform some important activities to keep rivers healthy. Mussels can clean up up to 38 liters of river water each day, removing algae, metals and other materials. The process can create a better river environment for fish, amphibians, plants and insects.

虽然淡水贻贝体型很小，但它们的一些活动对河流的健康起到重要的作用。贻贝每天可以清洁38升河水，移除藻类、金属等物质。这个过程可以为鱼类、两栖动物、植物、昆虫创造更好的河流环境。

For this reason, scientists are working to find the cause of the large drop in mussel populations.

出于这个原因，科学家正在努力寻找贻贝族群数量大量减少的根本原因。

Jordan Richard is a biologist with the U.S. Fish and Wildlife Service. He told The Associated Press that officials have estimated that hundreds of thousands, possibly even millions, of mussels have died in the Clinch River.

乔丹是美国鱼类及野生动物管理的一位生物学家。他在接受美联社采访时表示，一些工组人员估测，上万只贻贝甚至上百万只贻贝在克林奇河中死亡。

The mass die-off in the river of one kind of mussel, called the pheasantshell, has been especially worrisome. Officials say the population of pheasantshells dropped from 94,000 in 2016 to less than 14,000 in 2019. They measured the decrease along a 200-meter stretch of the Clinch River.

克林奇河里某类贻贝的大量死亡让人尤为担忧，这种贻贝名叫

Similar die-offs have been reported on at least five U.S. rivers and another in Spain. Richard has studied reports of similar die-offs over the years in rivers around the world. But so far he has not come up with many answers about why they happened.

美国的一些河流和西班牙的另一条河流也出现了贻贝数量类似的大量下降现象。过去几年间，理查德研究了世界各地的许多河流中出现的类似现象。不过，目前为止，他还没有得出这些现象的几项答案。

Speaking about the Clinch, Richard said the river could even be compared to the Amazon because it contains so many different kinds of life. He spoke to the AP while examining the river's mussel population in a rural community in Tennessee.

说起克林奇河，理查德表示，这条河甚至可以跟亚马逊媲美，因为这条河里包含许多种类的生命。他在接受美联社采访时，正在检查田纳西中某农村社群的贻贝族群。

Mussel populations around the world have dropped sharply over the past 100 years. Scientists blame this on pollution, habitat loss and climate change. But they suspect the most recent decreases have another cause.

过去100年间，世界各地的贻贝数量都急剧下降。科学家认为其原因是污染、生境丧失、气候变化。但他们认为最近贻贝数量的大量减少有另一个原因。

Richard and his team believe an infectious disease could be responsible. The team is comparing healthy pheasantshell mussels to dying ones in an attempt to narrow down a list of possible diseases.

理查德及其团队认为，某感染病可能是罪魁祸首。该团队正在将健康贻贝跟濒死贻贝进行比较，目的是缩小可能疾病的数量。

"All living things are chock-full of microorganisms, and we don't have any sort of map for what is healthy inside a mussel," Richard said.

University of Wisconsin disease specialist Tony Goldberg is helping with the investigation. He specializes in wildlife illnesses of unknown cause. Goldberg told the AP that often disease is the final thing to kill a species that has already been harmed by other environmental conditions.

However, he says he is hopeful that the freshwater mussel team will be able to discover the cause of the massive die-offs and find a way to prevent them. The team includes scientists from the U.S. Geological Survey and a nonprofit conservation group.

"I see it as a race against time, not an impossible task," Goldberg said, adding "...if we lose these mussels, the rivers we all love are never going to be the same."

Words in This Story

species – n. a group of animals or plants that are similar and can produce young animals or plants

algae – n. a plant with no stem or leaves that grows in or near water

amphibian – n. a type of animal that can live both on land and in water

habitat – n. the natural living environment for living things

chock-full – n. very full