VOA常速英语:Unique Species of Shrimp, Anemones Thrive Near Caribbean Seafloor Vents

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A team of British scientists has published new details of the world’s deepest volcanic vents, discovered in 2010 in a canyon on the Caribbean seafloor. Although the vents are gushing liquid minerals estimated to be hotter than 450 degrees Celsius, they are surrounded by a remarkable abundance of marine life, including species of shrimp and snails never seen before.

The volcanic vents were discovered five kilometers down near the bottom of Cayman Trough - an undersea trench south of the Cayman Islands. Expedition co-leader Jon Copley, a marine biologist of the University of Southampton in England spoke to us via Skype.

“Deep sea vents are hot springs on the ocean floor. They are a little bit like the geysers you may know from Yellowstone Park in the U.S., except they are underwater... [and] they are not erupting steam. They are erupting really hot fluid, still liquid, loaded with dissolved minerals that form particles that looked like smoke and that’s why we nicknamed them 'black smokers',” said Copley.

Hot fluid from Earth's crust

Although they didn’t measure the vent temperatures directly, the scientists estimate that the dark material spewing out - mostly copper and other dissolved minerals - is hotter than 450 degrees Celsius.

“That’s the temperature you get right at the very throat of the vent, where the hot fluid is gushing out [from] the earth’s crust. But the animals don’t live there. They live a little bit further away. A few meters away the temperature is down to 20 to 40 degrees [Celsius].”                                                        
In those cooler waters around the vents’ six-meter tall mineral spires, the scientists found teeming populations of marine animals, including a new species of shrimp. Copley said the tiny white creatures exist in near-total darkness and feed mostly on bacteria.

New species discovered

“Instead of two eyes on stalks like shrimp normally have as an adult, these shrimp have a light-sensing organ on their back,” said Copley.

They also found hundreds of white-tentacled anemones, but they could not collect specimens.

Copley said that by studying the deep-sea vents and their animal colonies, scientists can better understand how marine life disperses and evolves in the deep ocean. He noted that in the coming years, the ecosystem will see an increasing human presence, in the form of deep-sea fishing, oil and gas extraction and mining operations.

“”If we are going to make responsible decisions about how we manage those ocean resources, we need to understand what determines the patterns of life in the deep ocean,” said Copley.

Copley and his team are now analyzing samples and data from “black smoker” vents recently found at four other seafloor sites around the world.