Chuck Bednar for redOrbit.com – Your Universe Online
NASA scientists are analyzing tiny shrimp living in one of the planet’s deepest underwater hydrothermal vents to determine if the creatures and their unusual ecosystem could offer clues as to what life might be like on Jupiter’s icy moon Europa and other planetary objects.
Those shrimp are piled one on top of another in layers, and they spend much of their time crawling on rock chimneys that eject hot water, the US space agency said. In addition, they play host to bacteria that live inside their mouths and in specially evolved gill covers, and the microbes produce organic matter upon which the crustaceans feed.
Those bacteria are able to survive in extreme environments because of a process known as chemosynthesis, which allows the organisms to get energy from chemical reactions and functions in the absence of sunlight. In this particular case, the bacteria use hydrogen sulfide, a chemical abundant at the vents, to create organic matter.
The temperatures at those vents can reach upwards of 750 degrees Fahrenheit (400 degrees Celsius), but waters located just an inch away are cool enough to keep the shrimp alive, NASA explained. Also, while hydrogen sulfide in high concentrations is toxic to organisms, the shrimp actually position themselves on the border separating normal, oxygenated ocean water and sulfide-rich water so that both they and the bacteria can survive.
Max Coleman, senior research scientist at NASA’s Jet Propulsion Laboratory (JPL) in California, was a member of a team lead by Woods Hole Oceanographic Institution (WHOI) researcher Chris German who discovered the vents off the coast of Cuba in 2009. Their research was funded by NASA’s Astrobiology Science and Technology for Exploring Planets (ASTEP) program and located the vents by detecting their chemical signals in the water.
“The overall objective of our research is to see how much life or biomass can be supported by the chemical energy of the hot submarine springs,” Coleman explained in a statement. “For two-thirds of the Earth’s history, life has existed only as microbial life. On Europa, the best chance for life would be microbial.”
“Whether an animal like this could exist on Europa heavily depends on the actual amount of energy that’s released there, through hydrothermal vents,” added Emma Versteegh, a postdoctoral fellow at JPL.
Coleman, German and their colleagues returned to the site in 2012 and collected extensive specimens from two different hydrothermal vent fields: the Von Damm field at 7,500 feet (2,300 meters) and Piccard, the world’s deepest vent at more than 16,000 feet (4,900 meters). They examined the shrimp for the first time the following year.
Image Above: Shrimp called Rimicaris hybisae at deep hydrothermal vents in the Caribbean seem to have different dietary habits depending on the proximity of other shrimp. In dense clusters, the shrimp live mostly off bacteria, but when the shrimp population is sparse, they are more likely to turn carnivorous. Credit: Courtesy Chris German, WHOI/NSF, NASA/ROV Jason © 2012 WHOI
“A bonus finding from studying this extreme oasis of life is that some of the shrimp, called Rimicaris hybisae, appear to be cannibalistic,” NASA noted. “When the shrimp arrange themselves in dense groups, bacteria seem to be the main food supplier, as the shrimp likely absorb the carbohydrates that the bacteria produce. But in areas where the shrimp are distributed more sparsely, the shrimp are more likely to turn carnivorous.”
While the researchers said that they did not directly observe any instances of the shrimp practicing cannibalism, they did report discovering small amounts of crustacean remains in the shrimps’ guts, and Rimicaris hybisae is the most abundant crustacean species in the area by far. Researchers from Duke University were also involved in the study, and the Schmidt Ocean Institute provided support for marine and underwater robotic operations.
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