W Washington, March 2 : A new study has determined that global warming is proving to be a threat to the sea's tiniest creatures, namely sea urchins.
  A team of marine scientists from the University of Calfornia, Santa Barbara, conducted the study. According to a report in National Geographic News, malformed seashells show that climate change is affecting even the most basic rungs of the marine food chain-a hint of looming disaster for all ocean creatures. "Climate change could drastically reduce sea urchin populations in particular," said Gretchen Hofmann, a marine biologist. The purple sea urchin is commonly found off the coast of Australia and Antarctica. It is an essential food source for many marine animals such as cod or lobster, as well as a common ingredient in sushi. According to Hofmann, increasing amounts of atmospheric carbon dioxide are also raising the amount of the gas dissolved in ocean water. This makes the seas more acidic, decreasing the available amount of shell-forming calcium carbonate. To test the theory, Hofmann tested sea urchins in highly acidic water similar to what is predicted for the oceans. "We checked if they can make the skeleton that forms their bodies, and yes it is formed," Hofmann said. "But it was shorter and stumpier-not the same shape-so they swim and move differently. Plus it comes at a cost, which is they are more sensitive to temperature," she added. Hofmann refers to this malformed skeleton and sensitivity to heat as "double jeopardy." Her research team went further than any previous research by analyzing the recently sequenced sea urchin genome to find out what genes were turning off and on under this new environmental stress. "We wanted to ask them how they were doing and get a sense of their health and physiology," said Hofmann. "We found it caused their shell-forming genes to go up threefold, so their developing system was having to put more energy into making the skeleton and less into other things," she added. According to Scott Doney, a chemical oceanographer at Woods Hole Oceanographic Institute, "From the short-term experiments that have been running, the best indication is that likely the population as a whole will suffer dramatically." "But, in addition to being a food source for things we eat, sea urchins are a harbinger of the damage we do to ecosystems," he added. (ANI) © 2007 ANI TAGS: Science  global warming
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