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| For more information on these science news and feature story tips, please contact the public information officer at the end of each item at (703) 292-8070. Editor: Cheryl Dybas
Contents of this Tipsheet:
ICY CLOUD SURFACES FACILITATE OZONE DEPLETIONAn exhaustive supercomputer modeling effort at the NSF-supported National Center for Atmospheric Research (NCAR) in Boulder, Colorado, has shown that hydrochloric acid (HCL) is broken down on the surface of ice particles found in stratospheric clouds over earth's poles. The breakdown of HCL to chlorine atoms is an important step in the cascade of chemical reactions that lead to ozone destruction in the stratosphere each spring over Antarctica. Scientists have known that hydrochloric acid molecules that stick to the surface of ice crystals in clouds play a pivotal role in ozone depletion, but the specific chemical processes have been the subject of much debate. The recent modeling project indicates that hydrochloric acid molecules trapped at the surface by ice particles can be broken down while still in the solid phase, triggering a stream of complex chemical reactions that results in the release of chlorine atoms. The chlorine atoms in turn destroy huge quantities of ozone molecules by stripping away oxygen atoms. "The icy surfaces of cloud particles are an active player in the ozone depletion process," says chemist James Hynes of the University of Colorado at Boulder. "It's almost as if the ice is acting as an enzyme [a facilitator] for these chemical reactions." [Cheryl Dybas]
SEABIRDS GIVE NEW MEANING TO "SIBLING RIVALRY"Taller than most seabirds, masked boobies live and breed in tropical oceans where they feed by making high-velocity fishing dives into the sea. To survive, however, they also kill members of their own family: siblings engage in lethal battles shortly after hatching from their eggs. In a new study subjecting Darwin's evolutionary theories to some of their most rigorous scientific tests to date, NSF-funded biologist David Anderson of Wake Forest University in Winston-Salem, North Carolina, found a curious irony: boobies kill in order to thrive. The explanation? "When you have more young in a brood than you can care for well," says Anderson, "it may pay to pare off some young. These findings are an extreme example from nature of that point." Masked booby parents facilitate and encourage early "siblicide"--setting up a contest between older and younger chicks that only one will survive, and stacking the odds in favor of the eldest. But why lay two eggs if the goal is only one child? The answer lies in boobies' poor hatching rates. The second egg, it turns out, is an "insurance policy." Should the first egg fail to hatch, there's another chance in the second egg. [Cheryl Dybas]
SEAGOING "FRISBEE" COULD ANSWER SOME CLIMATE QUESTIONSOne of the most elusive pieces of the climate and weather puzzle may soon be supplied by a simple ocean-going package of sensors the size and shape of a frisbee. Development of the "frisbee" was funded by NSF. Scientists have long known that climate and weather are driven largely by the flow of heat from the ocean to the atmosphere. However, reliable measurements of this "heat flux" have been almost impossible to obtain, according to John Anderson, a scientist at the University of Wisconsin at Madison. The development of a drifting ocean heat flux sensor may provide important clues to long-term climate questions as well as insight into seasonal weather events such as hurricanes and winter storms. The beauty of the new device, says Anderson, is its simplicity. It consists of a foam ring that serves as a float, and sheets of fiberglass mesh stretched across the float that, when wet, firmly hold a paper-thin suite of sensors just below the water surface. These sensors measure the flow of heat from the ocean to the atmosphere. The measurements are sent via a 30-foot floating tether to a buoy that houses batteries, a computer, and a transmitter that relays a continuous stream of data to the polar-orbiting ARGOS satellite. The heat flux sensor has been tested in two freshwater lakes in Wisconsin, in the Gulf Stream, in the Atlantic Ocean and in the Pacific Ocean off Pago Pago in American Samoa. [Cheryl Dybas]
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