Animal Engineering

The notion that the whole is greater than the sum of its parts holds true for the giant pink Queen conch — or rather its calcium carbonate domicile. The shell of Strombus gigas  is made of aragonite, a polymorph of calcium carbonate, and interlayered protein secreted by the animal. This natural composite material is one hundred to one thousand times stronger than solitary calcium carbonate thanks to ingenious engineering on the part of the conch. Stress is dissipated across layers through a series of microcracks rather than through one large fracture. Arthur Heuer and colleagues at Case Western Reserve University examined the structural basis for the strength of the conch shell and found that the key lies in the complex crossed lamellar structure of the aragonite. Their findings reveal details about the conch’s feat of engineering that may have applications for building stronger ceramics and other strong, lightweight materials.
L.W.

More tsunamis?

The East Coast tsunami lookout continued this summer with a report in the July 14 Science. Peter Flemings of Pennsylvania State University took sediment cores from the continental slope off the coast of New Jersey that have revealed subsurface zones of undercompacted sediment with high fluid pressure. Flemings believes these pressures may lead to sediment failure — and possibly a tsunami. Earlier this summer, Neal Driscoll of the Woods Hole Oceanographic Institution and his colleagues drew attention to submarine features off the East Coast as potential tsunami threats, but they concluded that high-pressure gas is the most likely explanation. Flemings sampled sediment in 1997 at Ocean Drilling Program site 1073 from the JOIDES Resolution.  Like Driscoll, who discovered large zones of disturbed sediment off the coast of Virginia and the Carolinas (Geotimes, July 2000), Flemings claims that the sediments could violently release their pressurized contents if disturbed. Such a sediment collapse could cause a tsunami. However, the probability of a tsunami striking the New Jersey shore has not been determined and the scientists plan to continue their research.
L.W.
 
 
 
 

Yellowstone hot spot Combining data from about 200 Global Positioning System (GPS) receivers and 300 seismometers, a team of geophysicists will model the Yellowstone hot spot, which fuels geothermal activity beneath and around Yellowstone National Park and the Yellowstone caldera. The team hopes to determine whether the hot spot is powered from the mantle or extends to the core-mantle boundary, says co-leader Eugene Humphreys of the University of Oregon. Most of the seismic array will sit at the park’s northeast corner and measure the arrival times of earthquake waves from the Tonga and Fiji islands. The hot spot and its tectonics extend beyond Yellowstone for at least a 200-kilometer radius, says lead researcher Robert Smith of the University of Utah. The six seismic arrays contain about 300 seismometers and cover Montana, Idaho, Utah, northern Nevada and Wyoming. The researchers will collect data this winter. K.B.   Figure at right from www.nimes.utah.edu/~ggcmpsem/UUSATRG/CD-Yel/GPS/FIGS/topo.html.

Distribution of GPS campaign stations in the Yellowston-Snake River Plain region.

 

Diversity mandate

July 13, WASHINGTON
Science, engineering and technology jobs continue to increase, greatly outpacing the number of Americans qualified to fill them, according to the Commission on the Advancement of Women and Minorities in Science, Engineering and Technology Development (CAWMSET). Also called the Morella Commission after its advocate, Rep. Connie Morella (R-Md.), the congressionally mandated commission released its report today, calling for immediate, focused action to increase diversity in the science, engineering and technology workforce. By 2020, the commission reports, almost one-third of the American workforce will be racial and ethnic minorities, and almost one-half women. “Growing the American talent pool will require a major shift in how we now educate, train and recruit citizens in the fields of science, engineering and technology,” said Elaine Mendoza, chair of the commission.
B.M.

A story on the CAWMSET report will appear in the September Geotimes. For more on the commission, visit www.nsf.gov/od/cawmset.