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CSUB researcher peers into past
| Saturday, Dec 1 2007 9:05 PM
Last Updated: Saturday, Dec 1 2007 9:11 PM
In 130 feet of dirt, Rob Negrini hopes to extract 200,000 years worth of data.
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Core samples from Soda Lake in the area of the Carrizo Plain are being studied for past precipitation and climate data of central California by CSUB geology professor Rob Negrini and his students.
CSUB student Robert Privett uses the Munsell Color Chart to color code core samples from Soda Lake in the area of the Carrizo Plain.
The Cal State Bakersfield geology professor is using a soil core from Soda Lake on the Carrizo Plain National Monument to determine historical precipitation and climate records for coastal Central California.
To do so, Negrini and a team of student researchers are analyzing remnants of microscopic crustaceans, called ostracodes, and plant pollen in the dirt. Relative temperature and rainfall can be extrapolated from the quantity and type of organisms found, Negrini said.
"If there's critters in the lakes, they often tell us what the conditions were like throughout the history of the lake," he said. "Some of the ostracodes will only live in warm water, some will only live in cold water."
The work is intended to create an on-shore compliment to an existing historical record for the same region developed in the 1990s by James Kennett, an oceanography and earth science professor at University of California, Santa Barbara.
Kennett used ocean sediments from the Santa Barbara Basin to create the detailed off-shore records.
Cold waters from the north and warm water from the south come together off the coast of California, Kennett said. The effects of those currents are recorded in the sediments at the bottom of the ocean over the years.
"It's the equivalent of tree rings in the ocean -- each year another layer is added," Kennett said.
Unique conditions in the Santa Barbara Basin preserve the sediment, making the body of data culled from it one of the best climate records in the world, Kennett said.
Negrini took his core sample from Carrizo's Soda Lake because it's near the Santa Barbara Basin and because of the unique hydrology of the area. Because the lake is located in a closed basin, with no inlet or outlet, it collects only rain that falls in the surrounding area.
"So you know you're sampling ancient rainfall amounts," Negrini said.
By contrast, lakes fed by rivers may contain rain that falls hundreds of miles away.
Soda Lake gets its name from the white sheet left on the lake bed when water evaporates, leaving a crusty layer of sulphate and carbonate salts. It is one of the largest remaining alkali wetlands in California.
From the Soda Lake core, Negrini expects he will be able to draw conclusions about temperature change in 100-year intervals -- the equivalent of roughly one inch of core.
"We can't come up with what the temperature used to be to half a degree, but we can see if it was relatively warmer or colder," he said.
He expects the research to take several years to complete.