Scientists Core Into Clear Lake in California to Explore PastClimate Change May 04, 2012 University of California, Berkeley, scientists are drilling intoancient sediments at the bottom of Northern California's Clear Lakefor clues that could help them better predict how today's plantsand animals will adapt to climate change and increasing population. The lake sediments are among the world's oldest, containing recordsof biological change stretching back as far as 500,000 years. The core drilling is part of a unique, multifaceted effort at UCBerkeley to determine how Earth's flora and fauna responded to pastchanges in climate in order to improve models that project how lifeon Earth will adapt to today's environmental pressures. What theresearchers learn from their look-back in time will be crucial forstate or local planners clamoring for better predictive tools toguide policies crucial to saving ecosystems threatened by climatechange. |
"We are reconstructing the past to better forecast the future,because we need to know what's coming in order to adequatelyprepare for it," said project leader Cindy Looy, UC Berkeleyassistant professor of integrative biology. Looy and 16 other UC Berkeley faculty members -- includingpaleontologists, pollen experts, botanists, ecologists and climatemodeling experts -- will examine the lake cores for pollen grains,charcoal and fresh-water organisms going back at least 130,000years, long before humans arrived in the area. Using isotope andchemical analysis as well as carbon dating, the researchers willobtain a long series of detailed snapshots -- ideally, every 10years -- of the plant and animal communities in the Clear Lake areaand how the communities changed in response to "natural" globalwarming events. The analysis will also provide a measure of thetemperature, oxygen content and nutrient levels of the lake, whichreflect rainfall and water level. "One way to check our predictions is to go back in time to a statevery similar to today, with the same plants and animals and aboutthe same temperature.
The fossilized plant and animal remains fromClear Lake will give us a baseline for what this region ofCalifornia looked like under similar climatic conditions, and whenit was colder or warmer. We use that information to fine-tunepredictive models being developed today," Looy said. "Rates ofglobal warming almost as fast as what we see today last happenedduring the shift from the last glacial to the current interglacialroughly 12,000 years ago, so that is one time interval we willfocus on." Focusing on two glacial-to-interglacial transitions Looy and her team also will look at an even earlier transition froma glaciated Earth 130,000 years ago to a time 113,000 years agowhen it may have been locally warmer than today. Learning what thearea looked like during that time will help Northern Californiansanticipate how conditions will change as global temperaturecontinues to rise over the coming decades. "There are indications from ice cores and ocean drilling cores thatthe beginning of the previous interglacial may have been warmerthan it is now, which is where it becomes interesting," said Looy."We know what the Earth is like at today's temperature, but a lotof people are trying to predict what will happen if the Earth warms1 or 2 degrees Celsius (2-4 degrees Fahrenheit), or even more." Charcoal in the lake sediments will also tell the researchers howNative Americans altered the environment through deliberate firesdesigned, for example, to increase acorn production by oaks.
One member of the team, Anthony Barnosky, UC Berkeley professor ofintegrative biology, will correlate this information with mammalianfossils collected from cave deposits in the area and that have beenstored for decades in the Museum of Paleontology. "You can view the core as a time machine by which we can define acontinuous record of change, both climatic and vegetational, thoughthe past 130,000 years, and then we have all these floatingsnapshots of the ecosystem -- the mammal communities -- from cavedeposits around here," Barnosky said. "We can put names on thesefossils and radiocarbon-date them and begin to build a 3-D pictureof change through time from the late Pleistocene, some 130,000years ago, through the last glacial/interglacial transition 13,000to 11,000 years ago, all the way up to the present." The study will help to evaluate and refine current models thatpredict how plants and animals will adapt to a changing world bytesting predictions of the models against what actually happenedduring past times of climate change. Such models are important forstate and local planning agencies that must deal with futureconsequences of climate change, including sea level rise, watershortages and increasing fire incidence that can threatenecosystems.
"Based on this type of research at UC Berkeley, we want to make thecase that adaptation to a changing climate is an issue we have totake more seriously, we have to bring it more into the mainstreamof Bay Area planning," said Bruce Riordan, director of the Bay AreaJoint Policy Committee, which coordinates regional planningagencies in responding to climate adaptation. "By starting planningnow and understanding the problems, the strategies we need toimplement and the costs involved, we may find less costly solutionstoday rather than later. The research can really help inform aboutboth the problems and about the solutions." Half million years of sediment Clear Lake is unusual in having survived the advance and retreat ofglaciers that scoured and obliterated most lakes outside thetropics, including the large lakes in California's Sierra Nevada.Previous coring in Clear Lake by the U.S. Geological Survey (USGS)in 1973 and 1980 revealed lake sediments half a million years old,with only three breaks in continuity. At the site where UC Berkeleyplans to obtain cores, in the upper arm of the lake about 1-3 mileswest southwest of the town of Lucerne, the USGS obtained acontinuous core in 1973 going back 130,000 years.
Looy and her team hired Utah-based DOSECC (Drilling, Observationand Sampling of the Earths Continental Crust), a non-profitscientific drilling company, to obtain two 120 meter-long(400-foot) cores, each about 8 centimeters (3 inches) in diameter.The cores are obtained in 3-meter (10-foot) chunks that are cappedand labeled at the site and will be shipped to a cold-storagefacility in Minnesota operated by LacCore (National Lacustrine CoreFacility), a non-profit organization funded by the National ScienceFoundation and the University of Minnesota. In the facility's coldlab, the team will split each chunk longitudinally, photograph thehalves, and then bring one half of each chunk back to UC Berkeleyfor analysis. While the USGS sampled its cores once every meter, Looy and herteam will sample parts of their cores every centimeter, theequivalent of about 10 years of sediment. "We will get 100 times better time resolution, and can follow whathappens when you rapidly warm the Earth up," Looy said. "The detail we can get from Clear Lake is really impressive," sheadded.
"The material is well preserved, and the USGS did a greatjob in describing the whole time interval so that now we know whatthe interesting areas are to focus on. We know this is not a shotin the dark." The Clear Lake drilling project is one of seven research projectsinvolving global change forecasting funded by a $2.5 million grantfrom the Gordon and Betty Moore Foundation to UC Berkeley'sBerkeley Initiative in Global Change Biology, or BiGCB. Eachproject focuses on a particular California environment andleverages UC Berkeley's unique museum collections of vertebrates,insects, plants and fossils to provide details about past changesin plant and animal populations.
The e-commerce company in China offers quality products such as RF Skin Tightening Machine Manufacturer , China E-Light Laser Hair Removal, and more. For more , please visit 808nm Diode Laser Hair Removal today!
Related Articles -
RF Skin Tightening Machine Manufacturer, China E-Light Laser Hair Removal,