Featured Research

from universities, journals, and other organizations

Ancient Sea Creatures Serve As Natural Thermometers For Climate Prediction

Date:
December 11, 2002
Source:
Texas A&M University
Summary:
Three-hundred-million-year-old fossil creatures serve as "natural thermometers" and hold clues to Earth's past and future climate, believes Texas A&M University professor Ethan Grossman, who's been studying the fossils for years.

COLLEGE STATION, December 9, 2002 – Three-hundred-million-year-old fossil creatures serve as "natural thermometers" and hold clues to Earth's past and future climate, believes Texas A&M University professor Ethan Grossman, who's been studying the fossils for years.

Mineral deposits in fossilized brachiopod shells allow geochemists to plot changes in sea temperatures over millions of years. These patterns of climate change serve as tests for climate models used to predict global warming.

Grossman researches the isotopic make-up of fossilized brachiopods, sea creatures whose distant relatives – such as lampshells – are still found in today's oceans.

"We drill tiny holes in the fossilized shells, then through isotope-ratio mass spectrometry, analyze the extracted powder for different forms of oxygen," said Grossman of the Department of Geology and Geophysics in the College of Geosciences. "Oxygen always has eight protons but can have different numbers of neutrons. Regular oxygen [O-16] has 8 neutrons in its nucleus, but a nonradioactive isotope with 10 neutrons [O-18] is naturally present in seawater in measureable amounts. The O-18 has a temperature-dependent affinity for the calcium carbonate which forms the shells of many sea creatures.

"By analyzing the ratio of O-18 to regular oxygen in the shells, we can tell the temperature of the ancient seawater. Higher values of O-18 correspond with periods of colder temperatures, and fluctuations in the isotopic ratios of oxygen in the shells over time reflect transitions between icehouse and greenhouse periods in Earth history."

Grossman, along with collaborators David Pollard, Pennsylvania State University; Christopher Scotese, University of Texas at Arlington; and William Hyde, Duke University, presented a paper on their latest analysis of relationships between O-18 distribution and global paleoclimate models at the October annual meeting of the Geological Society of America.

"Oxygen isotope estimates of paleotemperature show good agreement with computerized global climate models for some intervals in the past but not with others," Grossman noted. "We're in the process of investigating possible reasons for this lack of agreement. But study of the patterns of transition during ancient times from periods of cold temperatures, with widespread glaciation, to warmer periods of a more tropical Earth, can lend support to current computer models projections that the Earth has entered another warming period."

Grossman's oxygen isotope research also correlates with studies indicating that increased carbon dioxide in the atmosphere coincides with higher temperatures. This work relies on the measurement of stable carbon isotopes (C-13/C-12) in the shells, a proxy indicator for the carbon cycle.

"Research indicates that drawdown of carbon dioxide, with sequestration of carbon into biomass and sediments, can trigger periods of glaciation," Grossman observed. "Correlating fluctuations of carbon dioxide and carbon and oxygen isotopes in the past may help us better calibrate computer models of future global climate change.

"Our research doesn't prove that increased CO2 is currently causing global warming, but oxygen isotopic measurements of ancient Earth temperatures suggest that this has caused global warming in Earth's past."


Story Source:

The above story is based on materials provided by Texas A&M University. Note: Materials may be edited for content and length.


Cite This Page:

Texas A&M University. "Ancient Sea Creatures Serve As Natural Thermometers For Climate Prediction." ScienceDaily. ScienceDaily, 11 December 2002. <www.sciencedaily.com/releases/2002/12/021211084123.htm>.
Texas A&M University. (2002, December 11). Ancient Sea Creatures Serve As Natural Thermometers For Climate Prediction. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2002/12/021211084123.htm
Texas A&M University. "Ancient Sea Creatures Serve As Natural Thermometers For Climate Prediction." ScienceDaily. www.sciencedaily.com/releases/2002/12/021211084123.htm (accessed July 30, 2014).

Share This




More Earth & Climate News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Thousands Flocking to German Crop Circle

Raw: Thousands Flocking to German Crop Circle

AP (July 30, 2014) Thousands of people are trekking to a Bavarian farmer's field to check out a mysterious set of crop circles. (July 30) Video provided by AP
Powered by NewsLook.com
In Virginia, the Rise of a New Space Coast

In Virginia, the Rise of a New Space Coast

AP (July 30, 2014) Every summer, tourists make the pilgrimage to Chincoteague Island, Va. to see wild ponies cross the Assateague Channel. But, it's the rockets sending to supplies to the International Space Station that are making this a year-round destination. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com
Climate Change Could Cost Billions According To White House

Climate Change Could Cost Billions According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins