Featured Research

from universities, journals, and other organizations

Prehistoric greenhouse data from ocean floor could predict Earth's future, study finds

Date:
October 30, 2011
Source:
University of Missouri-Columbia
Summary:
New research indicates that Atlantic Ocean temperatures during the greenhouse climate of the Late Cretaceous Epoch were influenced by circulation in the deep ocean. These changes in circulation patterns 70 million years ago could help scientists understand the consequences of modern increases in greenhouse gases.

New research indicates that Atlantic Ocean temperatures during the greenhouse climate of the Late Cretaceous Epoch were influenced by circulation in the deep ocean. These changes in circulation patterns 70 million years ago could help scientists understand the consequences of modern increases in greenhouse gases.
Credit: © jim / Fotolia

New research from the University of Missouri indicates that Atlantic Ocean temperatures during the greenhouse climate of the Late Cretaceous Epoch were influenced by circulation in the deep ocean. These changes in circulation patterns 70 million years ago could help scientists understand the consequences of modern increases in greenhouse gases.

"We are examining ocean conditions from several past greenhouse climate intervals so that we can understand better the interactions among the atmosphere, the oceans, the biosphere, and climate," said Kenneth MacLeod, professor of geological sciences in the College of Arts and Science. "The Late Cretaceous Epoch is a textbook example of a greenhouse climate on earth, and we have evidence that a northern water mass expanded southwards while the climate was cooling. At the same time, a warm, salty water mass that had been present throughout the greenhouse interval disappeared from the tropical Atlantic."

The study found that at the end of the Late Cretaceous greenhouse interval, water sinking around Greenland was replaced by surface water flowing north from the South Atlantic. This change caused the North Atlantic to warm while the rest of the globe cooled. The change started about five million years before the asteroid impact that ended the Cretaceous Period.

To track circulation patterns, the researchers focused on "neodymium," an element that is taken up by fish teeth and bones when a fish dies and falls to the ocean floor. MacLeod said the ratio of two isotopes of neodymium acts as a natural tracking system for water masses. In the area where a water mass forms, the water takes on a neodymium ratio like that in rocks on nearby land. As the water moves through the ocean, though, that ratio changes little. Because the fish take up the neodymium from water at the seafloor, the ratio in the fish fossils reflects the values in the area where the water sank into the deep ocean. Looking at changes through time and at many sites allowed the scientists to track water mass movements.

While high atmospheric levels of carbon dioxide caused Late Cretaceous warmth, MacLeod notes that ocean circulation influenced how that warmth was distributed around the globe. Further, ocean circulation patterns changed significantly as the climate warmed and cooled.

"Understanding the degree to which climate influences circulation and vice versa is important today because carbon dioxide levels are rapidly approaching levels most recently seen during ancient greenhouse times," said MacLeod. "In just a few decades, humans are causing changes in the composition of the atmosphere that are as large as the changes that took millions of years to occur during geological climate cycles."

The paper, "Changes in North Atlantic circulation at the end of the Cretaceous greenhouse interval," was published in the October online edition of the journal Nature Geoscience. Coauthors include C. Isaza Londoño of the University of Missouri; E.E. Martin and C. Basak of the University of Florida, and A. Jiménez Berrocoso of the Unviersity of Manchester, United Kingdom. The study was sponsored by the National Science Foundation.


Story Source:

The above story is based on materials provided by University of Missouri-Columbia. Note: Materials may be edited for content and length.


Journal Reference:

  1. K. G. MacLeod, C. Isaza Londoño, E. E. Martin, Á. Jiménez Berrocoso, C. Basak. Changes in North Atlantic circulation at the end of the Cretaceous greenhouse interval. Nature Geoscience, 2011; DOI: 10.1038/ngeo1284

Cite This Page:

University of Missouri-Columbia. "Prehistoric greenhouse data from ocean floor could predict Earth's future, study finds." ScienceDaily. ScienceDaily, 30 October 2011. <www.sciencedaily.com/releases/2011/10/111027150213.htm>.
University of Missouri-Columbia. (2011, October 30). Prehistoric greenhouse data from ocean floor could predict Earth's future, study finds. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2011/10/111027150213.htm
University of Missouri-Columbia. "Prehistoric greenhouse data from ocean floor could predict Earth's future, study finds." ScienceDaily. www.sciencedaily.com/releases/2011/10/111027150213.htm (accessed September 22, 2014).

Share This



More Earth & Climate News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Will Climate Rallies Spur Change?

Will Climate Rallies Spur Change?

Newsy (Sep. 21, 2014) — Organizers of the People's Climate March and other rallies taking place in 166 countries hope to move U.N. officials to action ahead of their summit. Video provided by Newsy
Powered by NewsLook.com
Thousands March in NYC Over Climate Change

Thousands March in NYC Over Climate Change

AP (Sep. 21, 2014) — Accompanied by drumbeats, wearing costumes and carrying signs, thousands of demonstrators filled the streets of Manhattan and other cities around the world on Sunday to urge policy makers to take action on climate change. (Sept. 21) Video provided by AP
Powered by NewsLook.com
Climate Change Rally Held in India Ahead of UN Summit

Climate Change Rally Held in India Ahead of UN Summit

AFP (Sep. 20, 2014) — Some 125 world leaders are expected to commit to action on climate change at a UN summit Tuesday called to inject momentum in struggling efforts to tackle global warming. Duration: 00:41 Video provided by AFP
Powered by NewsLook.com
New Music With Recycled Instruments at Colombia Fest

New Music With Recycled Instruments at Colombia Fest

AFP (Sep. 19, 2014) — Jars, bottles, caps and even a pizza box, recovered from the trash, were the elements used by four musical groups at the "RSFEST2014 Sonorities Recycling Festival", in Colombian city of Cali. Duration: 00:49 Video provided by AFP
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