Featured Research

from universities, journals, and other organizations

Polar oceans key to temperature in the tropics

Date:
June 21, 2010
Source:
Newcastle University
Summary:
Scientists have found that the ocean temperature at Earth's polar extremes has a significant impact thousands of miles away at the equator.

Icebreaker in the Arctic. Scientists have found that the ocean temperature at the earth's polar extremes has a significant impact thousands of miles away at the equator.
Credit: iStockphoto

Scientists have found that the ocean temperature at Earth's polar extremes has a significant impact thousands of miles away at the equator.

Related Articles


Newcastle University's Dr Erin McClymont is part of an international team of researchers who have published research in Science June 18, 2010 demonstrating a close link between the changes in the subpolar climate and the development of the modern tropical Pacific climate around two million years ago.

The team believes this solves another piece of the puzzle concerning oceanic behaviour and its influence on climate.

This research, led by the Institut de Ciència i Tecnologia Ambientals in Barcelona, studied the Northern Pacific and Southern Atlantic sea-surface temperatures from the Pliocene Era (3.65 million years ago) to the present day. Data obtained during the reconstruction indicates that the regions close to the poles of both oceans have played a fundamental role in the way the tropical climate has evolved.

The cooling and expansion of polar waters between 1.8 and 1.2 million years ago increased the temperature difference between the equator and the poles. This intensified atmospheric circulation and helped to develop the modern day 'cold tongue' in the east Pacific.

Created by a shallow thermocline -- the layer of ocean water in which temperatures fall rapidly -- the cold tongue brings cold, deep waters to the surface in the east tropical Pacific. Under the warmer climate of the Pliocene, the thermocline was deeper and the cold tongue was much smaller, creating a situation more like the 'El Niño' events that hit the Pacific every three to five years.

"Our results show that the polar oceans play a key role in the global climate, and that one outcome of a rise in global temperature could be an increase in the depth of the thermocline and contraction of the cold tongue in the eastern Pacific," said Dr McClymont. "The high-latitudes are currently experiencing large climate changes, and our data show that this could impact on tropical climates as we saw in the Pliocene."

The study of Pliocene climate has been the subject of intense research as this era represents the most recent climatic period in Earth's history when average temperatures were significantly higher than today over a sustained period. As a result, the Pliocene is thought to be the closest predictor of Earth's climate in the future.

How it works: Analysing deep sea 'fossils'

Researchers analysed marine sediment collected by the international Integrated Ocean Drilling Program, which is supported in the UK by the Natural Environment Research Council (NERC). Sediment cores were drilled in water depths exceeding 3km to measure the composition of alkenones -- highly resistant organic compounds produced by phytoplankton.

The phytoplankton live in the surface ocean and change their alkenone chemistry in response to temperature changes. The researchers used these 'biomarkers' or 'chemical fossils' to reconstruct the temperatures of the surface ocean.

"These molecules are 'fossils' in the same way that shells or fish fall to the bottom of the ocean and are preserved," said Dr McClymont, who is a member of the Quaternary Research Group within Newcastle University's School of Geography, Politics and Sociology. "Molecules which remained from the phytoplankton were gradually buried beneath layers of sediment beneath the ocean floor, and by analysing these we were able to reconstruct the temperatures of the surface ocean in the past."

Reconstruction of the surface temperature in the Northern Pacific and Southern Atlantic has enabled a simultaneous sea-surface cooling to be identified in the subpolar regions of the two hemispheres in the period between 1.8 and 1.2 million years ago. This finding coincides with the formation of the equatorial Pacific cold tongue -- which currently almost disappears during any El Niño conditions.

Previous studies have shown that, during the warm conditions of the Pliocene, this cold tongue was not present, creating a situation similar to a permanent El Niño situation in the equatorial Pacific.

(i) The research is based on Dr Alfredo Martínez-García's doctoral thesis, who is currently a researcher with both the Swiss Federal Institute of Technology, ETH Zurich, and with the DFG-Leibniz Centre at the University of Postdam, Germany). The thesis was undertaken at the UAB and directed by Dr Antoni Rosell Melé, an ICTA ICREA researcher and adjunct professor with the Department of Geography. This work was carried out in collaboration with Dr Gerald H. Haug, of ETH and DFG-Leibniz Centre; Dr Erin L. McClymont of Newcastle University (UK); and Dr Rainer Gersonde, of the Alfred Wegener Institute (Germany).


Story Source:

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


Journal Reference:

  1. Alfredo Martínez-García, A; Rosell-Melé, A; McClymont E L; Gersonde R; Haug G. H. Subpolar link to the emergence of the modern equatorial Pacific cold tongue. Science, 18 June 2010 DOI: 10.1126/science.1184480

Cite This Page:

Newcastle University. "Polar oceans key to temperature in the tropics." ScienceDaily. ScienceDaily, 21 June 2010. <www.sciencedaily.com/releases/2010/06/100617143934.htm>.
Newcastle University. (2010, June 21). Polar oceans key to temperature in the tropics. ScienceDaily. Retrieved December 20, 2014 from www.sciencedaily.com/releases/2010/06/100617143934.htm
Newcastle University. "Polar oceans key to temperature in the tropics." ScienceDaily. www.sciencedaily.com/releases/2010/06/100617143934.htm (accessed December 20, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, December 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Lava on Track to Hit Hawaii Market

Raw: Lava on Track to Hit Hawaii Market

AP (Dec. 19, 2014) — Lava from an active volcano on Hawaii's Big Island slowed slightly but stayed on track to hit a shopping center in the small town of Pahoa. (Dec. 19) Video provided by AP
Powered by NewsLook.com
Birds Might Be Better Meteorologists Than Us

Birds Might Be Better Meteorologists Than Us

Newsy (Dec. 19, 2014) — A new study suggests a certain type of bird was able to sense a tornado outbreak that moved through the U.S. a day before it hit. Video provided by Newsy
Powered by NewsLook.com
Navy Unveils Robot Fish

Navy Unveils Robot Fish

Reuters - Light News Video Online (Dec. 18, 2014) — The U.S. Navy unveils an underwater device that mimics the movement of a fish. Tara Cleary reports. Video provided by Reuters
Powered by NewsLook.com
Arctic Warming Twice As Fast As Rest Of Planet

Arctic Warming Twice As Fast As Rest Of Planet

Newsy (Dec. 18, 2014) — The Arctic is warming twice as fast as the rest of the planet, thanks in part to something called feedback. 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:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

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