Corporate Banner
Satellite Banner
Environmental Analysis
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Ancient Climate from Plankton Shells

Published: Monday, November 04, 2013
Last Updated: Monday, November 04, 2013
Bookmark and Share
Climate changes from millions of years ago are recorded at daily rate in ancient sea shells, new research shows.

Using the Advanced Light Source (ALS) in California, scientists have revealed growth bands in plankton shells that show how shell chemistry records the sea temperature. Work currently continues at Diamond Light Source.

The results could allow researchers to chart short timescale changes in ocean temperatures hundreds of millions of years ago.

Plankton shells show features like tree rings, recording historical climate.

 It’s important to understand current climate change in the light of how climate has varied in the geological past. One way to do this, for the last few thousand years, is to analyse ice from the poles. The planet’s temperature and atmosphere are recorded by bubbles of ancient air trapped in polar ice cores. The oldest Antarctic ice core records date back to around 800,000 years ago. 

As microbial plankton grow in ocean waters, their shells, made of the mineral calcite, trap trace amounts of chemical impurities, maybe only a few atoms in a million getting replaced by impurity atoms. Scientists have noticed that plankton growing in warmer waters contain more impurities, but it has not been clear how and why this “proxy” for temperature works. 

When the plankton die, they fall to the muddy ocean floor, and can be recovered today from that muddy ocean floor sediments, which preserve the shells as they are buried. The amount of impurity, measured in fossil plankton shells, provides a record of past ocean temperature, dating back more than 100 million years ago. 

Now, researchers from the Department of Earth Sciences at the University of Cambridge have measured traces of magnesium in the shells of plankton using the “Advanced Light Source” synchrotron in Berkeley, California.

The powerful X-ray microscope has revealed narrow nanoscale bands in the plankton shell where the amount of magnesium is very slightly higher, at length scales as small as one hundredth that of a human hair. They are growth bands, rather like tree rings, but in plankton the bands occur daily or so, rather than yearly. 

“These growth bands in plankton show the day by day variations in magnesium in the shell at a 30 nanometre length scale. For slow-growing plankton it opens the way to seeing seasonal variations in ocean temperatures or plankton growth in samples dating back tens to hundreds of millions of years”, says Professor Simon Redfern, one of the experimenters on the project. 

“Our X-ray data show that the trace magnesium sits inside the crystalline mineral structure of the plankton shell. That’s important because it validates previous assumptions about using magnesium contents as a measure of past ocean temperature.”

The chemical environment of the trace elements in the plankton shell, revealed in the new measurements, shows that the magnesium sits in calcite crystal replacing calcium, rather than in microbial membranes in their impurities in the shell. This helps explain why temperature affects the chemistry of plankton shells - warmer waters favour increased magnesium in calcite.

The group are now using Diamond's Imaging and Coherence beamline (I13) to measure how plankton shells grow and whether they change at all in the ocean floor sediments. Their latest results could allow scientists to establish climate variability in Earth’s far distant past, as well as providing new routes to measure ocean acidification and salinity in past oceans.

Results published in the journal Earth and Planetary Sciences Letters.  


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,500+ scientific posters on ePosters
  • More than 3,800+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.


Scientific News
Low-level Arsenic Exposure Before Birth Associated with Early Puberty in Female Mice
Study examine whether low-dose arsenic exposure could have similar health outcomes in humans.
Intensity of Desert Storms May Affect Ocean Phytoplankton
MIT study finds phytoplankton are extremely sensitive to changing levels of desert dust.
Determination of Phosphate in Soil Extracts in the Field: A Green Chemistry Enzymatic Method
New method for phosphate determination which can be carried out in the field to obtain results on the spot.
Open-Source Photometric System for Enzymatic Nitrate Quantification
New method proposed for developing a cheaper, more accessible open-source water testing platform capable of performing Nitrate Reductase Nitrate-Nitrogen Analysis.
Toxic Algae is a Threat to Our Water
A report concludes that blooms of toxic cyanobacteria, or blue-green algae, are a poorly monitored and underappreciated risk to recreational and drinking water quality in the U.S., and may increasingly pose a global health threat.
Significant Part of Greenhouse Gas Emissions Comes From River and Sea Organisms
Running streams are key sources of the greenhouse gas carbon dioxide, but why is it so?
Better Estimates of Worldwide Mercury Pollution
New findings show Asia produces twice as much mercury emissions as previously thought.
Real-Time Data for Cancer Therapy
Biochemical sensor implanted at initial biopsy could allow doctors to better monitor and adjust cancer treatments.
New Biosensors for Managing Microbial ‘Workers’
Researchers at Harvard’s Wyss Institute have unveiled new biosensors that enable scientists to more effectively control and 'communicate with' engineered bacteria.
Playing 'Tag' with Pollution lets Scientists See Who's It
Using a climate model that can tag sources of soot from different global regions and can track where it lands on the Tibetan Plateau, researchers have determined which areas around the plateau contribute the most soot — and where.
Scroll Up
Scroll Down
SELECTBIO

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,500+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!