Longest-lived animals reveal climate change secrets

June 13, 2012, Bangor University
Longest-lived animals reveal climate change secrets
Arctica islandica Clam shells, which can live to a great age.

(Phys.org) -- Researchers at Bangor University have used some of the world’s longest-lived animals to look at how the North Atlantic Ocean has affected our climate over the past 1,000 years. 

By looking in great detail at the shell of a species of clam that can live for at least 500 years, they have shown that a weakening of the Gulf Stream – the current that brings warm water from the Caribbean to northwest Europe - may have contributed to exceptionally cold conditions in Europe from the 15th to the 19th centuries.   This is the period known as the Little Ice Age, and it was a time of bitter cold, poor harvests, famines and revolutions, but also of spectacular ice fairs on the frozen River Thames.

“If the Gulf Stream is weaker, then less heat is being transported north, so that temperatures in northwest Europe became more like temperatures at the same latitude in Canada”, said Dr. Paul Butler of School of Ocean Sciences at Bangor University.

The research, published in the leading journal Nature Communications, uses radiocarbon analysis of the shells – which come from animals that lived north of Iceland - to work out the source of the water in which the clams were living.  “The radiocarbon tells us how long it has been since the last time the water was at the surface,” said Dr. Butler. “If the water is ‘old’, we know that it originated deep within the Arctic Ocean. On the other hand, Atlantic sourced water, like the Gulf Stream, was at the surface more recently, so it is expressed in the shells as ‘young’. During the Little Ice Age, the older Arctic water seems to have been dominant north of Iceland, and there was less Atlantic-sourced water. We interpret this as meaning that the Gulf Stream was weaker. Before the 15th century – in what we call the Medieval Warm Period – the situation was reversed.”

Longest-lived animals reveal climate change secrets
The banding on the shells seen under a microscope. These can reveal secrets about the climate.

The announcement by Bangor scientists in October 2007 of the remarkable lifespan of these clams generated worldwide interest and achieved a place in Time magazine’s ten most significant scientific discoveries of the year.  The latest results show how this field of research can be used in the study of the marine environment of the past.  

“The nice thing about these shells is that they have distinct annual growth lines, so we can accurately date the shell material”, said Dr. Butler.  “What makes them even more useful is that the lines have the same patterns throughout the population, so by comparing patterns in dead shells with patterns in shells from live animals, we can work out the dates of the dead shells. That’s just the same as what archaeologists do when they use tree rings in dead wood to work out the dates of old buildings.”     

Explore further: Dolomite discovery ends 100-year treasure hunt

Related Stories

Cool species can take the heat

May 17, 2011

(PhysOrg.com) -- Two scientists from Simon Fraser University and one from Deakin University (DU) in Australia have made a discovery that is overturning conventional wisdom about how land and marine animals react to heat.

China to launch space station module prototype

August 17, 2011

China’s space program is in the news again, this time with unconfirmed reports that the Tiangong 1 space lab may be launching into orbit sometime this year – possibly later this month.  Previous news reports ...

Lefties more likely to look before they leap

February 8, 2012

(Medical Xpress) -- New research from the University of Abertay Dundee has found evidence that left-handed people may be better decision makers than their right-handed counterparts.

A swirling oasis of life

February 14, 2012

A serpentine eddy swirls in the southern Indian Ocean several hundred kilometers off the coast of South Africa in this natural-color image, acquired by NASA’s Terra satellite on December 26, 2011.

Recommended for you

Mystery solved for mega-avalanches in Tibet

January 23, 2018

An international scientific effort determined the cause of a highly unusual and deadly glacier avalanche in Tibet in 2016, a new Nature Geoscience paper says.


Adjust slider to filter visible comments by rank

Display comments: newest first

5 / 5 (3) Jun 13, 2012
Interesting clams. More confirmation of an old theory.
5 / 5 (2) Jun 15, 2012
Rubberman. I agree. What an interesting way of looking at past environments; CLAMS. Sounds like it could backup the tree rings for CO2.
5 / 5 (1) Jun 15, 2012
Shells have been used for a long time in paleoclimatology.

It is confirming that they document that the MWP and the LIA were largely regional events and not truly global in scope as has been repeatedly claimed by Denialists.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.