Posted on 11/14/2007 2:53:47 PM PST by blam
Ice Age Imprint Found On Cod DNA
ScienceDaily (Nov. 14, 2007) — An international team of researchers, led by the University of Sheffield, has demonstrated how Atlantic cod responded to past natural climate extremes. The new research could help in determining cods vulnerability to future global warming.
Atlantic cod. Professor Bigg of the University of Sheffield said: "This research shows that cod populations have been able to survive in periods of extreme climatic change, demonstrating a considerable resilience. However this does not necessarily mean that cod will show the same resilience to the effects of future climatic changes due to global warming." (Credit: NOAA)
With fishing pressures high and stock size low, there is already major concern over the current sustainability of cod and other fisheries. The new findings show that natural climate change has previously reduced the range of cod to around a fifth of what it is today, but despite this, cod continued to populate both sides of the North Atlantic.
The researchers used a computer model and DNA techniques to estimate where cod could be found in the ice age, when colder temperatures and lower sea-levels caused the extinction of some populations and the isolation of others.
The computer models used to estimate ice-age habitats suitable for cod were developed by Professor Grant Bigg, Head of the University of Sheffield's Department of Geography. These climatic analyses were combined with genetic studies by US researchers at Duke University and the University of California, and ecological information prepared by colleagues at the University of East Anglia and the Institute of Marine Research in Norway.
On land, plants and animals (including humans) are known to have moved further south when the northern ice sheets reached their maximum extent around 20,000 years ago. Similar migrations must have happened for plankton and fish in the sea.
But there were two added complications: firstly, greatly reduced sea levels meant that many shallow and highly productive marine habitats around Europe and North America ceased to exist. Secondly, the ice-age circulation patterns in the North Atlantic caused the temperature change between tropical and polar conditions to occur over a much shorter north-south distance, reducing the area suitable for temperate species -- such as cod.
The new analyses included these effects, together with other environmental and ecological information, in order to estimate where it was possible for Atlantic cod to reproduce and survive.
The results indicated that the ice-age range of Atlantic cod extended as far south as northern Spain, but the total area of suitable habitat was much more restricted. Nevertheless, populations of cod continued to exist on both sides of the North Atlantic. These findings were confirmed by genetic data, based on over a thousand DNA analyses of present-day cod populations, from Canada, Greenland, Iceland and around Europe.
Professor Bigg said: "This research shows that cod populations have been able to survive in periods of extreme climatic change, demonstrating a considerable resilience. However this does not necessarily mean that cod will show the same resilience to the effects of future climatic changes due to global warming."
The journal article 'Ice age survival of Atlantic cod: agreement between palaeo-ecology models and genetics' is published online in the journal Proceedings of the Royal Society B on 14 November 2007.
Adapted from materials provided by University of Sheffield.
What hath cod wrought?
Shirley Temple
Song Lyrics
At The Codfish Ball
(Captain January 1936)
Lyrics/Music S.Mitchell/L.Pollack
Next Friday night your all invited
To dance from 8 to 5
All the fishes still alive
Are having a ball
Its some affair they’ll all be there
From the Herring to the Whale
They’ll turn out to shake a scale
In Neptune’s Hall
Come along and follow me
To the bottom of the sea
We’ll join in the Jamboree
At the Codfish ball
Lobsters dancing in a row
Shuffle off to Buffalo
Jelly fish sway to and fro
At the Codfish ball
Finn-an-haddie leads the eel
Thought an Irish reel
The Catfish is a dancing man
But he can’t can-can like a sardine can
Tunas trucking left and right
Minnies mooching what a night
There won’t be a hook in site
At the Codfish ball
I thought the same thing when I read this:
"However this does not necessarily mean that cod will show the same resilience to the effects of future climatic changes due to global warming."
He covered both religions...Climate Change and Global Warming just to be safe.
The AGW cult is going to start throwing virgins into volcanoes any day now.
Neat, thanks.
The future of lutfisk is secure.
Lutfisk: The piece of cod that passes all understanding.
I still think there’s something fishy about global warming!!
The cult is certain that (A) man is the cause of global climate change (although I read one global warming scientist make the claim that man has pushed back the next Ice Age by hundreds of thousands of years, making it clear that the climate would change even WITHOUT man), (B) man is capable of changing the climate to suit his whims, and (C) there exists an “optimal” climate and this “is” (or “was”) it.
You just wrote that for the halibut!!! :-)
Kneel before cod!
That's Buddy Ebsen dancing with Shirley
Was the Grand Bank off Newfoundland above sea level during the Ice Age? If it was did it have vegetation or was it barren? If it was vegetated this might contribute to the suitability of the region for fish habitation now.
Was the Grand Bank off Newfoundland above sea level during the Ice Age? If it was did it have vegetation or was it barren? If it was vegetated this might contribute to the suitability of the region for fish habitation now.
I think it was above water but under a mile of ice.
Nowhere in the article is the DNA imprint identified. Just trust 'em, I guess!
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