There’s a new article at Nature News where they report on an amazing new paleoclimatology breakthrough with temperature reconstructions using clamshells. The Nature article reports on a new paper in PNAS from William Patterson at the University of Saskachewan. Here’s a short excerpt:
The study used 26 shells obtained from sediment cores taken from an Icelandic bay. Because clams typically live from two to nine years, isotope ratios in each of these shells provided a two-to-nine-year window onto the environmental conditions in which they lived.
Patterson’s team used a robotic sampling device to shave thin slices from each layer of the shells’ growth bands. These were then fed into a mass spectrometer, which measured the isotopes in each layer. From those, the scientists could calculate the conditions under which each layer formed.
Unlike counting tree rings which have varying widths due to all sorts of external influences such as rainfall, sunlight, temperatures, available nutrients, and available CO2, this method looks at the levels of different oxygen isotopes in their shells that vary with the temperature of the water in which they live. One simple linear relationship.
The data resolution from isotope counts is incredible.
“What we’re getting to here is palaeoweather,” Patterson says. “We can reconstruct temperatures on a sub-weekly resolution, using these techniques. For larger clams we could do daily.”
The reconstruction is shown below. We see familiar features the little ice age, the medieval warm period and the downturn which led to the extinction of Norse settlements on Greenland.
And the feature of this reconstruction to surely stick in the craw of many who think we are living in unprecedented times of warmth is the “Roman Warm Period”. Have a look:
From Nature: Shellfish could supplant tree-ring climate data
Temperature records gleaned from clamshells reveal accuracy of Norse sagas.
Richard A. Lovett
Oxygen isotopes in clamshells may provide the most detailed record yet of global climate change, according to a team of scientists who studied a haul of ancient Icelandic molluscs.
Most measures of palaeoclimate provide data on only average annual temperatures, says William Patterson, an isotope chemist at the University of Saskatchewan in Saskatoon, Canada, and lead author of the study1. But molluscs grow continually, and the levels of different oxygen isotopes in their shells vary with the temperature of the water in which they live. The colder the water, the higher the proportion of the heavy oxygen isotope, oxygen-18.
The study used 26 shells obtained from sediment cores taken from an Icelandic bay. Because clams typically live from two to nine years, isotope ratios in each of these shells provided a two-to-nine-year window onto the environmental conditions in which they lived.
Patterson’s team used a robotic sampling device to shave thin slices from each layer of the shells’ growth bands. These were then fed into a mass spectrometer, which measured the isotopes in each layer. From those, the scientists could calculate the conditions under which each layer formed.
“What we’re getting to here is palaeoweather,” Patterson says. “We can reconstruct temperatures on a sub-weekly resolution, using these techniques. For larger clams we could do daily.”
It’s an important step in palaeoclimatic studies, he says, because it allows scientists to determine not only changes in average annual temperatures, but also how these changes affected individual summers and winters.
“We often make the mistake of saying that mean annual temperature is higher or lower at some period of time,” Patterson says. “But that is relatively meaningless in terms of the changes in seasonality.”
For example, in early Norse Iceland — part of the 2,000-year era spanned by the study — farmers were dependent on dairy farming and agriculture. “For a dairy culture, summer is by far the most important,” he says. “A one-degree decrease in summer temperatures in Iceland results in a 15% decrease in agricultural yield. If that happens two years in a row, your family’s wiped out.”
Technically, the molluscs record water temperatures, not air temperatures. But the two are closely linked — specially close to the shore, where most people lived. “So, when the water temperatures are up, air temperatures are up. When water temperatures are down, air temperatures are down,” Patterson says.
Read the complete article at Nature News
Pascvaks (07:47:28) :
Are we such lepers?
Some of my colleagues express the thought that there is enough pseudo-science peddled on WUWT to keep them away [or rather not admitting in public that they lurk]. So, we are lepers. Luckily, the nuts are only a handful and are well-known, so we live with them with only an occasional swipe.
Leif Svalgaard (07:07:36) — 2: the real difficulty [and why clams have not been used so much as trees] is that it is very hard to find clams that can be dated as well as trees [on a time scale of centuries].
Why is it necessary to locate methusaleh clams? Perhaps I misunderstand this stuff, but it seems one could dig up a buried clamshell sample, carbon date it, and then do the magical/mystical oxygen isotope process and have a number. Dig up enough buried shells — rinse/lather/repeat — and you would have the same data as with a death defying ageless clam.
Where did I go wrong?
There is an obscure record by Arlo Guthrie (I don’t think it was ever released as a CD) that has an “Alice’s Restaurant” style song called “The Ballad of Rueben Clamzo and His Strange Daughter”. This is the story of early American settlers having to kill the giant, humungous, Mann-eating clams that threatened the Atlantic coast. I’ve GOT to dig that one out of my vinyl collection and render it to digital.
So it would appear that the Lord of the Tree Rings needs to clam up.
Mann and RC are going to respond with “local/regional anomaly – not global” in 5… 4… 3… 2…
These temperature variations are also present in the Greenland ice cores, but does anyone know if they show up in the Vostok (Antarctica) cores? I’ve tried a few times to dig up information on it with no luck.
G.L. Alston (09:04:49) :
but it seems one could dig up a buried clamshell sample, carbon date it, and then do the magical/mystical oxygen isotope process and have a number.
There are contributions from atmospheric carbon dioxide, fermentative CO2 from bottom muds, and from carbonates from dissolving limestones, making errors of shell radiocarbon dates as large as several thousand years.
I’m sorry but my computer model of clam life does not verify any of this. It merely shows a (surprisingly agile) clam traversing a maze, eating plankton. Several cephalopods chase it until excess CO2 causes them to turn blue at which point the clam begins to prey on the weakened cephalopods. The model is called Pac Mann.
Paul Dennis (05:35:04) :
Thank you for taking the time to address 18O variability in the water! I could not get the right search on google to find that. Terrific.
Oxygen 18 abundance in sea water does not just vary with air and water temperatures.
Yes/No
We all know that if the carbon date does not match the supposed order of the sedimentary layers, they throw out the carbon date.
If you fuss about that, you become a carbon date denier and a flat earther.
I rather doubt that this interesting approach can accurately measure hotter and colder paleo-weather at a weekly scale of resolution, for a few reasons:
1. Clams don’t actually live in the water. They live buried beneath the sea floor sediment (some species at depths of a foot or more). Here temperature variations will be moderated by insulation, due to the sediment layer above them and lack of water circulation around them (though granted they do ingest, circulate and expel sea water through a siphon that reaches up to the water/sediment interface)
2. Many live in the inter-tidal zone, where at low tides the sediment above them may be warmed directly by the sun, chilled by evaporation, particularly on windy days, etc. Though of course part of the point of being buried is that it protects them from the greatest extremes at low tide, when they also cease to ingest water from above.
3. As anybody who swims regularly in shallow ocean waters can experience, the wind direction along a shallow shoreline can make a huge difference to the shoreline water temperature:
In summer, when there is a cool onshore sea breeze at our local beach, here in Western Australia (Cottesloe, which incidentally has very small tides), water from the topmost, warmest surface layer of the indian ocean is driven onshore and piles up against the beach, so that you feel like you are stepping into a warm bath.
Conversely, when there is a searingly hot, dry, offshore easterly breeze blowing, it skims off the warmest uppermost layer of surface water, driving it out to sea, leaving chilly deeper water to well up in its place along the the shoreline, so that by contrast you feel like you are stepping into an icy pond.
CLAMS GOT LEGS!
Johnny Hart – B.C. Comic
http://wattsupwiththat.com/2010/03/10/paleo-clamatology/#more-17233
““Roman Warm Period”. Have a look”
Perhaps explained by ?:
The data is from:
“The study used 26 shells obtained from sediment cores taken from an Icelandic bay. ”
http://www.ncdc.noaa.gov/paleo/globalwarming/holocene.html
“These orbital changes can be easily calculated and predict that the northern hemisphere should have been warmer than today during the mid-Holocene in the summer AND colder in the winter. The paleoclimatic data for the mid-Holocene shows these expected changes”
Dr Leif S. — There are contributions from atmospheric carbon dioxide, fermentative CO2 from bottom muds, and from carbonates from dissolving limestones, making errors of shell radiocarbon dates as large as several thousand years.
OK, thanks, radiocarbon seems out. There are other dating technologies out there; are you aware of the application of any of these to this type of study or are these used exclusively by paleontologists and/or archaeologists?
(I don’t know enough about dating tech, obviously.)
Oh, and is radiocarbon really out? I read where a new curve was being applied that allowed better archaeological dating, although it seems you’re saying that the samples are too contaminated for *any* corrections.
Thanks,
Regarding my previous, wrong time period.
I have ever been tempted to believe a clam over a mann. The lowly clam has no reason to lie and is not subject to human enticements. The lowly mann is many reasons to lie and is subject to many enticements.
Would that the clam will ever out number the mann and the harmony and balance of the universe be forever maintained.
Zeke the Sneak
The 18-oxygen composition of seawater is not temperature dependent per se. If we look at the North Atlantic the surface waters plot on a mixing line with the freshwater end member very similar to Arctic runoff. i.e. the isotope composition depends on the relative proportion of the sea water end member and the admixed freshwater.
Anthony, many thanks for the valuable service to the truth in climate research that your blog provides.
After lurking here for about two years or so, this is the first time I posted a comment to any topic at your blog. The reason for doing that is that the many clam-jokes pertaining to the article this discussion thread is based on detract considerably from the message of the study report interpreted by the article.
As interpretations go, usually much gets lost in them in successive stages, so much so that eventually much of any relationship to the reality offered in the original story hopelessly loses itself in a wild tangle of assumptions, many of those being expressions of misinformed humor and often unsubstantiated assumptions.
In the process of the discussion of the message getting lost like that, wattsupwiththat.com loses credibility. That is not good but not so much the fault of the moderators as it is caused by the many attempts at uninformed humor and jumps to preconceptions that are based on wrong assumptions, not facts.
The study report (http://www.pnas.org/content/early/2010/03/02/0902522107.full.pdf) is only 5 pages long (including the 39 bibliographical references that put the study into context). Reading those few pages would have precluded many of the comments made in this discussion thread.
The study points to the resolution and accuracy of “reconstructions of North Atlantic atmospheric and oceanic conditions [that] have focused mainly on the ice core records of Greenland but more recently have also been derived from marine sediment records.” Those sedimentary records, as the study quite properly identifies, are, as Leif Svalgaard chose to call them, “old hat”, but that is not what the study by Patterson et al. called them, for good reasons. Instead the study took 26 high-resolution snapshots in the form of isotope-ratio analyses of individual clam shells that could individually be placed (within the limits of the error bars identified) in the time progression of the marine sediment cores in which the shells had been found.
The study does not claim to be a replacement for any climate reconstructions that were used for the study.
I am a little confused by what is happening in this discussion thread. Jokes about clams, jokes that are widely off-target, drown out the important message of the Patterson et al. study report. It seems to me that those jokes should have been judged off-topic, especially those about clams being shaved. The original study report states nothing about shaving of any clams. It is apparent in this discussion thread that the jokers do not seem to be serious about using academic standards to be able to seriously challenge climate hype and hysteria.
–Walter
IMO there is a telling clue, reading between the lines, the reason for this article that nobody has spotted…
Pascvaks (07:47:28) : I imagine WUWT advises people like the author of this article that you’re putting their work up for comments and that they’re welcome to drop by and comment if they wish. I further assume that the good author of this piece has decided to remain mum for various personal and professional safety/security reasons that do not have to do with us, or WUWT, but rather with his colleagues and his professional associations. Are we such lepers?
roger samson (08:28:26) : I did a search on the research proposal and it seems it was supposed to be until the present, so the question is why isn’t the present data… present?
Bruce M. Albert, Ph.D., PDRA [Durham University] (08:47:37) : Dear Sirs, You realize that were one to try, one could find 10,000 Quaternary Research papers covering aspects of the above results… The on-going mystery is why an entire sub-discipline was in essence ignored in the period of AGW hypothesis formation…
Dr Albert bears out Leif Svalgaard, and points to what has really happened.
My hunch is that Nature is, so to speak, dipping their toes to test the temperature of the water: that it would be far too much for them at this moment to run an article that shows evidence right up to the present time… Do a drip feed instead… acclimatize… and eventually claim they discovered the evidence for no AGW. Forget about the skeptics. Nature did it. People have short memories.
If the good ship Nature is slowly turning now, the sea change we want is surely happening – perhaps the best we can hope for – but slowly enough for all the rascals to fade and change their tunes without being hauled in front of the enquiries like Jones.
Leif Svalgaard (20:14:49) :
phlogiston (19:58:23) :
Now you’re shifting from plankton to molluscs.
That is still old hat as I showed with some cites. And for ‘climate’ studies, the lifetime of weeks, month, years, etc doesn’t make much difference. What makes a difference is how often the claims are sampled, and from the Figure shown that leaves a lot to be desired. Looks like centuries to me.
Leif, the clamshells were sampled from sediment cores, the 26 reported were selected from the core in regions of forminifera δO18 extrema. Dating was apparently by C14.
Steve in SC (06:16:34) :
…and now we have:
4. Clams of great accuracy!
ErnieK (06:49:10) :
Nothing new. To Mann, AGW has always been a shell game.
Well done.
Dave Wendt (23:04:17) :
Anu (21:33:47) :
Even the “Roman Warm Period” in this Icelandic bay was about 13.5 deg C.
A quick Google indicates the present annual mean temp for Iceland is about 5 deg C
———-
A similar datapoint during the “Little Ice Age” shows 12 deg C, so I doubt temperatures at the bottom of the Bay were similar to those at the surface, which is also mentioned in the paper.
Also, different clams show different temperatures – Astarta, Macoma, Nuculana, Talina and Thyasira. What’s up with that ?
And why do the datapoints arrange in vertical lines with 8 to 12 deg C spreads ?
Anyway, interesting start. I’d like to see data on other parts of the world using this technique.
_Jim (07:36:25) :
The study used 26 shells obtained from sediment cores taken from an Icelandic bay. Because clams typically live from two to nine years, isotope ratios in each of these shells provided a two-to-nine-year window onto the environmental conditions in which they lived.
There are 26 ‘brackets’ at the bottom of the chart above with the chart spanning from approx. -400 AD through to 1800 AD; do these brackets represent the 26 sample clams in this study (I think they do, but, I must phrase this in the form of a question and make no assumptions)?
If so, the longest period encompassed by one of the last brackets would seem to depict a period of approx. 250 years.
Why, then, is this statement in the introduction: “Because clams typically live from two to nine years …”
It lies in the figure reproduced above, the error bar shows the ±1sd uncertainty in the carbon dating of the clamshell.
G.L. Alston (10:06:36) :
the samples are too contaminated for *any* corrections.
Radiocarbon is not *out*, but must be applied carefully and all contamination estimated or compensated for. I’m just saying that it is not *simple* to get the dating correct. There may also be other methods of dating, like counting annual rings in the clam, etc. Not impossible, but not simple, is all.
Cletus Wilbury.
Was just going to post about wrong time period, but you beat me to it!