From the University of Toronto, Underwater ‘tree rings’
Calcite crusts of arctic algae record 650 years of sea ice change
Almost 650 years of annual change in sea-ice cover can been seen in the calcite crust growth layers of seafloor algae, says a new study from the University of Toronto Mississauga (UTM).
“This is the first time coralline algae have been used to track changes in Arctic sea ice,” says Jochen Halfar, an associate professor in UTM’s Department of Chemical and Physical Sciences. “We found the algal record shows a dramatic decrease in ice cover over the last 150 years.”
With colleagues from the Smithsonian Institution, Germany and Newfoundland, Halfar collected and analyzed samples of the alga Clathromorphum compactum. This long-lived plant species forms thick rock-like calcite crusts on the seafloor in shallow waters 15 to 17 metres deep. It is widely distributed in the Arctic and sub-Arctic Oceans.
Divers retrieved the specimens from near-freezing seawater during several research cruises led by Walter Adey from the Smithsonian.
The algae’s growth rates depend on the temperature of the water and the light they receive. As snow-covered sea ice accumulates on the water over the algae, it turns the sea floor dark and cold, stopping the plants’ growth. When the sea ice melts in the warm months, the algae resume growing their calcified crusts.
This continuous cycle of dormancy and growth results in visible layers that can be used to determine the length of time the algae were able to grow each year during the ice-free season.
“It’s the same principle as using rings to determine a tree’s age and the levels of precipitation,” says Halfar. “In addition to ring counting, we used radiocarbon dating to confirm the age of the algal layers.”
After cutting and polishing the algae, Halfar used a specialized microscope to take thousands of images of each sample. The images were combined to give a complete overview of the fist-sized specimens.
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  IMAGE: This is a diver dislodging coralline red algal crust from rock surface using hammer and chisel while enduring the near-freezing water temperatures of the Labrador Sea.
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Halfar corroborated the length of the algal growth periods through the magnesium levels preserved in each growth layer. The amount of magnesium is dependent on both the light reaching the algae and the temperature of the sea water. Longer periods of open and warm water result in a higher amount of algal magnesium.
During the Little Ice Age, a period of global cooling that lasted from the mid-1500s to the mid-1800s, the algae’s annual growth increments were as narrow as 30 microns due to the extensive sea-ice cover, Halfar says. However, since 1850, the thickness of the algae’s growth increments have more than doubled, bearing witness to an unprecedented decline in sea ice coverage that has accelerated in recent decades.
Halfar says the coralline algae represent not only a new method for climate reconstruction, but are vital to extending knowledge of the climate record back in time to permit more accurate modeling of future climate change.
Currently, observational information about annual changes in the Earth’s temperature and climate go back 150 years. Reliable information about sea-ice coverage comes from satellites and dates back only to the late 1970s.
“In the north, there is nothing in the shallow oceans that tells us about climate, water temperature or sea ice coverage on an annual basis,” says Halfar. “These algae, which live over a thousand years, can now provide us with that information.”
The research, which was published in the Proceedings of the National Academy of Sciences, was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) and Ecological Systems Technology.
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here is the paper:
Significance
The most concerning example of ongoing climate change is the rapid Arctic sea-ice retreat. While just a few years ago ice-free Arctic summers were expected by the end of this century, current models predict this to happen by 2030. This shows that our understanding of rapid changes in the cryosphere is limited, which is largely due to a lack of long-term observations. Newly discovered long-lived algae growing on the Arctic seafloor and forming tree-ring–like growth bands in a hard, calcified crust have recorded centuries of sea-ice history. The algae show that, while fast short-term changes have occurred in the past, the 20th century exhibited the lowest sea-ice cover in the past 646 years.
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Great to have some actual climate science practiced & published now & then.
As expected, the Little Ice Age had already begun by the 1360s, & Arctic ice cover has decreased during the past 150 years, as climate recovered from the LIA, which ended around 1860, after double bottoming during the sunspot Minima of Maunder c. 1645-1715 & Dalton c. 1790-1830.
Just the normal fluctuations of the Holocene, although with a disturbing longer-term (millennial scale) downtrend.
The findings are in agreement with the world emerging from the LIA in the mid 19th century, leaving the 20th century as the only one during that time to be free of the effects of the LIA.
Once again, someone tell Michael Mann that the Little Ice Age really existed.
Too bad the mainstream media, when the pick up on a study like this, refuse to examine how it relates to the iconic hockey stick.
As usual all this is behind paywall. Thus the conclusions cannot be verified, in particular the arctic is vast and where in the Arctic is paramount to drwaing conclusions on atmopshere, sea ice and climate.
A bona fide question from a non-scientist:
Re: “Longer periods of open and warm water result in a higher amount of algal magnesium.” (emphasis mine)
How do they know that the controlling variable is not the temperature of the water? How do they know that sea ice extent (i.e., amount of light) is a significant causation?
Isn’t a parallel (and erroneous) assumption commonly made about the controlling cause of tree ring width?
In other words….
How does this study prove ANYTHING?
“While just a few years ago ice-free Arctic summers were expected by the end of this century, current models predict this to happen by 2030.”
🙂
pokerguy says:
November 18, 2013 at 6:07 pm
The authors probably know this is garbage, but made the obligatory obeisance to the One True Gas in order to get published under our Neo-Lysenkoist anti-science regime.
Well, I guess I asked such a stupid question it wasn’t worth addressing. Sigh. What would a better question be? …… Is there a teacher in the house??
@ur momisugly Poker Guy — heh. “… models predict ” tells me, at least, to be highly skeptical of this paper. It reeks of the Cult of Climatology’s spew. The faux science du jour, no doubt.
Janice Moore says:
November 18, 2013 at 6:03 pm
To answer a question with a question:
You are aware are you not that most algae are photosynthetic, ie they use sunlight to make their own food?
“2012 exhibited the lowest Arctic summer sea-ice cover in historic times.”
If they are referring to the satellite record I’m not impressed.
Q: How do they know the decreased ice cover is the result of climate warming instead of soot?
A: They don’t.
Steve from Rockwood says:
November 18, 2013 at 6:39 pm
In consensus climate science, “unprecedented in history” means since 1979. Since anything less than 30 years at absolute minimum is weather, not climate, that gives us a record of observations on 1.13 climate units out of 150,000,000 such climate units. More than enough for post-modern climate science to make policy recommendations affecting the lives of seven going on eight billion people. Of course if the consensus, settled climate scientivists have their way seven going on one billion would be better, as long as they’re among the one out of seven saved by neo-Calvinist grace of superior election.
pokerguy says:
November 18, 2013 at 6:07 pm
“While just a few years ago ice-free Arctic summers were expected by the end of this century, current models predict this to happen by 2030.”
🙂
—————————————-
I saw that too, they forgot their /sarc tag
cn
Dear Milodon Harlani,
Thank you for your reply. Telling the student to take the basic premises and reason it out for herself is good didactics. Good for you to encourage scholarship. I’ll try to figure out the warmth vs. light problem and how the paper’s assertions prove ANYTHING about causes of global climate myself. Until then, I’ll just have to take it on your (and others’) authority alone that this paper is a good one. I was wrong to ask for free tutoring, here.
I hope that you have many lovely hours of enjoyment playing in the woodwind section (clarinet? oboe? bassoon?).
Take care.
Disappointed but grateful,
Janice
Janice Moore says:
November 18, 2013 at 7:00 pm
Don’t know why you’re disappointed.
I’d have thought the relevance of light to the growth of algae was obvious, but you’re none the less welcome.
I hope the information will encourage you to study biology, in which case you’ll realize that the anti-scientific paid lying pseudo-philosophers from the Discovery Institute whose mendacious videos you keep linking in lieu of actual learning & thought on your part are not only not biologists but blasphemous imps of Satan who have led you astray on the path to eternal damnation, since their image of God is of a cruel, sadistic, incompetent, deceptive liar.
Dear Milodon Harlani,
Have you ever watched the videos I linked? Every time I ask that, you do not answer. Did you think I did not notice? I think that, if you look into it, you will find that Dr. Stephen Meyer’s and Dr. David Berlinski’s credentials provide an excellent basis for their scholarship.
You accuse me of not learning, but you refuse to watch the lectures I posted (I only re-posted them because from your remarks, it was pretty clear that you had not watched them). How do you know that they are not well-reasoned and persuasive without listening to them?
I take great hope from your snarling response! Why? Because only one who senses that he is in danger lashes out like that. Watch out, Mr. Harlani — you are being prayed for and I believe God is going to reveal the truth to you!
And I still love (agape) you. #(:))
Yours,
Janice
P.S. How’s the clarinet (or oboe or bassoon) playing going? I hope it gives you much joy.
Janice Moore says:
November 18, 2013 at 7:38 pm
I don’t need to look into it, Janice Moore, because I’m thoroughly familiar with their total lack of credentials. They have practically no knowledge of biology, except just enough to know that they are lying shamelessly, but they don’t care, because they’re paid to hoodwink suckers. I’ve listened to their pack of lies for over a decade. To call their mendacity “scholarship” is the deepest possible insult to every scholar who has ever lived.
I don’t refuse to listen to your pathetic videos. I’ve heard them & talked to them in person. They’re paid liars, plain & simple.
I’m not the least bit in danger. It is you whose soul is in mortal danger. Your heroes are liars against the God of creation, Janice Moore. I pray you learn that before it’s too late.
God has revealed Himself to me through His creation. His Works in creating the universe(s) take precedence over your satanic, bibliolatrous, blasphemous interpretation of His Word. Wake up! You’ve been sold a bill of dangerous goods. Learn actual science instead of false religion. Worship the Creator & not a book written by men (& maybe one woman) trying to grasp the Infinite.
BTW, please don’t try to tell me what an English neologism from corrupted Koine Greek roots “means”. Greek “agape”, as dragooned into biblical English in the 17th to 19th centuries is cognate with English “agape”, as in slack-jawed. I’ll let you figure out how that could be. The hint is that it has to do with an early Christian ceremony.
Like most creationists, you have almost as much to learn about science as about the Bible, about which you need to unlearn almost everything, your satanic tutors having intentionally misled you.
Another study matching well with either the sun or black carbon and not so well with CO2 as the main drivers in the Arctic.
Almost 650 years of annual change in sea-ice cover can been seen in the calcite crust growth layers of seafloor algae, says a new study from the University of Toronto Mississauga (UTM).
[…]
During the Little Ice Age, a period of global cooling that lasted from the mid-1500s to the mid-1800s, the algae’s annual growth increments were as narrow as 30 microns due to the extensive sea-ice cover, Halfar says. However, since 1850, the thickness of the algae’s growth increments have more than doubled, bearing witness to an unprecedented decline in sea ice coverage that has accelerated in recent decades.
Their proxy covers less than 650 years and they have the gall to use “unprecedented”?! What idiots.
“It’s the same principle as using rings to determine a tree’s age and the levels of precipitation,” says Halfar.
Wow, how’d that get past the censors? Tree rings respond to precipitation? Mann must be scurrying around in circles screaming “off with his head!”
Katherine says:
November 18, 2013 at 7:58 pm
Unprecedented is another obligatory buzzword. Please cut researchers some slack who try to fit real science into the cracks of the CACA paradigm. If unprecedented means since 1360, they might be right. If since AD 1060 or 60 BC or 1060 BC or 2060 BC or 3060 BC or earlier, then OK, precedented. CACA corrupted quackademia is a bitch right now.
But maybe you’re a scientist with the integrity not to play that game & still survive. If so, & you can still get published so as not to perish, then more power to you! You go, girl!
Recently, sea ice area increases in Antarctica seem to balance out most of the sea ice decreases in Uncle arctica. I would like to see algal growth rates from both poles compared.
Okay good start. Now about going back further, you know to that medieval warm period. I wonder why they chose the starting date that they did? Hmmm?
” lowercasefred says:November 18, 2013 at 6:45 pm
Q: How do they know the decreased ice cover is the result of climate warming instead of soot?
A: They don’t.”
Good point. The industrial revolution has put a lot of soot up there especially lately. It would be interesting to see if there is a correlation between their data and soot.
http://www.pnas.org/content/suppl/2013/11/14/1313775110.DCSupplemental/pnas.201313775SI.pdf
supporting data
they seem to have only six samples, of which only two go back further than 1800. The other two have a glaring discontinuity about 1850. Will be interesting to see if SteveM decides to pick this one apart.
Mushroom George says:
November 18, 2013 at 8:07 pm
Excellent point.
Of course the Antarctic & Arctic are very different environments, but your allusion to ice algae in the Antarctic reminds me of one of my favorite species, ie Antarctic krill, one of the animals whose biomass challenges the human. Besides phytoplankton, one of their main food sources is, wait for it, you guessed it…ice algae. Here’s a tight shot of the tiny krill in action, grazing on the ice algae:
http://en.wikipedia.org/wiki/File:Krillicekils.jpg
Needless to say, the tiny krill feed the biggest animals & organisms ever to have evolved, baleen whales. By D. H. Lawrence, edited for biological correctness:
“Whales Weep Not!
They say the sea is cold, but the sea contains
the hottest blood of all, and the wildest, the most urgent.
All the whales in the wider deeps, hot are they, as they urge
on and on, and dive beneath the icebergs.
The right whales, the sperm-whales, … the killers
there they blow, there they blow, hot wild white breath out of
the sea!…”