The rapidly rising levels of carbon dioxide in the atmosphere affect plants’ absorption of nitrogen, which is the nutrient that restricts crop growth in most terrestrial ecosystems. Researchers at the University of Gothenburg have now revealed that the concentration of nitrogen in plants’ tissue is lower in air with high levels of carbon dioxide, regardless of whether or not the plants’ growth is stimulated. The study has been published in the journal Global Change Biology.
Researcher Johan Uddling has been working with Swedish and international colleagues to compile data on how raised levels of carbon dioxide impact on plant growth and nitrogen absorption.
Plant quality impaired by increased carbon dioxide levels
The study examines various types of ecosystems, including crops, grasslands and forests, and involves large-scale field experiments conducted in eight countries on four continents.
“The findings of the study are unequivocal. The nitrogen content in the crops is reduced in atmospheres with raised carbon dioxide levels in all three ecosystem types. Furthermore, we can see that this negative effect exists regardless of whether or not the plants’ growth increases, and even if fertiliser is added. This is unexpected and new,” says Johan Uddling, senior lecturer at the Department of Biological and Environmental Sciences at the University of Gothenburg.
Significance of food quality, biodiversity and productivity
When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally. The study also reveals that the strength of the effect varies in different species of grassland, which may impact on the species composition of these ecosystems.
“For all types of ecosystem the results show that high carbon dioxide levels can impede plants’ ability to absorb nitrogen, and that this negative effect is partly why raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems,” says Johan Uddling.
Accepted “truths” do not hold
Reduced nitrogen content in atmospheres with raised carbon dioxide has previously been attributed to a kind of dilutive effect, in which nitrogen absorption fails to keep pace with the increase in plants’ photosynthesis and growth.
“The findings of this study show that this interpretation is simplified and partly incorrect. We are seeing reduced nitrogen content even when growth has not been affected. Moreover, the effect is there in trials with powerful fertiliser, which indicates that it is not down to limited access to nitrogen in the soil. Future studies should look at what is causing the effect, but it appears to be linked to plants’ capacity to absorb nitrogen rather than to changed levels in the soil,” says Johan Uddling.
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Link to article: http://onlinelibrary.wiley.com/doi/10.1111/gcb.12938/abstract
And a video that suggests this study might very well be off the mark:
From the abstract
“As the ecosystems were markedly N limited, plants with minimal productivity responses to eCO2 likely acquired less N than ambient CO2-grown counterparts because access was decreased, and not because demand was lower. ”
First we limit N availability “markedly” (how much limitation?) then we wonder why plants acquire less even if they did have a positive response to eCO2. The demand would not have been lower, it just was not there to absorb so it could not but the plant managed to increase growth anyway. All this says is that plants do not need increased levels of N to keep up with the increased growth possible due to eCO2.
Or did they expect the plant to absorb additional N due to increased biomass even when it was not available?
What about doing the study again where N is not restricted and applied as per normal farming practice.
When will there be a “study” that shows that increased C02 makes water not wet?
I think they are working on that.
They are caught up a bit now proving that increased C02 makes happy-go-lucky people miserable and depressed and bigger donuts more fattening.
The abstracts notes that the ecosystems studies were N limited and the acquisition of N was down by 10% in C02 enriched systems that resulted in “neutral or modest changes in productivity”. If N is limited and growth was not enhanced, than doesn’t it suffice to say that N content of the plant would be down.?? It also appears that they did not measure for actual protein content?? So how do we really know that limited N uptake created a problem especially if plant growth was enhanced.
Could you please find a more reliable source than Natural News for greenhouse CO2 usage? That is a really scammy and conspiratorial website. Sure they don’t believe that CO2 is destroying the world but they think everything else like vaccines, GMOs, and “chemtrails” (The delusional belief that the government is spraying toxins from jets) are.
One example of the idiocy. They correctly state that Monsanto is trying to make aluminum tolerant seeds. But then they say that the chem planes are spraying aluminum so only Monsanto’s crops will grow. Well aluminum is the 3rd most abundant element on earth. Maybe there are regions with too much for plants. And the only way you could significantly affect aluminum content in soil is by crashing planes into it. And even then I doubt it would be enough.
“Maybe there are regions with too much for plants. ”
There sure are. Anyone who has studied physical geography should remember that in tropical climates, soil becomes depleted in nearly everything except aluminum, since it is the least soluble metal.
Heavy leaching due to high rainfall rates wash nutrients from the soil quickly.
So aluminum concentrations become very high.
It clogs rainforest soils, which are the primary source for bauxite.
See ultisols.
http://4.bp.blogspot.com/-4hLyX8gm6f4/TwcS1RStHPI/AAAAAAAAA4g/kQHH2hk9edk/s1600/soilprofiles.jpg
Let’s see. We need to get rid of the Medieval Warming Period. Check. We need to get rid of the Pause. Check. We need to get rid of that pesky increase in Antarctic ice. Check. We need to erase the idea that increases in C02 follow temperature. Check. Now, We need to get rid of the idea that plants benefit from C02. Check.
All done to provide ‘studies’ that refutes Skeptic positions, that can be cited with the illusion of legitimacy.
Do I really need to point out who are the real ‘Merchants of Doubt’?
Propaganda 101.
“Zackly!
Gluten is a wheat protein. Reducing gluten in the diet is supposedly desirable. CO2 to the rescue once again. CO2 is like Spiderman, whose amazing powers are always denigrated in the press.
The best value for this paper is as a model for manure in a computer model providing nitrogen to rapidly growing plants in enhanced CO2 environments.
It would be not be surprising to see this paper idiotically used as proof of CO2 being damaging to plants. I wonder if the White House has gotten hold of this paper yet, they like the whole CO2 as pollutant thing.
Meanwhile, thank goodness these bozos are not responsible for growing our food supply.
Not surprising that this is from Gothenburg U. Here are a few references that debunked this rather ancient hypothesis:
Mueller, K.E., Hobbie, S.E., Tilman, D. and Reich, P.B. 2013. Effects of plant diversity, N fertilization, and elevated carbon dioxide on grassland soil N cycling in a long-term experiment. Global Change Biology 19: 1249-1261
Zavaleta, E.S. and Kettley, L.S. 2006. Ecosystem change along a woody invasion chronosequence in a California grassland. Journal of Arid Environments 66: 290-306
Richter, M., Hartwig, U.A., Frossard, E., Nosberger, J. and Cadisch, G. 2003. Gross fluxes of nitrogen in grassland soil exposed to elevated atmospheric pCO2 for seven years. Soil Biology & Biochemistry 35: 1325-1335
Drissner, D., Blum, H., Tscherko, D. and Kandeler, E. 2007. Nine years of enriched CO2 changes the function and structural diversity of soil microorganisms in a grassland. European Journal of Soil Science 58: 260-269
Seems the warmistas are not in line with the scientific consensus…..
Re soil microorganism’s, my guess is generating a high level of CO and letting it diffuse into the air in a certain area will do nothing to alter soil chemistry in that area, as higher atmospheric CO2 will do. It almost surely is constantly just being diluted and blown away.
Another flaw in this deeply flawed, IMO, study.
Hey, just occurred to me…I wonder how much CO2 the cited studies pumped into the air?
using ambient CO2, in all cases, as the control the lowest additional was +180ppm, the highest was ambient x 2 (~760ppm total)
They were concerned with plant growth so this paper supplied some fertilizer.
What’s the problem?
It is a sorry state of affairs that this paper is so heavily pay-walled because if people could actually read the darned thing they would see that the claim is a lot less than it seems. There is no new research involved, and the actual finding is almost misrepresented in the paper. I will try to describe it one more time. In effect they have found a regression equation from a metastudy. The equation suggests that for some species, especially certain species found in grasslands and forests, enhance CO2 does not lead to eenhanced net primary production, and for these species, all that enhanced CO2 really does is reduce nitrogen accumulation. So, as an example, in the sequence of pine trees and Dr. Idso above, the trees obviously have greatly increased NPP–the regression equation would suggest that these also have a greatly enhanced accumulation of nitrogen. Show me a species that does not respond to enhanced CO2 and that is the sort of species this study really describes.
Just a little research I carried out some time ago on this subject:
It appears that a concentration of about 1,000ppmv would be beneficial to life on earth,
this being the concentration that Glass House growers prefer.
http://api.ning.com/files/XAPctmkiwvgEI5fT6iiGjWFvKNX*
cWuzeO4qmDVbgA_/Greenhouses.CarbonDioxideIn
Greenhouses.pdf
Our exhaled breath is about 4500ppmv
http://www.biotopics.co.uk/humans/inhaledexhaled.html
Up to 5000ppmv is acceptable for work places.
(American Conference of Governmental Industrial Hygienists.).
Up to 3000ppmv is acceptable for residences
(Canadian exposure guideline for residential buildings)”
Medical oxygen has between 10,000 ppmv and 20,000 ppmv in it.
http://www.bocsds.com/uk/sds/medical/10_carbondioxide_oxygen.pdf
http://www.bocsds.com/uk/sds/medical/10_carbondioxide_oxygen.pdf
(Look at datasheets under “O”)
Currently our atmosphere has about 400 ppmv in it.
Furthermore, some scientists credit the extra CO2 in our atmosphere as the reason for our
current increased food production.
http://www.sciencedaily.com/releases/2009/02/090209205202.htm
In other words, CO2 is plant food. So important is CO2 that at approximately 180 ppmv all
life on earth would cease.
Cheers
Roger
http://www.rogerfromnewzealand.wordpress.com
Roger, you dropped a zero in your exhaled breath. 4% equates to 40,000 ppmv.
ps the link above for “Glass House Growers” is
http://api.ning.com/files/XAPctmkiwvgEI5fT6iiGjWFvKNX*
cWuzeO4qmDVbgA_/Greenhouses.CarbonDioxideIn
Greenhouses.pdf
is correct but because of its length you may need to carefully copy and paste it into a new tab on your browser.
Cheers
Roger
Actually my copying and pasting seems to miss out the hyphen after “files/X”.
Try this
http://api.ning.com/files/X-APctmkiwvgEI5fT6iiGjWFvKNX*cWuzeO4qmDVbgA_/Greenhouses.CarbonDioxideInGreenhouses.pdf
Cheers
Roger
“When carbon dioxide levels in the air increase, crops in future will have a reduced nitrogen content, and therefore reduced protein levels. The study found this for both wheat and rice, the two most important crops globally”.
What they either ignore or unaware of, is that the same can be said for water, or soil moisture content. It is a well known and an established fact that the protein levels of wheat vary inversely to the yield. In years of below average rainfall, yields fall but protein increases. Conversely in years of above average rain, yields will increase whilst protein will fall. At least that is what happens in Australia’s wheat growing country.
Ok, so let’s float this theory, since it ties various observations together:
When Man evolved, some 250 million years ago, CO2 levels in the atmospere was much higher – 1000 to 2000 ppm. Due to this level of CO2, the plants he evolved to eat had far less protein than today. The lower CO2 levels experienced in the past few thousand years have resulted in much higher protein levels in plants. Man has not yet fully evolved to adjust to these higher levels, particularly wheat protein, better known as gluten. This is the cause of gastrointestinal problems many people suffer. The higher CO2 levels projected in the future will reduce the number of people experiencing gluten sensitivity.
No where could I get a grant to research this? Oh, nowhere. It could result in a positive attribute for higher CO2 levels. Never mind.
“When Man evolved, some 250 million years ago…”
Ok, this must not be what you meant to say, is it?
‘Claim: Increased carbon dioxide levels in air restrict plants’ ability to absorb nutrients’
____
given the same soil, same area, the same time to grow: the bigger plant aggregates less minerals, develops less flavones, vitamines, whatever per mass.
the claim’s just the academic way to say you need more salt, pepper, vinegar – whatever – to like a salad from the bigger plant.
Regards – Hans
asking – who pays for such paywalled peer reviewed papers.
Some climate armageddonism does it?
Hans
Paywalled papers are paid for primarily by universites and colleges and by scientists’ grant funding.
don’t let me be misunderstood:
the studie’s OK for me.
but we have a problem when science needs ‘public relations’.
Hans
So this is just drawing conclusions from a bunch of other people’s papers?
Isaac Asimov wrote about such fallacy in the 1950’s in the original “Foundation” trilogy where one character was attempting to locate Earth by comparing the published works of other people who had attempted to find the planet, instead of actually looking for Earth himself. Being a genuine scientist himself, Asimov must have run into such coattail riding a lot.
“that this negative effect is partly why raised carbon dioxide has a marginal or non-existent effect on growth in many ecosystems,” says Johan Uddling”
Doesn’t this fly in the face of what farmers tell us?
Amongst all the other problems highlighted in the comments about this paper:
Nitrogen does not exist in the plants as N2, a gas, it is used by the plant to create proteins and nitrates. The NIR analysis determines the total amount of nitrogen in the dry sample, but cannot distinguish between proteins and nitrates. Protein levels are estimated as a percentage of the total Nitrogen in the sample. However we don’t know whether the ratio of proteins to other nitrates in plants grown in high CO2 atmospheres remains the same as for those grown in low CO2 atmospheres. The actual amount of protein could be higher or lower than estimated by NIR analysis.
As pointed out in comments above, rice, most cereals and plants grown as forage for domestic animals are relatively low in protein.
High protein in forage plants is not recommended for long term feeding of equines and ruminants, it can cause a number of problems in these species.
The presence of protein and nitrates in hay and forage is a function of the amount of nitrogen in the soil. An excess of nitrogen fertilizer results in high levels of protein and nitrates in the plants. The high levels of nitrates in hay and forage causes adverse health effects in equines and ruminants, including abortions and still births.
Furthermore high protein in hay and forage requires the feeding of supplemental Lysine, an essential amino acid in order to avoid dietary imbalance and deficiency.
The amount of protein reported on feed analyses is reported as a percentage of the sample dry matter. In other words, they dry the sample and test for the amount of various elements, including Crude Protein, Estimated Lysine, Lignin, Acid Detergent Fiber (ADF), Neutral Detergent Fiber (NDF), WSC (Water Sol. Carbs.), ESC (Simple Sugars), Starch, Non Fiber Carb. (NFC) Crude Fat, Ash, Major Minerals (Phosphorus, Magnesium, Potassium, Sodium, Calcium) and Trace Minerals (Zinc, Copper, Manganese, Molybdenum, Selenium, Cobalt).
Furthermore the amount of protein as a percentage of the dry matter is not the only consideration, the availability of that protein is as important, or more important then the amount present. For instance, in the case of a horse, protein in grass hay is only around 50% available through digestion, whereas protein from whey isolate is almost 100% available. So if you want to increase the protein in feed it is more cost effective and targeted to feed a protein supplement that is 100% available to the organism than feeding larger amounts of forage which can result in providing too much digestible energy to the animal for its level of activity. In other words you feed the animal too much and it gets fat (which has adverse health implications) just because you are trying to supplement protein.
Also, while the percentage of protein produced by the plant, as a percentage of sample dry matter may be lower, the plant may have produced the same total amount of protein, or more, than it did on the low CO2 regime.
For example a plant that grew to 1kg under low CO2 and produces 13.3% protein = 133g protein
The same plant that grew to 1.25kg under high CO2 and produces 11% protein = 137.5g protein
Also NIR analysis is not as accurate as wet chemistry analysis and can be off by 2 to 5% of the values determined by wet chemistry analysis, but it is a much faster and cheaper analysis.
George, what you say about the increase in total protein has been established by the FACE (Free Air Carbon Enrichment) wheat growing trials that have been carried out for a number of years at Horsham, Victoria, Australia. Whilst increased yields have occurred under CO2 fertilisation conditions, and % protein has decreased, the bottom line is that the total protein produced per unit area of soil increases which means more efficient use of the soil providing greater ability to feed the masses.
However as I mentioned in an earlier post the same effect occurs dependent on the amount of rainfall during the growing season. Years of lower rainfall generally sees lower yields but an increased % protein, whilst generally years of higher rainfall sees higher yields but lower % protein, all other things being equal.
Thank you for the comment/info and pointing out yet another problem with the study. This study is just another example of bad science and ignoring well established facts.
Good day, all; I’m just a layman, so there’s plenty of scope to be wrong, but…. When the water that the plants will eventually absorb passes through the atmosphere, it absorbs carbon dioxide. More Carbon dioxide in the atmosphere, more carbon dioxide in the water, less nitrogen can be absorbed before the water reaches saturation. The effect of this reduced nitrogen intake would vary from plant to plant; In some it might be suboptimal, in others not. Seems simple to me, but I’m sure someone will point out the error of my ways,,,,,,
Wait, what?
About this research … how many people smell a rat? Come on … plant quality impaired by increased carbon dioxide levels??????? Believe that and you will believe anything.
A plant’s primary protein is one called rubisco. This is your photosynthesis protein.
In chemistry, a shortage of one reactant can be partly made up for by an increase in another. So in today,s world of severe CO2 deficiency, plants had to have a lot of rubisco to function at all. With reduced hypocapnia (I just googled that to verify spelling–very interesting results in human physiology), plants can relax a bit on the rubisco, which will mean they have more energy for making other substances, which means more micro-nutrients. This probably means better health, less disease and greater longevity in the animal or human who eats the plants.