December 29, 2010
Increased Ocean Acidity To Reduce Nitrification
A substantial portion of the rising atmospheric carbon dioxide dissolves into the ocean and increases ocean acidity. The effects this acidification will have on marine organisms is a topic of research. One researcher at UC Merced finds slight acidification changes caused substantial reduction in nitrogen metabolism by microbes in the oceans.
“Microbial nitrification rates decreased in every instance when pH was experimentally reduced at multiple locations in the Atlantic and Pacific oceans,” wrote researchers led by University of California, Merced, biogeochemist J. Michael Beman in the Dec. 21 Proceedings of the National Academy of Sciences. “Our results suggest that ocean acidification could reduce nitrification rates by 3 to 44 percent within the next few decades … fundamentally altering nitrogen cycling in the sea.”
That's not good. Via our fossil fuels burning we are conducting a massive real life experiment on ocean acidity. This is the aspect of rising CO2 emissions that worries me most. We can always find ways to quickly and cheaply cool the planet. But if more CO2 dissolved in the oceans will cause big shifts in marine ecosystems it is hard to see how to reverse it quickly.
"Between 1751 and 1994 surface ocean pH is estimated to have decreased from approximately 8.179 to 8.104"
Great. In 1751 they could measure pH levels to 3 decimal places. Who would of thought they could do that?
7 is neutral. Above 7 is alkline. The ocean is stil alkiline.
Look Randall, I don't mind you helping out the AGW fanatics from diverting attention to one of the coldest decembers in the UK in 300 years. But please ... not the "ocean acidification" con game. It insults our intelligence too much.
You could temporarily inhibit nitrification by reduced pH, but the population of nitrifying bacteria will quickly rebound with individuals adapted to the lower pH. This is the case down to about 5.5, at which point you've got substantially more problems than reduced nitrification.
Can you read? Do you know what the word "estimated" means?
So if an individual believes the evidence supports AGW, then they are "fanatics"?
I think it is you whom is on the "fanatical" edge...
bmack500: One does not estimate to 3 decimal places when one cannot come close to making such measurements. That is not estimation, it is fabrication.
bmack500 wins the most idiotic comment of the year. Congratulations.
Bmack, can you defend the data used to "estimate" the pH? Mind telling us where to find it and the work? ("Scientific method", remember?)
Can you show us the evidence and the actual work developing the claims of Anthropomorphic Global Warming? ("Scientific method" again.)
Another point. Cool water holds MORE CO2. Warm water holds LESS CO2.
"more than twice as much CO2 can dissolve into cold polar waters than in the warm equatorial waters"
Rapidly cooling the planet would cause even more "acidification".
Those with he ability to think critically might notice the contradiction.
'but the population of nitrifying bacteria will quickly rebound with individuals adapted to the lower pH'
Maybe but not necessarily; in fact, probably not. The issue here is more likely to be the increasing instability of nitrites as the pH gets lower. There are two oxidation steps in converting ammonia to nitrate: first the creation of the nitrite, then the oxidation of nitrite to nitrate. These are accomplished by different microorganisms. If you have ever set up a saltwater aquarium, you've had to deal with trying to establish a colony of both (generally nitrosomonas and nitrobacter, though there are other types).
Anyway, nitrite decomposes at lower pH levels. It is generally said to decompose at acid or slightly acid pH, but presumably decomposes at some rate even at a pH of 8.2 or 8. This decomposition results in its removal from the cycle; regardless of how well adapted the nitrifying bacteria are, they can't eat what is no longer available.
BTW this is also why medieval nitre beds, used to produce saltpeter, had layers of lime in them. These too were big piles of nitrifying bacteria, and they also found through long experience that alkaline conditions maximized the nitrate yield.
'Another point. Cool water holds MORE CO2. Warm water holds LESS CO2.' ... 'Rapidly cooling the planet would cause even more "acidification".'
Straw man argument. Who has proposed 'rapidly cooling the planet', assuming such a thing were even possible? I also like the bizarre use of scare quotes around 'acidification', as if acidification by dissolution of CO2 were some questionable hypothesis dreamed up by leftist kooks rather than bedrock established chemistry. People like you give global warming skeptics (I am one) a bad name.
If someone insane group of "scientists" had actually convinced insane politicians to shoot SO2 in the atmposhere, I wonder how many more people would have died in the UK or Northeast or Mongolia or Germany this winter?
This from a "major" magazine - The Atlantic
"If we were transported forward in time, to an Earth ravaged by catastrophic climate change, we might see long, delicate strands of fire hose stretching into the sky, like spaghetti, attached to zeppelins hovering 65,000 feet in the air. Factories on the ground would pump 10 kilos of sulfur dioxide up through those hoses every second. And at the top, the hoses would cough a sulfurous pall into the sky. At sunset on some parts of the planet, these puffs of aerosolized pollutant would glow a dramatic red, like the skies in Blade Runner. During the day, they would shield the planet from the sun’s full force, keeping temperatures cool—as long as the puffing never ceased."
My point is that if the planet gets too hot we can cool it down. That does not mean I am advocating cooling the planet. We face no imminent danger from the melting of Antarctica and Greenland. We have not experienced warming at a level that causes the central part of the United States to become a massive desert.
But again, cooling the planet does not address the problems that come from CO2 dissolving into the oceans.
> If you have ever set up a saltwater aquarium, you've had to deal with trying to establish a colony of both (generally nitrosomonas and nitrobacter, though there are other types).
Many times, in fact, and have observed reliable nitrification right down to about 7.8 in seawater systems (and all the way to 5.5 in freshwater) - nitrogenous waste is a prime food source, and as long as there is oxygen in the water, whichever autotrophs can best compete at a given pH will expand their population to take advantage of it. From a practical standpoint, you're not going to go much below 7.7 - 7.8, since carbonate/bicarbonate buffering is stable at that point, and additional acidification (from nitrification itself, among other sources) will be dissolving calcium carbonate. Of course, that means you'll be killing (or have killed) all of the corals and dissolving coral sand beaches -- at which point inhibition of nitrification is going to be pretty low on the list of the ocean's problems.
But Randall, allegedly the oceans have warmed. The warmer oceans would hold LESS CO2, making it much more likely the CO2 in the atmosphere came from warmed oceans, not that CO2 caused warming.
"The oceans contain 37,400 billion tons (GT) of suspended carbon, land biomass has 2000-3000 GT. The atmosphere contains 720 billion tons of CO2 and humans contribute only 6 GT."
Mans contribution to ocean CO2 levels is laughably miniscule. "OCean Acidification" is a con, like AGW.
"That does not mean I am advocating cooling the planet"
Glad to hear you aren't insane. Unfortunately other insane people are actually advocating injecting enough CO2 into the atmosphere to end this intergalcial and plunge us back into the inevitable ice age.
No, warmer oceans don't hold less CO2. The absolute capacity of water to hold CO2 doesn't matter when it's not close to its absolute capacity, as is the case in Earth's oceans. (The rate of uptake decreases as temperatures rise, but this is not the same thing...and given that net surface temperature fluctuations with climate are on the order of a few degrees C, this effect is not large anyway AFAIK.)
"Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation." http://www.nature.com/nature/journal/v437/n7059/full/nature04095.html
I think you need to spend more than three minutes learning about the chemistry before spouting vitriol. Throwing around words like "insane" just confirms your commitment to a political viewpoint regardless of physical evidence.
'have observed reliable nitrification right down to about 7.8 in seawater systems'
Sure, I don't doubt it. But, first of all, in these setups you aren't trying to maximize nitrate yield; you're trying to remove toxins. If some part of the nitrites decomposed before being converted to nitrates, you'd neither care nor likely even notice. Second of all, the higher concentrations in an aquarium (compared to the ocean) mean that the mean time that a nitrite ion exists before it is used by some organism may be vastly different. Thus a rate of non-biotic decomposition that would not even be noticeable in an aquarium (let's say a half-life of ten hours or something), where the nitrite eating bacteria are always close at hand, could still have a noticeable effect on the total nitrate output in the oceans.
Umm, I know I'm going to regret asking an actual chemistry question of Bruce, but here goes...
pH is a logarithmic scale (where what precisely it's the logarithm of is apparently a sophisticated chemical question, but let's say it's the number of moles of hydrogen ions in a litre of solution). So a the difference corresponds to a difference of 0.002649 of a mole on the current value of 0.154739 of a mole. So it's a linear change of 1.7 percent. Do you have any chemical or measurement mechanism technical reason to believe this level of accuracy is not acheivable? (After all, 50 km/hour is just 4.6328346555298899e-08 expressed in the natural scheme whre c=1, but we have no difficulty measuring the difference between 50 and 60 km/h despite how it sounds like a hugely accurate difference when expressed in terms of the speed of light. Just because we have a scale defined on the basis of giving simple numbers for quantifying things like the strength of hydrocholoric acid doesn't mean that the only interesting things happen at differences on the order of unity on the scale.)
Oops, the numbers above are completely wrong due to a cut and paste screw-up (which I should have spotted from the numbers). So the old value is believed to be 6.6221650370176e-09 of a mole, the new value is believed to be 7.87045789695099e-09 of a mole, a difference of 1.24829285993339e-09 of a mole. This corresponds to a linear "number of moles" change of 15.86 percent. With these numbers, the above question still stands.
Gnoll/Troll "No, warmer oceans don't hold less CO2."
"First, more than twice as much CO2 can dissolve into cold polar waters than in the warm equatorial waters. As major ocean currents (e.g., the Gulf Stream) move waters from the tropics to the poles, they are cooled and can take up more CO2 from the atmosphere. Second, the high latitude zones are also places where deep waters are formed. As the waters are cooled, they become denser and sink into the ocean's interior, taking with them the CO2accumulated at the surface."
Temperature does matter. If the ocean really was warming in the tropics and the arctic, it would hold less CO2 than it could if the coean was cooling or staying the same temperature.
embryonic: "Do you have any chemical or measurement mechanism technical reason to believe this level of accuracy is not acheivable?"
In the 1700's?
"The concept of pH was first introduced by Danish chemist S. P. L. Sørensen at the Carlsberg Laboratory in 1909."
I think you can assume that values for ocean pH that go back into the 18th century are reconstructed from samples, whether ice cores or geological strata or indirect measures of weathering. While I certainly don't trust climate scientists in general, and I also don't think I can trust peer review of the paper on this topic, it still doesn't follow that we must be unable to reconstruct ocean pH with this degree of precision. Proving that no useful measurements could have been taken at the time does not clinch the case. In fact, since ocean pH must vary from place to place, I have to assume that the paper uses some sort of average. Of course it's also possible that they use premodern values for ocean pH spit out by some computer model they've constructed, which would indeed be the worst sort of chicanery. If I had the time and patience I imagine I could dig out the details from the paper... but I don't.
The pH of the ocean varies not only from place to place, but diurnally, as my experience in Caribbean waters during a bright sunny day with predominant photosynthesis showed, followed by a dark night with predominant respiration.
You're still wrong, and name-calling won't change that. Permit me to demonstrate.
First, you're continuing to confuse the ability to absorb CO2 with the ability to store CO2. My contention "Warmer oceans don't hold less CO2" is correct for any reasonable value of global temperature (i.e. able to sustain humans on Earth.)
Furthermore, surface temperature is not the limiting factor in absorption. I'll quote the article you linked:
"The uptake of anthropogenic CO2 by the oceans is driven by the difference in gas pressure in the atmosphere and in the oceans and by the air–sea transfer velocity. Because the pCO2 is increasing in the atmosphere, CO2 moves into the ocean in an attempt to balance the oceanic and atmospheric gas pressures.
The mechanisms that control the speed with which the CO2 gas can move from the atmosphere to the oceans (air–sea transfer velocity) are not well understood today."
Once again, your 3-minute reading of the chemistry and science is leading you astray. I'll explain further:
More CO2 is absorbed by cooler water: but that doesn't mean CO2 is not absorbed by warmer water. In a system in equilibrium, CO2 will be net absorbed by cooler water and net outgassed by warmer water, because the pCO2 is the same in the air and water...so the net addition to the ocean must be zero. But in today's system, which is not in equilibrium due to anthropogenic CO2 emissions, the net CO2 addition to the ocean will be positive. This means that sufficiently warm water might still outgas some CO2...but in the balance, the ocean will absorb it until its pCO2 is no longer greater than the atmosphere's.
Assuming, of course, that ocean circulation continues, which it might not if global temperatures rise too greatly...causing an anoxic event. But that's a whole different discussion.
Can your reply to this comment without ad hominems or insults?
"Can your reply to this comment without ad hominems or insults?"
Like the comment you made here:
I think you need to spend more than three minutes learning about the chemistry...
Pot calling the kettle black there Gnoll?
Mr Troll: "My contention "Warmer oceans don't hold less CO2" is correct for any reasonable value of global temperature (i.e. able to sustain humans on Earth.)"
Wrong. Tropical oceans hold half the CO2 that polar oceans do under current current global temperatures.
Warm up the oceans, and they hold less CO2. How can you not see this?
And since that is so, and since CO2 rise LAGS temperature in the Vostok ice core data, one could assume that a warming ocean (due to warming from the LIA) has caused most of the CO2 increase in ther atmosphere as the oceans have warmed.
"As the world's oceans warm, they are absorbing less carbon dioxide, a new study in the November 25 issue of Geophysical Research Letters has found. With the oceans currently absorbing over 40 percent of the CO2 emitted by human activity, this could quicken the pace of climate change."
You're still misunderstanding the difference between absorption rate and absorption capacity. I'll illustrate, once again using the article you linked:
"A similar study from 20 years ago found a five-month lag between interannual temperature changes and the resulting changes in CO2 levels. The new study has now found that this lag has increased from five to at least 15 months."
An increase in lag time means that the rate of absorption has decreased: but unless that rate is zero, the pCO2 of the ocean is nowhere near its absolute capacity. 15 months is insignificant on the timescale of climate change. And neither is it clear exactly why that is the case:
"Weaker CO2 absorption could be caused by a change in ocean circulation or just an overall increase in the surface temperature." Or, quoting the first article again: "The mechanisms that control the speed with which the CO2 gas can move from the atmosphere to the oceans (air–sea transfer velocity) are not well understood today."
More importantly, what is the ocean's ultimate ability to absorb CO2?
"The oceans have taken up some 118 billion metric tons of this carbon dioxide between 1800 and 1994. ... The international team of scientists who completed the survey said this total is approximately one-third of the oceans' long-term potential."
So 1) we're not near the ocean's carrying capacity for CO2, and 2) the limitation is pCO2, not temperature. My point stands.
Let's continue. The record from marine mass extinctions is consistent with the theory that hypercapnia (excessive CO2 levels) causes acidification, impeding protein synthesis, and impedes production of carbonate shells: heavily calcified taxa are preferentially affected by mass extinctions involving substantial global temperature increase (example: Permo-Triassic). This is another strike against your theory that increased temperatures will stop the ocean's ability to absorb CO2 before it affects marine life.
Back to the original point: "Sensitivity of Earth's climate to changes in the greenhouse gas carbon dioxide (CO2) has been consistent for the last 420 million years. ... This study confirms that in the Earth's past 420 million years, each doubling of atmospheric CO2 translates to an average global temperature increase of about 3° Celsius, or 5° Fahrenheit."
And here are 50 years of data from the Mauna Loa observatory, showing atmospheric CO2 increasing by 22.5% during those five decades -- and by 38% to 93% compared to the range of the past 400,000 years (200-280 ppm):
Finally: thanks for proving that you're incapable of posting a reply without ad hominems or insults -- and that you are throwing these insults around because you don't understand the science.
Look - this topic total bullcrap
1st of all, this is NOT a real life study on actual living organisms - THIS STUDY IS A MODEL SIMULATION. Models are usually just bullsh*t - perhaps useful for examination of potential principle components analysis, but not ACTUAL real world numbers - just because we don't know all that much about the specifics of oceanic nitrogen cycling.
2nd pH MAXIMUM alteration from burning ALL OF THE ECONOMICALLY AVAILABLE fossil fuels in the WORLD will only change ocean pH from approximately 8.3 to 8.1 [ http://www.tos.org/oceanography/issues/issue_archive/issue_pdfs/22_4/22-4_tans.pdf ]
3rd as previously mentioned, pH shifts MUCH LARGER than the anticipated pH range alteration from the shift in the carbonic acid equation are seen diurnal cycles as well as seasonal cycles. All life is well adapted to this kind of TRIVIAL pH change. You drink pH 2 liquids all the time and yet maintain a steady ~7.35 blood pH no sweat.
4th general ocean pH is meaningless. The pH of the water in immediate contact with the organism is what counts - consider - what happens when a nitrogen fixing blue green algae takes up CO2 from the ambient water ? The pH carbonic acid equation changes immediately. What happens when the shell building organism sucks up carbonate ? same thing.
5th actual studies on oceanic organisms have repeatedly demonstrated absolutely inconclusive or POSITIVE effects from increasing CO2 up to 2,000 ppm but actual CO2 from the Tans paper concludes that atmospheric CO2 will peak at MUCH less than that if all fossil fuel is burned up. Sure, we will likely see some effects, just as we would no matter what changes, and believe me, EVERYTHING changes period.
Please learn to read, people. I did not defend the data or it's conclusions, only that the word "estimated" was used. I believe that unless you are a scientist in the area, you probably don't know to how many decimal places they can estimate.
Phillep Harding, crawl back into your cave on your flat earth.
Troll, I'll stop with this line: "Weaker CO2 absorption could be caused by a change in ocean circulation or just an overall increase in the surface temperature."
As I said, increased water temperature causes "weaker CO2 absorption".
Even a primitive cave dweller as myself can tell if proper procedures are followed in proving something, Bmack. I've heard of nothing indicating it has, and that degree of accuracy qualifies as an "extraordinary claim".
BioBOB: "pH MAXIMUM alteration from burning ALL OF THE ECONOMICALLY AVAILABLE fossil fuels in the WORLD will only change ocean pH from approximately 8.3 to 8.1"
There are two terms you need to familiarize yourself with: "permafrost carbon" and "methane clathrates". (Try wikipedia.) The problem isn't just the carbon we burn: it's that the carbon we burn releases a much greater reserve of CO2 from elsewhere.
To quote the paper you cited: the reservoir of permafrost carbon is "estimated to be ~ 1400 GtC, or ~ 1700 GtC when northern peat lands are included. That amount is almost five times the cumulative fossil fuel emissions through 2008." ... "If there should be significant net emissions, out of our control, from permafrost carbon or other sources, CO2 will become much higher than in our scenarios."
And what is the potential reservoir of methane clathrates? 500 - 2500 gT. Methane has a GWP of 72 over 20 years, and 25 over 100 years, relative to CO2. You do the math.
All this has happened before, during previous mass extinctions like the PETM and Permo-Triassic...and as I said before, it results in the preferential extinction of heavily calcified oceanic taxa, as one would expect during a period of oceanic hypercapnia that disrupts carbonate formation.
Bruce: I've already demonstrated that the ocean isn't near its capacity, that slower absorption doesn't stop absorption, and that the geological record clearly refutes your bizarre claim that rising temperatures will somehow stop ocean acidification. You lose.
This is all way too easy...it's like shooting fish in a barrel, and I'm not even a climate scientist. Get past the initial blast of irrational hatred and a few disconnected statistics, and we quickly realize that the deniers don't understand the science and have nothing to say.