Carbon cycle: the problem of ocean acidity

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Carbon cycle: the problem of ocean acidity




by Christophe » 18/10/14, 10:51

Image

Representation of carbon stocks on Earth likely to fuel exchanges at the scale of the century (this diagram does not represent the carbon contained in the limestone, which is by far the largest stock of the planet), and annual flows, all in billions of tons of carbon (rated GtC).

The flows in black represent "natural" exchanges, in other words those which were the only ones to exist before the start of the industrial age, and the values ​​in black for stocks represent the (reconstituted) state of 1750, before the start of the industrial era. industrial activities. The flows in red represent the effect of human activities (reinforced, reduced, or created flows), for the average of the 1990s, and the values ​​in red for stocks represent the variation from 1750 to 1994.

This diagram means for example:


whereas surface sediments (the fraction of oceanic sediments in contact with water) contain 150 billion tonnes of carbon, unchanged since the beginning of industrial activities,

that the intermediate and deep ocean contained 37.100 billion tons of carbon in 1750, amount that has increased by 100 billion tons of carbon since the beginning of industrial activities,

that terrestrial ecosystems contained 2.300 billion tons of carbon in 1750 (in plants, soils and humus), an amount which has increased by 101 billion tons of carbon since the beginning of industrial activities as an increase in the productivity of plants (more CO2 and warmer = faster growth) but which has fallen by 140 billion tons of carbon over the same period because of deforestation and possibly the destocking of part of the soil carbon,

that the atmosphere contained 597 billion tons of carbon in 1750, amount that has increased by 165 billion tons of carbon since the beginning of industrial activities following CO2 emissions,

that the influence of human activities led the surface ocean to emit 20 billion tonnes of carbon per year in addition to what it emitted in 1750 (red arrow up), mainly because of the increase in its surface temperature (warming ocean water "degasses" part of the dissolved CO2 it contains), but also to absorb 22,2 billion tons of carbon per year in addition to what it absorbed in 1750, in response to the increase in atmospheric CO2 concentration (more CO2 in the air "pushes" the CO2 harder to dissolve in ocean water),

that the stock of fossil fuels (all aggregated: oil, gas, coals) was worth around 3700 billion tonnes of carbon in 1750 - before we started digging into it - and that at the end of 1994 we had "destocked" (in fact burned, therefore with transfer to the atmosphere) about 244 billion tons of carbon (for information between 1994 and 2005 this value increased by 30%).

NB: CO2 emissions of fossil origin, which are 6,5 billion tons of carbon - about 24 billion tons of CO2 - per year on this chart (the average of the 1990 decade) are now almost 8 billion tons of carbon per year.

Source: IPCC, 4e Evaluation Report, 2007.


More: http://www.manicore.com/documentation/serre/acide.html
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Re: Carbon cycle: the problem of ocean acidity




by Did67 » 18/10/14, 15:12

Christophe wrote: that the influence of human activities led the surface ocean to emit 20 billion tonnes of carbon per year in addition to what it emitted in 1750 (red arrow up), mainly because of the increase in its surface temperature (warming ocean water "degasses" part of the dissolved CO2 it contains), but also to absorb 22,2 billion tons of carbon per year in addition to what it absorbed in 1750, in response to the increase in atmospheric CO2 concentration (more CO2 in the air "pushes" the CO2 harder to dissolve in ocean water),


Things that we know very well when opening a bottle of sparkling water: the decrease in the pressure of CO² "above" the sparkling water (or Coke) triggers the bubbles ...

And that we know very well in artificial gasification (the "machines" to produce sparkling water).

Like sparkling water, which "stings", the ocean is therefore becoming slightly more acidic, which coral does not like at all!
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by chatelot16 » 18/10/14, 22:42

CO2 could make the water more acid if it was in a glass container ... but as long as there is limestone to eat in huge quantity, the CO2 dissolves limestone and ten sous is cheap

I'm not sure that we are able to quantify everything in the carbon cycle
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by Did67 » 19/10/14, 12:06

Limestone is an essentially terrestrial sediment - even if there are some calcareous limestones or some arms that are calcareous soils covered by the sea (the sleeve) ...

Most of the oceanic basins are of magmatic origin ...

I think that limestone is peanuts, at the level of the oceans ...

Of course, these are "fishy" figures: but the consumption of C of fossil origin has been such, for a century or a little more, that indeed, even if they are fishy, ​​the major balances are disturbed
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by moinsdewatt » 19/10/14, 12:59

The acidity of the oceans has increased by 26% in 200 years

the 08 Oct 2014 VR with AFP

Our oceans are becoming more and more acidic. The pH of the oceans has fallen by an average of 26% over the last 200 years, absorbing more than a quarter of the emissions of CO2 emitted by human activities, said a report released Wednesday in Seoul.

Our oceans are becoming more and more acidic. The pH of the oceans has fallen by an average of 26% over the last 200 years, absorbing more than a quarter of the emissions of CO2 emitted by human activities, said a report released Wednesday in Seoul. However, the lower the pH, the more it indicates that the measured solution is acidic.

About 30 researchers, commissioned under the Convention on Biological Diversity (CBD), reviewed hundreds of existing studies on this phenomenon to write a synthesis presented in Pyeongchang, South Korea, on occasion of the 12th meeting of the CBD, the UN convention framing the protection of biodiversity.

"Massive impacts"

This report underlines the seriousness of the phenomenon - its speed is unprecedented - its very varied impacts and the fact that acidification will continue in the decades to come. "It is now inevitable that within 50 to 100 years, anthropogenic emissions (due to human activity, Editor's note) of carbon dioxide will further increase the acidity of the oceans to levels that will have massive impacts, the most often negative, on marine organisms and ecosystems, and on the goods and services they provide, "write the scientists.

The acidity of the oceans varies naturally over the course of a day, seasons, locally and regionally and also according to the depth of water, they specify, before warning that "coastal ecosystems and habitats experience greater variability than those located on the high seas ".

Coral barriers in danger

For example, studies have shown that the fertilization of some species is very sensitive to ocean acidification, and that others are more tolerant. Corals, molluscs and echinoderms (starfish, sea urchins, sea cucumbers, etc.) are particularly affected by this change, which reduces their growth rate and survival rate. Some algae and micro-algae can however benefit, as some types of phytoplankton.

The report highlights the socio-economic impacts already visible in certain regions of the world: on aquaculture in the northwest of the United States or on oyster farming. The risks to coral reefs in tropical areas are also "of great concern, as the livelihoods of some 400 million people depend on these habitats," they argue. Finally, while affirming that the impacts of oceanic acidification are a field of study still largely to be cleared, the researchers underline "that only a reduction of CO2 emissions will make it possible to stop this problem".


http://www.msn.com/fr-fr/actualite/fran ... ar-BB8b4XU
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by chatelot16 » 19/10/14, 16:52

what does a ph that drops 26% ??

ph is a logarithmic scale: ph7 - 26% = ph5,18 would be an absurd calculation
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by Christophe » 19/10/14, 18:58

chatelot16 wrote:what does a ph that drops 26% ??

ph is a logarithmic scale: ph7 - 26% = ph5,18 would be an absurd calculation


Really?

It is not because one speaks on a log scale that one can not speak in% even if it is deceiving for the common people ...

Let us take the sound level more understandable: from 100 to 50 dB it is a reduction of 50% of the decibels but in "noise" power it is a reduction of 50 dB or a factor of 100! (when we double the sound power, we only increase the dB by 000)
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by chatelot16 » 19/10/14, 19:41

good example of absurdity!

to go from 100db to 50db is to go from the noise to the silence ... it would be ridiculous to call it 50% reduction

to reduce the noise of 50% is to divide by 2, but to divide by 2 what? intensity or power

to divide by 2 the power is to reduce 3 decibel thus to go from 100 to 97

divide the intensity by 2 that divides by 4 the power and makes a reduction of 6 dB
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by Did67 » 19/10/14, 19:49

It is indeed, a little curious as presentation.

I did not read the link, the report probably gives the figures in "pH" ???

Conversely, exclaim that the ion concentration H3O + has changed from 10power-7 to 10 power - 5,6, who will understand ???

I do not know how much is the pH of a sparkling water (to the 4 or 5?) Or that of the coke ???

If we understand that the "pH figure lowered by 26%, that would mean that we are close to 5 and a few ...

Deserves to be dug!
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by chatelot16 » 19/10/14, 20:12

according to http://fr.wikipedia.org/wiki/Eau_de_mer The pH varies between 7,5 and 8,4, for an average of about 8,2.

if this 8,2 had descended from 26% the fish would be all belly up!

So it's up to the person who wrote it to explain what it means ... without any more precise information, it's to be stored in the multitude of absurd figures that hang out

and if it's the concentration of ion that has changed by 26% it makes a variation of ph of some numbers behind the decimal point
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