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Does the Amazon provide 20% of our oxygen?

yadvindermalhi.org

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Re: Does the Amazon provide 20% of our oxygen?

#131

Post by atoav »

nearbuy wrote: post #128
EB66 wrote: post #127

Earlier quoted context omitted.

> This is not happening. Because forests don't produce surplus oxygen. Our atmosphere doesn't work that way. This is just plain wrong. The blogger is completely wrong on this point as well. In normal atmosphere conditions, photosynthesis does result in net oxygen gain. Plants do require oxygen for respiration, but they require far less oxygen than what they produce during photosynthesis. Furthermore, at night when th…

Then where is the carbon going?

Into the plant? Btw. you can easily test this yourself in a closed glas sphere.

Re: Does the Amazon provide 20% of our oxygen?

#132

Post by jgeerts »

dev_dull wrote: post #12
tcgv wrote: post #6

This subject has been treated so irresponsibly these past few days that not only people are making inaccurate statements such as "the Amazon provides 20% of our oxygen", but also high profile people such as Emmanuel Macron (France's President) and Cristiano Ronaldo (World famous soccer player) are sharing false information and photos[1] [1] http://translate.google.com/translate?hl=&sl=pt&tl=en&u=http...

It’s almost like these people are more interested in pushing a narrative and not the facts?

In present days it's really hard to get factual, correct, unbiased news.

Re: Does the Amazon provide 20% of our oxygen?

#133

Post by nearbuy »

EB66 wrote: post #130
nearbuy wrote: post #128

Earlier quoted context omitted.

Then where is the carbon going?

We're talking about oxygen production. Not carbon sequestration. Regarding sequestration: the carbon goes into the trunk, branches, roots and leaves of the tree. Leaves fall off the tree, rot and become soil. The tree eventually dies, rots and becomes soil. Some carbon will be given off by various decomposition processes, but the overall net effect is by far a carbon sink.

> We're talking about oxygen production. Not carbon sequestration.

BurningFrog said the carbon from CO2 goes into plants. Since plant matter isn't accumulating, carbon can't be accumulating, and therefore oxygen can't either. You replied, "This is just plain wrong".

So you're saying the part that is sequestered goes into the soil. That means some significant fraction of the 20 billion tonnes of carbon the Amazon photosynthesizes each year is turning in to soil. You're claiming the amount of soil increases by this amount each year, correct?

Re: Does the Amazon provide 20% of our oxygen?

#134

Post by nearbuy »

atoav wrote: post #131
nearbuy wrote: post #128

Earlier quoted context omitted.

Then where is the carbon going?

Into the plant? Btw. you can easily test this yourself in a closed glas sphere.

I meant overall in the long term, in response to EB66 saying BurningFrog is wrong.

The plants can't be net collecting carbon each year unless the Amazon contains more and more plant matter each year.

Re: Does the Amazon provide 20% of our oxygen?

#135

Post by mirimir »

strainer wrote: post #114
wcunning wrote: post #3

The basic gist of the article is found about 1/2 way in: "First, the phytoplankton in the oceans also photosynthesise [...] Therefore in terms of TOTAL global photosynthesis, photosynthesis in the Amazon contributes around 9%. [...] Second, a bigger point that is often missed is that the Amazon consumes about as much oxygen as it produces." This reminds me, as we should all be reminded on a regular basis, the bulk of…

The blogged claim that Amazon "consumes about as much oxygen as it produces" is not sourced and the piece seems to fly in the face of professional work on the subject. eg: "The global oxygen budget and its future projection" [1] > Fig. 4 summarizes the annual averaged global O2 budget from year 1990 to 2005, with the mass of O2 in gigatonnes (Gt) listed in each sink and for each process mentioned above (see Section 2…

The paper that you cite is talking about small changes.

> Under the Representative Concentration Pathways (RCPs) RCP8.5 scenario, approximately 100Gt (gigatonnes) of O2 would be removed from the atmosphere per year until 2100, and the O2 concentration will decrease from its current level of 20.946% to 20.825%.

    2018  209460 ppm
    2100  208250 ppm
That's 15 ppm per year.

From Stolper et al. (2016) A Pleistocene ice core record of atmospheric O2 concentrations:[0]

> We present a record of Po2 reconstructed using O2/N2 ratios from ancient air trapped in ice. This record indicates that Po2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources.

That's 7000 ppm decrease over 800000 years, or 0.009 ppm per year. And so yes, atmospheric oxygen concentration is dropping lots faster now. But TFA's point that it's slow, and regulated by long-term processes, is still valid.

0) https://science.sciencemag.org/content/353/6306/1427

Re: Does the Amazon provide 20% of our oxygen?

#136

Post by pvaldes »

sambal wrote: post #78
pvaldes wrote: post #56

Earlier quoted context omitted.

> Have they been suppressing natural fire in this region for too long? This is confusing for many people, I know. Ecosystems tend to increase its complexity with time. From lava field to savanna to forests. This is how it works. Life fills the gaps. If untouched, forests aim for the higher state of organisation possible, the so called "climax": A big forest, with huge old trees. Plants accumulate water, big plants ac…

I’d love to read more on this humid forest climax narrative from any credible sources, it sounds interesting and I don’t know anything about this sort of thing really , but at the same time it’s tripping my “just-so” sensors something heavy!

I bet that you will find plenty of credible sources if you study biology and learn some basic ecology (ecology as science, not as ideology). None of what I'm saying is a secret and is also easily verifiable empirically.

There are also parts of this science that deal with the study of stress in ecosystems. A low or medium source of stress can increase the biodiversity. A mix of healed and degraded ecosystems can provide habitats for different types of life beings. A big source of stress otherwise will distroy all the job done by time and simplify the ecosystem. Moreover, the damage can be so deep that the new state of organisation enters in a loop. The remain is just too flammable to advance and the only species surviving benefit from fire so they need fire to keep competitors at bay, germinate and survive. And they make fire creating flammable structures. Fire triggers water quiting the area and will distroy soil organic structure. Without water the future of the area enters in a reverse path, to savanna, then arid, finally desert. Is happening in California for example.

For climate change figthing purposes, the closer to the ecological climax, the better chance for long-term human survivorship.

Climate change will actively distroy climactic ecosystems also (more hurricans, etc), so the problem is more complicated that "just stop chopping trees and damaging coral reefs with tourist cruises". We can expect a lot of problems and extinction cascades in the future.

Re: Does the Amazon provide 20% of our oxygen?

#137

Post by Erlich_Bachman »

majos wrote: post #75
xmprt wrote: post #39

Earlier quoted context omitted.

Your comment illustrates the point even more in my opinion. You understand more about physics than politics, sports, and business, and so you're able to see how journalists can get it wrong. However, if you actually dived into the world of sports and similar fields about "human actors" there's a lot of interpersonal relations and complexity that can't be described in a 500 word article. If journalists were just repor…

Maybe my original point was vague: I'm arguing that the "what" is simpler when human actors are involved. Person x said this, did this, accomplished that. The story is for the most part straightforward and understandable. And a lot of the reporting in these areas is just "what". But people don't even have a good handle on the "what" of a lot of science (what are these new particles? what is p vs np?) which is why we…

> I'm arguing that the "what" is simpler when human actors are involved.

Where would you get that idea? It is definitely the other way around.

In hard sciences at least you can easily construct experiments and find out truths with time, which while complex, are basically predictable. In human sciences everything is much more complex and chaotic effects and problems with definitions and inherent unpredictability of humans make everything more complicated.

Re: Does the Amazon provide 20% of our oxygen?

#138

Post by shkkmo »

EB66 wrote: post #127
BurningFrog wrote: post #123

Earlier quoted context omitted.

Let's demystify how plants "produce oxygen". They do it by splitting CO₂ molecules. The oxygen part (O₂) goes into the air, and the carbon (C) part becomes the plant. So for the Amazon to continually produce surplus oxygen to the atmosphere, it must also continually produce an ever expanding amount of plant material ("wood") that would form an ever growing pile there. This is not happening. Because forests don't prod…

> This is not happening. Because forests don't produce surplus oxygen. Our atmosphere doesn't work that way. This is just plain wrong. The blogger is completely wrong on this point as well. In normal atmosphere conditions, photosynthesis does result in net oxygen gain. Plants do require oxygen for respiration, but they require far less oxygen than what they produce during photosynthesis. Furthermore, at night when th…

> The blogger is completely wrong on this point as well.

I think you may not have read the article closely enough:

>> Plants produce oxygen through photosynthesis (green arrow). However, the the same plants consume the equivalent of over half the oxygen they produce in their own respiration ... my own team's research suggests this is more like 60%

>> The remaining 40% of the Amazon oxygen budget is consumed mainly by microbes breaking down the dead leaves and wood of the rainforest, a natural process called heterotrophic respiration

> Similarly, we should all be reminded that when skimming blogs and comments you're likely to come across misleading and inaccurate content

The "blogger" who wrote this article is "Professor of Ecosystem Science, University of Oxford" and "Founding Director, Oxford Centre for Tropical Forests" and probably knows more about this than you or I. This is not a peer reviewed paper, but it is probably more accurate than science journalism by a non-ecologist on this topic.

Re: Does the Amazon provide 20% of our oxygen?

#139

Post by PeterisP »

atoav wrote: post #131
nearbuy wrote: post #128

Earlier quoted context omitted.

Then where is the carbon going?

Into the plant? Btw. you can easily test this yourself in a closed glas sphere.

Exactly, it goes into the plant, and is then released as the plant decomposes - so in a stable rainforest, where the total plant mass isn't increasing, the new plants growing (creating O2 and absorbing CO2) is fully balanced by old plants decomposing or burning (absorbing O2 and creating CO2); so there's no net creation of O2.

Re: Does the Amazon provide 20% of our oxygen?

#140

Post by shkkmo »

strainer wrote: post #114
wcunning wrote: post #3

The basic gist of the article is found about 1/2 way in: "First, the phytoplankton in the oceans also photosynthesise [...] Therefore in terms of TOTAL global photosynthesis, photosynthesis in the Amazon contributes around 9%. [...] Second, a bigger point that is often missed is that the Amazon consumes about as much oxygen as it produces." This reminds me, as we should all be reminded on a regular basis, the bulk of…

The blogged claim that Amazon "consumes about as much oxygen as it produces" is not sourced and the piece seems to fly in the face of professional work on the subject. eg: "The global oxygen budget and its future projection" [1] > Fig. 4 summarizes the annual averaged global O2 budget from year 1990 to 2005, with the mass of O2 in gigatonnes (Gt) listed in each sink and for each process mentioned above (see Section 2…

> the piece seems to fly in the face of professional work on the subject.

The blogger does professional work on the subject. The article makes it pretty clear that the net positive production of oxygen the the Amazon is so close to zero that it is only relevant on the time scale of millions of years.

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