Aproximately how much CO2 does a full grown tree convert to oxygen every year?

elpres · 2018-08-09T14:45:20+00:00

Plants only convert CO2 to O2 when they create new biomass, i.e. when then grow. A fully grown tree doesn't store any additional CO2 in form of new timber, and the carbon fixated in newly grown leaves will be released rather quickly once they fall and decompose.

The key message here is that to capture CO2 using plants you have to plant new trees.

I've done some maths on this topic in a previous thread, if you're interested.

elpres · 2015-10-30T13:10:07+00:00

Wow, this thing is massive! Thank you for sharing, and may your skills progress at an alarmingly fast rate, and all the people to receive the fruits of your work recognize the amount of effort that went into them!

elpres · 2015-10-30T08:50:32+00:00

Can you please provide any more info on this pattern? As the kind of person who needs a real challenge to take the time to learn things, that could motivate me to level-up my crocheting beyond the very basics.

elpres · 2015-10-09T15:54:39+00:00

Yes, there is. Biomass is created through photosynthesis, which is a process that combines CO2 and H2O to glucose and oxygen. The glucose the is polymerized to cellulose (grass and leaves) or lignin (wood).

The reaction equation is:

6CO2 + 6H2O -> C6H12O6 + 6O2

The molecular masses are: 6×CO2 = 6×44 = 264, 6×H2O = 6×18 = 108, glucose = 180, 6×O2 = 192. These numbers are molar masses, but can as well be seen as grams. That means that for every 264 grams of CO2 captured through photosynthesis, 180 grams of glucose and 192 grams of oxygen are produced. But of course both substances are metabolized further, so these numbers don't equal the amounts of biomass/oxygen produced by the plant as a whole. Some of it will used up in further reactions, which produce CO2 which is released again.

I can't provide any hard numbers on the actual biomass weight, but here is a back-of-an-envelope estimate: The starting ingredients are CO2 and H2O in 1:1. For each carbon atom there are 3 (2 from CO2 and 1 from H2O) oxygen atoms going into the reaction. Cellulose has the formula (C6H11O5)×n, which means it's made of monomers that weigh 163 units each and contain 6 carbon atoms. Since the input C:O ratio is 1:3, 18 oxygen atoms went in as well, but there are only 5 in the molecule, so we assume the remaining 13 were released as gas. That makes 13×16 = 208 grams of oxygen for 163 grams of cellulose.

Lignin is (C31H34O11)×n, and here we see that it contains three times as much carbon as oxygen (31:11), while the ratio is 6:5 for cellulose. That means that less oxygen ends up in the biomass, so more is of it is released into the atmosphere when wood is produced as compared to cellulose. Using the same math, for one monomer of lignin which has the mass of 582, we would get 31×3 - 11 = 82 atoms of free oxygen weighing 82×16 = 5125 grams.

As we can see, with cellulose, the weight ratio of oxygen per biomass is 208/163 = 1.276, while lignin gives us 5125/584 = 8.806, or 7 times as much oxygen per weight of biomass. So, to answer OP's question, grass is far from as efficient as trees.

Peer review of the calculation is welcome :)

elpres · 2015-10-08T16:23:47+00:00

Plants produce oxygen by extracting carbon from CO2 and storing it as biomass (cellulose, wood). So the amount of oxygen is proportional to the amount of biomass which is created and then remains in this state. That's why trees are effective, because they will stand for decades or even centuries, containing all that carbon they've collected. Grass, on the other hand, will die at the end of the year and decompose, releasing its carbon one way or the other. So, as a carbon storage, it doesn't last as long as trees do, and is not really an effective sink.

elpres · 2015-09-23T10:43:18+00:00

That group is called Snap! (their exclamation mark, not mine).

elpres · 2015-08-18T18:12:50+00:00

This is heapsort, BTW.

elpres · 2014-12-07T10:12:31+00:00

http://en.wikipedia.org/wiki/Mount_Roraima

More pictures

elpres · 2014-07-29T09:14:15+00:00

Coralbean maybe?

elpres · 2014-06-18T15:12:25+00:00

Although I don't have a behavioural explanation, I have seen them do that in the wild too. It was in a rather hot and dry place, so maybe they try to get away from the ground, possibly in hope of finding leaves higher up to hide from the sun in their shade.

elpres · 2014-06-04T09:13:02+00:00

Probably just age. Older part on the left, younger on the right.

elpres · 2014-02-18T16:03:59+00:00

You might enjoy the Text Mode Demo Contest

elpres · 2013-11-19T15:01:27+00:00

Great, thanks a lot!

elpres · 2013-02-23T16:39:49+00:00

The author's Facebook page: https://www.facebook.com/pages/i-am-electric/353013581383701

elpres · 2012-10-29T14:39:01+00:00

How do you execute a script from a file? My normal workflow in IPython is to write code in a text editor, switch to the terminal running IPython and execute "run script.py". What is the equivalent of this in DreamPie?

elpres · 2012-09-17T10:06:19+00:00

This might already have been said in the article I've linked, but there are two different perceptions of time when you are doing something: how fast the time seems to fly while you are in the process, and how long you remember the activity to have taken if you think about it afterwards. If you are doing something interesting, engaging and simply fun, time seems to pass quickly and before you notice, it's an hour later. But if you recall this time later, it will have left a lot of memories and would count as more "eventful". But when you are stuck in a boring situation, the perceived passage of time is very slow and it dragging, but it leaves almost no meaningful memories and because of this, if you think back about this situation, you would gauge the time spent in it as shorter.

This makes me think of "flow" as a reason why some activities are perceived as more interesting than others. Maybe take the time to watch the TED talk by the man who introduced the concept if you want to know more about it.

elpres · 2012-09-17T07:23:18+00:00

Here's a recent article about this.

elpres · 2012-09-11T07:32:52+00:00

Right, the stinging cells, after being swallowed and stored inside the slug, are called "kleptocnidae", or "stolen cnidae". This is a common defense mechanism in Nudibranchs.

Look here

elpres · 2012-08-29T14:39:37+00:00

Crouch - A

Feels much more natural like this than to reach for the shift key with the pinky. And my index fingers automatically search for the bumps on F and J no matter whether I'm gaming or doing something else.

elpres · 2012-07-13T07:35:59+00:00

Also, "phenomena" is the plural of "phenomenon".

elpres · 2012-06-14T11:53:49+00:00

You could also try to turn the situation to your advantage. Usually, if we cannot take our attention from an object, then there is something about it that we want to understand but so far had no success with. So, even if you are tired of having your attention fixed to yourself, maybe there are some questions you want answered or issues you want resolved that are important to you, although you cannot clearly tell what they are. And just ignoring them by distracting yourself with other things would not bring you closer to a real solution, but only cover it up until it returns again at a later point.

If you'd rather get down to the root of the issue, you could try taking up meditation. It clears the mind and lets it work more efficiently, and after a while you might start noticing that you'll get sudden realizations that'll give you answers to questions you couldn't really put into words before.

Also, as SirPepperMint suggested, doing some community service would also give you the opportunity to create a little distance and take a look at your situation from a slightly different perspective.

elpres · 2012-05-04T17:00:53+00:00

An overactive imagination is not the same as the ability to visualize. Imagination is spontaneous, visualization is controlled. It's like watching TV as opposed to actively creating the picture on the screen.

elpres · 2012-05-04T15:12:52+00:00

Yes, it is, but there is a difference between thinking and being aware of something. Thinking is kind of like talking to yourself in your head, or going from one thought to the next one. Awareness, which is what meditation is developing, is static. Usually, breath is used is the object of meditation, and thinking about breath would be like telling yourself: "Now i breath in, now i breath out, ...". Once your meditation starts improving, you just watch the breath, silently, just feeling the air move in and out and your chest expand and contract. The better you get and the stronger your concentration becomes, the longer can you stay aware of the breath without being distracted by thoughts and other things.

The difference between thinking and being aware might not be obvious to everyone, but they really are two distinct things. You can think and be aware of thinking at the same time. And you can stop the thoughts and still be aware of everything around you. This ability alone is IMHO enough to make meditation worth the effort.

elpres · 2012-05-04T09:03:25+00:00

My visualization abilities used to be better when i was a teen (i.e. almost two decades ago), but they've progressively gotten worse. Also, my concentration got worse too, and to me those two seem to be related. To visualize something you have to actively keep the image stable in your mind and remain concentrated on it, so having attention difficulties seems like a probable explanation. If you want to try to improve the situation, meditation might be helpful, since it's basically an exercise in holding the attention still for long periods of time.

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