I thought (maybe i'm wrong?) that they still respire... so taking in Oxygen, and breathe out CO2... and that photosynthesis is a different mechanism that extracts CO2 from the air and produces O2
Pretty sure I read somewhere that some trees can take around a decade to grow to the point where they become net extractors of CO2?
You are correct, but unless a photosynthesising plant is killed when it's ridiculously young it will end up consuming far more CO2 through photosynthesis than it produces through respiration over it's whole lifetime.
EDIT: And vice versa for O2; it will create more than it will consume.
Yes, all plants do that. However, over time, the net is more CO2 is taken out of the atmosphere, and more O2 is out into the atmosphere (while the tree is still alive). Trees are still carbon based life form, and as they grow, carbon is needed to construct their cells. The main place to get carbon is from the atmosphere, and no where else come close.
When I was young I assumed they extracted their mass mostly through their root system. Then one day it occurred to me that to do that they would be creating sinkholes for themselves.
I wonder if OOP thinks trees are taking it from the ground?
Veritasium did a video about that since it does seem so counter intuitive. But then if you remember a potted plant cn get quit large, it makes more sense.
It's a bit more complicated that that. While plants do breathe out CO2 AND take in CO2 during photosynthesis. The amount in takes in is way larger than the amount it breather out. In fact, most of that CO2 ends up in the plant itself. It's why plants burn when they're set on fire. It's that same C that came from CO2 that's now being released back into the atmosphere again.
Most life generates the energy to life by oxidizing the carbon from organic molecules, including trees.
What's unique about photosynthesis is that they also create new organic molecules (reduced carbon) from CO2 (carbon fixation) from free sunlight.
Biomass relies on having lots of organic molecules available. Whereas animals need to eat organic molecules both for energy and new mass, plants generate their biomass entirely from the CO2 in the air (with the exception of parasitic plants and such). That means any amount of living plant biomass is a net reducer of atmospheric CO2: the sugars it burns to live simply return what was taken from the air, and the rest becomes part of the growth.
However, because plants die and decompose, we have to think about, "How much CO2 is in plant or other photosynthetic organism biomass at any one time?" That's where calculating total carbon sequestration is important because it conversely means "How much less carbon is in the air at any one time?" Forests are a great way to sequester carbon because trees are massive and long-lived. All coal in the world represents carbon sequestered in the Carboniferous period that was then buried for a long time. However, by far the greatest carbon sequestration is in oceanic algae and the processes that cause dead algae to be buried on the ocean floor (where all the oil in the world came from). This is what ecological scientists such as marine biologists dedicate a lot of effort to researching: how we can prevent disrupting the protective carbon sequestration of the natural world.
Life on earth is made mostly by carbon (and water) in various forms. That carbon mostly comes from the CO2 used by photosynthesis, and is passed up the food chain to all life.
Vast majority of plants don't quite have a way of eating other things with carbon, so the carbon that they give off has to have come from their own photosynthesis.
When they're super young, they have no leaves for photosynthesis, so they rely upon the energy stored in the seed/nut that spawned them, turning that into CO2 and energy.
But their seed/nut was created from CO2 by their parent. It isn't like they are created from oil/coal.
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u/cheeseybees 2d ago
I thought (maybe i'm wrong?) that they still respire... so taking in Oxygen, and breathe out CO2... and that photosynthesis is a different mechanism that extracts CO2 from the air and produces O2
Pretty sure I read somewhere that some trees can take around a decade to grow to the point where they become net extractors of CO2?