#if you would like to correct me abt a mistake or a simplification pls assume i already know and i did it on purpose

[exopelagic]

hello dirt truthers I love you but I do not respect you and here’s why

plants photosynthesise. that’s their whole deal. photosynthesis is when plants convert carbon dioxide and water into glucose and oxygen, in the equation below:

6CO2 + 6H2O -> C6H12O6 + 6O2

that just means they’re taking up 6 carbon dioxide molecules (from the air! famously a gas in the air, you may know her from her recent work in Climate Change) and 6 water molecules (from the soil! but soil is also famously Not made of water and we will get to that later), making 1 glucose molecule and 6 molecules of oxygen (which go back into the air! different kind of air). this is cool because it’s the same process as respiration (how we break down sugars to release energy!) in reverse!

BUT MR PELAGIC — I hear you ask — what about the SUNSHINE?

that’s the fun complicated part for all you contrarian third party motherfuckers :)

the ENERGY for this process comes from light. I said before that this is respiration in reverse: which means that energy needs to go IN, it can’t do this on its own. but! light is VERY good at carrying energy! you may have experienced this with sunburn. you may also know that photosynthesis uses a green pigment called chlorophyll, which is the star of the show here

(I’m lying it’s really rubisco but we’re not going there rn)

yknow when you’re wearing something black when it’s sunny and it gets hot. same thing happens with chlorophyll when it’s absorbing light. but all that energy has to go SOMEWHERE, so instead of just sitting there, the chlorophyll breaks down a little and releases an electron.

stay with me here. we’re getting back to the air. so this electron is carrying a bunch of energy now — this is gonna get passed around and sent to play with the big kids. carbon dioxide is the big kids. as well as her friend ribulose bisphosphate (big carbon based molecule! CO2 has one carbon, this one has 5, and was initially made by joining CO2s together!). the electron here provides the ENERGY for these two to join together — energy was released to break something, needs to be put back in to make something. light -> energy -> bond. which leaves us with glucose! which is MADE of carbon dioxides! a bunch of them!

(you may have noticed the water is missing from this! you remember our friend chlorophyll who’s sad and broken and missing an electron? water (H2O) can ALSO be broken apart by light in the same way, into oxygen, 2 hydrogen ions, and 2 electrons! the oxygen is released as a gas, and the hydrogen ions and some electrons are used as fuel while the rest of the electrons are passed back to patch up ms chlorophyll. everything gets used up!)

SO. altogether, that’s:

carbon dioxide is taken in from the air

water is taken up from the soil (water ≠ soil)

light knocks an electron off the chlorophyll

carbon dioxide joins with ribulose bisphosphate (big 5 carbon molecule) to make glucose, USING THE ENERGY from the electron

water is broken down to replenish electrons and fuel the whole process

NOW! as my dear friend mx splash said above, a big chunk of plants is made of cellulose, which is created by chaining glucose molecules together. most of the things in plants are made of carbon, and all that carbon has to start off in this process -- from glucose molecules, made of carbon dioxide, made of air.

i fear this might be where i lose some of the soil truthers. what about the nutrience?

the main stuff that plants take up from the soil are things like nitrogen, phosphorous, and potassium (absorbed through their roots, dissolved in water). these are what fertilisers are made of! they're needed to make up many things -- all proteins (nitrogen), for example, as well as DNA (phosphorous). however!

MOST OF THOSE MOLECULES ARE MOSTLY CARBON. carbon's super good at making a framework to stick stuff onto. for example, proteins are long chains of amino acids joined together. the simplest amino acid is called glycine:

which has a ratio of 2 carbon atoms for every 1 nitrogen! most amino acids have a couple more carbons (all other amino acids stick something on instead of a hydrogen) -- which means that there is more carbon than nitrogen even in the vast majority of proteins, which make up a whole bunch of the mass of everything currently alive because they can be used for so many things.

(if you want some stats pulled from the first random paper I could find talking about this, under optimal conditions, tomato leaves in this study have a carbon:nitrogen ratio of roughly 6:1 -- there's 6 times more carbon than nitrogen in a given leaf. [1])

water is also fun, because while plants need a bunch of water (they use it like a skeleton! isn't that cool as hell??) their STRUCTURES aren't made of water. water maintains pressure and a consistent environment and keeps everything standing up (vs wilting when they run out of water), but they're not physically made of water for the most part -- we saw earlier that it's mostly used to drive the process of photosynthesis, while stuff is actually built from the carbon dioxide.

soil itself is also made of a lot of carbon: it's dead plants and rocks and shit. mostly dead plants. but this is a one way relationship: we know that plants are mostly carbon, and plants get the vast majority of this carbon as carbon dioxide from the air -- the stuff they need from soil is instead the extra nutrients like nitrogen, which are released as the dead plants and shit decompose. plants become soil, but soil doesn't become plants (soil is made of plants, plants are not made of soil). when everything works right, the nutrients get put back in the soil by things decomposing, and that layer keeps building up (carbon storage!). soil is really good at sittin there. that's also why air plants can exist, and why we can grow most plants in just water -- all they really need from soil is the water, nutrients and support.

IN CONCLUSION:

plants take in carbon dioxide (air) and use it to make glucose (via photosynthesis, powered by energy from light) which is then used to make the majority of the stuff in the plant. soil isn't taken up directly -- plants suck up nitrogen and other nutrients dissolved in water, which are important, but there is so much more carbon than anything else, which is needed for basically everything because it's used as a base to build on.

plants are made of fucking air <3

dirt propaganda: he says ‘the plants eat the dirt with their roots’ and ‘soil has nutrients’

air propaganda: air plants are a thing and also i reckon we would have run out of soil by now otherwise