So I'm designing a world where the air has its own ecosystem, separate from the one on the land, because sky whales are cool. However, I'm having trouble figuring out what the plants and other producers would use to, you know, produce.

In the ocean, you have stuff like phytoplankton, which get nutrients from stuff dissolved in the water. I don't know that that would work in the air, especially on a scale big enough to support larger animals.

On land (and also in the ocean,) you have bigger plants, like grass, trees, and kelp, which all rely on having some sort of soil or something to grow in, to get nutrients from.

My question is, where can an airborne plant or microorganism get the nutrients it needs to grow and sustain a few tiers of consumers, without having a phase of life on the ground?

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    $\begingroup$ Phytoplankton probably wouldn't work in air, as air isn't viscous enough to suspend small organisms the way water is. Wind isn't as consistent or strong as ocean currents. This is why there aren't any airborne filterfeeders and the closest you get are bats which hawk small, individual insects out of air. Alternatively you could always magic organisms up that have adaptation specifically to get around that. $\endgroup$ Jan 28 '20 at 5:49
  • $\begingroup$ Related question: worldbuilding.stackexchange.com/questions/98297/… $\endgroup$
    – Willk
    Jan 28 '20 at 15:17
  • $\begingroup$ maybe insect pollinators never evolved on said planet so airborne pollen and spores are super abundant. $\endgroup$
    – John
    Jan 28 '20 at 20:12


Plants get their carbon from carbon dioxide in the air, not from the soil. Trees anchor themselves into the ground for sake of structural stability and hydration, but they aren't dependent on specific soil nutrients like crops are.

Your airborne plants can gather carbon from the air through respiration, and plausibly, they can get their water from vapor in the air too. Any other trace elements required for life could be filtered in through their pores from atmospheric gases, or they could eat airborne bacteria.

In general, the nutrients you need are accessible - but you may be limited in terms of size. Plus, it may be hard to keep these plants airborne consistently unless they're filled with gas, such as hydrogen synthesized from water they take in.

  • $\begingroup$ Kelp and many other types of seaweed use gas bladders filled with air to keep themselves upright while being battered by ocean currents. A similar system with hydrogen could work for an airborne ecosystem, but would be vulnerable to lightning strikes. Even so kelp and seaweed usually have an end attached to a physical substrate of some kind. $\endgroup$ Jan 28 '20 at 5:46
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    $\begingroup$ Strong winds is enough to keep a lot of dust and backteria airbone all the time. So on, say planet without any continents, there would be constat stable system of cyclons that woud suspend water, dust and small organisms in the air all the time. $\endgroup$
    – ksbes
    Jan 28 '20 at 9:07

You mention whales, so: consider our baleen whales, who take in a few gazzilion litres of water and then strain microorganisms out as the spit the water back out. Your air-whale can do a similar thing on a giant scale, essentially deploying a huge net which passes air but catches particles. Every now and then it'll collapse the net and dump the contents into its digestive system. Or maybe the net itself is a digestive system, feeding the results via a arterial-like system to the main body.

As other comments point out, there's always tons of edibles from either other airborne species or junk blown up from the earthbound lifeforms.


Giantic plant life.

Semi-airborne beigns are possible if your trees are tall enough, several kilometers up in the sky (maybe because the atmosphere is too dense to let light pass to the surface?) That led to the evolution of several species that never touch ground, just fly or jump between the treetops. Some could even feed on the aboundant flying pollen carried by the winds.


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