Just think how much deeper the ocean would be if sponges didn't live there.

That's a joke, not really a shower thought. But thank you for a Stephen Wright one-liner, they are always welcome.

You can't have everything. Where would you put it?

Sorry did not get this one, is it because if there would more leaching on ocean floor, and possibly increasing depth (i dont think that would have any realistic impact) or is it in a joke-y sense saying that sponges have soaked up water and if they were not there, then sea level would be higher? If that is the one, then actually if sponges were to be removed, then the total sea level would technically decrease (not going into any biology here) purely because sponges in non expanded form will have some volume, and that is a non zero amout, going in water, they just have absorbed it - or to be more precise - swollen, so the original volume is still there, and if no sponges, that miniscule amount would be removed. And maybe if no sponges, then lots of fauna would die, and now i need a biologist (the marine kind) to confirm that for most aquatic stuff, they tend to have densities close to water itself (so they can be gravitationally neutral, and some puff up/release air from stomach to change densities slighlty so as to adjust to water density) and remove that much amount of fish would just remove there volume, and assuming same density, sea level would decrease. But maybe no fauna means huge algae bloom, and floor fauna to die, and reduced co2 capture levels by seas, and due to then possible increase in co2 levels would cause accelerated glacial melting and higher sea levels so more depth, but maybe in that case humans would not survive, and possible our emmissions gone would mean on land co2 capture would be more feasible, and maybe further decrease.

Recursion depth reeached NaN. Halting.