Exceptitturnsoutthatweareimaginingallofthisincorrectlyframewereinhereindicatesthatif a finalplanktonandtheplantsstoppedproducingoxygenwithin a year, wewouldrunout.
ButlikebasicallyoxygenconsumptiononLeehappenswhenplantmaterialisburned, eitherin a fireorinanorganism.
Sinceoxygenisabundanttotheatmosphere, carbondioxideisthelimitingagentinthiscarboncycle, whichiswhythere's such a tinyamountofseeyoutwointheatmospherethatcarbondioxideiswhatgetstrappedandbroughttothebottomoftheocean.