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Comment by Netcob | Hacker News Reader

I heard this too and somehow just accepted it, even though I could not imagine how this should have happened. So during this major extinction event all the big dinosaurs just gathered in giant groups, fell over, then never really decomposed but got covered with something and turned into coal, oil and gas?

Plankton is new to me too though. I thought it was plants, which could not be fully digested by anything at the time, so they just broke down a bit and formed layer after layer, until other organisms caught up and started digesting them completely - so this sort of concentrated organic matter doesn't exist in upper layers.

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You're thinking of coal. There was a 60 million year period between the evolution of lignin (the key ingredient of wood, which allows plants to grow very tall) and the evolution of fungi which could break it down - so dead wood just stacked up, higher and higher. We call that period the Carboniferous, and almost all coal comes from then.

That may not actually be the case. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780611/

There’s direct fossil evidence of fungal rot during the period, and that much lignin production without corresponding decay would have sucked all the CO2 out of the atmosphere in a few million years.

Well, they did suck most of CO2 out of atmosphere and many times hundred of million years ago: https://earth.org/data_visualization/a-brief-history-of-co2/

At no point on that chart does it go lower than about 200ppm.

Well, look again - some of the group of points reach right to 200ppm.

Equation of line has nothing to do with reaching 200ppm, as that is average - adapted to whole timeline. Would look completely different in a different scope.

> Despite feedbacks with weathering rates, much smaller imbalances would have resulted in the complete removal of atmospheric CO2 in less than a million years. Without evidence of such dire consequences, lignin production in the absence of lignin decay for more than 100 million years into the early Permian is untenable.

The study addresses CO2 levels closely, as well as other significant pieces of evidence. I would tend to assume the peer reviewers at one of the world’s most prestigious journals thought to Google up historical CO2 levels.

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