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After a decade there's a couple extra inches of wood and leaf matter sitting on the ground. I've always wondered what our planet looked like in the millions of
by dangrossman 13y ago
After a decade there's a couple extra inches of wood and leaf matter sitting on the ground. I've always wondered what our planet looked like in the millions of years between the evolution of trees, and the evolution of the first fungus that could break down cellulose. With nowhere to go, those dead forests eventually fossilized and became coal deposits -- but what was it like to actually be there when those forests were growing. How thick did the dead wood stack up? How did anything grow after the first few generations of trees covered the ground in so much dead carbon?
- Someone 13y agoWas there such a time? A quick google gives me, for trees, http://en.wikipedia.org/wiki/Evolutionary_history_of_plants#Tree_form http://en.wikipedia.org/wiki/Evolutionary_history_of_plants#... "The early Devonian landscape was devoid of vegetation taller than waist height." and "The first plants to develop this secondary growth, and a woody habit, were apparently the ferns, and as early as the middle Devonian one species, Wattieza, had already reached heights of 8 m and a tree-like habit.", Comparing that with http://en.wikipedia.org/wiki/Evolution_of_fungi http://en.wikipedia.org/wiki/Evolution_of_fungi "A rich diversity of fungi is known from the lower Devonian Rhynie chert", and lower Devonian = early Devonian, I very tentatively conclude fungi precluded trees. Given that, I (not hindered by much specific knowledge of the subject) expect that fungi breaking down cellulose co-evolved with trees.
- grey413 13y agoActually, the period between the development of woody plants and the development of wood-eating fungi was approximately 60 million years, and is known as the carboniferous because of all of the carbon that got sequestered. Also, the key chemical wasn't cellulose, but rather lignin. Lignin is an astoundingly complex polymer* that plants use as "concrete" to create their woody cells. As far as I know, white rot fungi is the only group that can break it down. *seriously, look at that thing: http://cse.ksu.edu/REU/S11/emd4y8/breakdown.html http://cse.ksu.edu/REU/S11/emd4y8/breakdown.html. That's a big goddamn molecule.
- malandrew 13y agoI wish I could upvote you twice. The beauty of HN is the shear quantity and quality of comments that result in a TIL moment.
- croisillon 13y agoGreat answer indeed! Now do you maybe have an idea of "how thick did the dead wood stack up" as @dangrossman asked? Thanks !
- TeMPOraL 13y agoLet's post it on whatif.xkcd.com :).
- Someone 13y agoThanks. That first lignin-eating fungus must have had quite a population explosion when it entered the world.
- deleted 13y ago[deleted]
- js2 13y agofungi precluded trees s/precluded/preceded/ (not to be confused with proceeded).
- russell 13y agoDecomposition of plant matter in the Carboniferous period wasnt hindered by the lack of microbes of fungi, rather the plant matter was covered by shallow seas and swamps. It was the water that inhibited the breakdown. You can see the same process going on today in peat bogs. I speak as an expert. I spent one summer between grade school and high school cutting peat in a peat bog. It wasnt wet like the Everglades, but you could squeeze a handful of peat and see the water drip out.
- sitkack 13y agoOr a beat bog person!
- apw 13y agoThe dead forests you mentioned may have became massive coal beds via the "charcoal route"; i.e. a global firestorm may have incinerated essentially the entire biosphere. The global debris layer created by the end-Cretaceous impact at Chicxulub contained enough soot to indicate that the entire terrestrial biosphere had burned. Source: K-Pg extinction: Reevaluation of the heat-fire hypothesis; Robertson, Lewis, Sheehan & Toon, 2013; Journal of Geophysical Research: Biogeosciences http://onlinelibrary.wiley.com/doi/10.1002/jgrg.20018/abstract http://onlinelibrary.wiley.com/doi/10.1002/jgrg.20018/abstra...
- fhars 13y agoNo, the coal beds are far older and far thicker than the bit of end-cretaceaous soot that paper is talking about. The K-Pg boundary sediments are thin: http://en.wikipedia.org/wiki/File:Cretaceous_Paleogene_clay_at_Geulhemmergroeve.jpg http://en.wikipedia.org/wiki/File:Cretaceous_Paleogene_clay_... Your typical coal bed is quite a bit thicker: http://en.wikipedia.org/wiki/File:Coal_mine_Wyoming.jpg http://en.wikipedia.org/wiki/File:Coal_mine_Wyoming.jpg
- runeks 13y agoIt's like the evolution of lignin-consuming fungi needs to start all over: this time the fungi in question needs to be able to both break down lignin, and be radiation-resistant. Let's wait 60 million years and see.
- samstave 13y agoWe should try this: http://www.ted.com/talks/paul_stamets_on_6_ways_mushrooms_can_save_the_world http://www.ted.com/talks/paul_stamets_on_6_ways_mushrooms_ca...