General Discussion
Related: Editorials & Other Articles, Issue Forums, Alliance Forums, Region ForumsDid you know this fact about wood, microbes and coal?
Because there were no microbes to deal with the wood, the layers of plant material compressed as they were buried over time, forming coal.
More info: http://bit.ly/ZJoIVK
Found on the I fucking love science Facebook
LiberalAndProud
(12,799 posts)Happy Arbor Day.
Buzz Clik
(38,437 posts)Fungi are mostly responsible for degrading wood, and fungi appeared on land about 40 to 60 millions years prior to the evolution of woody species. Considering the life cycle for fungi is measured in days, it is highly unlikely that fungi were unable to adapt to degrade the specialized tissues and molecules in wood.
We do know, however, that the decomposition of wood is an aerobic process. When a tree falls in a swamp, decomposition is far slower due to low oxygen contents. Coal deposits mostly arose from these swampy environments, typical of the period.
LiberalAndProud
(12,799 posts)Since the linked article in the OP specifically mentions lignin as the agent that was introduced to resist decay, I went on a little google tour to find that lignin acts as a barrier against insects and fungi. So there's that.
Buzz Clik
(38,437 posts)A toughened crosshatch of carbon-based molecules is all that stands between plants and their total destruction at the hands of an array of microbes and fungi. Called lignin, the compound enables redwoods to tower and woody herbs to resist rot. As a result, lignin is the second-most abundant biological compound on the planetand the bane of would-be biofuel-makers everywhere, blocking their best efforts to make fuels from the inedible parts of plants. It is also the reason for the vast deposits of coal laid down millions of years ago.
Now a new genomic analysis suggests why Earth significantly slowed its coal-making processes roughly 300 million years agomushrooms evolved the ability to break down lignin. "These white rot fungi are major decomposers of wood and the only organism that achieves substantial degradation of lignin," explains mycologist David Hibbett of Clark University in Massachusetts, who led the research published in Science on June 29.
By comparing 12 newly sequenced genomes of mushroom fungi with 19 existing genomes, the researchers determined that an ancestral white rot fungi (Agaricomycetes) first evolved the ability to break down lignin. The scientists then used so-called "molecular clock analysis"a dating technique based on the hypothesis that genes accumulate mutations at a relatively regular rate like trees form rings that record their growth. Such an analysis suggests that an ancestral white rot fungi developed this lignin-degrading ability roughly 290 million years ago, a conclusion backed by comparison with the appearance in the fossil record of three other types of fungi (although the first definitive white rot fossil does not appear until roughly 260 million years ago) and the subsequent expansion and refinement of the arsenal of enzymes employed. The 60-million-year-long Carboniferous periodwhen the bulk of the world's coal deposits were laid down and atmospheric CO2 levels declinedended roughly 300 million years ago.
The coincidental timing suggests the appearance of this ability to break down lignin helped slow the massive burial of organic carbon via nondegraded tree trunks and other wood, such as the lignin-rich fernlike plants known as arborescent lycophytes, now extinct. Previous explanations largely argued that such coal formation was a result of the Carboniferous's swampy conditionsafter lignin-rich plants fell into these swamps, they simply were buried rather than broken down by fungi or microbes and turned to peat and then coal over geologic time frame. "They're not mutually exclusive," Hibbett notes, although more of the easily overlooked fungal fossils would need to be found to determine the truth.
http://www.scientificamerican.com/article.cfm?id=mushroom-evolution-breaks-down-lignin-slows-coal-formation
Ok. So, it looks like your OP is basically correct, but it's a theory in the making. This is me taking a step back and reminding myself to read Scientific American more frequently.
Please accept my humble apologies.
LiberalAndProud
(12,799 posts)I am constantly needing the reminder to double check factoids found on the internet. BTW, this was not my OP, so your apology, though much appreciated, is misdirected.
Sentath
(2,243 posts)Wrong about evolution of the ability to digest lignin not being a factor.
http://www.scientificamerican.com/article.cfm?id=mushroom-evolution-breaks-down-lignin-slows-coal-formation
was the first good Google hit.
I'm a bit of a fungus fan.
Buzz Clik
(38,437 posts)My retraction and apology...
Sentath
(2,243 posts)Thank You
Buzz Clik
(38,437 posts)I was checking out the evolution of fungi and trees, but neglected to put "white rot" in my search stream until after I posted.
Are you a hobby mycologist or do it for a living?
Sentath
(2,243 posts)I found the article with 'fungi evolve cellulose' as my search terms.
Purely hobbyist (fan not pro), and I've moved somewhere relatively hostile to the fun ones and home of a threatening one. Arizona's famous valley fever http://en.wikipedia.org/wiki/Coccidioidomycosis.
mike_c
(36,281 posts)We're burning the irreplaceable legacy of the Carboniferous. Dukes has estimated that each year of fossil fuel combustion uses the energy stored by 400 years of global photosynthesis.
Do you think peat accumulations only happened 400 milion years ago?
geez -- Is there a science teacher in the house? Oh, wait...
mike_c
(36,281 posts)I'm a biologist, not a geologist, so if you have expertise that I lack I appreciate your informing me. My understanding is that modern peat accumulation is different in the sense that it happens only under conditions that slow or stop microbial and fungal decomposition, i.e. saturated anerobic conditions with high humic acid concentrations, etc, not to mention different in the sense that it is at much more limited geographic scale than were vegetation deposits during the Carboniferous. AND that's just some small scale peat accumulation-- not processing of raw peat into hydrocarbons. The latter requires prolonged geologic heating and compression, development of which would likely disrupt the conditions that shield peat from microbial decomposition.
But even if some proportion of modern peat deposits WERE geo-processed into hydrocarbons, the scale of such production would be miniscule compared to the scale of prehistoric fossil fuel production. That's my understanding, at least. Since I teach that to my ecology students, I'd very much appreciate your correcting me if that's wrong.