where do the organisms that live in hot compost piles live without us (or compost pile birds)

In the process of composting, microorganisms break down organic matter and produce carbon dioxide, water, heat, and humus, the relatively stable organic end product. Under optimal conditions, composting proceeds through three phases: 1) the mesophilic, or moderate-temperature phase, which lasts for a couple of days, 2) the thermophilic, or high-temperature phase, which can last from a few days to several months, and finally, 3) a several-month cooling and maturation phase.


Different communities of microorganisms predominate during the various composting phases. Initial decomposition is carried out by mesophilic microorganisms, which rapidly break down the soluble, readily degradable compounds. The heat they produce causes the compost temperature to rapidly rise.

As the temperature rises above about 40°C, the mesophilic microorganisms become less competitive and are replaced by others that are thermophilic, or heat-loving. At temperatures of 55°C and above, many microorganisms that are human or plant pathogens are destroyed. Because temperatures over about 65°C kill many forms of microbes and limit the rate of decomposition, compost managers use aeration and mixing to keep the temperature below this point.

During the thermophilic phase, high temperatures accelerate the breakdown of proteins, fats, and complex carboydrates like cellulose and hemicellulose, the major structural molecules in plants. As the supply of these high-energy compounds becomes exhausted, the compost temperature gradually decreases and mesophilic microorganisms once again take over for the final phase of "curing" or maturation of the remaining organic matter.

From Cornell.

So, where do these thermophilic species live? Do they simply occur at low levels at room temperature? What function do they play when they are not inhabiting compost piles? Some birds do build compost piles, but they are rare. In the wild, organic wastes are rarely heaped into a large, dense, balanced pile that would allow high temperatures.

I don't have a learned answer, but my best educated guess is that the microbes are in suspended mode, such as spores. I started my initial compost piles by seeding them with soil taken from areas where the vegetation was growing robustly in rich looking soil. Since then, I charge each new pile with some of the composted material from previous piles. It seems obvious that the microbes have sporated in the cooled off previous piles.

Nature's compost piles (some are hot and some are not) that I can quickly think of...,
...malleefowl's nest. (Bird)
...alligator's nest
...vegetative build up in the bends of creeks and rivers, especially during floods
...landslide debris pile
...brush/leaf piles often found in the woods, especially in depressions

Anybody think of other examples?

I'm with you on this Su as we live in a soup of spores of all sorts of stuff all around us all the time scary

David

Gilbert Fritz wrote:

Different communities of microorganisms predominate during the various composting phases. Initial decomposition is carried out by mesophilic microorganisms, which rapidly break down the soluble, readily degradable compounds. The heat they produce causes the compost temperature to rapidly rise.

From Cornell.

So, where do these thermophilic species live? Do they simply occur at low levels at room temperature? What function do they play when they are not inhabiting compost piles? Some birds do build compost piles, but they are rare. In the wild, organic wastes are rarely heaped into a large, dense, balanced pile that would allow high temperatures.

Would these microorganisms be similar to natural occurring yeast?  Or yeast captured from air?  (I am not sure what is the correct phrase)

Anne
In short yes we are surrounded by spores in numbers uncountable

David

Su Ba wrote:
Nature's compost piles (some are hot and some are not) that I can quickly think of...,
...malleefowl's nest. (Bird)
...alligator's nest
...vegetative build up in the bends of creeks and rivers, especially during floods
...landslide debris pile
...brush/leaf piles often found in the woods, especially in depressions

Anybody think of other examples?

Wikipedia, on the Thermophile page, mentions peat bogs. https://en.wikipedia.org/wiki/Thermophile

I found this where the abstract says they live in soil.  http://www.sciencedirect.com/science/article/pii/0141022979900437

Finally, this page gives temperature ranges for thermophilic and mesophilic bacteria, so it seems they can survive at lower temperatures in active state, but at high temperatures become the "last man standing" as the only species able to take the heat. Probably spores will survive the temperatures below (or above, for other bacteria) the temperature range. http://archive.bio.ed.ac.uk/jdeacon/microbes/thermo.htm

The survival of spores makes sense. Is there any such thing as a "native" bacteria? It seems floating spores will have introduced all organisms to any environment they can thrive in.

However, the various suggestions for native habitats for the thermophile organisms in a hot compost pile, both here and elsewhere online, don't seem to stack up well to me, for one of two reasons.

The geothermal sites, hot springs, hot vents, volcanic vents, etc. seem to differ so radically from a compost pile in pH, salinity, pressure, moisture content, oxygen content, organic matter availability, mineral balance, etc. that it wouldn't seem organisms from these areas would have the requisite skills to break down organic matter efficiently enough to maintain such high temperatures. The high temperatures means that breakdown is proceeding "like a house on fire."

The natural organic matter accumulations mostly seem to be too low nitrogen and/or too small to heat up well. Animal droppings usually would have too little mass, and if they were accumulated over time, slowly, by free living animals they'd have volatilized most of the nitrogen, and wouldn't have enough air to harbor the organisms that thrive in a hot, aerated compost pile. Mesophilic organisms would probably like such areas, but not thermophiles.

Mallee fowl and alligator nests would be the best candidates, but I'd guess they'd cook the eggs at the higher end of compost pile temperatures.

Wikipedia aside, peat bogs seem particularly unlikely spots for this activity. They are high carbon, waterlogged, and slowly accumulating, very poor sites for hot composting. Also, if it did happen, I'd expect spontaneous peat fires to be common!

A few thermophilic prokaryotes can continue to grow during peak-heating and persist during the prolonged high-temperature plateau, when the termperature is maintained at between 40-60oC. At this stage, a second group of thermophilic fungi start to grow (c in Fig. E). These fungi include Chaetomium thermophile, Humicola insolens, Humicola (Thermomyces) lanuginosus (Figure G), Thermoascus aurantiacus (Figure H), a Paecilomyces-like fungus (Figure I) and Aspergillus fumigatus (Figure J). By their combined activities, these fungi bring about a major phase of decomposition of plant cell-wall materials such as cellulose and hemicelluloses, so that the dry weight of the compost can be halved during the relatively high temperature phase lasting 20 days or more after peak heating.
Eventually the temperature declines and mesophilic organisms then recolonise the compost and displace the thermophiles (d in Fig. E). However, some heat-tolerant species such as Aspergillus fumigatus can continue to grow. This fungus can grow at temperatures ranging from 12o to about 52-55o. Strictly speaking, it is not a thermophile because its temperature optimum is below 50o, but it is a very common and important member of the high-temperature compost community.

Very interesting about Aspergillus fumigatus.

Thanks everyone for all the links above!

Reading through them, it looks like most of the high temperature organisms are also able to grow at lower temperatures, which makes a lot of sense.

The ones that only thrive at high temperatures are still hard to understand, though.

And, one of the links pointed out that some of the high temperature bacteria are doing just what they would do in hot springs. They are not breaking down organic matter; instead, they are oxidizing sulfur or hydrogen, and getting their carbon from carbon dioxide.

"The survival of spores makes sense. Is there any such thing as a "native" bacteria?"
In the micro world there are lots of differing types of spore like things that have different triggers of activation and life span . It is even argued by some that life originated in the stars and arrived here on earth in the form of spores https://en.wikipedia.org/wiki/Panspermia

The variety of microorganisms that can be found in one square centimeter would astound most people. Since these organisms can travel via air currents, they can spread over an incredible distance in a very short time.
Most Thermophilic species can replicate at temperatures where they do not thrive, some of them do equally well in temperatures up to 60 C, others more or less mark time, waiting for the right conditions to bloom.

Native bacteria are normally thought of as those species usually found in a particular geographic area, year after year, with a historic past in that same area per the fossil record.

With the changing weather patterns, it is possible that some species will be found far outside their historically defined areas, time will tell if this is the case or if they can't compete with the bacteria already there.

The origins of life is a huge subject and it almost has as many theories of the beginnings of life as there are scientist studying it. One thing we do know is that life can be created with the right minerals, water and lightening. It has been done many times in the lab.

The bog theory is founded in the fact that heather bogs (peat) are one of the natural features that create a heating environment and thermophilic bacteria are found thriving in these bogs.  

Redhawk

Bryant:

Have labs created self replicating life forms? And if so, are they new species? I was under the impression that amino acids had been created, and that existing DNA can be modified and recombined and reinserted, but that actual life from basic minerals has not been done.

In any case, I take a rather more mystical view of the force behind living things; but that is probably a topic for the cider press!

Back on topic; I never realized that so many of the thermophiles were fungi, not bacteria; I'd always been under the impression that bacteria dominated the hot phase of the pile.

The classic Millar Uray experiment as far as I know "just" produces amino acids and other complex organics https://en.wikipedia.org/wiki/Miller%E2%80%93Urey_experiment
Not sure if this can be counted as life as such but its certainly a step in that direction . other experiments have produced cell like objects based on fats . But life ....... not so sure about that yet .

To date no one has let a reaction chamber run long enough to find out. Everyone stops at the complex amino acids phase since the experiment costs about 75 thousand in electricity use to get to that stage.

To me the most interesting things are when previous dates are pushed back to the time periods my people have always talked about such as the beginning of humans on turtle island and Australia.