Is it possible to have life that feeds on thermal energy

Question

On earth, as far a we know, there are two main ways that bacteria gain energy.

First, there is Photosynthesis, the transition of light into chemical based energies such as ATP.

Second, there are chemical processes in which the cell breaks down a variety of molecules down to gain energy from the reactions. A example of this is Chemosynthesis.

Is it possible for their to be a bacteria or type of organism that gains energy from thermal energy?

For example, there could be a bacteria that lives in a volcanic area, somewhere hot enough that there is a excess of thermal energy. Would there be a way for such a cell to use this thermal energy in much the same way that some cells use Sunlight in Photosynthesis?

Answer 1

It is theoretically possible but no known organisms does it. The problem is you need a pretty strong and persistent temprature gradient to generate usable work out of it, and those are not that common in nature.

Answer 2

Heat is probably the most inconvenient pain-in-the-behind energy source to use (as bacteria). Main reason is that you have to harvest it as it moves across a membrane/gate, and then the cell or whatever has to be built to handle the temperature on the other side.

Even worse: as the bacteria harvest heat, they will end up the same internal temperature as their food source, requiring them to move somewhere and cool off (infeasible for bacteria).

A somewhat viable theoretical example: highly mobile partially amphibious reptile that lives in a beach-type environment in tropical climates. It would harvest heat while basking on the sand and jump in the water to cool off. Energy harvesting occurs as heat moves across the lizard's hide outside to inside. The harvesting is 1-way: cooling off doesn't cost energy.