Photoheterotrophy
What two energy sources do aerobic anoxygenic phototrophic (AAP) bacteria use?
Organic matter and light
How old can dissolved organic matter (DOM) in the deep ocean be?
Up to approximately 12,000 years old
What is functional redundancy in a microbial community?
Different microbial taxa can perform the same function, so the function may persist even if some taxa disappear
Why do AAP bacteria not produce oxygen and still depend on organic carbon?
They use light to supplement heterotrophic energy. They do not use the oxygen-producing photosynthesis pathway and lack Rubisco, so they still need organic carbon
What is the main immediate microbial source of soil organic matter (SOM)?
Heterotrophic microbial biomass and residues, including cell wall and membrane fragments, rather than plant litter directly
Why did rare microbial taxa respond to the Deepwater Horizon oil spill in 2010?
Some rare taxa could respond to the sudden abundance of hydrocarbons, while dominant taxa adapted to low hydrocarbon concentrations could not cope as effectively
What is the role of proteorhodopsin in aquatic bacteria, and how can it help during starvation?
Proteorhodopsin captures light energy. It may extend survival under starvation, although it rarely increases growth rates.
Why can some organic carbon persist for thousands of years even though microbes can degrade many complex compounds?
A small fraction escapes degradation and accumulates. Protection by minerals, aggregation, and other environmental mechanisms can limit microbial access
How can microbial diversity act as ecological insurance during environmental change?
Different taxa may have overlapping functions but respond differently to environmental conditions. If some taxa fail, others can maintain degradation, especially under certain environmental stresses.