Final answer:
Bacteria living in salt marshes are most likely halophiles, which are organisms that thrive in extremely salty environments.
Step-by-step explanation:
The bacteria living in salt marshes are most likely halophiles, which are organisms that thrive in extremely salty environments. These bacteria can tolerate high salt concentrations and can survive in environments like the Dead Sea or certain salty lakes in Antarctica and south-central Asia.
Halophiles require a very high concentration of sodium chloride (salt) in their aquatic environment, close to saturation at 36%. They have adapted to these extreme conditions and can perform photosynthesis using the protein bacteriorhodopsin.
For example, the archaeon Halobacterium salinarum is a halophile that lives in the Dead Sea, thriving in a high-salinity environment.