Importance of rare and abundant populations for the structure and functional potential of freshwater bacterial communities

Dilution-to-extinction cultures of freshwater bacterial communities were incubated in unamended, phenol-enriched and humic substance-enriched lake water, to study the importance of rare and abundant bacteria for community performance. Biomass yield was not strongly affected by dilution, but exploitation of humic substances and resistance to phenol were restricted to less abundant populations, demonstrating that the performance of microbial communities may depend on rare as well as on abundant species.