Dormancy contributes to the maintenance of microbial diversity

Abstract

Dormancy is a bet-hedging strategy used by a variety of organisms to overcome unfavorable environmental conditions. By entering a reversible state of low metabolic activity, dormant individuals become members of a seed bank, which can determine community dynamics in future generations. Although microbiologists have documented dormancy in both clinical and natural settings, the importance of seed banks for the diversity and functioning of microbial communities remains untested. Here, we develop a theoretical model demonstrating that microbial communities are structured by environmental cues that trigger dormancy. A molecular survey of lake ecosystems revealed that dormancy plays a more important role in shaping bacterial communities than eukaryotic microbial communities. The proportion of dormant bacteria was relatively low in productive ecosystems but accounted for up to 40% of taxon richness in nutrient-poor systems. Our simulations and empirical data suggest that regional environmental cues and dormancy synchronize the composition of active communities across the landscape while decoupling active microbes from the total community at local scales. Furthermore, we observed that rare bacterial taxa were disproportionately active relative to common bacterial taxa, suggesting that microbial rank-abundance curves are more dynamic than previously considered. We propose that repeated transitions to and from the seed bank may help maintain the high levels of microbial biodiversity that are observed in nearly all ecosystems.biodiversity | ecosystem function | microbial ecology | modeling | seed bank

Vertical Distribution of Functional Potential and Active Microbial Communities in Meromictic Lake Kivu

“…In contrast, rare OTUs were detected in a high proportion exclusively in either bulk or potentially active bacterial communities. As suggested for estuarine and coastal ocean waters, the metabolically active rare biosphere of Lake Kivu might be potentially important for the functioning and the temporal dynamics of microbial communities as they shift between seasons [13][14][15].…”

“…Even though potential biases can be introduced during DNA and RNA extraction, complementary DNA (cDNA) synthesis, and PCR amplification [12], parallel comparisons of DNA-and RNA-based pyrosequencing approaches can help differentiate whether abundant taxa are active or whether rare but active taxa exist. In addition, stronger evidence on the links between biogeochemical processes and microbial communities might be obtained if active communities are monitored rather than bulk communities [13][14][15][16].…”

Effect of long-term industrial waste effluent pollution on soil enzyme activities and bacterial community composition

“…Studies suggested that the indigenous bacteria are very sensitive to contaminants and respond rapidly to organic pollutants (Tian et al 2008). In short-term pollution-affected soils, bacterial diversity may be maintained through either natural resistance or dormancy (Jones and Lennon 2010). However, long-term chronic exposure to contamination will have deleterious and unrecoverable effects on the structure and function of the community as the dormancy may not be a useful survival option any longer.…”

Deciphering associations between dissolved organic molecules and bacterial communities in a pelagic marine system

“…Calculated rarefaction curves, as well as diversity indices (data not shown), revealed that our surveying effort discovered the majority of-yet not all-the bacterial species and phyla (480%) at 3% and 20% genetic distance. The active community yielded a higher number of OTUs than the total BC, resulting in a DNA/RNA ratio of OTU richness ranging from 0.76 to 0.88 and denoting that a significant portion of the rare taxa may be proportionally more active (Jones and Lennon, 2010;Campbell et al, 2011;Wilhelm et al, 2014). The percentage of OTUs that appeared in both, the RNA …”