Scientists studying the Lost City hydrothermal vent field have found what appears to be microbes just waiting to thrive; that is, when their perfect ecosystem arrives. At the Lost City, microbes known to be rare in hotter, more active vents flourish in the cooler, moderated ecosystem of the older vent. And when those microbes’ ideal environment changes, another set of rare, pre-adapted microbes are ready to spring up, says William Brazelton from the University of Washington who co-authored a study published this week in the Proceedings of the National Academy of Sciences.
As Brazelton explains in his paper:
The rare biosphere of the Lost City microbial community represents a large repository of genetic memory created during a long history of past environmental changes. The rare organisms were able to rapidly exploit the new niches as they arose because they had been previously selected for the same conditions in the past.
He suggests this cycle of near-disappearance followed by dominance has probably been repeating for more than 30,000 years.
Discovered in 2000 during a National Science Foundation expedition, the Lost City vents 200 degrees F cooler than the metal sulfide-rich, black smoker vents scientists have been studying since the 1970s—those vents reach higher than 700 degrees F. The chimneys and vents at the Lost City are nearly pure carbonate, and the surrounding waters are highly alkaline and enriched with methane and hydrogen gases.
Comparing this ecosystem and its microbes with the species at vents 1,000 years younger, scientists were able to analyze which species would thrive in a certain ecosystem and when their turn in the spotlight would be up. The scientists say this is the first evidence of microbes this close to disappearance remaining in an ecosystem before becoming dominant again.
Brazelton, W., Ludwig, K., Sogin, M., Andreishcheva, E., Kelley, D., Shen, C., Edwards, R., & Baross, J. (2010). Archaea and bacteria with surprising microdiversity show shifts in dominance over 1,000-year time scales in hydrothermal chimneys Proceedings of the National Academy of Sciences DOI: 10.1073/pnas.0905369107