congresos y reuniones científicas
Life on floating pumice
JAMES ELSER; JESSICA CORMAN; ZARRAZ LEE; JANET SIEFERT; MARCELA BASTIDAS NAVARRO; FLORENCIA CUASSOLO; CECILIA LASPOUMADERES; MARIA S. SOUZA; BEATRIZ MODENUTTI; ESTEBAN BALSEIRO
Conferencia; Astrobiology Science Conference; 2012
One 4 June 2011 a major eruption occurred in Puyehue-Cordón Caulle Volcanic Complex (Chile; Figure 1A), ejecting massive amounts of ash and pumice into the surrounding region, especially to the east and southeast in the vicinity of Bariloche, Argentina. Indeed, the pumice formed massive rafts in Lake Nahuel Huapi and other lakes that were visible from satellite in the weeks after the eruption (see Figure 1B). These floating pumice spherules provide unique, initially sterile, substrates that should be colonized by microbes over time. If we saw such an image from another world, would we recognize such islands as potential microbial habitats? Furthermore, it has recently been hypothesized that floating pumice may have provided a suitable substrate for the origin of life itself(Brasier et al. 2011) but what is life like on floating pumice? How do biota cope with environmental conditions and acquire the necessary nutrients for growth and proliferation? The events in Chile and Argentina have opened a window to allow us to answer these questions and to gain knowledge of these unique Earth habitats. We sampled pumice in these lakes from July 2011 until March 2012, preserving samples for determination of microbial community composition (via DNA barcoding approaches based on IonTorrent technology). Samples were taken in several of the lakes at approximately monthly intervals for comparison of successional changes and assessment of the similarity of the communities in different lakes. We also assessed the kinetics of nutrient (inorganic N and P) use via 15N-labeled NH4 and NO3 and 18O-labeled PO4 andprepared isotopically labeled samples for visualization of nutrient utilization using Nano-SIMS. Finally, we tested the effects of nutrient (P) amendment on microbial community succession.This talk will involve a guided tour through the pumice-impacted zone and present preliminary data from these ongoing field studies.