2012 Annual Science Report
Arizona State University Reporting | SEP 2011 – AUG 2012
Stoichiometry of Life - Task 2c - Field Studies - Other
We continued analyses of organic matter in samples of porewaters from a deep ocean hydrothermal mound; concluded a study on element acquisition by biological soil crusts, and initiated a new study that may shed light on a recent hypothesis that floating pumice may have been a site for the origin of life. In this new study, the eruption of the Puyehue / Cordon Caulle volcano on 4 June 2011 near Bariloche, Argentina, provided a unique opportunity to investigate floating pumice as a unique habitat for microbial life. To assess this, we sampled floating pumice from various regional lakes to assess the make-up of the associated microbial communities using genomic techniques and to evaluate the use of key elements (nitrogen, phosphorus) by these microbes using chemical and isotopic methods.
Biological Soil Crusts: Metal Use and Acquisition. Katherine Alexander Noonan successfully defended her PhD thesis entitled Element use and acquisition strategies in biological soil crusts in May 2012.
Marine Hydrothermal Systems: Deep Hot Biosphere We have completed organic matter characterization by 2D fluorescence analysis of sediment porewaters from drill cores collected at an active hydrothermal mound. Organic carbon concentrations in these pore waters are generally very low and relatively similar with depth in the cores. Down-core temperature data suggest these sediments are presently too hot to host microbial life; however, uniform distributions of organic carbon and similar carbon compositions suggest these sediments they may have been cooler (and inhabited) at some time in the past. Results of this work will be presented at the IODP Leg 331 post-cruise meeting in fall 2012 and a manuscript is preparation for Deep-Sea Research.
Life on floating pumice: Director’s Discretionary Fund project. During 2012 we obtained supplementary funding from the NAI DDF to take advantage of the opportunity for astrobiological research presented by the massive eruption of the Puyehue / Cordon Caulle volcano near Bariloche, Argentina (Elser’s sabbatical leave location). During January / February 2012, Elser along with student J Corman, postdoc Z Lee, and NAI collaborator J Siefert collaborated with Argentinian colleagues E Balseiro and B Modenutti to sample floating pumice, perform nutrient uptake studies, and extract DNA for 16S sequencing. Pictures from the field and preliminary data are shown in Figure DDF. The DNA samples are being processed by ASU student M Kellom and will be run at University of Illinois sequencing center. Elser presented preliminary findings from this work at the 2012 ABSCICON in Atlanta and also at the 2012 ASLO meeting in Japan. This work was highlighted in an article in Astrobiology Magazine (“Microbes Go Rafting on Floating Volcanic Rocks”; http://tinyurl.com/9xyaj4a).
PROJECT MEMBERS:James Elser
RELATED OBJECTIVES:Objective 4.1
Earth's early biosphere.
Co-evolution of microbial communities
Biochemical adaptation to extreme environments
Effects of environmental changes on microbial ecosystems