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Seeking UBRP Students for Summer 2024 (and beyond?)
The Meredith Research Group is currently seeking an undergraduate student(s) from the 2024 UofA Undergraduate Biology Research Program. We will use a mass spectrometer and soil incubations to measure how abiotic and biotic soil factors changes with the addition of specific VOC with time. We expect to identify VOC-consuming microbes and try to elucidate how VOC stabilizes carbon in soils. Some of the questions that we will ask will be: i) How microbial communities changes in diversity and abundance with specific VOC addition? ii) Identify VOC- consuming microbes to identify consumption and production of VOCs. Over Summer 2024 (and potentially into Fall) the student will help with volatilome, metagenome, transcriptome,…
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Microbial drivers of N2O emissions in the Biosphere 2 Tropical Rainforest
Post by Juliana Young The Rainforest at Biosphere 2 is a unique study system because it operates under very high temperatures and has adapted to the Arizona heat. In 2002, Dr. Joost van Haren studied nitrous oxide (N2O) flux in the Rainforest at Biosphere 2 and found that there is a high and low pulse zone of emissions of this gas under the condition of post-drought (van Haren et al., 2005). Our study builds from the foundations of this experiment. We are testing what could be responsible for the spatial difference in N2O gas fluxes. While there are many facets of the Rainforest to study, my interests and area of…
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Soil art!
I’ve had the pleasure of working with two fantastic UA art students (Luke Williams and Melissa Yepiz) through an Infographics class with Prof. Karen Zimmerman. Stay tuned for our infographic on carbon cycle tracers! As a side project, I’ve given the students some of each of the 20 soil samples from my recent study to constrain soil fluxes of carbon cycle tracers (COS and 18O-CO2, see story). I asked them to make a creative piece with the soils, highlighting differences in color, texture, etc… Luke’s piece nicely contrasts soil color using red Colorado river, gray Moab soils, and black Hawaiian soils within a geometric framework burned into wood. I’ll look forward to…
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Soil survey: microbial, chemical and physical drivers of carbon cycle tracers
Two trace gases (carbonyl sulfide and the oxygen isotopes of CO2) show promise to help disentangle carbon cycle processes, but their soil fluxes need additional characterization. As in leaves, we anticipate that carbonic anhydrase (CA) enzymes in soil microbes drive uptake of atmospheric COS by soils (COS + H2O -> CO2 + H2S) and exchange of the oxygen isotopic signature between atmospheric CO2 and water (CO2 + H2O <-> HCO3– + H+). We performed a soil survey to test whether soil microbial CA drive the soil fluxes of these two potential carbon cycle tracers. By measuring the microbial, chemical, and physical properties of a diverse set of soils, we set out to determine…
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Soil systems – the challenges of complexity and scale
Soils are complex systems, in which physical, geochemical and biological processes interact in aggregate structures situated in dynamically shifting air- and water-filled spaces. It is difficult to adequately sample soil properties and to model processes related to those soil measurements. These challenges were discussed in a stimulating three-day conference on Complex Soils Systems in Berkeley a few weeks ago. Attendees came from an incredible diversity of backgrounds with a common interest in tackling issues in soil science. The need to better understand soils was motivated by the importance of soil processes in climate and for figuring out “How to feed the soil and the planet?” in the anthropocene – a question posed…
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Manuscript evaluating a suite of flux-gradient methods for determining ecosystem H2 fluxes
A manuscript I’ve been working on entitled “Ecosystem fluxes of hydrogen: a comparison of flux-gradient methods,” was now been published in Atmospheric Measurement Techniques (view paper online). Our goal was to present a detailed experimental approach for measuring ecosystem fluxes of H2 and to test different so-called “flux-gradient methods” for calculating the H2 fluxes. Some common trace gas flux methods, e.g. eddy covariance, are not available for species like H2 that cannot be measured precisely at high frequencies (<1 Hz). We hope this paper will help inform the design of future studies for which flux-gradient methods might be the best option for measuring trace gas fluxes. Here are a couple…
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Undergraduate Researcher Shersingh’s SURGE Experience
Congratulations to visiting undergraduate researcher Shersingh Joseph Tumber-Davila on completing and thriving in the demanding eight-week Summer Undergraduate Research in Geoscience and Engineering (SURGE) program! Shersingh came to the Welander lab with a strong background in environmental research (news article) from his home institution of the University of New Hampshire. SURGE is a competitive earth science research and graduate school preparation program, which is specifically designed to recruit students of diverse backgrounds from other universities across the country. I was amazed at the number of activities the program had for the students including GRE test preparation, faculty seminars, career and grad school panels, and field trips. This was all while performing graduate-level research including…
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Manuscript linking consumption of atmospheric H2 to the life cycle of soil-dwelling actinobacteria
Microbe-mediated soil uptake is the largest and most uncertain variable in the budget of atmospheric hydrogen (H2). In Meredith et al. (2014) in Environmental Microbiology Reports, we probe the advantage of atmospheric H2 consumption to microbes and relationship between environmental conditions, physiology of soil microbes, and H2. First, we were interested in whether environmental isolates and culture collection strains with the genetic potential for atmospheric H2 uptake (a specific NiFe-hydrogenase gene) actually exhibit atmospheric H2 uptake. To expand the library of atmospheric H2-oxidizing bacteria, we quantify H2 uptake rates by novel Streptomyces soil isolates that contain the hhyL and by three previously isolated and sequenced strains of actinobacteria whose hhyL sequences span the known hhyL diversity. Second, we…
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I survived the AGU 2011 Fall meeting
I just returned to Boston after the six weeks of travelling. My two weeks in California, filled with conferences and colleagues, was quite different from the intensive and somewhat isolated period spent in India. First stop was San Diego, where I attended the 44th Meeting of Advanced Global Atmospheric Gases Experiment (AGAGE) Scientists and Cooperating Networks at the Scripps Institute of Oceanography in La Jolla. Anita Ganesan’s instrument in Darjeeling may pave the way for the first AGAGE site in India, so the crowd was eager to hear her describe our success in deploying her instrument. Her dedicated and diligent work is paying off as she is collecting some of…