School of Natural Sciences – Life & Environmental Sciences, University of California, Merced
A postdoctoral position in terrestrial biogeochemistry is available in the Berhe lab (www.aaberhe.com) to work on interactive effects of fire and erosion on persistence of soil organic matter. The aim of this postdoctoral project is to investigate decomposition and incorporation in microbial biomass of fire altered or pyrogenic organic matter in order to further our understanding of the mechanisms that control pyrogenic organic matter and bulk organic matter persistence in the soil system. The initial appointment will be for one year and is renewable, depending on performance and availability of funding.
Candidates must have completed a Ph.D. in soil science, biogoechemistry, ecology, or related fields by January 1, 2014. Preference will be given to candidates who have experience working with enriched isotopes of carbon and nitrogen in soil, secondary ion mass spectroscopy (NanoSIMS), or X-ray spectroscopy [Scanning Transmission X-ray Microscopy (STXM) coupled with Near Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS)]. The successful candidate must be driven, creative and has demonstrated experience with accomplishing established goals in a timely manner.
Initial review of applications will begin November 30, 2014. Recruitment will remain open until filled.
Interested applicants are required to submit 1) a cover letter 2) a curriculum vitae 3) a statement of research 4) a list of three references with contact information including mailing address, phone number, and e-mail address.
Extreme changes in seasonality in the Sierra Nevada can have lasting impacts on meadow health and could mean less water and carbon storage in high elevation wetlands, according to research conducted at UC Merced.
The results of our work indicate that changes in meadow soils and vegetation caused by extreme weather conditions in the mountains over the past three years have decreased the ability of those meadows to bank water and store carbon.
If you are a finishing grad student or postdoc interested in joining our research group, consider applying for the UC President’s Postdoctoral Fellowship. The deadline for applications is November 1, 2014.
Note that the President’s Postdoc fellowship is a very competitive fellowship that provides salary support for a postdoc for 2 years to work with UC faculty and it also provides some research funds. But, perhaps even more important, these fellowships are highly prized because the fellows are included in the President’s hiring incentive that was setup to allow schools to hire fellows in to tenure track faculty positions at any one of the UC campuses.
A feature article on Chelsea Arnold’s dissertation research on the coupled hydrological and biogeochemical implications of the ongoing drought in the Sierra Nevada Mountains of California was published by the University of California Office of the President.
The article authored by Susan Suleiman states that “Carpeting the high valleys of Yosemite and other parts of the Sierra Nevada, mountain meadows are more than an iconic part of the California landscape. The roughly 17,000 high altitude meadows help regulate the release of Sierra snow melt into rivers and streams.
But climate change and California’s severe drought threaten to permanently alter these fragile and important ecosystems, according to research by Chelsea Arnold, who was awarded a doctorate in environmental systems from UC Merced in May. Her findings reveal that soil changes already are taking place that could have long-term implications for California’s water supply.”
On Tuesday June 24, 2014, Congressman McNerney (D-CA) gave a floor speech on the research conducted in the Berhe Biogeochemistry lab at UC Merced.
The speech that the congressman gave included: “In the midst of California’s worst drought on record, researchers at UC Merced are studying the effects that drought, fire and global climate change are having on soil and water resources. One such researcher, Dr. Berhe is supported by the National Science Foundation to investigate the implications of fire, erosion, and climate change on soil processes. Catastrophic events, such as California’s Rim Fire which burned over 250,000 acres in the Sierra Nevada last year, can alter the soil carbon storage potential and water holding capacity. Additionally, changes in climate and drought also lower the water holding capacity of meadow soils and lead to high rates of surface runoff. These changes affect the ability of the soil to help regulate the climate and store water in the Sierra Nevada, California’s largest source of water storage. Research like Dr. Berhe’s is critical for addressing challenges to the soil’s ability to sequester atmospheric carbon dioxide, water security and the health of the ecosystem.”
Previously, Asmeret also met and discussed research in our lab with Congressman Costa (D-CA); Congressman McNearney (D-CA); congressional staff from the offices of Congressmen Garamendi, McClintock, Denham, and Valadao; and staffers from Senator Feinstein and Senator Boxer’s offices in Washington DC, on May 7, 2014.
Asmeret receives NSF’s most prestigious award for early career scientists for work dealing with “CAREER:Persistence of soil organic matter in dynamic landscapes: interactive effects of fire and erosion”
Fire, erosion, and soil carbon (C) storage and persistence overlap in space and time. However, we currently lack complete understanding on how and why the interaction of fire and erosional distribution of soil materials control persistence of bulk soil organic matter (SOM) and pyrogenic C (PyC, also referred to as black carbon) in dynamic landscapes. This work will use molecular- and nano-scale techniques to determine how SOM persistence varies along multiple spatial (plot, hillslope, and watersheds) and temporal scales (seasonal, annual, and decadal). The outcome of this project will be better integration of biogeochemical and geomorphological approaches to derive improved representation of mechanisms that regulate SOM persistence in dynamic landscapes that routinely experience more than one perturbation.
This CAREER project will develop improved understanding on the dynamics of bulk SOM and PyC in fire-adapted upland ecosystems and enable teaching of graduate and undergraduate students, and K-12 teachers. The findings from this project will transform the way we (a) account for changes in C storage in fire-prone systems, and (b) model response of fire-prone upland ecosystems to changes in climate and/or management practices. Moreover, in this project, I will: (1) teach undergraduate students and high school teachers about the critical zone, and develop and publish lesson plans for high-school level earth system science; (2) provide scientific training for a graduate student and a postdoc; and (3) learn advanced techniques that I will apply in my research and teaching.
Two Research Experience for Undergraduates positions are available for work that focuses on water resources and soil nutrients in the Southern Sierra Critical Zone observatory. Please visit http://criticalzone.org/sierra/news/story/reu-2014/ for more information, and don’t hesitate to contact Asmeret if you have any questions. The deadline for submission is 11:59 pm PDT, May 13, 2014.
Chelsea Arnold successfully defended her dissertation on friday May 2, 2014. The title of Chelsea’s dissertation is ” Coupled hydrological and biogeochemical dynamics in high elevation meadows: thresholds, resiliency and change.”
Abstract: High elevation meadow ecosystems play a fundamental role in the storage and movement of water from the snowpack to the streams. Due to the coupled nature of the hydrological and biogeochemical cycles in the meadows, it is expected that a change in hydrology will impact biogeochemistry and vice versa. My dissertation research investigated the gaps in our knowledge of the coupled hydrology and carbon cycling of meadow soils, and forges new territory in our understanding of the impacts of lowered water tables and desiccation on the hydrologic resiliency of those soils. This knowledge is critical in snowmelt-dominated watersheds, where meadows (both high elevation and montane) serve as natural storage reservoirs that feed both streams and groundwater. Using the last three extreme precipitation years in the Sierra Nevada Mountains, I specifically focused on three main themes of resiliency, thresholds and change in high elevation meadow ecosystems, I found that a) nonlinear responses in ecosystem processes can cause ecosystems to shift from a sink to a source of carbon contributing to local (degradation of ecosystem), regional (loss of ecosystem services) and global effects (feedback to atmosphere), b) winter drought and spring frost events can significantly damage vegetation, reducing the productivity of vegetation, which leads to a decrease in carbon sequestration, c) thresholds in moisture availability can influence the magnitude of carbon loss via soil respiration, d) Longer growing season with little summer precipitation contributed to severe desiccation of meadow soils which caused an irreversible change in the structure of the soil and subsequent loss of porosity and permeability.
Congratulation to the super-mom/teacher/scientist and pastry chef extraordinaire!
Chelsea was one of the two University of California graduate students that were chosen to accompany University of California President Janet Napolitano and Nobel Prize winner Prof. Randy Schekman to meet with California governor Jerry Brown in his office.
This is a great honor and recognition for Chelsea and UC Merced. Congratulations Chelsea and great job being an ambassador for graduate education in the UC system.
Chelsea’s dissertation research was also highlighted as one of the important topics of discussion with lawmakers in the state capitol.