Category Archives: Mentoring

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 a oral and poster presentation at the end of the program. Shersingh approached all these demands with amazing energy and attitude, which we’d really like acknowledge!

SURGE student Shersingh

SURGE student Shersingh

In Shersingh’s research, he asked whether microbe-mediated hydrogen (H2) uptake support C mineralization in soils. Soils are a strong sink for atmospheric H2, which is presumably used by soil microorganisms to fuel their energy metabolism. In addition, emissions of H2 have grown since the industrial revolution, so the availability of H2 energy to soil microbes likely also increased. Shersingh tested the influence of excess H2 on the ability of soil microbes to mineralize soil carbon for a variety of carbon substrates, especially those that can be energy intensive (e.g., lignin and lignocellulose). He used Streptomyces ghanaensis as a model organism containing high affinity hydrogenase (H2 uptake) and laccase (lignin breakdown) genes. By measuring carbon dioxide respiration rates and intermediate products involved in the breakdown of lignin and lignocellulose, we found evidence for increased breakdown of lignocellulose (straw) with elevated levels of H2. This may point to a  link between the H2 and C biogeochemical cycles in soils that will be interesting to pursue further. This project is in collaboration with Stanford postdoc Marco Keiluweit who specializes in soil carbon cycling.

BioDesign course – bridging science and art

Biologist/architect team Tobi Lyn Schmidt and Mike Bogan created a course linking artists, designers, architects, and biologist from the California College of the Arts (CCA) and Stanford University. I served as a postdoc mentor to help inspire and guide the process of cross-hybridizing biology and design (some examples) with three really talented undergraduate CCA students: Leslie Greene, Sakurako Gibo, and David Lee.

The students were first charged with creating designs to illustrate scientific concepts in my field of research. I challenged them think about the issue of scale with respect to the biogeochemical cycles I study. The processes I investigate occur over a wide range of spatial and temporal scales, which is a challenge for their measurement and interpretation. David focused on a selection of atmospheric trace gases with a wide range of abundances, and that interact with each other through key reactions. In his image, the hydroxyl radical (OH) is illustrated by the white dot from which orange and blue strings respectively represent the path length to molecules of  hydrogen (H2) and methane (CH4) in the surrounding space. The density of the strings is representative of the concentration of H2 and CH4 relative to OH. I love the sense of competition in this image. These reduced molecules compete for reaction with OH, and with other trace gases not shown, which helps explain the relatively their long lifetimes of H2 (~2 years) and CH4 (~10 years) in the atmosphere.

Concentration Burst, by David Lee

Concentration Burst, by David Lee

The second task for the students was to manipulate a biological system for design or artistic ends. All three students visited the Welander geobiology lab at Stanford and the Berry lab at Carnegie on campus where atmospheric trace gases are measured. For her project, Leslie was interested in manipulating microorganisms to reveal art. Using a combination of strains from the lab and purchased online, Leslie created competitive interactions between organisms and against antibiotics to reveal structures that were both patterned and complex. In the example below, she laid a cross-pattern of Streptomyces ghanaensis and Bacillus subtilis colonies and let them grow and compete. Intriguing features arose, appearing as if the Streptomyces strain grew on top of the Bacillus strain, perhaps antagonistically or not. Leslie overlaid emergent patterns in topology and color from microbial cultures with and without competition to create an amazing image that reveals some very aesthetic order in the systems.

Bio-manipulation of Streptomyces ghanaensis and Bacillus subtilis

Bio-manipulation of Streptomyces ghanaensis and Bacillus subtilis

Emergent patterns from competition

Emergent patterns with and without competition


Finally, the students illustrated various concepts related to my work including artistic renditions of Streptomyces colonies and concepts of complexity (see related post). I really love the feel of the image created by Sakurako Gibo showing the atmospheric H2 concentrations that I measured between the ground and top of a measurement tower (y-axis) over the year-long experiment (x-axis) at Harvard Forest as an ephemeral curtain. Higher concentrations of H2 are represented with a deeper intensity of blue. The impact of the soil sink is illustrated by the lightening of the color near the base of the image caused by high rates of soil microbial H2 consumption in summer and fall.

Curtain of H2 Harvard Forest

Curtain of H2 at Harvard Forest, by Sakurako Gibo


Deepa blogs about AGU 2012

Connecting H2 consumption to life cycles of soil microbes

Deepa’s AGU Poster “Connecting H2 consumption to life cycles of soil microbes”

Read Deepa Rao’s Blog Post

It’s a wonderful piece (highlighted on the EAPS department website) about her first the AGU experience written through her uniquely balanced scientific and artistic perspective. For example, she writes, “Science, nature, life, emergence, and the universe have always inspired my art. And it is the unnecessary beauty of science that makes it deeply mysterious and so inviting to my mind… AGU was an incredible week of reconnecting with friends, advisors, professors, fellow researchers. It was also unexpectedly a way for me to connect a path to a foreseeable future where my two passions can be combined, perhaps even muddled, into an exciting career.”

ISME 14 – The power of the small

Last week I attended ISME 14 (International Symposium on Microbial Ecology) in Copenhagen, Denmark. It was a delight to see the city – its juxtaposed giant modern, cool, sterile buildings surrounding the historic old city. More of a delight was unexpectedly running into friends from the MBL Microbial Diversity summer school (2010) and realizing they are now my colleagues.

Presenting a poster that Deepa Rao and I co-authored on the “Physiology of the microbe-mediated soil sink for atmospheric H2” at ISME in Copenhagen, Denmark.

The conference itself was quite good. I appreciated the range of content from very big picture and abstract to focused experimental projects. One message I took away from the community was a sort of -omics backlash, or perhaps whiplash, to the idea that generating more and more -omics data is the sole future for microbial ecology. It seems that presenters coming from both the -omics and experimental side were acknowledging the importance of both tools, and especially of using them together. Those seem to be a lot of tools for any one scientist to master, so I am encouraged that the tone was of collaborative holistic approaches for tackling scientific questions.

Wind turbines and modern architecture outside of Copenhagen

I really enjoyed a somewhat unique session. It was a discussion entitled “Frontiers in microbial ecosystem science: Energizing the research agenda” sponsored at this and other conferences by the US National Science Foundation. All sorts of issues were raised in a discussion of “what needs to be done” – what are the important topics and how should we advance microbial ecology. I was struck by how strong the arguments were that microbial ecology is important for understanding, and possibly mitigating, climate change. This is my main interest, but I often find the microbial ecology literature and research interests so focused on minute points (I think my own project included), that it is difficult to see the link between the microbial and global scales. At this session I learned that it is not only because it is difficult to do, but also because the funding agencies seem to push scientists to write grants in one or the other. It is difficult to be interdisciplinary (falling under more than one NSF department). It has been a (fun) challenge for me to try to get a foot in both atmospheric and microbial ecology science, and it was encouraging to hear from the community that the intersection of the two is valued.

Tuborg beer and the Royal Copenhagen porcelain company

Deepa receives Goetze Prize for Undergraduate Research

At the 2012 EAPS Student Awards Ceremony Deepa Rao received the Christopher Goetze Prize for Undergraduate Research for her thesis entitled : “Exploring the Microbe-mediated Soil H2 sink: A lab-based study of the physiology and related H2 consumption of isolates from the Harvard Forest LTER.” The award recognizes “ innovative experimental design, care in data collection, and sensitive application of results to research problems.”

Click here for a description of her Senior Thesis Presentation 

It has been a pleasure to supervise Deepa’s thesis research and her results will contribute to our research efforts to understand the mechanisms driving the soil sink for atmospheric H2. Professor Ron Prinn acts as the faculty advisor for both Deepa and I.

Deepa Rao accepting the award from her academic advisor Sam Bowring