While working on my bachelor's at UC Berkeley, I  was a member of the Bishop Lab under Prof. James Bishop. In that role, I worked as a research assistant on 5 research cruises in the Pacific examining the flux of PIC and POC in the water column. More terrestrially, I spent a summer working with Prof. Bishop to quantify subsurface dissolved gas concentrations to infer possible microbial activity in a critical watershed in northern California. For more details, read on!

The marine research was aimed at understanding the role of detritus in oceanic carbon cycling, with an emphasis on diurnal variations. On 5 research expeditions in the Pacific, I operated CTD rosette systems, filtered seawater samples to sample for PIC/POC, and deployed automated PIC/POC collection instruments.

The dissolved gases work was primarily in support of the NSF-CZO project, which aims to understand the "critical zone" of the subsurface. In that role, I designed and implemented a novel method for sampling subsurface dissolved gases in a riparian zone, analyzed samples on RGA and FID GC’s, reduced data and performed statistical analysis, presented results to faculty and post-doctoral fellows.


From 2011 to 2014 I was fortunate to work under the guidance of Dr. Tori Hoehler at NASA Ames, exploring subsurface microorganisms through a "follow the energy" approach. As a fun tidbit, it was this initial exposure to thinking of microbiology through energetics that lead to my current dissertation work! Read on for a bunch more information!                                                                                                              

May 2011 – July 2011

Helped establish a subsurface microbial observatory in a serpentinizing system in California by quantifying natural abundance of subsurface dissolved gases and establishing the role those gases play in the metabolisms of in situ microbial life. The latter was done through a microcosm experiment, and gases concentrations for both were measured with RGA and FID GC’s.

June 2012 – August 2012

The wells sampled in 2011, with an additional eight wells, were resampled for dissolved gases and well water. Two parallel microcosm experiments were performed, to determine if oxygen is required for any observed metabolisms. The dissolved gases and those used in the microcosms were measured with RGA and FID GC’s.

The work done in California was expanded to include additional extremophiles in the hot springs at Yellowstone, via collaboration with professors from Montana State and the University of Montana. Hot springs in Yellowstone were sampled for dissolved gases and microbial biomass, and microbial consumption rates of H2 and CO2 were tested. Other duties included operation, maintenance, and repair an RGA GC, and reduction and analysis of data.

Additional RGA and FID GC work included analysis of gases samples from serpentinizing systems in Iceland.Intern in Biogeochemistry                                     

July 2014 – December 2014

Capped work from 2011 and 2012 by expanding that research into an honors thesis, collaborating with an advising professor at UC Berkeley. Subsurface gases and well water were sampled from the same system as in 2011 and 2012 and two additional microcosm experiments were performed, again using a reducing gas analyzer (RGA) and a flame ionization detector (FID) gas chromatograph (GC) to track changes in gas concentrations.

To corroborate the data from 2011, each microcosm included artificially anaerobic and aerobic samples.

Samples were also prepared for organic acid, ion concentration, and DNA analyses.        

©2020 Addien Wray