Home Publications CV

This is an overview of selected recent and ongoing research projects to which I have contributed.

Microbial community characterization in the Clarion-Clipperton Zone (CCZ)

The DeepCCZ cruise to the Clarion-Clipperton Zone aimed to sample the biodiversity present in
Areas of Particular Environmental Interest set aside as refugia for polymetallic nodule fields of
the western CCZ, prior to potential mining activity in the region. I was part of the team sampling
microbial communities on manganese nodules and in the sediments and water column. I am now
analyzing these samples for taxonomic composition using 16S rRNA marker genes. This analysis
will both fill a gap in a poorly-sampled region of the ocean and will further allow us to examine
trends in benthic microbial biodiversity along a latitudinal gradient and between the abyssal plain
and seamounts.

This project also included a workshop, held in October 2019, focused on synthesizing the available
biodiversity data from the CCZ and the ability of the no-mining Areas of Particular Environmental Interest
to represent that biodiversity. I was a member of the working group conducting a meta-analysis on
bacteria and archaea.

Resulting publication: technical report to the International Seabed Authority

Bacterioplankton community metabolic ability across an eddy dipole

In spring 2018, I participated in a SCOPE cruise that transited from a cyclonic eddy to an anti-cyclonic eddy
located to the north of Hawai`i. To test the hypothesis that bacterioplankton communities in different
eddy types would be pre-conditioned to respond differently to variable DOM, I set up experimental bioassays
to measure DOM remineralization along the gradient from eddy center to eddy center, testing responses to both
in situ DOM and lysates from cultures of Prochlorococcus and a coccolithophore. While eddy effect had no obvious
impact on community metabolic abilities in the short term, these experiments suggested that eddies might promote
the formation and turnover of semi-labile DOM in the photic zone of stratified, oligotrophic systems.

Resulting publication

16S rRNA gene primer comparison in an ecological context

I tested four 16S rRNA gene primer sets on both mock communities of known composition and time-series
samples from the Santa Barbara Channel. Unsurprisingly, we found that all primer sets had strengths and
weaknesses and that the most recently developed primer sets were overall the best choices. However,
we also found that ecological conclusions (e.g., depth and temporal patterns, and correlations with
environmental parameters) were largely unaffected by primer choice. This suggests that, while the field needs
to be cautious when comparing relative abundances produced by different primers, it is valid to compare
broader ecological findings - an important point as primer sets fall in and out of favor over time.

Resulting publication