Hi there! I am a marine microbial ecologist. I study how microorganisms affect the environment, each other, and respond to processes like climate change. What do I mean by microbe? Well, generally speaking, I mean small, simple organisms that do not have complex tissues like we do. Despite their tiny size, these organisms have outsize roles in keeping our planet habitable. To paraphrase a participant of the X-CHEM program in 2024, “we wouldn’t even be here if the cyanobacteria hadn’t pooped out all the oxygen” (google “great oxidation event” if you’re curious to know more). Microbes don’t just “poop out” oxygen, they also produce / consume greenhouse gases like carbon dioxide, methane, and nitrous oxide. They are the base of the food web in most areas of the ocean, regenerate nutrients for algae, and can do just about any biochemical process you can imagine if it benefits them.

Microbial communities are complex. In a given milliliter of seawater, there’s usually about a million microbial cells, and these are comprised of many different species (probably hundreds to thousands, depending on the location, season, etc). And that’s just 1 mL of seawater. Imagine how many different microbes there are out there on our whole planet! To dissect this incredible complexity, I use techniques that take a “census” of this microbial community diversity. These are variously referred to as “amplicon sequencing”, “metabarcoding” or “eDNA sequencing”. They use PCR to amplify “barcodes” which are little stretches of DNA that allow us to make an identification without actually looking at these “bugs” under the microscope or culturing them in the lab.

A key question underlying my research program is determining how sensitive “microbial ecosystem services” (e.g. sulfide detoxification, methane consumption) are to environmental stressors such as climate change and nutrient pollution. Katherine Rutherford and I are working closely together to develop ways to answer this question experimentally. We are planning to use techniques such as rRNA-FISH combined with single-cell metabolic asssays to determine how natural microbial communities respond in short-term incubations that simulate these stressors. As part of this work, we are collaborating with Dr. Bruce Hatcher (CBU) to access water samples from a unique site in Western Whycocomagh Bay. In addition, undergraduate student Shaye Close is working to understand what we can learn from metagenomic data collected from this site last summer.

In addition to this more marine-focused work, I have begun several interdisciplinary research projects. The first, which is being led by Jillian Davies (a recent StFX grad) and assisted by Katherine Rutherford, seeks to understand the effect of microplastic ingestion on the gut microbiome of zebrafish (in collaboration with colleagues at the NRC). Finally, I have also roped in two students for collaborative honours theses at StFX - Julia Crean (co-supervised with Dr. Graham Clark) and Laura Riendeau (co-supervised with Dr. Donnelly Archibald). Julia will be looking at bog microbes and their relationship to methane emissions, whereas Laura will be looking at rock microbes in relationship to geochemistry.

I also teach core courses in microbiology / microbial ecology for the Biology department at St. Francis Xavier University, including a course where students do their own amplicon sequencing from environmental samples in a single semester. Please check out the “contact” tab if you want to know more about possibly taking my courses at StFX or working together on a research project.