Dr. Cameron M. Callbeck - Research Interests
On a broad scope, my work has centered around the biogeochemical cycles of nitrogen and sulfur in engineered systems [12, 10, 1-4], freshwater lakes , and marine upwelling systems [11, 5-9] – essentially anywhere where the nitrogen cycle prevails. My recent work has tackled open questions regarding the distribution and activity of sulfur-storing nitrate-reducing bacteria in the Peruvian upwelling region (related to the cryptic sulfur cycle) , and have explored nitrogen loss activity by anammox and denitrification in the Bay of Bengal – a poorly studied marine oxygen minimum zone . Moreover, I am interested in the effects of deep anoxic phototrophic blooms and their role in moderating nitrogen loss in Lake Tanganyika, and in other similarly stratified water columns . Apart from water column research, my work also looks to disentangle the various inorganic and organic nitrogen transformation processes operating in the upper sediment boundary layer of small Swiss lakes.
In the Anthropocene epoch, it is imperative that we understand the fundamentals of nitrogen cycling and the factors that govern nitrogen loss in order to know how such processes may shift as a result of climate change and warming induced stratification.
A core tenet of my research has employed 15N labelled inorganic and organic substrates to quantify the various nitrogen transformation processes (anammox, denitrification, DNRA, nitrification, organic matter remineralization). These short-term tracer additions are also performed in parallel with natural abundance isotope measurements to assess the cumulative imprint of the nitrogen cycle. We complement our biogeochemical approaches with molecular and single-cell techniques to further shed light on key microbial players, and to quantify their role within the broader context of the nitrogen cycle.
2021-Present: Postdoctoral researcher – University of Basel, Switzerland
2018-2020: Postdoctoral researcher – Swiss Federal Institute of Aquatic Science and Technology, Kastanienbaum, Switzerland (Eawag)
2012-2017: PhD in Biogeochemistry (NSERC fellowship) – Max Planck Institute for Marine Microbiology, Bremen, Germany
2005-2011: BSc and MSc in Environmental Microbiology – University of Calgary, Alberta, Canada.
Dr. Cameron M. Callbeck