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The C.A.B.O.O.M. Laboratory
(Chemistry and Biology of Oceanic Organic Matter)

The Journey From Organic Molecules to Global Biogeochemical Cycles

The research in my laboratory focuses on interactions between organic molecules, microorganisms (autotrophic and heterotrophic), and the global cycles of carbon and nitrogen. I am specifically interested in identifying the imprint of biological communities and biological processes on the chemical composition of organic compounds in the marine environment and how these compounds in-turn influence microbial and phytoplankton ecology.

My students and post-docs employ a diverse array of tools including novel analytical techniques, organic synthesis, natural abundance stable isotope measurements, radiocarbon dating, molecular biological techniques (e.g. FISH, DGGE, phylogenetic profiling, functional gene based PCR), and laboratory based culturing experiments to study specific algal (unicellular), bacterial (autotrophic and heterotrophic) and archaeal processes that control the inventory, composition and size of the dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) reservoirs in the ocean.

My philosophy is to first identify interesting, challenging and globally significant problems and then design an experimental approach to solve these problems. This often entails the development of new methods and novel applications of existing methods. It also insures that the typical analytical tools of the trade do not limit the research questions that we pose. We hope that this philosophy will give us a unique research approach that will help to transport us beyond the current limitations in our knowledge of marine biogeochemical processes. A more firm understanding of modern-day biogeochemical processes will allow us to better predict the biosphere's future response to both natural and anthropogenic climate forcing, and also provide better tools for interpreting proxies used in paleoceanographic research.

Although we work on many aspects of marine chemistry, the starting point for any project is often firmly rooted in dissolved organic matter (DOM). My bias towards DOM has been very eloquently captured by the late John Hedges and I quote him below:

"Ultimately, however, the biogeochemical usefulness of any class of chemical tracers is limited by its structural diversity and the range of its sources, input functions, and chemical reactivities. It is clear, therefore, that the information content of organic molecules, which also carry imbedded stable isotopic signatures and radiochemical clocks, is unsurpassed by any other seawater component. The 1012 diverse organic molecules dissolved in every milliliter of seawater are the only constituents whose stored information approaches the richness needed to understand where the water has been and what has happened within it over time. The future of oceanographic research belongs in part to those who can learn to read these molecular messages." - John Hedges

From Biogeochemistry of Marine Dissolved Organic Matter. D. A. Hansell, C. A. Carlson, Eds. (Academic Press, San Diego, CA, 2002)