Ecological and evolutionary importance of molecular diversity in dissolved organic matter
Dissolved organic matter (DOM) is central to the functioning of freshwater ecosystems that support life on Earth.  For example, DOM has a major role in global carbon (C) cycling by helping to bury four times more C in the bottom of lakes and rivers than across all of the world’s oceans.  DOM also majorly influences the growth of aquatic organisms and impedes drinking water treatment for millions of people, such as by increasing microbial growth.  Yet, despite its importance, DOM remains poorly understood because it has been measured with little resolution for nearly 200 years.  Recent technological advances have now shown that a handful of lake water can contain thousands of different molecules of varying origin and composition.  But the role of all these different molecules in aquatic ecosystems largely remains a mystery.
This project will discover the importance of the tremendous diversity of molecules – termed chemodiversity – found in DOM for lake functioning and human wellbeing.  It will do so by combining cutting-edge techniques in analytical chemistry, genomics, and statistical modelling with careful lab-based studies, proven field experiments, and large-scale observational surveys.  By thinking about species of molecules as we would species of organisms, this project will draw upon rich theory and methods developed for the study of biodiversity.  The work will allow us to learn how variation in chemodiversity across lakes is driven by associations with different microbes and how these microbes reciprocally adapt and evolve to different DOM.  In the process, we will improve predictions of how important functions and services provided by lakes, such as C cycling and drinking water, vary with chemodiversity.  An exciting application of this work is to improve emerging technologies for water purification by identifying microbial consortia that can consume chemodiversity and make water clearer.