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. But despite its importance, DOM remains poorly understood because it has been measured with little resolution for nearly 200 years. Recent technological advances have shown that a handful of lake water can contain more than 2,000 different molecules of varying origin and composition. A key question that now needs answering is what do all these different molecules do in aquatic ecosystems? With funding from the European Research Council, we have embarked on 5-year project (2019-2024) to resolve this mystery.

Our project sEEIngDOM aims to 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.