The biogeochemistry group investigates the characteristics and reactivity of organic matter in aquatic environments by examining its molecular and isotopic composition. Aron Stubbins employs a suite of techniques at SkIO and through collaborating laboratories to identify the optical (UV-visible absorbance, fluorescence), isotopic (d13C, D13C), structural (Fourier transform infrared and nuclear magnetic resonance) and molecular (high resolution mass spectrometry and biomarkers) signatures. The information provided enables us to read the molecular messages carried by organic matter. These messages tell of the organisms responsible for synthesizing organic matter, the processes that have acted upon the organic matter since its formation, and the likely fate of the organic matter in biosphere. Tracked through time in rivers, glaciers, sediments, the open ocean, and at hydrothermal vents, this information provides insight into how ecosystems have evolved in the past and how present ecosystems may be altered in the future in response to natural cycles and human-induced changes.