In the Anthropocene humans have a global impact on the atmosphere and ecosystems. This became first visible with the discovery that man-made chlorine emissions modify stratospheric ozone (O₃) over South Pole. More recent evidence suggests that atmospheric chemistry of bromine and iodine radicals dominates the relevance of halogens in the troposphere, and may be more active today than 100 years ago.

All living organisms conserve energy by catalyzing redox biochemical reactions, which constitute respiration.  In most cases, respiration is achieved through the action of metalloenzymes and electron-transfer networks, wherein oxidation of reduced substrates is coupled to reduction of cofactors that pass along the electrons to a terminal oxidant.  The latter is O₂ in aerobic respiration and eukaryotes have no respiratory flexibility at the level of O

Iron(II) and 2-Oxoglutarate (2OG) dependent non-heme iron (Fe(II)/2OG) enzymes catalyze a large array of chemical transformations, including hydroxylation, desaturation, epoxidation, halogenation, epimerization, endoperoxidation, as well as ring expansion/contraction reactions. Many of these transformations are key chemical steps in the biosynthesis of natural products having antibiotic and antimicrobial activities.

This presentation reveals the profound ways in which isotope ratio mass spectrometry (IRMS) can provide information about the geographic origin and history of almost everything around us, including our fellow humans. The presentation explains the ways in which we are and are not exactly what we eat, and it explains how researchers use IRMS measurements of hair to determine the geographic origin and travel histories of animals and humans.

Dr. Todd Harrop and Dr.