Developing novel tools to explore the marine volatilome

Key volatile organic compounds (VOCs) such as dimethyl sulfide (DMS) and isoprene have been extensively studied for their importance as semiochemicals and in climate regulation. In contrast, disentangling the myriad of signature VOCs in gas chromatographicdata has received much less attention. This thesis aims to develop novel analytical tools that utilise chromatographic information for the understanding of dynamic behaviour and interactions of organisms in the environment, assuming that every organism produces a characteristic volatile profile that reflects its physiological status. Five lab-based experiments combined with one final field study took place to begin building the foundations of such a tool. Studies were conducted with the aim to collect dataon species specific volatile profiles, to comprehend what effects biophysiological factors may have on the organisms’ volatilomes, and to learn if there is any seasonality in VOCs just as there are in plankton succession. During lab-based experiments, VOCs characteristic to species as well as biological and physical factors could be observed. Stress from heat resulted in higher production of VOCs that were likely to be induced by stress and mortality. Competition reduced VOC production amongst the two species grown together, and grazing behaviour reflected on VOC profiles obtained as numbers and concentrations would increase in samples that included individuals with high mortality. Field based studies showed a link between seasonal succession of plankton, with trends in VOCs prevalent over 8 months sampling time. Taking the results of the lab-based and field-based study into consideration, it can be said that there is potential in utilising VOC profiles to develop a novel, non-invasive tool to be used for environmental monitoring.