Final Activity Report Summary - BIOTRACS (Bio-transformation of trace elements in aquatic systems) The BIOTRACS Early Stage Training (EST) project focussed on the interactions of microbiological and geochemical processes in a range of aquatic systems ranging from glaciers to deep sea sediments, that have implications for global biogeochemical cycles now and in the past. This highly inter-disciplinary project involved four Centres of Excellence at United Kingdom Universities: Southampton (UoS), Bristol (UoB), Leeds (UoL) and Manchester (UoM). BIOTRACS was hosted from the National Oceanography Centre, Southampton and twelve three year early stage researchers (50 % female, and 50 % from less favoured regions of Europe) were trained. Further six short term (three month) fellows were also trained. Fellows were able to develop a range of skills at the cutting edge of their respective areas of science, plus acquire knowledge, and training in essential key skills needed for a career in science. Science highlights: - Alex Xylouri (UoL) demonstrated atmospheric processing of Saharan particles can make the biologically essential Fe (and Mn) more dissolvable in seawater and thus available for uptake and reactions. - Marek Stibal (UoB) has studied cryoconite holes in the surface of glaciers; these small unique freshwater systems can be an important source of C and nutrients (and especially organic forms of P) to glacial ecosystems. - Massimo Lupascu (UoB): Methane is a potent greenhouse gas and release from sub-polar tundra zones are important in the global climate system. As global warming advances, temperature was been identified as a major variable in this system. - Alfred Aquilina (UoB) studied bacterial destruction of methane in near-shore sediments, through anaerobic oxidation of methane, using lipid biomarkers, and found that processes are similar to those in cold seeps. - The Southern Ocean is a key zone in global climate transitions, and lipid and geochemical proxies for Fe induced productivity were used to better understand these climate transitions and their biological impact by Maite Hernandez-Sanchez (UoS). - Marine aggregates formed from biological debris and bacteria are hot spots of biogeochemical recycling. Sergio Balzano (UoS) showed release of reduced dissolved forms of biologically important Fe and Mn. - Moritz Muller (UoS) used combinations of electrochemical, bacterial and biomarkers measurements to show a Marinobacter species was shown to significantly enhanced alteration / oxidation of metal sulphides. - The 3D alteration of sulphide phases in situ in the ocean and lab was followed using vertical scanning interferometry by Ellen Avery (UoL), to help generate new rate estimates of oxidative loss of the sulphide phase. - Loredana Brinza (UoL) has measured the kinetics and mechanisms of Mo and V-ferrihydrite transformation to hematite for the first time, and examined the bonding environments and partitioning of Mo and V during hematite transformations. - The hydothermal community at Santorini was examined in detail by Kim Handley (UoM), who found that all the Fe (II) oxidising bacteria cultivated are novel. - Sarah Monteiro (UoM), used proteomic and gene expression analysis to probe for novel detoxification pathways in Hydrothermal bacteria. - An important finding across several projects is that marinobacter species, previously thought to catalyse only a restricted range of biogeochemical reactions, actually have a very wide metabolic diversity that allows them to thrive in gradient systems including marine snow and hydrothermal sediments. Other studies in BIOTRACS have identified bacteria that can detoxify toxic metals in hydrothermal systems via novel mechanisms that could be incorporated into biosensors or bioremediation technologies. - Thanos Gkritzalis (UoS), developed an in situ water sampler for better temporal sample collection in aquatic systems, in which water is slowly drawn into a narrow long tube Teflon tube by an osmotic pump.