Award: OCE-1455924

Summary The mission of the GEOTRACES Program (www.geotraces.org) is "to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes (TEIs) in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions". This is extremely relevant to the Arctic, where rapid climate change and accompanying biogeochemical responses are occurring. This project provided the core support to carry out the US GEOTRACES transect in the western Arctic, in collaboration with pan-Arctic efforts from a large international community. These expeditions involved the deployment of ice-capable research ships from 3 nations (US, Canada, Germany) across different parts of the Arctic Ocean in 2015, and application of state of the art geochemical tracers to unravel the complex biogeochemical dynamics of the Arctic Ocean and its continental shelves. Scientists from countries without icebreaker capability also participated in this endeavor. The field effort of the program was unprecedented in regional scope and scientific breadth. The US cruise track included Pacific end member stations, a highly resolved shelf-basin interaction segment, and two deep basin transects that designed to capture critical features of physical circulation. In addition, two "crossover" stations (Canada Basin, Makarov Basin) provide intercalibration among participating international partners. This track resulted from several open planning workshops coordinated with international participants. Intellectual Merit The project provided the essential support and management structure for acquiring samples and hydrographic data needed by other investigators who were funded through individual science proposals. Support was used to (1) plan and coordinate a 65 day research cruise; (2) obtain samples for a wide variety of TEIs using a conventional CTD/rosette, the contamination-free GEOTRACES CTD/carousel sampling system, and an atmospheric sampling system (for aerosols and precipitation); (3) acquire appropriate hydrographic data including CTD (with transmissometer, fluorometer, and oxygen sensor) and water samples for salinity, dissolved O2, plant pigments, and nutrients at micro- and nanomolar levels; (4) acquire TEI samples from the ice environment, (snow, melt pond, and ocean-ice interface); (5) collect surface sediment samples for analyses; (6) ensure proper QA/QC and GEOTRACES inter-laboratory calibration protocols are followed and reported; (7) prepare and deliver all hydrographic data to the GEOTRACES Data Center and US data centers; and (8) coordinate cruise communications among investigators, including preparation of a hydrographic report/publication. In addition, the management team is coordinating data synthesis activities through national and international meetings. Our original plan was a highly ambitious one. Thinner than expected ice allowed relatively rapid transit, which, when coupled with extremely efficient deck deployments, led to a fulfilment of nearly all our over-the-side operations, both from the GEOTRACES and Repeat Hydrography perspectives. Ironically those same ice conditions which facilitated smooth station progress hindered the ability to perform all the ice stations we had hoped for, although we did attain 60% of our most optimistic expectation in that regard. Deteriorating weather conditions near the expedition?s end cost us only a small fraction of our intended goals. In the end we occupied 66 combined GEOTRACES, Repeat Hydrography, and ice stations. Given the highly complex nature of this expedition, which included the harsh environment, uncertainties of weather and ice, diversity of scientific operations, and working within an unfamiliar military framework, this expedition was an enormous success. Broader Impacts This expedition was historic for two reasons. One, it marked the first time a US surface ship arrived unaccompanied to the pole. Second, this project involved the deployment of three ice-capable research ships from three nations (the U.S., Canada, and Germany) across different regions of the Arctic Ocean which provide a pan-Arctic geochemical data set unprecedented in regional scope and scientific breadth. In addition, there were numerous opportunities for training and development: 1. Eleven graduate students participated in this expedition and will be incorporating results into their theses. There were also three postdoctoral scientists involved in the expedition. 2 . The coastguard offered an oceanography course to its crew for college credit. Several investigators, and two students, offered lectures for this effort. 3. We also presented science lectures every Wednesday night geared to the Coast Guard crew. Bill Schmoker, our on-board PolarTREC science teacher, posted over 65 blogs (with descriptive text and photos) to the PolarTREC web site: www.polartrec.com/expeditions/us-arctic-geotraces/journals. In addition, Journals and videos from Bill Schmoker are posted at: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.polartrec.com_expeditions_us-2Darctic-2Dgeotraces&d=AwIFAg&c=1QsCMERiq7JOmEnKpsSyjg&r=ooN6_yXa23lQoVNTupdxFw&m=I2jwKvt1ww--qu3pDbYFad93VW0DiaOt5DGrzE3ZnpE&s=2UHYf7xfiITBAxHCu8KvWpw3FkjlK7jdfaI0mdcx3_8&e= and https://urldefense.proofpoint.com/v2/url?u=https-3A__www.youtube.com_user_PolarTRECProgram_&d=AwIFAg&c=1QsCMERiq7JOmEnKpsSyjg&r=ooN6_yXa23lQoVNTupdxFw&m=I2jwKvt1ww--qu3pDbYFad93VW0DiaOt5DGrzE3ZnpE&s=IfC6YyxkOk22nBkGSd4__CRQ3MYztYqhBE0KLt7Gtv4&e There were also outreach efforts: As part of the US Arctic GEOTRACES outreach effort,several PIs put together a package for presentation at the 2015 Kawerak Conference in Nome. This was a meeting for rural Alaska natives and other rural Alaska residents. Dr. Aguilar-Islas made a presentation for GEOTRACES, passed out a brochure we constructed, and was available for interviews and discussions with attendees. The local radio station did a story, and it was picked up by Alaska Dispatch News. Last Modified: 07/02/2018 Submitted by: David C Kadko