RAPID: Fingerprinting new water-carbon interactions in the Arctic: Isotopic measurements through the Northwest Passage and in Baffin Bay

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The Arctic carbon and water cycles are undergoing fundamental changes as the Arctic experiences an entire suite of new conditions. At the core of this restructuring is rapid Arctic warming, the loss of sea ice, shifting atmospheric and ocean circulation patterns, increasing precipitation, permafrost thaw, and enhanced melt of the Greenland Ice Sheet and other mountain glaciers and ice caps. These changes have resulted in the simultaneous freshening of the Arctic seas and humidification of the Arctic atmosphere due to more evaporation from what was previously ice-covered ocean. Concurrently, riverine discharges are driving the fertilization of the Arctic seas and increasing ocean water productivity by carrying ancient carbon and old nutrients from thawed permafrost into the fjords, bays, and ocean. It is urgent to monitor and quantify these new ice-ocean-land-atmosphere interactions to understand the magnitude and variability of carbon and water cycle changes across the Arctic. This project capitalizes on an autumn 2021 research expedition of the USCGC Healy Icebreaker. The project will use continuous isotope fingerprinting to delineate key linkages between ice-ocean-land-atmosphere interactions along the west coast of Alaska, through the Northwest Passage and in Baffin Bay. The project will measure carbon and water isotopes of marine air and ocean water continuously with some spot intense sampling locations. These measurements will enable quantification of the geochemical patterns that record freshening, fertilization, evaporation, and productivity variations driven by differing degrees of ice-ocean-land-atmosphere interactions. These data will be the first of their kind in terms of coordination at this large scale with a transect spanning ~15 degrees of latitude and over 100 degrees of longitude in the western and central Arctic. This project will: 1) delineate the intensity of land-ice freshwater injections including the extent to which these freshwater plumes carry new sources of ancient (permafrost derived) carbon and nutrients that may drive productivity increases and ocean carbon exchange; 2) quantify the connectivity of and mechanisms controlling Arctic Ocean water evaporation and atmospheric humidification which may be altering precipitation patterns in the Arctic and in the mid-latitudes; and 3) determine ocean carbon gain or loss continuously across the Arctic seas with implications for marine food webs, support of subsistence hunting, and climate warming via atmospheric carbon dioxide and methane concentrations. This project will offer valuable contributions and data to studies of Arctic change by groups examining changing atmospheric, ocean, cryospheric processes, and marine and terrestrial ecosystems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.