Project: CAREER: Gulf of Maine Temperature Trends and Variability from the early Holocene to the Present

NSF Award Abstract:
The Gulf of Maine supports a highly productive marine ecosystem extending from Cape Cod to Nova Scotia. Ocean temperatures in this region are sensitive to changes in the relative influx of colder currents from the north and warmer currents from the south, which are ultimately linked to the greater regional and global ocean-atmosphere circulation. From 2004 to 2013, the Gulf of Maine warmed faster than 99% of the world's oceans, but the processes driving recent temperature change here are not fully understood. A deeper understanding of oceanographic trends on time scales beyond instrumental records (older than ~100 years) can elucidate the causes of change, determine whether abrupt changes have happened in the past, and shed light on environmental impacts on past coastal communities. This project brings together a multi-disciplinary team of researchers and Native American students in New England, who will conduct a 10-day research expedition in the Gulf and delve into the region's past using geochemical evidence buried in ancient marine sediments. Results and research experiences of students will be shared with the broader community via development of an innovative multi-media online storytelling environment and through partnership with local schools. The project has the potential to enhance long-term environmental prediction and planning in an area where human populations and ocean ecosystems have been interlinked for millennia.

Long-term records of ocean temperature and seawater oxygen isotope composition (d18O) will be reconstructed from the magnesium to calcium ratio (Mg/Ca) and d18O of fossil foraminiferal calcite derived from a suite of sediment cores from the Gulf of Maine and Scotian Shelf and Slope. High-resolution (~100 to 200-year interval) records will extend from the start of the Holocene ~11,600 years ago to the present, providing insight into long-term temperature trends as well as any abrupt changes. In addition to traditional whole-shell geochemical analysis, micro-analysis of individual foraminiferal specimens will be conducted to provide complementary data for assessing environmental variability. A research cruise in the Gulf of Maine will provide sediment-core and plankton-tow material as well as hydrographic data for refinement and regional calibration of the geochemical proxies. One key goal is to test and extend the Mg/Ca-temperature calibration for a common high-latitude foraminifer species, Neogloboquadrina incompta. In parallel with paleoceanographic research, artifacts from coastal archaeological sites will be radiocarbon-dated to refine the chronology of fishing practices in the region. In particular, the beginning and end of intensive sword-fishing in coastal communities will be re-dated and reassessed in light of new paleotemperature data. All work will be carried out by a team of high school, undergraduate, and graduate students who will gain both technical and communications training in partnership with the Wabanaki Center and the New Media and Internet Technologies Lab at the University of Maine. In addition to developing online narratives that can be widely shared, high school students will practice presenting their research verbally to different groups, including at national meetings. A diverse team of women and men, including a member of the Penobscot Nation, will collaborate to guide and mentor students through the scientific process and to help them develop a voice that can effectively reach diverse audiences.

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.