Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • BCO-DMO Processing Description
• Data Files
• Related Datasets
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

These data were collected on R/V Endeavor cruise EN669 from 12 stations across the Gulf of Maine. Water samples were collected using Niskin bottles on the CTD rosette. Equipment included a Seabird Scientific SBE9plus CTD equipped with a transmissometer, oxygen, and fluorescence sensors.

Total Alkalinity, Dissolved Inorganic Carbon (DIC), and d13C-DIC:
Samples for total alkalinity (TA), dissolved inorganic carbon (DIC), and d13C-DIC were collected simultaneously. Water from the Niskins was passed through a 0.45-micron cartridge filter and all bubbles were removed from the line. Ground-glass stoppered 250-milliliter (mL) bottles were rinsed 3 times with flowing, filtered seawater and then filled. Each sample bottle was left to overflow for approximately double the amount of time it took to fill the bottle. Excess water was gently dumped out to leave a ~2-3 mL headspace below the ground glass fitting. Following collection, samples were poisoned with 100 microliters of saturated mercuric chloride solution. Bottles were sealed with a greased stopper (Apiezon-L). A rubber band was placed over the stopper to ensure sample closure. Samples were stored cool and in the dark prior to analysis at the Woods Hole Oceanographic Institution.

DIC and d13C analyses were performed first immediately after opening the bottle. DIC and d13C-DIC were determined simultaneously using an Apollo AS-D1 analyzer connected to a Picarro G-2121i cavity ringdown system on a 5 mL sample of seawater. Samples were run in at least triplicate and calibrated against seawater Certified Reference Materials. Isotopic values were calibrated against an in-house seawater standard that was intercalibrated against known solid materials (NBS-19, IAEA-C2, and NBS-20). Intercalibration was performed on the same Picarro instrument using an Automate-Liaison front-end unit. Total alkalinity was determined using an open-system Gran titration on 5-mL samples in triplicate, using a Metrohm 805 Dosimat and a robotic Titrosampler, calibrated against seawater Certified Reference Materials.

- Imported the first sheet of the original file "EN669_CTD_Bottle_BCODMO.xlsx" from into the BCO-DMO system.
- Removed the empty column (column M in Excel file).
- Renamed fields to comply with BCO-DMO naming conventions.
- Created the ISO_DateTime_UTC column by converting the julian date (TimeJ) column to ISO 8601 format.
- Saved the final file as "915709_v1_en669_bottle.csv".

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.