Cruise Report AR76-01 (AR2307) The Baffin Bay Deglacial Experiment (BADEX)

AR76-01 was a 33-day expedition of R/V Neil Armstrong in support of the Baffin Bay Deglacial Experiment (BADEX) to the western Labrador slope and Baffin Bay. The cruise began in Woods Hole, MA on July 11th, 2023 and ended in Nuuk, Greenland on August 13th, 2023. The shipboard science party included participants from the University of Florida, Lamont Doherty Earth Observatory, the University of North Carolina Wilmington, Oregon State University, the University of Colorado Boulder, the Greenland Climate Research Center, the University of Central Florida, and the University Centre of Westfjords. The cruise was led by three early career, pre-tenured, assistant professors, half of the science berths were staffed by a post-doc and graduate students, and over half of the science party identified as female. Support for the expedition came from the US National Science Foundation.

Our primary goal was to identify and sample sedimentary deposits suitable to reconstruct the mechanisms and processes involved in initiating and sustaining the large-scale deglaciation of a marine-terminating ice sheet. Our central hypothesis asserted that increasing subsurface ocean temperature at the grounding line of marine-terminating glaciers is a primary driver of ice-sheet instability. To test this hypothesis required a unified program of geophysical seafloor mapping, sub-seafloor imaging, biological and water sampling, and sediment coring.

Over the course of 33-days at sea, we occupied 27 stations and sampled five major trough mouth fan systems spanning 9 degrees of latitude in Baffin Bay. Shipboard data and physical sample collection were given the sample prefix AR2307 and included multibeam bathymetry, Chirp subbottom data, plankton net tows, CTD casts and hydro-casts (Niskin bottle rosette sampling), and multi-core, gravity, and piston coring. In total, 109 deployments were made from the ship. These deployments comprise; 20 phytoplankton and zooplankton tows, 20 CTDs and water samples, 11 multicores (MC), 45 gravity cores (GC), 13 trigger cores (TC), and 13 jumbo piston cores (JC). In total 396.15 meters of sediment was collected, and 2,520 liters of water was sampled. Phytoplankton experiments were conducted on the ship, water samples were filtered for biomarkers and radiogenic isotopes, and the gravity and piston cores were CT-imaged and measured on a multi-sensor core logger. A subset of the cores were split, imaged, and described at sea when time and resources allowed. All geological samples were curated at the Oregon State University Marine and Geology Repository (OSU-MGR) following the expedition.