Jennifer Kosty (Yale University)

October 11, 2025

19:00 local, 75.23◦N, 143.25◦W

Conditions:

· Cloudy, flurries

· 90% sea ice cover

· -4◦C

·Sunrise: 11-Oct-2025 11:01

· Sunset: 11-Oct-2025 19:36

· Day length: 8 hours, 35 minutes

The night shift completed a 3600 m CTD rosette cast at CB-17 early this morning. The cold weather made this cast extra challenging, as the wire block and chummy kept freezing. Sampling was completed by 9 am, and the night watch went to enjoy a highly anticipated late breakfast/lunch of eggs, diced hashbrowns, and banana pancakes with chocolate syrup.

At 1 pm, senior engineer Travis MacDonald led members of the science team on a tour of the engine room. Travis and chief engineer Jeff Seitz have been kind enough to lead several of these tours over the past couple of weeks to accommodate everyone’s different schedules. Travis showed us the steering gear, propeller shafts, main engines, engine control room, freshwater makers, and bubblers.

Around 2 pm, we reached 75.4N, 143.5W, the newest science station added to the 2025 BGOS/JOIS expedition itinerary! During yesterday’s science meeting, we decided it would be beneficial to add this science station (CB-GC) near the center of the Beaufort Gyre, which we were passing through on our transit from CB-17 to CB-3. Here, the BGOS team (Jeff O’Brien, Tim McDonough, Jim Ryder, and Cory Beatty) worked with the deck crew to deploy our final tethered ocean profiler (TOP). Unlike the previous TOPs which were deployed on the sea ice, TOP17 was deployed in the open ocean. The deployment procedure remained largely unchanged and was completed by 4 pm.

After a quick dinner of BBQ pork chops, baked chicken drumsticks, and hashbrown casserole, the day watch then completed a 3700 m CTD rosette cast. We are excited to add this profile data to our catalogue, as it will help us identify gradients in water mass properties across the Beaufort Gyre. Tonight, we continue steaming towards CB-3, with an anticipated arrival time tomorrow afternoon.