Jennifer Kosty (Yale University)

October 22, 2025
15:00 local, 69.01◦N, 105.48◦W

Conditions:

• Cloudy
• 0% sea ice cover
• -1^◦C
• Sunrise: 22-Oct-2025 8:39
• Sunset: 22-Oct-2025 16:58
• Day length: 8 hours, 19 minutes

Today is our last day on the Louis! We enjoyed a relatively quiet morning, with members of the science team continuing to organize and quality-control sample data, scan cruise documents, and write the cruise report. At 11 am, we met in the boardroom for our final science meeting, during which Jeff O’Brien gave a presentation on the technology behind the tethered ocean profilers (TOPs). We then enjoyed our last lunch on board, which consisted of toasted lumberjack sandwiches, Swedish meatballs, buttered noodles, Thai mixed veggies, and one final amazing salad.

As we spend the afternoon wrapping up any remaining work, now is a good time to reflect on the incredible 5 weeks we have spent at sea on the 2025 BGOS/JOIS expedition! In total, we spent 509 hours in transit, covering more than 5000 miles (8000 km), which is roughly the length of Canada from coast-to-coast. We completed 65 CTD rosette casts, during which the rosette traveled more than 300 vertical kilometers in the ocean. We also collected 9,402 water samples, 66% of which were processed on board, as well as 88 plankton samples. We recovered and redeployed 3 full-depth moorings (BGOS A, B, and D), recovered 7 buoys, and deployed 4 TOPs and 2 seasonal ice mass balance (SIMBs) buoys. We additionally completed 2 ice thickness transects, collected 3 ice cores, and completed 397 on-board ice observing surveys. Huge thanks to Captain Briggs and his wonderful crew for helping us complete all this work!

There were also plenty of non-science related highlights from this year’s cruise. We were lucky enough to see 6 polars (including 3 cubs!), a snowy owl, several breathtaking auroras, and countless Arctic sunsets/sunrises. We enjoyed many hacky sack sessions, rounds of Dutch Blitz, and late-night conversations in the CTD lab during casts. Other memorable moments included our egg-speriment, the “shrinky” cup cast, and post-ice day hot chocolates. It’s safe to say that this year’s expedition was an unforgettable one!

Tomorrow morning, we will say our final goodbyes and begin the long journey home. Thank you for following along on our Arctic expedition and stay tuned for more next year!

Signing off,

Jennifer