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Dispatch 29: Penultimate science station + more northern lights!

Jennifer Kosty (Yale University)

October 17, 2025
17:00 local, 72.39◦N, 144.05◦W

Conditions:

  • Cloudy
  • 50% sea ice cover
  • -6◦C
  • Sunrise: 17-Oct-2025 11:16
  • Sunset: 17-Oct-2025 19:25
  • Day length: 8 hours, 9 minutes

We were treated to more incredible views of northern lights around 2:30 this morning! The combination of colorful auroras and fresh pancake ice made this the perfect start to one of our final few days in the Arctic. The night shift spent the rest of the morning running salinity and fluorescent dissolved organic matter (FDOM) samples. Around 10 am, the ice observing team (Kazu Tateyama, Shotaro Muraoka, Takuji Waseda, and Michiharu Shibata) redeployed their electromagnetic sea ice thickness sensor (EM-31), which was brought on board for the last week as we were cruising through open water. Meanwhile, the night shift completed a 3600 m CTD rosette cast at STN-A. This cast was particularly challenging due to the strong winds (25-30 knots), cold temperatures (-19◦C wind chill), and dynamic sea ice conditions. Captain Briggs had to keep adjusting the Louis’ position to dodge large, fast-moving ice floes. Thankfully, the CTD rosette was safely back on board around noon, and the day watch took over for another round of sampling.

The rest of the afternoon was relatively quiet due to the 10-hour long steam between STN-A and CB-27. Our on-board analysts continued to process the numerous samples collected on the MK-line. Around 4:30 pm, we enjoyed another excellent supper of BBQ chicken, lamb, rice pilaf, and veggies. We anticipate arriving at CB-27 around 10 pm tonight, where the watches will complete the last CTD rosette cast of the 2025 BGOS/JOIS expedition!

 

Figure 1: The most recent sea ice concentration map for the Beaufort and Chukchi Seas (Source: https://data.seaice.uni-bremen.de/databrowser/).
Figure 1: The most recent sea ice concentration map for the Beaufort and Chukchi Seas (Source: https://data.seaice.uni-bremen.de/databrowser/).
Figure 2: Map showing our current location along the planned 2025 cruise track.
Figure 2: Map showing our current location along the planned 2025 cruise track.
Photo 1: The night watch (left to right: Marguerite Larriere, Paige Hagel, Magali Pucet, and Collette Leclerc) after the cast at STN-A. Photo by Sarah Zimmermann.
Photo 1: The night watch (left to right: Marguerite Larriere, Paige Hagel, Magali Pucet, and Collette Leclerc) after the cast at STN-A. Photo by Sarah Zimmermann.
Photo 2: (left to right) Michiharu Shibata, Kazu Tateyama, and Shotaro Muraoka assembling the electromagnetic sea ice thickness sensor (EM-31). Photo by Paul Macoun.
Photo 2: (left to right) Michiharu Shibata, Kazu Tateyama, and Shotaro Muraoka assembling the electromagnetic sea ice thickness sensor (EM-31). Photo by Paul Macoun.
Photo 3: The EM-31 sea ice thickness sensor deployed over the Louis’ port side. Photo by Paul Macoun.
Photo 3: The EM-31 sea ice thickness sensor deployed over the Louis’ port side. Photo by Paul Macoun.
Photo 4: Jennifer Kosty (left) and Dominique Baker (right) helping Chris Clarke draw dissolved oxygen and dissolved inorganic carbon (DIC) samples. Photo by Sarah Zimmermann.
Photo 4: Jennifer Kosty (left) and Dominique Baker (right) helping Chris Clarke draw dissolved oxygen and dissolved inorganic carbon (DIC) samples. Photo by Sarah Zimmermann.
Photo 5: Céline Guéguen (left) and Dominique Baker (right) posing with sample bottles as Chris Clarke and Annabel Payne draw samples. Photo by Sarah Zimmermann.
Photo 5: Céline Guéguen (left) and Dominique Baker (right) posing with sample bottles as Chris Clarke and Annabel Payne draw samples. Photo by Sarah Zimmermann.
Photo 6: More northern lights!
Photo 6: More northern lights!