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Dispatch 13: Polar bear sighting

Jennifer Kosty (Yale University)

September 30, 2026

13:30 local, 78.08◦N, 140.14◦W

Conditions:

  • 100% sea ice cover
  • -4.3◦C
  • Sunrise: 08:51 PDT (local)
  • Sunset: 19:27 PDT (local)
  • Day length: 10 hours, 36 minutes

We had our first polar bear sighting of the cruise! Around 6 pm last night, the bridge announced that a polar bear had been spotted wandering nearby. We all quickly donned our layers and headed out to the foredeck to see. Everyone felt incredibly grateful to witness this beautiful creature in its natural habitat.

After last night’s excitement, we felt energized and ready for another day of science! The watches completed a 3800 m CTD-rosette cast at CB13, followed by another deep cast at CB16. In between these science stations, Koya Sato deployed an expendable XCTD probe. These probes are launched from the Louis’ stern and return depth profiles of temperature and salinity from the surface to 1100 m deep. XCTDs are deployed every 30 nautical miles as we transit between full science stations to increase the spatial resolution of our profile data.

We are currently on the hunt for a good floe for our upcoming ice work. Our on-board ice specialist Roxane helped identify a few promising candidates that we will visit later today to assess their thickness. In the meantime, Kazu Tateyama walked the science team through the plan for our upcoming ice core and transect work. Fingers crossed that we can complete our first ice station tomorrow!

 

The most recent sea ice concentration map for the Beaufort and Chukchi Seas (Source: https://data.seaice.uni-bremen.de/databrowser/).
The most recent sea ice concentration map for the Beaufort and Chukchi Seas (Source: https://data.seaice.uni-bremen.de/databrowser/).
Map showing our current location along the planned 2026 cruise track.
Map showing our current location along the planned 2026 cruise track.
Our first polar bear sighting! Photo by Paul Macoun.
Our first polar bear sighting! Photo by Paul Macoun.
Fresh polar bear tracks under the recently re-deployed “sushi” sea ice measuring instrument. Photo by Jennifer Kosty.
Fresh polar bear tracks under the recently re-deployed “sushi” sea ice measuring instrument. Photo by Jennifer Kosty.
Kazu Tateyama explaining the ice core sampling procedure. Photo by Jennifer Kosty.
Kazu Tateyama explaining the ice core sampling procedure. Photo by Jennifer Kosty.
An XCTD probe being deployed from the Louis’ stern. Photo by Jennifer Kosty.
An XCTD probe being deployed from the Louis’ stern. Photo by Jennifer Kosty.