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22 July, 2003

From our fearless leader:

Chief Scientist's Report #3

R/V Nathaniel B. Palmer SBI Survey Cruise

23 July 2003

James H. Swift

23 July 2003, ca. 2:00 pm Alaska time - from R/V Nathaniel B. Palmer on the Chukchi Slope

We continue our Shelf-Basin Interactions survey cruise, mostly following the plan made before the cruise.

We have now completed two long, high-resolution sections across the Beaufort shelf and slope well into the deep Canada Basin. Both were east of Barrow Canyon, the principal bathymetric cut from the deep ocean into the Chukchi shelf in US waters. Both shelf-basin sections showed a narrow zone of high-oxygen water throughout most of the water column sited over the same isobath. Other measured characteristics were also distinctive in this zone.

It was thus with heightened interest that we began our Barrow Canyon survey of four high-resolution cross-canyon sections. The first was across the mouth of the canyon, and the second, occupied one tidal cycle later, was approximately 50 km up-canyon, with the other two sections each an additional 50 km up-canyon. These proved to be interesting sections from an oceanographic standpoint, each clearly exhibiting a zone of water similar to the distinctive water seen a few days earlier over the Beaufort Slope, the inference being that we were tracing the core of this year's version of the Barrow Canyon early summer outflow, first observing it over the Beaufort slope, then progressively up the canyon, and hopefully (as the cruise progresses in future weeks) at its source region on the Chukchi shelf. There is more to the story: we have observed features which might be interpreted as the shelf outflow water entering the upper reaches of Barrow Canyon on the west side, and then being pushed over to the east side, presumably by rotational effects.

Meanwhile, back in the hangar, the marine mammal group rejoiced over a brilliant turn in the weather, with several sparkling days in a row, which with other reasonable weather days provided fine flying conditions. They have now made seven aerial surveys with the helicopter over ice habitats in the basin and shelf zones. They encountered low densities of ringed and bearded seals, with higher densities of bearded seals over the shelf in the marginal ice zone. They also observed numerous groups of walrus at the ice edge, and have spotted beluga whales near the shelf slope. They are very pleased with the helicopter and ship support and - as it has turned foggy again - eagerly await continuing their flights.

Speaking of flying weather, good flying conditions coincided with proximity to Barrow, so we bade farewell to Community Parcticipant Chuck Menadelook (from Little Diomede), who was flown ashore. The helicopter returned with Luther Leavitt, Jr., from Barrow, who is now enjoying life and science at sea with us.

Today we are working our third shelf-slope-basin section, this time west of Barrow Canyon. We have completed 104 stations, and have experienced very few problems. The pace of the work for the CTD console & sampling team varies, but the analysts (especially Susan Becker, our nutrient chemist) are continually faced with daunting workloads.

We face heavy ice from time to time, but the pack has been loose enough that Captain Joe and his officers can work their way through it. Their performance, along with that of the entire ECO and Raytheon staffs, continues to be exemplary. We find it takes time to meet the engineering staff in parcticular because they keep everything working so well that they are rarely called upon on the science deck. The Palmer is a beautifully maintained research vessel, and a pleasure to be aboard.

We see polar bears from time to time and the other day had a fine photo opportunity with a mother walrus and her impressively large pup. But pretty much it's work, work, work, and in that regard we see early glimpses of a coherency of results that hopefully will provide the SBI science team with ample grist for their mill of ideas.

All is well.

Bearded Seal. Note "ice cliff" mirage on the horizon due to light refraction through dense layer of cold air just above the surface of the ice.

Pomarine Jaeger, a predatory seabird, flies by.

Wildlife watching from the Palmer's bow. From left to right: Jim Waters, Heather Smith, Stephanie Moreland, Jim Swift, Leopoldo Llinas, and Kathleen Gavahan.

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