arctic-trace-feature-970 FROM THE FIELD
TRACES of Change in the Arctic

Moving into the Realm of the Polar Bear

by |August 24, 2015
Looking out over the Arctic sea ice as the ship moves out over the deeper ocean. (Photo credit Tim Kenna)

Looking out over the Arctic sea ice as the ship moves out over the deeper ocean. Photo: Tim Kenna

The Healy has now moved off of the shallow continental shelf that extends around the Arctic land border (shown in white in the map below) into the deeper center of the Arctic Ocean. In our last blog we noted that some of the questions Arctic GEOTRACES is addressing include quantifying the fluxes of trace elements and isotopes into and out of the Arctic Basin from the two oceans through choke points like the Bering Strait, as well as characterizing how much comes from rivers. Arctic GEOTRACES is also studying what regulates the Arctic shelf to deep basin exchange, and the role of sea ice in the transport of trace elements and isotopes. (Follow the expedition here.)

The position of the research vessel Coast Guard cutter Healy on August 24, 2015.

The position of the research vessel Coast Guard cutter Healy on Aug. 24, 2015.

The oval shaped blue area in the map above is the basin of the Arctic Ocean, ranging from ~3,500 meters to ~5,000 meters at its deepest. The Healy is currently over a ridgeline named the Mendeleev Ridge, after a Russian chemist and inventor, Dmitri Mendeleev, long dead when the ridge was first discovered by fellow Soviets in 1948. Mendeleev Ridge is about 1,000 meters shallower than the deep Arctic, bottoming out at ~2,500 meters in depth. The Russians maintain that the ridge, with its long reach into the Arctic basin, gives them claim to large sections of the ocean stretching out to the North Pole. The claim remains unresolved, in part because there are so many questions that still remain about the Arctic. As we move into the basin, we will be sampling to try and better constrain what happens at the shelf/basin interface.

polar bear text

All hands on deck alert – huge polar bear 100 yards ahead! Photo: Tim Kenna

When we venture into the Arctic for research, for most of us there is the lingering hope that a polar bear will appear on our watch; at least as long as we are safely outside of its reach. Several polar bear have been spotted by the watchful eyes of the crew as we have moved into the more tightly packed heavy ice away from the marginal ice zone. However, today a very large bear (yes the alert text says “huge”!) was spotted, and it seemed to have us under thoughtful consideration. The following is a string of images that relay the majesty of this incredible creature in its natural environment, moving with great agility over the sea ice.

Polar Bear takes a drink. Photo: Tim Kenna

Polar bear taking a drink and assessing the ship full of researchers. Photo: Tim Kenna

Polar Bear (photo credit Tim Kenna)

Polar bear carefully testing the thinning stretch of sea ice.  Photo: Tim Kenna

Polar Bear (photo credit Tim Kenna)

The polar bear coloring matches easily to the Arctic ice surroundings. Photo: Tim Kenna

Polar bear live only in the Arctic and rely almost entirely on the marine sea ice environment for their survival. They use the ice in every part of their daily life, for travel, for hunting ringed seal, their favorite food, for breeding and in some cases for locating a birthing den. Their wide paws, which you might be able to see in these photos, distribute their weight when they walk on the sea ice, which late in the season can be quite thin in the annual ice region, melting down to only a thin crust over the water. Their large size, clearly visible in these photos, belies the fact that they are excellent swimmers, helped by their hollow fur, which traps air to keep them buoyant, as well as the stiff hair and webbing on their feet. For all their cuddly appearance, they are strong hunters. Currently polar bear range in conservation status from Vulnerable internationally, to Threatened in the U.S., primarily the result of a warming climate that is melting their habitat…sea ice.

Polar Bear moving easily across the ice. (photo credit Tim Kenna)

Polar bear move easily across the ice, even though males can weigh up to 1,500 lbs. Photo: Tim Kenna

Polar bear

Polar bear use their natural agility to avoid the thinner sections of sea ice. Photo: Tim Kenna

Polar Bear takes measure of the Healy. (Photo credit Tim Kenna)

Polar bear takes measure of the Healy. Photo: Tim Kenna

Polar bear taking a moment to drink. (Photo credit Tim Kenna)

Polar bear taking a moment to drink from an open lead in the Arctic. Photo: Tim Kenna

Arctic Sea Ice Extent

Daily Arctic sea ice extent Aug. 23, 2015. Source: National Sea Ice Data Center

The Arctic is approaching the annual low for sea ice extent, which occurs each year in September. An image of sea ice extent for today (shown in white) against an average of the last thirty years (outlines in yellow) shows how our annual sea ice cover has dropped. Today’s cover is 2.24 million square miles (5.79 million square kms), which is  521,200 sq. miles (1.35 million square kms) below the last 30 year average period. Aside from being of concern to the polar bear, this is part of why Arctic GEOTRACES is so important. We need to understand the role of sea ice in current circulation patterns and delivery of trace elements and isotopes in the Arctic, and then bring this more complete understanding forward to our careful examination of the changing Arctic.

Tim Kenna captures himself in the field surrounded by Arctic sea ice. (photo credit Tim Kenna)

Tim Kenna captures himself in the field surrounded by Arctic sea ice.

Margie Turrin is blogging for Tim Kenna, who is reporting from the field as part of the Arctic GEOTRACES, a National Science Foundation-funded project.

For more on the GEOTRACES program, visit the website here.


5 thoughts on “Moving into the Realm of the Polar Bear

  1. julie barker says:

    Great photos by a scientist in the field, and a very clear description of some of the stakes we face due to the shrinking sea ice cover.

  2. Brett Keane says:

    I’ll hazard an estimate that sea ice is in a similar state to the late 1950’s (which I remember, when my old neighbour was driving a farm tractor across Antarctica); past the cyclic minimum and increasing in volume and area, as measured.

    Also, that U. maritimus is very happy out on the floes, even scattered ones, in the mosquito season after another good hunting year. That said. good luck and research up there; please try not to get frozen in! Unless of course that is the intention. Brett Keane, New Zealand

  3. Hi Brett – Sea ice extent and thickness in the 50s was measured in much different ways than today’s more comprehensive look from space, although even today we can capture extent much better than thickness. We do, however, have a 40 year history of measurements from space and can watch the ice trajectory head downwards. From the 1950s we have discrete measurements from submarines and from floating stations set up on the ice floes in the 50’s. Lamont scientist Ken Hunkins was stationed to collect data on floating ice Station Alpha for almost 2 years and expanded our understanding of the Arctic throughout his career.

    If you are referring to the cyclic minimum which happens annually, yes mid Sept. each year we get the sea ice minimum. We should hit that minimum any day now and then as you note, as the temperature cools for the winter it will begin to rebuild.

  4. Johnny says:

    That’s awesome!!

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