Matthew Alkire, a PhD student in Chemical Oceanography, traveled in April 2007 to the North Pole Environmental Observatory to sample ocean water in order to understand the movement and composition of water masses in the Arctic Ocean. Arctic water masses — the range of natural variability in the system, how much fresh water is coming into the system, and where nutrient-rich waters are — have important implications for climate science and for fisheries. Alkire's research is part of a time series of data gathered since 2000 by Kelly Falkner of COAS and Jamie Morison of the University of Washington.

The greater research community will be interested in what this year's data shows about the relative location of Pacific and Atlantic waters. The two oceans — the Pacific with lower salinity and higher nutrients and the Atlantic Ocean with higher salinity and lower nutrients — meet in the Arctic Ocean. In the late 1980s and early 1990s, a change in atmospheric pressure over the central Arctic forced a change in the Arctic circulation and the Pacific Ocean was "muscled out" of the central Arctic.

Alkire did not get a soft introduction to Arctic science. The scientists arrived in Resolute Bay on April 9, to prepare for the flight up to their ice camp. However, storm winds of 50 knots (~60 mph) blew through the Pole for several days and fractured the ice that made up half the runway. Researchers stayed in Resolute for 13 days, making difficult decisions about what parts of the planned science program could be cut.

Researchers flew into camp in a much smaller aircraft and with more limited equipment and personnel than planned. Still, they were able to sample for one week at 11 observation stations (GPS coordinates). Sampling points were selected on transects from the North Pole.

The process for gathering samples is time-consuming and challenging. Pilots fly to the desired location and then begin looking for a safe landing spot. At each location, a hole is augered in the ice, a CTD (conductivity or salinity, temperature, and depth) instrument is lowered to a depth of 800 meters (one-half mile). This year, a nitrate sensor (ISUS) was added. After the scientists take a continuous profile of the water column, six Niskin bottles are lowered and triggered to sample at selected depths. The bottles are recovered and sampled aboard the plane for nutrients, barium, alkalinity, oxygen isotopes, salinity and oxygen. Researchers are able to sample two or sometimes three locations per day; the time spent at the station between landing and take-off is about three and a half hours.

Researchers can differentiate between Pacific and Atlantic ocean waters by such sampling; the Pacific has lower salinity and higher nutrients than the Atlantic. Other water masses are also identifiable with chemical tracers during sampling. For example, rivers deliver high concentrations of barium to the ocean, which is relatively lower in barium. River water concentrations are often found at a depth of 60 meters and below. The concentrations of river water found in measurements since 2000 is 20% or less most of the time; the concentrations are never above 25%.

Alkire and other researchers are also interested in nutrients in the water masses. The Chukchi Sea, north of Alaska's Bering Strait, is a high production area. How nutrients move within the system and how they vary impacts the ecology. As the globe warms, if the Arctic does indeed become ice free in the summer, the movement of the Pacific water that is feeding primary production in the central Arctic will be important for fisheries (where to go to catch fish). High productivity in the area could also act as a drawdown of carbon dioxide from the atmosphere. 

Alkire has long been interested in oceanography and then in Arctic Ocean research. As an undergraduate, he majored in marine science with minors in chemistry and mathematics. Alkire did a Master's at Florida Institute of Technology with John H. Trefry. His thesis traced Arctic river water plumes moving beneath the ice in May and June of 2004 on the north slope of Alaska.

He came to COAS for a Ph.D. because of Falkner. "If you're a chemical oceanographer and you want to work in the Arctic, Kelly Falkner is the person to come see. I have been fortunate to be able to work with her."

Falkner is presently working at NSF's Office of Polar Research during the International Polar Year. Alkire is also advised by Bob Collier of COAS, who participated in this year's Arctic trip.

Alkire will work toward his PhD for a planned two more years. He will analyze data, take a few more classes, prep for the 2008 field season, and then spend a year analyzing data through 2008 and writing it up. He hopes to stay in the field of Arctic research.

Researchers were held over for 13 days in Resolute Bay, in northern Canada, while waiting for the North Pole runway to be rebuilt after a large storm.

Camp is made each year near the North Pole Environmental Observatory, on an ice floe of the right size and smooth enough to land on with a plane. Camp is operated for a month.

A pilot, co-pilot and three researchers take samples of ocean water on each clear day. They fly to the GPS coordinates of the observation site. Then the pilot looks for a suitable ice floe on which to land and then makes five or six mock landings before committing to the landing.