Day 8: Canadian Arctic GEOTRACES Expedition

By Jay T. Cullen

Surface wind map of the Labrador Sea from July 16, 2015. Our first sampling occurred roughly in the centre of the map. Winds were ~30-40 knots during this period. Image by

We are now on Day 8 of the Canadian Arctic GEOTRACES Expedition the goals of which were stated in a previous diary. We left Quebec City on July 10 and have been moving farther north in the Labrador Sea to occupy two planned deep water sampling stations there before moving into the Baffin Basin.

The image above was generated using a great visualization tool by Earth which renders modeled atmospheric and ocean weather conditions. We have been experience a little weather over the past week beginning when we entered the Labrador Sea through the Strait of Belle Isle. The Captain of the icebreaker CCGS Amundsen is Alain Gariépy and he and his crew have been fantastic in scheduling our work and the ships course to minimize our exposure to weather and handling operations on the deck to achieve our objectives respectively.

Our work is quite specialized in that we wish to measure miniscule amounts of metals (parts per trillion and lower) in seawater. This requires us to be very mindful and take extreme precautions to avoid contaminating our sample with metal from the ship (hull, equipment, oil etc.) and ourselves. At every turn we attempt to minimize use of metal in the manufacture and construction of our gear. One of the specialized pieces of gear we use is a frame that holds water sampling bottles (called a rosette for obvious reasons if viewed from above) and sensors to measure seawater salinity, pressure (depth), temperature and dissolved oxygen. The frame is of aluminium (or aluminum if you prefer) that is powder coated to minimize metal contamination. The sampling bottles themselves are of PVC and the interior of the bottles are coated with Teflon. The whole instrument package is deployed on 5000 meters of non-metallic wire (vectran strength member coated with polyurethane) which allows to sample to the bottom of the major ocean basins we will visit on this trip. My PhD student David Janssen is shown next to this sampling rosette here with our clean sampling container in the background.

Dave next to the rosette on the CCGS Amundsen July 18, 2015 in the Labrador Sea.

One important part of any sea voyage north is the crossing of the imaginary line demarcating the Arctic Circle (~66°33′45.8″ N). This is the latitude above which there occurs 24 hours of daylight during the course of the year. Sailors crossing the major circles (Arctic, Antarctic, Tropics and Equator) go through a “ceremony” to be welcomed into the Kingdom of Neptune (God of the Sea). While I have previously crossed the Equator I have yet to cross the Arctic Circle and therefore am subject to the ceremony. Those who have previously crossed are having some good natured fun at our expense leading up to the ceremony. More detail on that later. How many of you have been through such a ceremony?

We will finish sampling our second station today and head north again to approach the circle and our next station in Baffin Bay. Below find some recent images from the expedition.

Northern Fulmars curious about our sampling operation this morning on a calm Labrador Sea. The sun was out too!

Working with UBC student Manuel Colombo to terminate our clean sea cable that deploys the trace metal rosette. The termination is a vectran tailed stainless steel stopper. The vectran is braided around the main cable to securely grab the sea cable and take the rosettes load.

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