Dispatch 2: First Science Day!     Print

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Fred Marin and Marshall Swartz

September 13 2019

Good luck was with us today - Friday the 13th - as we successfully conducted science on our first full day aboard the icebreaker CCGS Louis S. St-Laurent. Since 6pm the previous day, the vessel has been steaming west and north towards the first of many stations that will be sampled for the 17^th consecutive year.  Having sailed on many oceanographic research vessels, this was the first icebreaker I have had the honor and privilege to sail on.  The Amundsen Gulf at this time of year was free of sea ice, and the fetch allowed a moderate sea to build which hardly rocked the heavy, steady icebreaker.  A typical non-ice ship would have been pitching and rolling in a sea such as this one.

Given the delayed start (see Dispatch 1) the team had barely set up their laboratory spaces before the ship arrived on the first station (AG-5).  There were four activities during the three and a half hours on station. Two net tows were made down to 100 meters, retrieving plankton for analysis on the ship. Two CTD/Rosette stations were also taken to gather water property data and retrieve water samples in the water column down to near the seafloor at 630 meters.

The net tows are built to carefully filter plankton organisms and retrieve them from the depths without significant damage. The MORPAC net captures samples at precise layers, whereas the Bongo net captures samples over the entire depth of its deployment. Each are deployed and recovered over the ship’s foredeck on a special winch and wire.

During a CTD/Rosette station, a water sampler (Rosette) ringed with sample bottles and holding special instrumentation (including a CTD, short for Conductivity-Temperature-Depth) is deployed on a conducting wire over the side of the ship. The Rosette is carefully lowered close to the seafloor with a winch. The Rosette is then brought back up toward the surface, collecting water samples on the way up under command of a scientist on deck. The Rosette is landed on deck and brought into a protected shack so scientists can collect water samples and prepare for the next station in reasonably safe and comfortable conditions.

The water samples collected in the sample bottles will be analyzed on ship or ashore for water properties and contents including salinity, dissolved oxygen (DO), alkalinity, Colored Dissolved Organic Material (CDOM), nutrients, barium, DNA and others … just to name a few!