Dispatch 6: Arctic CO2     Print

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Fred Marin

September 17, 2019

Location: 77° 18’ N 143° 19’ W

Sea Conditions: 3763m water depth; patchwork of thin floes of ice covering the sea surface.

Today, after sampling station PP7 late Monday night, we traveled west and to a lesser degree (pun intended!) north to cover stations CB-15, and CB-13 towards the center of the Canadian Basin.

The CCGS Louis S. St-Laurent, is a large vessel with many work spaces hidden throughout the upper levels of the ship.   In the main laboratory, there are scientists busy processing samples between stations.  Others are busy writing reports, developing data processing code, and completing cruise logs in the science meeting rooms.  In the forward laboratory, there is another group of scientists who since boarding the ship have been preparing autonomous instrumentation that will remain deployed in the Arctic Ocean for 12-24 or more months.  For this year, aboard the CCGS Louis S. St-Laurent the autonomous instrumentation that will be deployed in the upcoming days are: four Ice-Tethered Profilers (ITP), two of which will have a Submersible Autonomous Moored Instrument measuring pCO2 (SAMI-CO2); and one Tethered Ocean Profiler (TOP), a new profiler which we will discuss in greater depth later in the cruise. 

The Beaufort Gyre Exploration Project is highly collaborative, and uniquely one of the constituents is from the University of Montana (you don’t have to live near the ocean to be an expert, and to study it!).  Representing Professor Mike DeGrandpre’s laboratory is Cory Beatty, who has been sailing aboard the CCGS Louis S. St-Laurent deploying SAMI-CO2 instruments on ITPs routinely since 2012, and on BGOS subsea moorings since 2013.  The SAMI-CO2 is a spectrophotometric instrument measuring the partial pressure of Carbon Dioxide (pCO2), or the concentration of CO2 that is dissolved into the Arctic Ocean surface waters through the air-sea interface.  Additionally, the SAMI-CO2 also measures: Photo Active Radiation (PAR); Dissolved Oxygen (DO); and Temperature.  The instrument takes a measurement every one or two hours (depends how it is programed for a particular deployment) for 18-24 months, or more!  The SAMI-CO2 attaches to the ITPs mooring cable and collects data from a fixed depth at ~4m below the ice/sea surface.  Data from the instrument is transferred back home via satellite when the ITP calls home twice daily.  The SAMI-CO2 is important for examining how ice cover affects CO2 flux between the air-sea interface and CO2 acidification in the Arctic Ocean.

Thank you for keeping up with us on our Arctic Expedition.  Check in with us again tomorrow where we plan to deploy our first ITP for this expedition in open water over the side of the ship!