Mud and Moorings

It has been a very busy start to our second FjordEco cruise with lots of coring and mooring operations at Station B (our outer shelf station) and in Andvord Bay. The sediment trap mooring at Station B was recovered smoothly and presented 20 bottles of preserved material that has been sinking to the seafloor over the last 5 months. From this mooring we will be able to determine the flux of carbon (i.e. the amount of food) sinking to the animals on the seafloor. This is important as these animals get little additional food during the winter when sea ice is thick and phytoplankton do not have sunlight to grow. It will be interesting to see how this flux compares to that in the fjord from the second sediment trap.

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Photo by A. Ziegler.

On our way to Andvord Bay we retrieved two physical oceanography moorings that were deployed in the Gerlache Strait back in November. The deeper mooring extended from 200m below the surface to the bottom at roughly 330m while the shallow mooring captured the upper water column from 20m to approximately 150m. This mooring was designed to detach from its flotation if hit by large icebergs. When the mooring surfaced we found the float was missing and the pressure sensor data revealed that the mooring had been hit several times by ice and dragged before breaking loose. Luckily the design allowed for the return of the instruments which continued to collect data at deeper depths without floatation. The physical oceanography team has downloaded all of the instrument data and is now processing and interpreting it all. These two moorings will give a long-term picture of the water properties (temperature, salinity, oxygen) and water movement over the outermost sill of the fjord. This is an important location for determining water exchange in and out of the fjord.

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Photo by D. Brinkerhoff.

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Photo by D. Brinkerhoff.

The FjordEco team then moved into the inner basin of Andvord Bay to investigate ice conditions for our other operations. The ice was clear enough for the benthic team to begin coring. We conducted successful boxcore, megacore and Kasten core deployments. During these operations, the air temperature rose 6°C which brought continuous heavy rain and winds of over 70 knots. Even the experienced crew have rarely seen such conditions in this area. After core sampling, we moved to the middle basin of the fjord to retrieve the time-lapse camera mooring.

The time-lapse camera captured a still image of the seafloor every 6 hours from deployment on December 5, 2015 to recovery on April 6, 2016. The benthic team now has 488 images to compare and analyze. Stay tuned for more about the exciting footage captured by the camera as well as the first trawl of the cruise and deployment of the sea glider!

Written by Amanda Ziegler.

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