March 27, 2017
Location: Bellingshausen Sea continental shelf
We have been collecting sediment cores for over a week now and so I can share some pictures showing how the cores are deployed and retrieved from the back deck of the ship.
We were in the deep ocean (>4000 m of water depth) most days last week, but since a couple of days ago we are on the continental shelf in much shallower water (~600 m). Up to today we have been to 9 locations collecting gravity cores, box cores, and multicores.
Box cores are a new addition to the cruise plans and we are using them instead of the multicores in some areas. Although multicores would be the preferred choice, box cores have a better potential to recover sediment. The box core is literally a metal box (about 70cm tall, 50cm wide, and 30cm long) that is lowered to the seafloor and collects about ~50cm of the sediment below the seafloor. When it is on the back deck, we have to subsample the sediment in the box using long plastic tubes so that the sediment column stays intact.
Yesterday we visited Eltanin Bay and we were only a few kilometers away from land. We collected some sediment and multibeam data. This was exciting because no other expedition has been able to recover data in this area of the bay. In fact, glaciers covered this area of the
bay until about 5000 years ago, according to some publications. And so it will be exciting to know what has been depositing in the seafloor during the past few millennia. The surface sediments (close to or on the seafloor) have an olive green color, possibly from a lot of diatoms, but the color of the sediment changes down core to a light grey color, which tells us there is not much organic matter in the sediment and it may be mostly silt and clay particles. In other areas we have seen light brown sediment and some dark grey, although the color alone cannot tell us much, it can give us an indication of what
is in the sediment.
No penguin sightings yet!