The Synoptic Arctic Survey (SAS) which is funding the expedition as a whole is an initiative that seeks to define the present state of the Arctic Ocean and understand the major ongoing transformations, with an emphasis on water masses, the marine ecosystems and the carbon cycle.

Our project, called ProMis, complements this program. We are focused on understanding how particles interact with fungi and impact the carbon cycle in the Central Arctic Ocean (CAO). This is why we're collecting water and ice samples on IB Oden.

Once we have collected our water and ice, we take our samples to our lab container which is at the front of the ship. We have a nice view of the ice in front of the ship and of the CTD winch collecting our water. Inside our container, we have a sink, a freezer and work benches where we have set up all our filtration equipment. We use two six funnel filtration manifolds which use a vacuum to suck the water through the filters. In addition, we have large 60L plastic boxes that we use as melting tanks to melt our ice core sections as quickly as possible at a controlled temperature.

Once we have the CTD water and the ice cores are melted, we take samples for different parameters. We sample for DNA to look at which microbes are present in the Arctic and lipids to give us a better idea of the biomass distribution. We're also interested in two types of particles, and how they interact with microbes. One type, TEP, are sugar-rich particles that are produced biologically, namely by algae that are either floating in the water column or associated with the sea ice. Microbes like to eat TEP, especially in regions like the Arctic where food is not readily available.

Gypsum on the other hand is formed physically in the sea ice at low temperatures and forms crystals. Even though gypsum doesn't get eaten by microbes directly, TEP can stick to it. In that way, TEP, that on its own is rather light, gets heavier and sinks out of the water column, taking down all the sugar and any microbes that are attached to it, with it and thus adds to the carbon export.

Although most of our analyses are done back at the lab, we are already seeing signs of biomass on our filters, especially from the ice samples. With the small microscope that we brought on-board, we can even see the first TEP and we are looking forward to properly analysing the samples back home in the lab.

Kim and Birthe

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Aug 31, 2021 By nerblo