Between boxes and containers

Our first heading was north east to cross the Barents Sea. We want to conduct a transect east of Svalbard (the archipelago with its well-known main island Spitsbergen) into the central Arctic up to the North Pole. The Barents Sea is a shallow shelf sea with 200 m water depth while the central Arctic has more than 5000 m deep basins. There are more differences between the two. Our transect shall help to understand how the transition between Arctic shelf seas and deep basin shapes ocean currents, ecosystems, and biogeochemical cycles.

So we started right away on Tuesday with the first station to take samples of sediment from the seafloor with a so-called Multicorer. This device consists of 8 cylinders that are lowered on a steel wire to the sea floor and are then pressed into the mud to collect mud samples. This works similar as the toys that children use at the beach except that the samples have to be taken blindly and at 200 m depth or deeper and thus much skill is needed. A plethora of organisms live on the sea floor feeding on tasty particles that sink from the near-surface waters. Taking up the food, the organisms consume oxygen just as we do.

Our two benthos specialists take the small mud cores into their cold lab (it is kept at polar deep sea temperature, hence at zero degree C) to measure how much oxygen is respired over time and from this they can tell how well developed life is on the sea floor of the Barents Sea.

As part of standard observations we continued our program by measuring the temperature and salinity of the sea water. We will measure these two basic parameters continuously for the coming two months using a multitude of instruments. At first we took our brand new “Underway CTD”. A small winch is mounted at the stern of the ship. As the ship is steaming, it releases a thin rope which has a small aerodynamic probe attached. The probe carries sensors for temperature, pressure and electric conductivity – from these the salinity can be calculated later on. The probe sinks to depth, and when the rope is fully released the winch rewinds it. It reappears at the surface, gladly welcomed by the watching scientist and by hungry sea gulls – and down again it goes for the next profile. Thus for the whole day the Underway-CTD cycled up and down like a spinning wheel and the members of the oceanography group were competing to be allowed to stand at the rail enjoying the sunshine, watching the waves and the birds, and every now and then pressing a button. This pleasure stopped, however, with the appearance of the first ice floes.

On Friday noon, the northerly winds in the wake of a small low pressure system sent us frosty temperatures of -1°C and the first sea ice. In the course of the day, the ice cover grew telling us we had arrived in the Arctic! Soon the first polar bears showed up, welcomed by a crowd of excited photographers. But giving us at the same time a silent warning for the imminent ice stations that so much care should be taken to avoid any encounter with them.

Yet the ice floes are still too thin and too small to work on. Hence, for the time being we continue a series of hydrographic profiles along 30°E northwards. Why we do these measurements will be the topic of the next week’s report.

Best regards by the whole team!

Ursula Schauer