Week 6: From East Svalbard towards the deep Arctic Ocean

While our bird and sea mammal observation team focuses on these charismatic animals, other scientists continuously monitor properties of the atmosphere using various automatic sensors.

In the framework of atmospheric characterization, the TROPOS remote sensing department utilizes a 35Ghz cloud radar as well as the OCEANET Container including the PollyXT lidar system, a multichannel microwave radiometer, and conducts long- and shortwave irradiance observations and meteorological measurements. Among other scientific applications, this set of observations produces key data to resolve two-dimensional cloud processes for comparison with high-resolution dynamical models.

For the investigation of local transfer processes of marine substances into the atmosphere, aerosols are collected permanently at the TROPOS container on the monkey deck of Polarstern. These samples were acquired either on quartz fibre filters, or size-resolved via five-stage BERNER impactors on aluminium foils. The sea surface microlayer works as a boundary layer between the oceanic water and the atmosphere and is highly enriched in several organic substances. From here, aerosols may enter the atmosphere. Polynyas, open leads and melt ponds as potential sources of these particles are investigated during PS 106. Samples from the sea surface microlayer are collected on a daily basis. 

The group of the University of Trier performs measurements of vertical and horizontal profiles of wind, turbulence and aerosols. The knowledge of wind profiles is of great interest, since the coupling of the ocean and sea-ice surface with the atmospheric boundary layer (and the free atmosphere above) determines the wind-driven sea-ice export of the Arctic. A Doppler Wind LIDAR was installed on the lower Peildeck. It sends out an eye-safe laser beam that is backscattered at aerosol particles and clouds. Using the Doppler Effect, vertical and horizontal wind profiles can be calculated.

The group from the department “Integrative Ecophysiology” at AWI is primarily interested in living individuals of polar cod (Boreogadus saida) for experiments on the physiological resilience of this species to climate change. These experiments will be carried out at the AWI in Bremerhaven and will include analyses at different organismic levels, from molecules to the whole animal, in order to characterize processes limiting fish performance under increasing water temperatures and ocean acidification. In the first fishery attempts using the bottom trawl in about 200 m water depth, a number of benthic organisms was caught, but no polar cod. Some smaller octopuses in good condition were transferred into one of the aquariums in the aquaria container. The octopuses immediately turned the aquarium container into a new attraction on Polarstern, with many colleagues visiting. In spite of the absence of polar cod from the first hauls, the group of physiologists does not lose hope, as many more fishing hauls are planned in the course of the expedition.

Where the Barents Sea shelf drops into the Arctic deep-sea basin, water masses from the shelf encounter Atlantic water advected through the Fram Strait and Polar water from the central Arctic Ocean. To study the complex fine-scale hydrography of these interacting water masses, the physical oceanography team of the University of Gothenburg in collaboration with Aquabiota conducted a high-resolution oceanographic survey across the shelf slope. However, sea ice often blocked the carefully chosen sampling points of our trans-slope transect, and forced us to turn around and start over from the basin up onto the shelf, making this survey a true challenge to crew and scientists on Polarstern. Finally, after 30 hours of hard working, the transect was completed successfully on July 1st. After conclusion of the hydrographic shelf-slope transect, we resumed our sampling programme comprising ecosystem parameters and atmospheric studies. On Sunday 2nd July, a new ice station was started. Today, we are continuing north into the Arctic basin, sampling with CTD, SUIT and RMT.

Best regards from Scientists and Crew,

Hauke Flores, chief scientist

With contributions from Thomas Ruhtz (Freie Universität Berlin), Ulrich Küster (FU-Berlin), Jonas Witthuhn (Tropos), Martin Radenz (Tropos), Sebastian Zeppenfeld (Tropos), Simonas Kecorius (Tropos), Hannes Schulz (Tropos), Teresa Vogl (Tropos), Andre Wetli (Tropos), Xianda Gong (Tropos), Svenja Kohnemann (Uni Trier), Gerit Birnbaum (AWI), Marcel König (CAU), Peter Gege (DLR), Philipp Richter (Uni Bremen), Christine Weinzierl (Uni Bremen), Nils Koschnik (AWI) und Fokje Schaafsma (WMR)