PS93.1 Weekly Report No. 1 | 29 June to 5 July 2015
From Longyearbyen through Fram Strait towards Northeast Greenland
At 8:00 am the embarkment of scientists starts. As Polarstern cannot enter the harbor pier directly, people have to use the Zodiac (Fig.1).
Monday , 29 June 2015. At 8:00 am the embarkment of scientists starts. As Polarstern cannot enter the harbor pier directly, people have to use the Zodiac (Fig.1). At 10:00 am, we are complete, ready for departure, and around noon we leave Longyearbyen, onboard 44 crew members and 50 scientists, helicopter pilots, and technicians from twelve different countries. Slowly, we steam through the fjord system towards the open sea and Fram Strait. Most of the scientists, especially the newcomers, are outside, impressed by this fascinating scenery.
Where are we going? What are the major goals of this expedition? The overall scientific goal of the marine-geological shipboard and following onshore work is to investigate the variability of key environmental parameters in the Fram Strait during warm periods (interglacials) of the geological and historical past. Of special interest are the last interglacial (Eemian, around 130-120 thousand years ago) and the Holocene (last about 12 thousand years). Key environmental parameters are the extent, density, and nature of the sea-ice cover, the properties of the water masses (temperature, salinity and stratification), the rates and causes of changes of these parameters, and the coupling of Fram Strait variability to the Arctic Ocean and the North Atlantic. On short (multidecadal to centennial) time scales details of this variability are unexplored so far, except for the Holocene in the eastern Fram Strait. To analyze the short-term climate variability, during the Expedition PS93.1 long sediment cores will be obtained from areas with potentially high sediment accumulation and analyzed for a large variety of paleoceanographic and paleoclimatic proxies in home laboratories and in collaboration with international partners. Target areas were selected on the NE Greenland continental margin, in the central Fram Strait and on the western Svalbard margin.
In addition to the marine-geological program that is the major focus of this expedition, several supplementary programs will be carried out:
· Recovery of oceanographic mooring systems and deployment of Sea-Gliders in the central Fram Strait (physical oceanography)
· Sampling of phytoplankton for cultural experiments (biology), and
· Measurements of water vapor and its isotope signature (atmospheric chemistry/glaciology)
Besides the scientific research program of Expedition PS93.1, a “Floating University” will be held onboard Polarstern under the umbrella of the International Research Training Group “Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic - ArcTrain”. Within this program, about 20 Canadian and German PhD students will be introduced to technical aspects of field work in marine sciences as well as to the concepts of teamwork, interdisciplinary and international collaboration and project leadership.
Tuesday, 30 June 2015. The first working day is dedicated to oceanographic work: Moorings are to be recovered – long chains of instruments for long continuous measurements of temperature, salinity and current velocity. They were left behind in the central Fram Strait last summer because of extreme sea-ice conditions and lack of ship time.
The search for the first mooring remains unsuccessful. However, a new mooring can be deployed at the same location, which resembles more a UFO than the usual chains (Fig. 2). The second mooring is located 12 miles toward the east. The sun returns and visibility improves. Many people gather on the bridge and the uppermost deck to spot the orange and yellow glass spheres that mark the upper end of a mooring. These flotation devices are finally discovered around lunch time. Because of the calm and sunny weather it is an easy task to bring them in. At about 20:00 three out of four moorings are on deck – a successful day for our oceanographers!
Around the same time the geologists are still searching for the perfect location to deploy the “kastenlot” (a coring device with a large rectangular cross section that greatly reduces the perturbation of the sediments). Then exactly at midnight the 12 m-long device equipped with a 3.5 t weight on top penetrates the sea floor at 79°12.2’N, 04°40.0’W and a water depth of 1570 m. Expectations are high when the kastenlot returns to deck (Fig. 3), and indeed, judging from the muddy outside the penetration depth was about 7.5 m. But how long is the sediment core really? What is actually inside the metal case? These questions we can only answer when the case is opened.
Wednesday, 1 July 2015. In the early morning hours, we are heading towards the north. Temperatures are decreasing, and we sight the first sea ice at 3:00 am at 79°14’N, 04°30’E. Four hours later we encounter the first sea ice directly. At noon thick fog is developing, and the sea ice is becoming denser and denser. Hopefully, we can continue our sight survey using the Hydrosweep and Parasound systems to map the seafloor and the uppermost sediment layers. Fortunately, the fog is clearing up, the helicopters can take off to check the ice conditions and find a way through the ice.
As early as 5:30 am on this day a few lucky people get to see a female polar bear with her two cubs (Fig. 4).
Thursday, 2 July 2015. Today we initiate the “ArcTrain Seminar” in the cinema/lecture room of Polarstern, starting with a short course for the ArcTrain students on visualizing and analyzing shipboard data on laptop computers.
In the evening, the fog has finally dissolved and between the sea and the low-lying clouds a thin band of sunshine appears, creating a very special atmosphere of solitude and peace.
Friday, 3 July 2015. We reach the eastern Greenland shelf. Parasound data from last year’s cruise to this region suggest that very old sediments or rocks outcrop at the seafloor, possibly dating back to the Cretaceous. The gravity corer is deployed four times, however, when it hits the seafloor it just turns over, because the rock is too hard. We decide to continue to the north, and we pass through extensive fog but a calm sea and little ice to reach the large polynya (a nearly ice-free area) at the north-eastern corner of Greenland (Fig. 5). Here we select several stations. At one station where we again deploy the kastenlot we successfully recover a particularly beautiful long sediment core (we will report on the kastenlot findings in the next issue of the weekly report).
The weekend not only brings lots of sunshine with a brisk and clear air (very different from the heat that currently plagues central Europe and North America) but another highlight: Those who participated in last year’s cruise PS87 celebrate reunion with Yngve Kristoffersen and Audun Tholfson (Fig. 6), whom along with their hovercraft we took to the central Arctic Ocean where we left them on 30 August 2014 on a large ice floe near the Lomonosov Ridge. Within the last ten months – during the winter in complete darkness – the ice floe with the camp, hovercraft and its two passengers on board drifted through the entire Arctic Ocean. This is a great achievement, and we congratulate Yngve and Audun on their success! However, the Hovercraft experiment is not quite over yet, and we will give an update in our next report.
The first week is over, and it will leave lasting impressions especially on those who travel the Arctic for the first time (see also the AWI Expedition Blog, which during our cruise is maintained by the ArcTrain students).
Kind regards to all our friends and families at home,
In the name of all cruise participants,
Rüdiger Stein (5 July 2015)