Parasound training cruise on "RV Polarstern"
Report by Jacqueline Krause-Nehring
In October 2009 the research vessel “RV Polarstern” was sailing from Bremerhaven to the Canary Islands (expedition ANT-XXVI/1a) on its way to Punta Arenas. Together with four other students, I participated in a two-week parasound training course given by Prof. Kuhn (Alfred-Wegener-Institute) on board the ship.
The parasound system on “RV Polarstern” is a hull-mounted parametric sub-bottom profiler, which can be used to explore the water column and seabed structure from 10 m to full ocean depth and which is able to penetrate the seabed more than 200 meters. The system utilizes the parametric effect to create a low frequency secondary signal by emitting two primary signals of higher frequencies. The parametric low frequency signal combines the high spatial resolution of the primary high frequency signal and deep sediment penetration with high spatial resolution.
As participants of this course, we were trained in techniques for high resolution sub-bottom sediment acoustics, ran the Polarstern parasound in watches, and learned about data storage, interpretation, and visualization.
Besides being trained in operating the parasound system, our stay on board gave us the opportunity to get insight into a variety of different research activities, sampling techniques, and data collection at sea (e.g. Hydrosweep DS-2 measurements, CTD operation, collection of deep sea sediment samples, and much more). The parasound training course as well as my stay on “RV Polarstern” was a fascinating experience and great opportunity to learn more about research outside my own field of science.
On board of research vessel "RV Sonne" in the West Pacific
Report by Theo Ridder
The campaign with research vessel “Sonne” started on 9th of October in Tomakomai, Japan. According to schedule it was planned to cast off in the early morning, but due to the hurricane “Melor”, that crossed Japan during these days, we left Japan with a bit delay. During the first days we strongly felt the offshoot of the hurricane, and the swell from behind made the work on board complicated and stressful.
The first leg of the cruise was a two-week-transit to Australia. Within the project TransBrom the aim of this leg was to analyze the transport of trace gases from the ocean through the troposphere into the stratosphere. For this purpose a variety of measurements systems (e.g., balloon sounding, MAX-DOAS, flask sampling sys-tems, etc.) from different working groups were set up on board of the ship. We con-tributed to the project with solar absorption and in-situ measurements.
Our measurement systems were mounted inside a ship container. For the solar ab-sorption measurements the light of the sun was directed via a mirror system on the roof of the container inside a Fourier Transform InfraRed (FTIR) spectrometer. The spectrometer measures the solar absorption spectrum of the sun, from which the concentrations of about 20 trace gases can be calculated.
In addition to the solar absorption measurements we performed in-situ measurements of trace gases with a FTIR analyzer. Air from outside was continuously pumped into the system to analyze the composition of the ground-level atmosphere.
After 17 days on sea we reached Townsville, Australia. In Townsville, the scientific goal of the cruise changed. While most researchers from leg I started back for home a group of geologists entered the ship. During this time, we were ready for shore and glad to leave the ship for two days.
Leg II started on the 29th of October with heading north towards the Woodlark Basin close to Papua New Guinea. While the geologists were looking downwards into the ocean, seeking for underwater volcanoes, we continued our atmospheric meas-urements during the whole leg.
We stayed in the Woodlark Basin for about five weeks before we were heading to-wards Auckland, New Zealand. On 6th of December we finally reached our port of destination.
The Southern Ocean’s role in Quaternary climate cycles
Report by Franziska Kersten
During the expedition ANT XXVI-2 with RV Polarstern, my main task was the work in the Multicorer (MUC)-team. My day-to-day (or more night-to-day-to-night) job included work on deck, such as unloading the samples and cleaning the MUC, as well as work in the lab, which entailed recording the recovery in various lists, lists and even more lists (analogue and digital), air-tight packing of the cores and freezing them.
But what is a MUC, how does it work and why did we deploy it at 50 stations during the cruise? The MUC is an instrument which obtains surface sediment samples, which are often disturbed or lost in piston or gravity cores. It is ca. 2m high, lands on spider-legs on the seafloor and, using heavy lead weights, pushes 12 plastic tubes into the sediment. During careful heaving of the instrument, the tubes are automatically closed, with sediment trapped inside. The retrieved surface sediment is in demand in various sub-disciplines within Marine Geosciences such as Micropaleontolgy and Geochemistry. In combination with surface water samples it is essential for core-top calibrations.