The year 2016 comes to an end and the AWI dive-group looks back on three busy and successful dive-missions in Svalbard's Kongsjord on 79°N.
The group opened the diving-season in the middle of winter in February 2016 when three AWI divers together with a team of technicians from 4H Jena and from the French cooperation partners "Laboratoire d'Océanographie Villefranche" travelled to Ny Ålesund. Their mission during this early time of the year was the regular surface- and underwater maintenance of the "Spitsbergen Underwater Observatory" (COSYNA@AWIPEV Underwater Observatory).
This observatory is located at the south shore of the Kongsfjord (West Spitsbergen) and includes various scientific instruments at land and under water. The observatory makes continuous remote controlled measurements of the main oceanographic data such as temperature, salinity, oxygen, turbidity, pCO2 and others. The system also supports a permanent operating ADCP (Acoustic Doppler Current Profiler - fig. 5) for continuous current and wave measurements, a remote-controlled stereo-optical unit to assess species abundance and length-frequency distributions of the macrobiotic community including the fish (fig. 3) and instruments from cooperating institutes (fig. 6).
The system is completed by a land based "ferry-box" system pumping seawater from the observatory's base station in 12 m water depth for further water analysis and sampling. Since this base unit including the seawater pumps and the so called under water node (the underwater supply unit for power and network - fig. 2) is operated year-round, it is heavily exposed to the harsh arctic conditions such as low temperatures, currents, high sedimentation and the omnipresent threat by drifting ice and icebergs. Therefore, together with the regular maintenance, the dive-team had to repair some ice caused damages and exchanged some technical parts and instruments to bring the observatory back to a 100% operating status for the upcoming season.
Even though the permanent darkness of the polar winter (fig. 1) was already replaced by some dawn light at least for a few hours per day, the divers under water had to work in almost complete darkness with underwater lights mounted to their equipment to illuminate the working area. Finally, everything went well during this first mission and even the repositioning of a 400 kg concrete anchor-block which was displaced by an iceberg, worked out quite well in complete darkness.
Unfortunately, only few weeks after the AWI dive team left NyAlesund, another iceberg hit the underwater cable so that the communication to the underwater part of the observatory started to become critical. With the help of the AWIPEV station personal, the REMOS part of the underwater observatory (the camera- and profiling observation unit of the COSYNA@AWIPEV Underwater Observatory) could be "parked" safely on the seafloor. Fortunately, the land based "ferry-box" system could be still operated in an emergency mode so that the measurements of the basic hydrographic variables could be continued. Because of this damage, the AWI dive-group carried out a second mission in April to repair the underwater system and to resolve some further damages.
During this second stay, the daylight was back, the weather conditions were good and the dive locker including the dive boat were prepared within 1½ days, so that the second mission could start. For this stay, a team of three experienced divers were chosen to recover the underwater observatory system, to exchange parts, repair pumps and bring the whole system back into operation mode within a few days.
The third dive-mission in 2016 took place in September/October for eight weeks with the overall goal to collect more scientific data and information on the polar fjord system during autumn and beginning winter. During this stay, the dive team supported a total of eight different scientific projects with seven projects, partly with own diving scientists on site which were integrated in the core dive team. The main task for most of the projects was the collection of samples such as macro algae, benthic animals or sediment cores. Furthermore, several experimental underwater set-ups had to be installed, maintenance of existing set-ups had to be carried out and long-term experiments had to be checked and evaluated. Additionally, the underwater observatory was upgraded by two new concrete fundaments carrying new light-loggers (PAR). In this regard, special thanks goes to the department "AWI technical workshop" (Erich Dunker and Matthias Littmann) which provided us, as always over the last years, with perfect scientific equippement to install and improove the under water installations at the Svalbard observatory.
Unfortunately, unusual strong rainfall and relatively warm temperatures dominated the last time of the year 2016 so that high sedimentation-rates caused a quite bad visibility under water, which sometimes made our efficient work under water quite problematic. Nevertheless, at the end everything worked out, all experiments for the winter season 2016-2017 were installed and all involved parties are looking forward to the winter results in spring 2017. Altogether, during the 2016 Svalbard dive-missions, the AWI dive team did more than 120 dives in the Kongsfjord with a total of eight different divers, supporting nine scientific projects with at least four scientific institutions involved.