Except for its surface skin the ocean has long defied human observation. Remotely Operated Vehicles (ROV) now offer the opportunity to extend the vertical range of human exploration far beyond the reaches of conventional SCUBA-diving. Equipped with high-resolution cameras and sensor packages, these unmanned submersibles transmit their data via umbillical cable to the surface, allowing researchers and engineers to collect stunning seafloor images and environmental information in real-time. While the collection of samples has so far been the privilege of large multi-million dollar ROVs operated by teams of engineers, the cleft between these so-called working class ROVs and the much smaller inspection class ROVs is narrowing: engineers and scientists from BPP and industry have now managed to mate a small inspection class ROV with a 7 degrees-of-freedom hydraulic arm, creating the likely smallest working class ROV to date. With a vertical range of 500 m permitting access to the Antarctic continental shelf, this system was deployed during the Polarstern cruise PS96 to explore the hanging benthos below the 150m thick shelf ice in the Drescher Inlet. Polarstern cruise PS111 offered the first time a chance to explore the grounding line where the antarctic shelf ice meets the sea-floor. Various missions operated from Polarstern, the antarctic sea-ice, or from small boats show the enormous potential of such hybrid-technology. Because of it 360 degrees of freedom, the ROV is able to operate upside down and therefore capable investigating struktures underneath rocky slopes, caves or beneath the sea ans shelf ice respectively.

The sampling of the seabed and the water column above is obligatory for the scientific work of the BPP section in order to obtain essential data.

We take water and sediment samples in the Weddell Sea (Antarctica) and Patagonian fjords (Chile), supported by well-equipped large research vessels such as the icebreaker POLARSTERN as well as but also by small, open working boats. Water samples: Niskin bottles, named after their inventor, take a defined amount of water at desired depth by closing the end caps of this tube-like bottle. As a rule, several bottles are always lowered together at depth. Each bottle „catches“ water from different depths. The bottles are locked at depth and taken on board the ship for analyses. In-situ measurements of physical water properties are carried out by CTD (Conductivity Temperature Depth) units, that is lowered together with the bottles. Seabed samples: in order to analyse the sediment of the seabed under laboratory conditions, cylindrical sediment samples of ca. 30 cm length are punched by Multicorer (MUC) and taken on board.

Henning SCHRÖDER

With the help of underwater cameras we document species, animal communities and habitats without destroying them (e.g. in contrast to trawling). To avoid that plankton is attracted like moths by the light of the spotlights, we use infrared cameras, which allow us to determine the plankton as food resource for cold-water corals in their natural habitat. Sometimes it is necessary to collect individual corals for laboratory experiments or tissue analyses. This is done by carefully using hammer and chisel to separate the individuals from the rocks. Scientific divers are indispensable for more complex underwater experiments. One example is the positioning of our Eddy measuring system on a coral and control wall (photo). For this it was necessary to drill holes with an underwater drilling system in the rocky underground and to fix the frame with heavy-duty dowels above the abyss. Coral transplantation experiments are also carried out by scientific divers: Cold-water corals are collected at different locations under different environmental conditions, installed on holders and then released at new locations. The aim of these experiments is to determine the effects of different environmental influences, e.g. on the growth of corals. The results obtained by scientific divers are important for a better understanding of the structure and function of our coastal ecosystems.

Satellite-relayed dive-loggers record water temperature and salinity profiles along the seals’ foraging dives and transmit these data to polar orbiting satellites when the seals are surfacing. The reconciliation of seal borne data with oceanographic features provides new insights into intermediate and upper trophic level interactions. Seal-mounted cameras spot prey objects from the seals’ perspective in coastal sea ice habitats even underneath Antarctic ice shelves. Seals as autonomous samplers and remotely operated vehicles facilitate novel approaches in observational ecology to improve our understanding of distribution patterns of Antarctic top predators and underlying bentho-pelagic processes in difficult-to-study areas and seasons in the high Antarctic sea ice zone. All data are accessible via PANGAEA’s Marine Mammal Tracking project.