Acoustic records of the underwater soundscape at PALAOA with links to audio stream files, 2005-2011

Scientific background: Marine mammals use sound for communication, navigation and prey detection. Acoustic sensors therefore allow the detection of marine mammals, even during polar winter months, when restricted visibility prohibits visual sightings. The animals are surrounded by a permanent natural soundscape, which, in polar waters, is mainly dominated by the movement of ice. In addition to the detection of marine mammals, acoustic long-term recordings provide information on intensity and temporal variability of characteristic natural and anthropogenic background sounds, as well as their influence on the vocalization of marine mammals Scientific objectives: The PerenniAL Acoustic Observatory in the Antarctic Ocean (PALAOA, Hawaiian "whale") near Neumayer Station is intended to record the underwater soundscape in the vicinity of the shelf ice edge over the duration of several years. These long-term recordings will allow studying the acoustic repertoire of whales and seals continuously in an environment almost undisturbed by humans. The data will be analyzed to (1) register species specific vocalizations, (2) infer the approximate number of animals inside the measuring range, (3) calculate their movements relative to the observatory, and (4) examine possible effects of the sporadic shipping traffic on the acoustic and locomotive behaviour of marine mammals. The data, which are largely free of anthropogenic noise, provide also a base to set up passive acoustic mitigation systems used on research vessels. Noise-free bioacoustic data thereby represent the foundation for the development of automatic pattern recognition procedures in the presence of interfering sounds, e.g. propeller noise.

Physical oceanography, sea-bed photographs and videos of benthos from the Weddell Sea taken with remote operated vehicle CHEROKEE during POLARSTERN cruise ANT-XXIII/8

The marine ecosystem on the eastern shelf of the Antarctic Peninsula was surveyed 5 and 12 years after the climate-induced collapse of the Larsen A and B ice shelves. An impoverished benthic fauna was discovered, that included deep-sea species presumed to be remnants from ice-covered conditions. The current structure of various ecosystem components appears to result from extremely different response rates to the change from an oligotrophic sub-ice-shelf ecosystem to a productive shelf ecosystem. Meiobenthic communities remained impoverished only inside the embayments. On local scales, macro- and mega-epibenthic diversity was generally low, with pioneer species and typical Antarctic megabenthic shelf species interspersed. Antarctic Minke whales and seals utilised the Larsen A/B area to feed on presumably newly established krill and pelagic fish biomass. Ecosystem impacts also extended well beyond the zone of ice-shelf collapse, with areas of high benthic disturbance resulting from scour by icebergs discharged from the Larsen embayments.

Description and composition iron-manganese concretions from the Pacific

One the most interesting features of ocean sedimentation is the manganese formations on the surface of the ocean floor in some areas. These are especially widespread in the Pacific Ocean as concretions, grains, and crusts on rock fragments and bedrock outcrops. Iron-manganese concretions are the most abundant as they completely cover about 10% of the bottom of the Pacific Ocean where there are ore concentrations. The concretions occupy from 20-50% of the bottom and up to 80-90% on separate submarine rises. Such concretions are found in different types of bottom deposits, from abyssal red clays to terrigenous muds, but they occur most widely in red clays and quite often in carbonate muds. Their shape and their dimensions are very diverse and change from place to place, from station to station, varying from 0.5-20 cm. They may be oval, globular, reniform, or slaggy and often they are fiat or isometric concretions of an indefinite shape. The concretions generally have nuclei of pumice, basalt fragments, clayey and tuffaceous material, sharks' teeth, whale ossicles, and fossil sponges. Most concretions have concentric layers, combined with dendritic ramifications of iron and manganese oxides.