Observation of manganese deposits in the Blake Plateau, Florida and Caribbean sea areas

Designed by the Westinghouse Corporation in collaboration with Jacques Cousteau, DEEPSTAR-4000 is a deep diving research vehicle based on Captain Cousteau's DIVING SAUCER. An evaluation of DEEPSTAR's operational performance at sea is presented in this report through a description of typical dive procedures and the actual NAVOCEANO dive results.

Swath sonar bathymetry during POLARSTERN cruise ANT-XIX/5 (PS61) with links to multibeam raw data files

Multibeam data were measured during R/V Polarstern cruise ANT-XIX/5 along track lines of approximately 4000 NM total length in the Scotia Sea. Data were achieved along the Scotia Arc from Burdwood Bank to King George Island. A multibeam box survey was conducted at the southern part of the Discovery Rise, located at 50°55'S / 35°30'W and covering an area of 90 x 15 NM. A bathymetric survey of 25 x 60 NM was carried out at the eastern part of the South Shetland Trench and its intersection with the Shackleton Fracture Zone, continuing multibeam data from former expeditions. The multibeam sonar system Hydrosweep DS-2 was operated using 59 beams and 90° aperture angle. The refraction correction was achieved utilizing the system's own cross fan calibration. The quality of data might be reduced during bad weather periods or adverse sea ice conditions. The dataset contains raw data that are not processed and thus may contain errors and blunders in depth and position.

A foraminiferal d18O record of sediment core GT90-3 covering the last 2,200 years

For many years the Torino Cosmogeophysics group has been studying sediment cores drilled from the Gallipoli Terrace in the Gulf of Taranto (Ionian Sea) and deposited in the last millennia. The gravity core GT90-3, in which the 18O series was measured, was drilled from the Gallipoli Terrace in the Gulf of Taranto (Ionian Sea) at 39°45'53''N, 17°53'33''E. It was extracted at a depth of 178 m and its length is 3.57 m. Thanks to its geographical location, the Gallipoli Terrace is a favourable site for climatic studies based on marine sediments, because of its closeness to the volcanically active Campanian area, a region that is unique in the world for its detailed historical documentation of volcanic eruptions. Tephra layers corresponding to historical eruptions were identified along the cores, thus allowing for accurate dating and determination of the sedimentation rate. The measurements performed in different cores from the same area showed that the sedimentation rate is uniform across the whole Gallipoli Terrace. We measured the oxygen isotope composition d18O of planktonic foraminifera. These measurements provided a high-resolution 2,200-year-long record. We sampled the core using a spacing of 2.5 mm corresponding to 3.87 years. Each sample of sediment (5 g) was soaked in 5% calgon solution overnight, then treated in 10% H2O2 to remove any residual organic material. Subsequently it was washed with a distilled-water jet through a sieve with a 150 µm mesh. The fraction > 150 µm was kept and oven-dried at 5°C. The planktonic foraminifera Globigerinoides ruber were picked out of the samples under a microscope. For each sample, 20-30 specimens were selected from the fraction comprised between 150 µm and 300 µm. The use of a relatively large number of specimens for each sample reduces the isotopic variability of individual organisms, giving a more representative d18O value. The stable isotope measurements were performed using a VG-PRISM mass spectrometer fitted with an automated ISO-CARB preparation device. Analytical precision based on internal standards was better than 0.1 per mil. Calibration of the mass spectrometer to VPDB scale was done using NBS19 and NBS18 carbonate standards. The strategic location of the drilling area makes this record a unique tool for climate and oceanographic studies of the Central Mediterranean.