Tabelle V. Zahl der Nordlichttage an Grönlands Küste

Die Peridogramme aus Grönland zeigen Maxima bei den folgenden Werten: W-Küste: 29, 57, 86 Tage, im Mittel also 28,7 Tage. O-Küste: 27, 57 Tage, im Mittel also 28 Tage- Zusammenfassend kann man feststellen, daß sich die Abhängikeit der Nordlichttätigkeit von der Sonnentätigkeit zwar auch aus dem grönländischen Material erweisen läßt, daß sie aber dort bei weitem nicht so deutlich erkennbar wird, wie bei Aufzeichnungen aus niedrigeren Breiten.

Characteristics of acoustic recordings of narwhals (Monodon monoceros) north of Disko Island, April 2007 and 2009

A total of 1,690 individual narwhal nonecholocation sounds were recorded over 5 h in 2007 and 2009. Each sound was classified as either tonal (FM) or pulsed (amplitude modulated). Omnipresent in all the recordings were the songs of bearded seals, Erignathus barbatus, which were often so loud and numerous that the lower frequency ranges of narwhal sounds could not be distinguished.

Magnetic properties of igneous rocks recovered at ODP Leg 127 sites

Measurements of natural remanent magnetization (NRM), initial susceptibility (K), anisotropy of magnetic susceptibility, frequency dependent susceptibility (Xfd), and viscous remanent magnetization (VRM) are reported from volcanic rocks recovered during ODP Leg 127 in the Japan Sea. The results indicate a significant difference between the basalts drilled in the Yamato Basin (Site 794 and 797) and in the Japan Basin (Site 795). The Koenigsberger ratios (Q) show very low values in the Yamato Basin attesting that the remanence is not dominant over the induced magnetization. This evidence could explain why no magnetic anomaly pattern has been recognized in this basin. Experiments of VRM acquisition and decay show that both the processes are multistage with the acquisition process proceeding more rapidly and deviates more from a log (t) law than the corresponding decay. The sediments interlayered with the basalts in the acoustic basement of the Yamato Basin show processes of remagnetization related to the emplacement of the dikes. Temperatures of heating between 200° and 250°C were estimated from the different unblocking temperatures of the two components of magnetization.

(Table 1) Compositional variation with depth in a nodule of sediment sample RVG-10D

A detailed study of a nodule from the Somali Basin dated by 230Thexcess was correlated with the paleoceanographic events recorded in Site 236 (Leg 24) Deep Sea Drilling Project (DSDP) cores. Tentative indications are that the phase of nodule accretion starting with the development of pillar structure at a depth of 20 mm in the nodule around 13 Ma coincides with increased Antarctic Bottom Water (AABW) flow and an elevated calciumcarbonate compensation depth (CCD). The Late Miocene lowering of the CCD is represented by the mottled zones between 8 and 18 mm in the nodule is characterised by an abundant silicate component (>20%) of aeolian origin. The Miocene/Pliocene boundary (5 Ma) occurs at a depth of about 8 mm and is represented by the development of pillar structure and a minimum of aeolian dust (10.3%). The increased biological productivity of the Somali surface water since the Middle Miocene is demonstrated by the increasing Corg content of the nodule (from 0.11 to 0.19%) towards its surface.

Age determination and stable isotope composition of sediment cores from the Arctic Ocean

On the basis of 52 sediment cores, analyzed and dated at high resolution, the paleoceanography and climate of the Last Glacial Maximum (LGM) were reconstructed in detail for the Fram Strait and the eastern and central Arctic Ocean. Sediment composition and stable isotope data suggest three distinct paleoenvironments: (1) a productive region in the eastern to central Fram Strait and along the northern Barents Sea continental margin characterized by Atlantic Water advection, frequent open water conditions, and occasional local meltwater supply and iceberg calving from the Barents Sea Ice Sheet; (2) an intermediate region in the southwestern Eurasian Basin (up to 84-85°N) and the western Fram Strait characterized by subsurface Atlantic Water advection and recirculation, a moderately high planktic productivity, and a perennial ice cover that breaks up only occasionally; and (3) a central Arctic region (north of 85°N in the Eurasian Basin) characterized by a low-salinity surface water layer and a thick ice cover that strongly reduces bioproduction and bulk sedimentation rates. Although the total inflow of Atlantic Water into the Arctic Ocean may have been reduced during the LGM, its impact on ice coverage and halocline structure in the Fram Strait and southwestern Eurasian Basin was strong.

Tab.1: Estimates for marine mammals populations south of the Antarctic Polar Front

The aim of this contribution is to supply summarized information on the distribution and numbers of marine mammals in the Antarctic. In relation to the topic of the workshop the question to be answered is: "Is there spatial or temporal variation in mammalian presence in the Antarctic area that has relevance to the operation of acoustic devices". If acoustic devices have impact on marine mammals, this does not stop at political borders. Nevertheless, since legal implementation of the Antarctic Environmental Protocol was the major stimulus behind the workshop, this contribution was asked to limit itself to the Antarctic Treaty area, that is south of 60°S.

Argon analyses of volcanic rocks from the Japan Sea floor

Volcanic rocks recovered from the Japan Sea during ODP Legs 127 and 128 were analyzed by 40Ar-39Ar whole-rock stepwise-heating experiments. All three experiments on samples from Site 795 in the Japan Basin revealed disturbed age spectra, but they are consistent with crystallization ages of 15 to 25 Ma for the samples. At Site 797 in the Yamato Basin, three of the five samples showed plateau ages of 18-19 Ma. At Site 794 in the northern Yamato Basin, three of the five samples revealed concordant age spectra of 20-21 Ma. The radiometric age results are consistent with the estimated ages for the oldest sediments at Site 797 based on the biostratigraphy, but are significantly older than those of the oldest sediments at Site 794. However, the radiometric ages are concordant with previously inferred ages for the formation of the Japan Sea floor based on radiometric age data from dredged igneous rocks from the Japan Sea. The present results indicate that formation of the Japan Sea floor started at least 19-20 Ma ago and give more precise age constraints.