ALBERT

Beschreibung: A collection of cephalopods from the British Antarctic Survey’s Offshore Biological Programme is described and the cephalopod prey of vertebrate predators at South Georgia is reviewed. Comparison of these data indicates that predators catch larger specimens and a greater diversity of species than nets. There are also differences between samples from different types of net. The RMT 25, the largest research net used to date, has caught most of the species thought to occur in the Scotia Sea but specimens are generally smaller than those taken by predators. Cephalopods which are thought to have potential commercial value are Martialia hyadesi, Kondakovia longimana, Moroteuthis ingens, M. knipovitchi, M. robsoni and Gonatus antarcticus. Other possibilities include species of brachioteuthid, psychroteuthid and neoteuthid. It is likely that Antarctic stocks will be sensitive to exploitation and liable to dramatic fluctuations if overfished. The possible consequences of commercial exploitation of cephalopods for the reproductive success of the vertebrate predators, which prey on cephalopods in the Scotia Sea, are examined.

Beschreibung: Serological methods for prey identification have been applied to detection of residues ofsandeel (Ammodytidae) protein in faeces of common seals (Phoca vitulina) and grey seals(Halichoerus grypus) from the Moray Firth, north-east Scotland. Antisera raised to muscleprotein from Ammodytes marinus were evaluated by testing their reactions with proteinextracts made from a range of North Sea fish species and protein residues in in vitro digestates,seal digestive tracts and seal faeces. It was concluded that, using fused rocketimmuno-electrophoresis, linkage of precipitin peaks from unknown samples with peaksfrom standard sandeel extract was a reliable indicator of the presence of sandeel in theunknown sample. Seasonal variation in the incidence of sandeels in common seal diet in theMoray Firth was examined by identifying otoliths, bones, and proteins, and all threemethods indicated that sandeels occurred in the majority of samples tested in the summer,but were less important during the winter. Proteins were detected in fewer samples thanotoliths, particularly in February and March. Possible reasons for this difference arediscussed. Serological identification of sandeel proteins is potentially applicable to dietarystudies on all marine predators.

Beschreibung: Thirty-four adult individuals of Loligo forbesi (males and females with dorsal mantle lengths from 27–77 cm) were observed in captivity in a 3 m diameter closed sea-water system on Faial Island, Azores. Squids were caught by jigging and were fed with horse mackerel (Trachurus picturatus) and chub mackerel (Scomber japonicus), either alive or dead. The maximum survival was 73 days. Feeding behaviour was dependent upon both the size of prey and its state of preservation;e.g. the squid would eat the head of small fish (〈 about 15 cm), reject the head of medium-sized fish (about 15–35 cm) and would eat only the dorsal part of a big fish (〉 about 35 cm) or a fish poorly preserved. Seventeen chromatic, 9 postural and 6 movement components of body patterns were observed and described. Conspecific interactions considered to be aggression and dominance were observed among males; no such interactions occurred when one male and two females were kept together. Body patterns in relation to relaxation, stress, shock, feeding, locomotion and aggression are also described.

Beschreibung: Antarctic petrels (Thalassoica antarctica) brooding young chicks at Scullin Monolith (67°7′S, 66°42′E), Antarctica, fed fish and crustaceans (87% and 13%, respectively, on a mass basis) to their young. Amounts of solids fed were equivalent to 6.6% of the body mass of adult birds with an empty stomach. The prey comprised species known to occur in the surface layers of the Antarctic ocean in the east wind drift, such as Pleuragramma antarcticum, Notolepis coatsi and Euphausia superba, consistent with the surface feeding habits of Antarctic petrels.

Beschreibung: The investigation on the geology of the Sierra Leone Rise contains seismic, petrographic and sedimentological data from the Soviet expedition of R/V »Professor Shtokman«. New results on bottom relief and structure of the Sierra Leone Rise (SLR) are documented in Figs. 1–7. Detailled descriptions of dredge samples of trachyandesites, trachytes, trachyte tuffs, trachybasalts and their tuffs and their chemical composition (Tab. 2) together with the seismic structure of the SLR allow some assumptions on the age and origin of the Rise. The SLR is part of the equatorial Atlantic oceanic crust, that formed in the initial phase of break-up of Gondwana (110–80×106y). During the period 80–90×106 years, when volcanic eruptions were highly intensified in the area, major parts of the SLR have been formed. Some of the volcanic seamounts appeared as islands above sea-level in the Late Cretaceous/Paleocene: the magmatic rocks are more similar to ocean island basalt than to normal oceanic crust. Cenozoic sediments of the SLR reveal continuous sedimentation, which was controlled by surface water productivity, carbonate dissolution and terrigenous matter supply. The Eocene chert sedimentation phase was followed by a period of cyclic carbonate sedimentation. In the Neogene tectonic activity lead to vertical displacements. On several peaked seamounts coral reefs grew. The reef phase was followed by a sinking of the area. At the end of the Neogene the SLR became aseismic. The Late Quaternary sediment cover is studied by means of grab samples and sediment cores from various water depths. The main finding is varying CaCO3 content with depth and with time, controlled mainly by dissolution.

Beschreibung: The Quaternary Herchenberg composite tephra cone (East Eifel, FR Germany) with an original bulk volume of 1.17·107 m3 (DRE of 8.2·106 m3) and dimensions of ca. 900·600·90 m (length·width·height) erupted in three main stages: (a) Initial eruptions along a NW-trending, 500-m-long fissure were dominantly Vulcanian in the northwest and Strombolian in the southeast. Removal of the unstable, underlying 20-m-thick Tertiary clays resulted in major collapse and repeated lateral caving of the crater. The northwestern Lower Cone 1 (LC1) was constructed by alternating Vulcanian and Strombolian eruptions. (b) Cone-building, mainly Strombolian eruptions resulted in two major scoria cones beginning initially in the northwest (Cone 1) and terminating in the southeast (Cones 2 and 3) following a period of simultaneous activity of cones 1 and 2. Lapilli deposits are subdivided by thin phreatomagmatic marker beds rich in Tertiary clays in the early stages and Devonian clasts in the later stages. Three dikes intruded radially into the flanks of cone 1. (c) The eruption and deposition of fine-grained uppermost layers (phreatomagmatic tuffs, accretionary lapilli, and Strombolian fallout lapilli) presumably from the northwestern center (cone 1) terminated the activity of Herchenberg volcano. The Herchenberg volcano is distinguished from most Strombolian scoria cones in the Eifel by (1) small volume of agglutinates in central craters, (2) scarcity of scoria bomb breccias, (3) well-bedded tephra deposits even in the proximal facies, (4) moderate fragmentation of tephra (small proportions of both ash and coarse lapilli/bomb-size fraction), (5) abundance of dense ellipsoidal juvenile lapilli, and (6) characteristic depositional cycles in the early eruptive stages beginning with laterally emplaced, fine-grained, xenolith-rich tephra and ending with fallout scoria lapilli. Herchenberg tephra is distinguished from maar deposits by (1) paucity of xenoliths, (2) higher depositional temperatures, (3) coarser grain size and thicker bedding, (4) absence of glassy quenched clasts except in the initial stages and late phreatomagmatic marker beds, and (5) predominance of Strombolian, cone-building activity. The characteristics of Herchenberg deposits are interpreted as due to a high proportion of magmatic volatiles (dominantly CO2) relative to low-viscosity magma during most of the eruptive activity.

Beschreibung: The challenges of collecting, transporting, and maintaining healthy wild squids have been nearly as formidable as those of determining the structure and function of ion channels in squid giant axons. The differences are a matter of scale, not complexity. Careful perusal of the literature indicates clearly that failures have been the rule, especially with squids of the genus Loligo. It is an unfortunate fact that the vast majority of biomedical research on Loligo has been done on animals that were moribund when they were prepared for experiments. This was due in most cases to skin damage incurred during capture and transport from the field to the laboratory, and to the secondary infections that invariably followed immediately. Furthermore, the availability of live squids for research is limited seasonally because of the migratory behavior of these fast-swimming invertebrates. Thus any improvements in maintenance, rearing or culture will lead not only to greater availability to meet the demand from researchers, but hopefully to the provision of healthy squids for a wide range of experimentation.

Beschreibung: Because of the implications of shallow gas accumulations to drilling and the integrity of platform foundations, it is important to determine whether gas accumulations can be considered as effectively static, unchanging for the duration of offshore operations, or dynamic. Shallow gas is frequently seen in association with seabed features, such as mud lumps, gas domes and pockmarks. These are considered to have been caused by the escape of gas through the seabed, consequently it can be implied that gas has migrated to, and through, the seabed. This indicates that shallow gas is not static, but it does not suggest a time-scale over which migration occurs. Is shallow gas mobile on a geological or a human time-scale?