ALBERT

Beschreibung: Carbonate precipitates on mounds and along tectonic scarps off the Costa Rica margin are manifestations of subduction-induced dewatering. The long-term dewatering history is recorded in mineralogical, petrological and isotope signals of carbonates recovered from these sites. The carbonates are strongly depleted in δ13C (−11 to −53‰ PDB) and enriched in δ18O (+4 to +8‰ PDB). Thermogenic methane and biogenic methane were identified as sources of the carbon. Chemoherm carbonates and seepage-associated carbonates formed in a focused flow regime have lighter δ13C values, while others formed in a more diffusive flow regime have slightly enriched C isotope values. Three fluid components were inferred based on the calculation of equilibrium δ18O: clay dehydration water, gas hydrate water and seawater. Calculated equilibrium δ18O values of carbonates from different down-core depths as well as from different precipitation stages show that the δ18O of the precipitating fluid is progressively depleted with time. Dolostones showing a methane-C source and a well constrained O-isotope signature are thought to have formed at depth in the sediment and subsequently became exhumed. Glauconitic sandstones cemented by methane-derived carbonate provide evidence that fluid and solid material have been expelled by the mud volcano.

Beschreibung: We examined the thermoregulatory behaviour (TRB) of roosting Humboldt penguins (Spheniscus humboldti) in north central Chile during summer and winter, when ambient temperatures (Ta) are most extreme. Each body posture was considered to represent a particular TRB, which was ranked in a sequence that reflected different degrees of thermal load and was assigned an arbitrary thermoregulatory score. During summer, birds exhibited eight different TRBs, mainly oriented to heat dissipation, and experienced a wide range of Ta (from 14 to 31°C), occasionally above their thermoneutral zone (TNZ, from 2 to 30°C), this being evident by observations of extreme thermoregulatory responses such as panting. In winter, birds exhibited only three TRBs, mainly oriented to heat retention, and experienced a smaller range of Ta (from 11 to 18°C), always within the TNZ, even at night. The components of behavioural responses increased directly with the heat load which explains the broader behavioural repertoire observed in summer. Since penguins are primarily adapted in morphology and physiology to cope with low water temperatures, our results suggest that behavioural thermoregulation may be important in the maintenance of the thermal balance in Humboldt penguins while on land.

Beschreibung: We quantified the nitrogen and enzyme hydrolyzable amino acid (EHAA) concentrations of sediments prior to and after corals sloughed, ingested, and egested sediments layered onto their surfaces, for the three coral species Siderastrea siderea, Agaricia agaricites, and Porites astreoides in Jamaica. The percent nitrogen of the sediments egested by all three species was lower than in the sediments available to the corals. Additionally, the sediments sloughed (not ingested) by A. agaricites and P. astreoides were lower in percent nitrogen, while the sediments sloughed by S. siderea had the same percent nitrogen as that of the available sediments. The percent nitrogen of the sediments sloughed and egested by P. astreoides showed significant negative and positive relationships, respectively, to increasing sediment loads, while the percent nitrogen of the sediments sloughed and egested by both S. siderea and A. agaricites showed no relationship to sediment load. EHAA concentrations were not significantly different between the sloughed and available sediments but were significantly lower in the sediments egested by S. siderea and A. agaricites (EHAA concentrations were not measured for P. astreodies sediment fractions). Comparisons of the nitrogen and EHAA concentrations in the sloughed and egested sediments to what was available prior to coral processing show that maximum ingestion was between 0.1 and 0.2 µg N µg−1 coral N cm−2 and between 0.5 and 0.6 µg EHAA·cm−2. Maximum assimilation efficiencies were estimated to be 30–60% of the available nitrogen. The data show that corals ingest and alter the nitrogen concentration of particles that land on their surfaces. The corals’ abilities to process these sediments, and the sediments’ possible contributions to coral nutrition, are discussed based on these results.

Beschreibung: A numerical model of the Atlantic Ocean was used to study the low-frequency variability of meridional transports in the North Atlantic. The model shows a behaviour similar to those used in previous studies, and the temporal variability of certain variables compares favourably to observed time series. By changing the depth and width of the sills between the subpolar North Atlantic and the Nordic Seas, the mean horizontal and overturning circulation as well as some water mass properties are modified significantly. The reaction of meridional oceanic transports to atmospheric forcing fluctuations remains, however, unchanged. The critical role of the surface heat flux retroaction term for the meridional heat transport in stand-alone ocean models is discussed. The experiments underline the role of atmospheric variability for fluctuations of the large-scale ocean circulation on time scales from years to decades, and they support the hypothesis that the mean overturning strength is controlled by the model representation of the density of the overflow water masses.

Beschreibung: Seismic reflection data document for the first time the existence of a BSR in a limited area west of the Dnieper Canyon in the northwestern Black Sea. Seismic wide-angle data suggest that gas hydrates occupy in average 15±2% of the pore space in a zone of 100 m in thickness. A conservative quantification of the amount of methane associated with this gas hydrate occurrence is about 12±3×1011 m3 (0.6±0.2 Gt of methane carbon). Conductive heat flow deduced from the BSR depth is in the range of 21±6 to 55±15 mW m−2.

Beschreibung: Sponges (phylum Porifera) are sessile marine filter feeders that have developed efficient defense mechanisms against foreign attackers such as viruses, bacteria, or eukaryotic organisms. Protected by a highly complex immune system, as well as by the capacity to produce efficient antiviral compounds (e.g., nucleoside analogues), antimicrobial compounds (e.g., polyketides), and cytostatic compounds (e.g., avarol), they have not become extinct during the last 600 million years. It can be assumed that during this long period of time, bacteria and microorganisms coevolved with sponges, and thus acquired a complex common metabolism. It is suggested that (at least) some of the bioactive secondary metabolites isolated from sponges are produced by functional enzyme clusters, which originated from the sponges and their associated microorganisms. As a consequence, both the host cells and the microorganisms lost the ability to grow independently from each other. Therefore, it was—until recently—impossible to culture sponge cells in vitro. Also the predominant number of “symbiotic bacteria” proved to be nonculturable. In order to exploit the bioactive potential of both the sponge and the “symbionts,” a 3D-aggregate primmorph culture system was established; also it was proved that one bioactive compound, avarol/avarone, is produced by the sponge Dysidea avara. Another promising way to utilize the bioactive potential of the microorganisms is the cloning and heterologous expression of enzymes involved in secondary metabolism, such as the polyketide synthases.

Beschreibung: Polyclonal antibodies that recognize the two subunits AmoA and AmoB of the ammonia monooxygenase (AMO) were applied to identify ammonia-oxidizing bacteria by immunofluorescence (IF) labeling in pure, mixed, and enriched cultures. The antibodies against the AmoA were produced using a synthetic peptide of the AmoA of Nitrosomonas eutropha, whereas the antibodies against the AmoB had been developed previously is against the whole B-subunit of the AMO [Pinck et al. (2001) Appl Environ Microbiol 67:118–124]. Using IF labeling, the AmoA antibodies were specific for the detection of all species of the genus Nitrosomonas. In contrast, the antiserum against AmoB labeled all genera of ammonia oxidizers of the β-subclass of Proteobacteria (Nitrosomonas, Nitrosospira, Nitrosolobus, and Nitrosovibrio). The fluorescence signals of the AmoA antibodies were spread all over the cells, whereas the signals of the AmoB antibodies were associated with the cytoplasmic membranes. The specificity of the reactions of the antisera with ammonia oxidizers were proven in pure and mixed cultures, and the characteristic IF labeling and the morphology of the cells enabled their identification at the genus level. The genus-specific IF labeling could be used to identify ammonia oxidizers enriched from various habitats. In enrichment cultures of natural sandstone, cells of the genera Nitrosomonas, Nitrosovibrio, and Nitrosospira were detected. Members of the genus Nitrosovibrio and Nitrosolobus were most prominent in enriched garden soil samples, whereas members of the genus Nitrosomonas dominated in enriched activated sludge. The antibodies caused only slight background fluorescence on sandstone and soil particles compared to oligonucleotide probes, which could not be used to detect ammonia oxidizers on these materials because of strong nonspecific fluorescence.

Beschreibung: Durch Vermittlung von Jörn Thiede gelangte das Geologenarchiv in den Besitz eines Videobands von einem Fernsehinterview mit Rosenqvist (auch gelegentlich Rosenquist), das Elen Roaldset (E.R.) im Geologischen Institut der Universität Oslo am 8.September 1988 führen konnte. Es umfasst den gesamten Lebenslauf und die wichtigsten wissenschaflichen Leistungen dieses aussergewöhnlichen Geologen und Mineralogen. Er wurde in Wien am 17. Mai 1916 geboren, kam aber mit seinen Eltern schon 1917 nach Oslo, wo er am 8. Oktober 1994 starb (K. Bjørlykke 1995). Im Folgenden sollen aus dem Interview nur seine wegweisenden Untersuchungen der Quicktone, seine fachliche Vielseitigkeit, sein gesellschaftliches Engagement und seine schwierigen Erfahrungen mit Deutschland herausgegriffen werden. Das in der Landessprache geführte Gespräch wurde von Geir Ebelfoff und Lars Erik Kastilan ins Deutsche transkribiert.