ALBERT

Description: Two case studies of the application of geoscientific maps for planning in semi-arid regions are presented, one for the Mediterranean province of Valencia and another for the island of Gran Canaria (Canaries). Both regions are very dynamic from the point of view of population growth and urban-touristic-industrial development, and they suffer from a serious degree of environmental degradation. The provincial/ island governments have undertaken programmes of geoscientific mapping and assessment to serve as a basis for the establishment of guidelines for future planning. Two map sets have been made (1:200,000 in Valencia and 1:50,000 in Gran Canaria), based on initial maps of homogeneous integrated units. These represent a series of hierarchical land subdivisions, progressively smaller and more detailed (morphodynamic environments, systems, units, elements), defined on the basis of morphostructure, climate, lithology, surficial deposits, landforms, topography, active processes, soils, vegetation and human influence. Each individual map unit is described by means of a form which includes 114 items, summarising its environmental features. Morphodynamic units have been evaluated in terms of qualities significant for planning, and a series of derivative maps has been developed (geologic hazards, soil capability, present degree of erosion, potential erodibility, quality for conservation). A final map shows the most advisable types of uses and the main limitations for human activities, mainly due to engineering geological factors. This is a synthesis document which can be used directly by planners.

Description: Middle Pleistocene strata of the Kidnappers Group consist of a conformable sequence of alternating fluvio-lacustrine and shallow marine sediments exposed along coastal cliffs near Cape Kidnappers, southern Hawkes Bay, New Zealand. Three major paleomagnetic polarity intervals are recognised and interpreted as Jaramillo Normal Subchron, upper Matuyama Reversed Chron and Brunhes Normal Chron. This and biostratigraphy indicates an age range of 0.97 to 0.54 Ma for the group, compared to 0.85 to 〈 0.33 Ma previously suggested by fission track ages of tuffs. The new age control and facies interpretations suggest that the upper part of the group represents oxygen isotope stages 22 to 15. The duration and magnitude of isotope stages is reflected in the relative thicknesses of lithological units. Glacial periods are recorded as alluvial aggradation in the form of braidplain conglomerates, while estuarine and subaerial sands and muds with temperate climate pollens represent interglacial periods. This contrasts with many coastal and shelf sequences where glacial periods are represented by unconformities. Chemical and paleomagnetic characterisation of silicic tuffs in the Kidnappers Group establishes correlation to other sections and cores in New Zealand, the Tasman Sea and the western Pacific Ocean, thus providing temporal correlation for a range of sedimentary environments.

Description: An acclimated mixed culture of degrading bacteria and a degradable substance (4-Nitrophenol) were introduced into differently treated water samples. It could be shown that in all cases where an acclimated inoculum was used, degradation took place almost immediately compared to not acclimated cultures, where it took at least 10 days. The rate and extent of mineralization was influenced by low temperature, the presence of other organic nutrients and especially protozoan grazing. The data suggest that one of the main reasons for the acclimation period was the very small initial population of degrading bacteria. The role of other carbon sources is ambivalent. Low concentrations of organic chemicals which cannot sustain growth slow down acclimation and the degradation rate. Another important factor slowing down growth is grazing by protozoa, which can inhibit effective degradation.

Description: A new technique to process sediment thin sections with fluorescent dyes is presented. It enables to examine the distribution of bacteria on and between sediment particles in the um-scale, using epifluorescent microscopy and/or simultaneous transmittent light and epifluorescence microscopy using a laser scanning microscope. It was possible to assign biomass data to the structures of sediment and organic matter of surface layers of young microbial mats, mature mats and stages of early (microbial) diagenesis. The gradual transformation of cyanobacterial mats after drastic events of sedimentation can be analyzed and demonstrated this way.

Description: Bacterial infections of fish caused by pathogenic bacteria lead to high losses in aquaculture but are also important in wild fish. Field investigations showed that such diseases are also present in the estuaries of the rivers Elbe and Eider (Germany). Three diseases apparently induced by pathogenic bacteria could be observed: "ULCER DISEASE", "FIN ROT" and the so called "YELLOW PEST", a newly described cod disease. Until now, epidemiological and histopathological examinations, as well as isolations and determinations of potential bacterial agents have been done. Investigations on the relationship between environmental factors such as temperature, salinity, organic pollution, and the appearence of these diseases are in process.

Description: About 500 marine bacterial strains isolated in 1987 during the "Hydronaut cruise" on the East Pacific Rise, from various deep-sea hydrothermal vent samples, were screened for the ability to produce exopolysaccharides (EPS). All the EPS-producing bacterial strains (17) were isolated from alvinellid polychaete samples on metal-amended media containing zinc, cadmium, silver, or arsenste. Sixteen of these strains belong to a same phenon (cluster l formed at 82%) on a strain similarity basis. Many strains of this cluster displayed single or multiple resistance to the 5 metals studied (zinc, copper, arsenate, selenate and cadmium), but correlation with EPS-production was not evident. Strains 1545 and 1582, for instance, gave good EPS-production but appeared to be sensitive to heavy metals.

Description: During the "Polarstern" expedition ARK IV /2 in June 1987, water samples from 8 stations were taken to study biomass and substrate utilization of cold adapted bacteria. Bacterial biomasses determined from acridine orange direct counts (AODC) were between 0.4 and 31.4 µg C/l, and ATP concentrations amounted from 〈O.l to 40 ng/l. Colony counts on seawater agar reached only 0.1 % of AODC, but with the MPN-method l to 10 % of AODC were recorded. With 14C-glutamic acid or 14C-glucose as tracer substrate in oligotrophic broth containing 0.5 mg trypticase and 0.05 mg yeast extract per liter of seawater, obligately oligotrophic bacteria could be detected in one water sample. Although incubation was at 2 °C, only psychrotrophic bacteria showing growth temperatures between l and 30 °C were obtained. Organic substrate utilizations by 106 isolates were tested at 4 and 20 °C. Most carbohydrates, organic acids, alcohols, and alanine were assimilated at both temperatures, but arginine, aspartate and ornithine were utilized only at 20°C by almost all strains.

Description: Versicoloured microbial mats (Farbstreifen-Sandwatt) in the intertidal zone of the North Sea island of Mellum were investigated with respect to oxygenic photosynthesis and nitrogen fixation. In laboratory cultures of the cyanobacterium Oscillatoria limosa a temporary separation of both incompatible processes occurs. Also in situ a negative correlation of sedimentary oxygen concentration and nitrogenase activity was found. If the sediment turned anaerobic during the night, no acetylene reduction was measurable. In systems, however, which stayed oxygenated during the night, nitrogenase activity was found at night. Peaks of nitrogenase activity were often detected at sunrise. Sometimes acetylene reduction was measured during the day when oxygenic photosynthesis was interrupted or depressed, due to light conditions (clouding effects). The diurnal pattern of nitrogenase activity as well as the acetylene reduction rate was influenced by the variation of all environmental conditions. The highest rate of nitrogenase activity (25 µmol C2H4/mg Chl a/h) detected in situ agreed well with maximal nitrogenase activity found in pure cultures of Oscillatoria limosa.