ALBERT

Description: The muon component of the cosmic rays has been measured by the German research vessel "Meteor" during the Atlantic Expedition IQSY 1965. The momentum distribution and charge ratio of the penetrating component of the cosmic radiation at sea level have been determined over the range (0,2-30) GeV/c at the geomagnetic equator. A magnetic spectrograph has been used for these measurements based on spark chamber technique for track location. There exists a significant difference in the low energy part between the muon equator spectrum in comparison with the spectrum at high geomagnetic latitudes (Kiel) and no difference concerning the charge ratio. The total integral measured latitude effect amounts to 15%.

Description: A program of geophysical research was carried out as a preliminary stage of study of the Santorini volcanic group. This area is of remarkable geothermal and volcanological interest, and the definition of a volcanological structural model is the starting point for an understanding of the local geodynamic processes. Gravity, magnetic and geoelectrical data proved that: (i) the core of the volcanic edifice consists of a sedimentary-metamorphic basement; (ii) the basement is tectonically disturbed and a linear tectonic system produces a graben-type structure in the middle part of the area.

Description: The internal shell of the cuttlefish, which acts as a rigid buoyancy tank, is structured to combine high compressive strength — since it must withstand the external hydrostatic pressure — with minimum weighT. The micro-architecture of cuttlebone has been examined by electron microscopy and the relevance of the structure to the mechanical duties required of the shellin vivo are briefly discussed. The inorganic calcareous structure is associated with an organic component which may act as a template for mineralization.

Description: Analyses of bottom trawl samples and feeding experiments in the laboratory revealed a reproduction period ranging from late March to early August in Eledone cirrosa of the Catalonian Sea (Western Mediterranean). The embryonic development, studied for the first time on eggs laid in the laboratory, shows no basic difference from that of other Octopodiae. The newly hatched animals are planctonic; Morphologically, this feature is expressed by a relatively small arm-length.

Description: Five species of Sepiola were reared in the laboratory from egg to adult size. Spawning was achieved in 3 species of Sepiola afteer 5 to 7 months. The growth rate of the species reared did not depend upon temperature, which ranged from 12,5° to 20°C. A fairly constant size increase (2,5mm mantle length/month) was observed in Sepiola during the 5 months after hatching. In Sepietta, the same growth rate was observed until the fourth month after hatching, when it increased to the rate of 5 mm mantle length/month.

Description: The main objectives of the Fladen Ground Experiment (FLEX) 1976 were an investigation of the dynamics of the mixed layer and the development of the spring plankton bloom. A quantitative consideration of individual chemical parameters (nutrients, particulate nitrogen and phosphorus) showed it to be advantageous to divide the water column into several layers which are separated from one another by measured temperature gradients. Measurements of particulate matter (phosphorus and nitrogen) revealed two plankton blooms at the central station. The first one (21.4.-14.5.76) was much more extensive than the second one, since the limiting thermocline was at a depth of about 60 m. Silicate was consumed most rapidly during this bloom and almost completely exhausted. The second bloom (19.-30.5.76) produced concentrations of particulate matter which were almost as high as the first one but were limited in only a few meters' water depth by a secondary thermocline, which prevented an influx of nutrients. Nitrate was completely exhausted during the second bloom. A high degree of nutrient depletion in the mixed layer from 24.4.-29.4. and from 22.5.-27.5.76 make these periods appear well-suited for determination of uptake rates. These periods are characterized. by a parallel course of concentration curves in the upper water layers for all nutrients except ammonium, and by the absence of !arge short-term fluctuations. Thus, disturbances due to hydrodynamic effects were minimal. The effects of tidal changes were minimized by using daily averages of the various concentrations. However, from 9.5.-13.5.7 6 in the upper layer a relatively strong and rapid increase was observed in the concentrations of all nutrients, which can probably only be explained by hydrodynamic influences. The nitrogen and phosphorus budgets can only be approximately balanced without considering dissolved organic matter. The strong decrease in dissolved inorganic nutrients during the first plankton bloom is almost comple,tely compensated by the increase in particulate matter. Not considering hydrodynamic influences, deficits after the plankton bloom could be explained by the fact that dissolved organic substances, as weil as sedimentaty matter and zooplankton, either were not considered at all, or at least not quantitatively. The time periods from 2.-7.4. and from 21.4.-14.5.76 show no strong short-term fluctuations in the nitrogen and phosphorus budgets and appear most suitable for calculations of mass fluxes, uptake and production rates, since biological-chemical processes seem to be dominant over hydrodynamic ones during these periods.

Description: Measurements of nutrients and the elements phosphorus and nitrogen from the central station in FLEX '76 were used to calculate mass fluxes and budgets for these elements in defined time and depth intervals. The intervals were defined using hydrodynamic and biological criteria. Within these periods rates of increase and decrease were calculated for nitrate, ammonium, phosphate, particulate nitrogen and phosphorus. These rates were also calculated for the layer above and below the main thermocline. The element budget was balanced within some of the defined intervals. This was possible by only considering biological, chemical, and vertical physical interactions at the central station. At the beginning of the phytoplankton bloom we found fluxes with a maximum of 28 ngat · l-1 · d-1 for phosphorus and 590 ngat · l-1 · d-1 for nitrogen. Interaction diagrams are shown for mass fluxes for three periods during the plankton bloom.