ALBERT

Description: During the Atlantic Expedition "Meteor" 1965 the standard visibility was measured aboard with an AEG/FFM-Scattered Light Recorder. The working principle, technique and accuracy of this instrument is described. Furthermore some empirical results are discussed, e. g. the errors due to the disturbing influences of the ship and those caused by contamination of the lenses, The measured values are compared with estimated values of visibility by eyeobservation. For certain periods with uniform atmosphericconditions, hourly mean values of visibility have been correlated with air temperature, humidity and wind. The visibility shows a rather weak daily period for pure oceanic aerosol, whereas about 100 miles off the African coast the period appeared more pronounced. Interesting differences have been found in the relative changes of visibility for different origins of the aerosol. 'fhis results into a dependence of visibility on the wavelength of scattered radiation.

Description: During the 1965 Atlantic Expedition of the "Meteor" concentrations of various atmospheric trace gases were measured. The following gases were considered: carbon dioxide (C02), sulfur dioxide (S02), nitrogen dioxide (N02), and nitric oxide (NO). The air whereof these components were measured was sucked in from a height of 14 m above the surface of the sea. The results allow conclusions upon the long term global increase of the atmospheric C02 content, the meridional distribution of the C02 on the Atlantic Ocean, and the dependance of its concentration upon the time of the day and the thermal structure of the atmosphere. Attempts at determining concentrations of sulfur dioxide and nitric oxide of non-continental origin failed at large. Concentrations of N02, however, could succesfully be measured.

Description: A radiosonde is described for measuring the upward and downward fluxes of visible light in the atmosphere. Photoresistors are used as sensors, the optical center of the spectral range beeing at 0.55 µ. The results of these flux-measurements obtained during the Atlantic Expedition 1965 with the research vessel "Meteor" are presented. The datas have been divided into three groups according to the amount of cloudiness. In group a) ( small cloudiness) the extinction coefficient of the prevailing linear radiation is derived as a function of the height. Characteristics of airmasses of maritime or continental origin are shown. In group b) (cloud covered sky) microphysical quantities are determined from the radiative lapse rate in the clouds. The average radius of droplets is found to lie between 5.5 µ und 14.4 µ. The albedo of cloud surfaces varies between 25 % and 54 %, the transmission values are between 58 % and 73 %. One ascent through a Cirrus cloud of considerable vertical thickness is treated seperately. The observed distribution of extinction is compared with theoretical values in water clouds leading to the same order of magnitude. The relation between the albedo of the surface of the sea and the amount of cloudiness is discussed.

Description: During the Atlantic expedition potential gradient, small ion density and space charge density have been recorded. Laborious efforts have been taken for receiving an exact estimation of the reduction factor for the field measurements. The mean value of the potential gradient on the free Atlantic Ocean was 105 V/m. The mean daily course is in very good agreement with the results of the Carnegie Institution. Even records taken on individual days near the equator show this course. For the first time it has been attempted to correlate the potential gradient at sea and the voltage between ionosphere and earth measured over land. A narrow relation has been found in 10 cases of balloon ascents with radiosondes. A further remarkable result is, that the short periodical fluctuations of the air electric field at sea with periods of 2 to 20 minutes have amplitudes of the magnitude of the mean field strength and exist all over the oceans. Recordings of the space charge density show, that positively charged air parcels drift in the first hectometer of the air near the sea surface and produce the fluctuation of the potential gradient. A period analysis did not indicate a recognizable relation to the wind velocity up to now, although an effect of air turbulence must be involved. The concentration of small ions also has been measured occasionally. With this and mean values of the potential gradient the air earth curent density has been computed. With η+ = 310 cm-3, η_ = 220 cm-3 the air conductivity would be Λ = 1, 14 · 10-14 Ohm-1 m-1. These values are smaller than values of other authors by a factor of 2 or 3. Therefore the computed air earth current density is also smaller. The discrepancy could not be explained yet.

Description: The study of textural, structural, chemical, and physical properties of fine-grained recent marine sediments leads to the conclusion that only a few compositional factors are responsible for significant changes in mass physical characteristics in the upper meters below sea bottom. Fossil-induced porosity (text fig. 6) increases water content and liquid limit. It also seems to have partially influenced the plastic limit and plasticity index of calcareous sandy silts from the Red Sea and the western Gulf of Aden so that they become similar to the montmorillonite rich prodelta clays from the Nile Delta. Diagrams based on liquid limit and plasticity loose their original meaning in these cases (text fig. 7 a). Activity of sediments rich in microorganisms can be higher than that of montmorillonitic clay (text fig. 7b). The shear strength-depth relationship of normally consolidated sediments (text fig. 8 a) is surprisingly little influenced by changes in sand or clay content and clay mineralogy. Only high lime content, submarine erosion and beginning cementation increase the strength considerably (part of curves in text fig. 8 b ). Erosional disconformities near the present surface can be deduced from the strength-depth curve when as little as 1 or 2 m sediment have been removed (text fig. 9). Flat or irregular strength-depth curves (text fig. 8 b, curves B and GO) indicate beginning cementation and probably discontinuous sedimentation, provided the composition of the material remains in some degree constant. In our samples diagenetic pyrite, but no recristallisation of carbonates could be detected under the microscope. Underconsolidation and excess pore-water pressure, factors which tend to foster submarine slides, mud lumps, and diapiric folding, seem to be restricted to areas with mainly rapidly deposited, homogeneous or layered sediments. But where an abundance of burrowing organisms increases the vertical permeability of the sediment, normal consolidation and stable deposits are to be expected, at least in the upper meters below the present surface. According to 14C-determinations on calcareous microorganisms the rate of deposition of the investigated sediments seems to range from 26 to 167 cm per 1000 years.

Description: Two water samples and two sediment samples taken in 1965 by the R. V. "Meteor" in the area of the hot salt brine of the Atlantis II-Deep were chemically investigated, and in addition the sediment samples were subjected to X-ray and optical analysis. The investigation of the sulfur-isotope-ratios showed the same values for all water samples. This information combined with the Ca-sulfate solubility data leads us to conclude that, for the most part, the sulfate content of the salt brine resulted from mixing along the boundary with the normal seawater. In this boundary area gypsum or anhydrite is formed which sinks down to the deeper layers of the salt brine where it is redisolved when the water becomes undersaturated. In the laboratory, formation of CaSO4 precipitate resulted from both the reheating of the water sample from the uppermost zone of the salt brine to the in-situ-temperature as well as by the mixing of the water sample with normal Red Sea water. The iron and manganese delivered by the hot spring is separated within the area of the salt brine by their different redox-potentials. Iron is sedimented to a high amount within the salt brine, while, as evidenced by its small amounts in all sediment samples, the more easily reducible manganese is apparently carried out of the area before sedimentation can take place. The very good layering of the salt brine may be the result of the rough bottom topography with its several progressively higher levels allowing step-like enlargements of the surface areas of each successive layer. Each enlargement results in larger boundary areas along which more eff ective heat transfer and mixing with the next layer is possible. In the sediment samples up to 37.18% Fe is found, mostly bound as very poorly crystallized iron hydroxide. Pyrite is present in only very small amounts. We assume that the copper is bound mostly as sul­fide, while the zinc is most likely present in an other form. The sulfur-isotope-investigations indicate that the sulfur in the sediment, bound as pyrite and sulfides, is not a result of bacterical sulfate-reduction in the iron-rich mud of the Atlantis II-Deep, but must have been brought up with the hot brine.

Description: As a result of the participation of R. V. "Meteor" in the International Indian Ocean Expedition during the winter 1964/65 altogether 37 sounding profiles were obtained in the Arabian Sea (plate 2-18). They are showing the topographic peculiarities of the main features of the sea bottom in this northwestern part of the Indian Ocean: Shelves, continental slopes and rises, deep-sea plains and hills, the Mid-Oceanic Ridge, fracture zones and seamounts. A control chart (plate 1) shows the geographical sounding lines. The coordination of the soundings with the bathymetric sketch and the map of physiographic provinces (B. C. HEEZEN and M. THARP) is represented in fig. 1 and 2. All soundings were obtained by the modern ELAC-Narrow Beam sounder which also accurately records very steep slopes of the sea bottom (fig. 3 and 4 ). Two series of sounding prnfiles (fig. 5 and 6) are showing the main topographic differences of shelf and slope between the eastern African and the western Indian continental margin. The descriptive analysis of all the sounding sections carried out by "Meteor" show the following main results: a) discovery of a very steep towering up seamount in the northern Somali basin at φ = 8° 16' N, λ 53° 12' E, which is rising up from a depth of 5000 m to about -2000 m (plate 3), b) registration of numerous steep canyons in the upper part of the eastern African continental slope near the coast of Kenya (plate 6 ), c) complete representation of a characteristic section across the Carlsberg-Ridge inclusively rift mountains and the Rift-Valley (plate 9), d) new characteristic results of sounding profiles across the Alula-Fartak trench showing very steep siopes on its flancs (plate 18).

Description: Sediments from a 3.40 m core out of the Persian Gulf were investigated for their content of straight chain paraffins and fatty acids. The samples range in age between 2000 and 9000 years (C-14-age of organic C). They contain 100-300 ppm of extractable fatcompounds and 20-70 ppm of hydrocarbons. There is no connection between the original distribution of the homologous series of n-fatty acids and n-paraffins. However, there is evidence that part of the n-fatty acids was reduced to n-paraffins, although the sediment itself does not look as if it were deposited under reducing conditions.

Description: 1. Coeloplana meteoris is described as a new platyctene ctenophore (with 11 photographs and 1 coloured figure). 2. Its systematic position is discussed and understood as preliminary. 3. A comparison is made of the gastrovascularsystem of the Platyctenea. These can be used for systematic characterisation.

Description: During the expedition of R.V. "Meteor" to the Indian Ocean 21 species of marine algae and 2 phanerograms were collected on the Sarso islands. A littoral zone (in the botanical sense) and three sublittoral zones could be diffentiated by means of the algae. Of these the most conspicuous is the Sargassum-Turbinaria belt. A small strip of Avicennia mangrove was observed. The collected marine plants belong to 5 types of geographical distribution which indicate the origin of the flora from the Indian Ocean.