ALBERT

Description: Some current meter data obtained from a mooring at 2450 m water depth near the continental slope off Portugal are presented. The mean currents at five levels with observations are northward. Mean speeds in the core of the Mediterranean Water exceed speeds at shallower levels by 2 to 3 cm/sec, indicating advection connected to this specific water mass. The current variability is dominated by semi-diurnal tidal components. Normal mode analysis reveals a predominant mode of order 2, representing 48% of the total kinetic tidal energy. Results for the barotropic tidal component are in good agreement with earlier predictions for this area. The motion at higher frequencies ω in the internal gravity wave band can be well described by a ω-2 power law for the energy density spectrum. This result is consistent with earlier observations in other parts of the ocean.

Description: Continuous temperature and salinity profiles from the NE-Atlantic frequently show a double-maxima straucture within the depth range of the Mediterranean outflow. Two explanations for this special thermohaline stratification con be found in literature: a) The density of the outflow is varied by different outflow channels with unequal mixing properties. b) In the Strait of Gibraltar two different outflowing water types are produced by tidal currents. in both cases the different water masses spread in different density levels in the Atlantic. Data presented here indicate that the bimodal straucture must be caused primarily by tidal currents at the source. Two-layered outflowing Mediterranean water was observed even before a splitting of the under-current in the Gulf of Cádiz takes place. The variability of the double-maxima can be explained by varying outflow rates in the source region rather than by a steady influence of the bottom topography.

Description: Data on the N2O contents of marine air and sea water from the Northeast Atlantic Ocean are presented. The N2O content of marine air is rather constant. The data are in accordance with earlier measurements. The sea water down to depths greater than 1,000 meters is considerably supersaturated with N2O with respect to air. Supersaturation values obtained from surface water allow the conclusion that part of the North Atlantic acts as a net source of atmospheric N2O.

Description: The expedition "Auftrieb '72" was conducted in the NW African Upwelling Region off the Banc d' Arguin and included two geological profiles off Cap Blanc and off Villa Cisneros. R.V. "Meteor" and R.V. "Planet", the research plane "Canberra" and the tourist vessel M.S. "Regina Maris" participated in the expedition. Several components added up to a coordinated programme of different disciplines: Current meter moorings, large-scale oceanography and intensive studies of frontal zones were the task of R.V. "Planet". Medium-scale oceanography, chemistry and various disciplines of marine biology were performed with R.V. "Meteor", while the airplane and M.S. "Regina Maris" supplied background oceanographic information for the whole programme. The work done with R.V. "Meteor" is reported here. lt has been organised in three sections: Cruise section I. Nutrient dynamics in upwelling water bodies, in continuation of the work done during the "Roßbreiten-Expedition 1970". Cruise section II. Circulation in an upwelling system, including direct measurements of the vertical velocity; mixing processes in an upwelling system. Cruise section III. Sediment and benthos in areas of strong and weak upwelling. The approach to the study of these processes varied according to the problem. During cruise section I a number of drift experiments similar to the experiment conducted during the "Roßbreiten-Expedition 1970" was performed, consisting of a regular station programme at a freely drifting buoy which served for marking a patch of upwelling water. Cruise section II consisted of repeated sections in the vicinity of the vertical current meters and the current meter moorings. Cruise section III concentrated on two profiles perpendicular to the coast off Cap Blanc and Villa Cisneros.

Description: Temperature data are presented which were obtained by means of a towed thermistor cable during the expedition "Auftrieb '72" in the immediate vicinity of the continental slope within the NW African upwelling region. While most of the data have been sampled on the offshore side of the upwelling front, the front is crossed on a few occasions, and some data cover the area of the upwelling coastal jet. They reveal a very deep homogeneous surface ]ayer within the coastal jet, indicative for increased turbulent mixing. These conclusions from the temperature sections are confirmed by the temperature and salinity data from CTD casts made in the same area at the same time. In spite of the complicated hydrography of the area and the large number of water masses involved, the existence of a zone of increased turbulent mixing within the jet is indicated in the data.

Description: During "Meteor" cruise 23 in spring 1971 intensive investigations of the Mediterranean outflow in the Gulf of Cádiz were carried out. In order to give a budget of the inflow and outflow numerous CTD-stations were taken. The observations also included six moored current meter arrays deployed in the known outflow channels. The considerations given here are based mainly on three hydrographic sections, current meter records averaged over one month, and geological observations from the bed forms beneath the Mediterranean undercurrent. The results show that the outflow essentially is determined by the bathymetry of the area. At least four separate outflow channels could be confirmed. The volumentric transport rates of three of them were calculated. These channels are the northerly near shelf branch (0.40 · 106 m3 sec-1), the main branch (1.39 · 106 m3 sec-1 in southwesterly direction, and an intermediate branch (0.24 · 106 m3 sec-l) found between both. In a static box model the progressive mixing of 0.95 · 106 m3 sec-1 pure Mediterranean Water with 1.97 · 106 m3 sec-1 North Atlantic Central Water is demonstrated.

Description: Oceanographic measurements by groups from the Federal Republic of Germany contributed mainly to the C-Scale Experiment (centered at 9° N, 23° W) and the Equatoria1 Experiment. In this paper the data are presented that were obtained from the moorings F 1 and F 2 in the C-area. After a short discussion of instrument problems, data processing and statistical analysis, the data are presented graphically as time series, progressive vector diagrams, frequency distributions and spectra of horizontal kinetic energy and of temperature variance.

Description: The results of measurements on currents and stratification obtained by FRV "Anton Dohrn" during the GATE-Equatorial Experiment are presented in graphical form. Remarks on data processing arid errors involved are made accordingly.

Description: We report, numerically and in graphical form, measured tritium concentrations from five hydrographic stations in the North Atlantic. Fairly homogeneous concentrations are observed in a surface layer typically 400 m deep. In the thermocline, concentrations decrease steadily down to the a σθ = 27.3 density horizon, and are more variable further down. The tritium in the lower part of the thermocline originates from the Subarctic Intermediate Water and the Mediterranean Water. There is a relative tritium maximum associated with the Mediterranean Water on the easternmost station of the section. In the deep water (σθ 〉 27.8), concentrations east of the Midatlantic Ridge are close to the limit of detection down to 2500 m, and undetectable further down, while west of the ridge tritium is found throughout the water column. The deep water tritium is associated with the deep-water advective cores of Arctic origin. The present tritium data can serve as northern boundary values in attempts to use tritium in studies of the North Atlantic main thermocline dynamics. The present data together with data from the literature point to a general division of the North Atlantic main thermocline into two layers separated by an isopycnal surface near σθ = 27.3.

Description: The distribution of 210Pb and 210Po in dissolved ( 〈 0.4-micron) and particulate (〉 0.4-micron) phases has been measured at ten stations occupied during cruise 32 of F. S. "Meteor" in the tropical and eastern North Atlantic. Both radionuclides occur principally in the dissolved phase. Unsupported 210Pb activities, maintained by flux from the atmosphere, are present in the surface mixed layer and penetrate into the thermocline to depths of about 500 m. Dissolved 210Po is ordinarily present in the mixed layer at less than equilibrium concentrations, suggesting rapid biological removal of this nuclide. Particulate matter is enriched in 210Po, with 210Po/210Pb activity ratios greater than 1.0, similar to those reported for phytoplankton. At depths of 100-300m, 210Po maxima occur, and unsupported 210Po is frequently present, an observation that suggests rapid re-cycling within the thermocline. Comparison of the 210Pb distributions with those reported for 226Ra at nearby GEOSECS stations confirms the widespread existence of a 210Pb/226Ra disequilibrium in the deep sea. Close to the bottom, profiles of 210Pb and 226Ra usually diverge, and 210Pb concentrations frequently decrease with depth, suggesting a sink for 210Pb near the seafloor. Particulate 210Pb concentrations ordinarily show little systematic variation with depth. At depths greater than 1,000 m, dissolved 210Po activities are, on the average, less than those of 210Pb by 12 % . A corresponding 210Po enrichment in the particulate phase is found.

Description: Pelagic tar has been collected daily on a transsect from off Prtugal to south of the Canary Islands in January/February 1975. A new neuston sampler was used which may be towed at speeds between 7 and 10 knots (DERENBACH & EHRHARDT 1975). A total of 22 samples was taken. Dimensions of tar balls ranged from potatoe-size to small specks approximately 1 mm in diameter. Concentrations were found to vary between 20.5 and 0.007 mg/m2, except for one instance of an extremely high tar concentration of 2270 mg/m2. 49 GC analyses were made. 61% showed bimodal peak distributions characteristic of crude oil sludges. The composition of tar balls was independent of their size suggesting diffusion controlled degradation.

Description: During the international "Overflow-Expedition" 1973 on R.V. "Meteor" oxygen concentrations in surface layers were measured in order to determine the oxygen gradients within the First two meters and to add some informations to the mechanisms of oxygen exchange at the air-sea interface. These investigations may be interesting also with regard to long-term-observations of the oxygen distribution in the Atlantic, especially the problem of the A.O.U. (apparent oxygen utilization) determination. To measure oxygen gradients a special sampler was built which is able to take water samples each 20 cm of the First 2 meters. These data were supplemented by further samples down to 150 m, taken by conventional water samplers, from which samples were also taken to measure N2/02-relations. By comparing these relations with theoretical relations in air-saturated water the influence of biological production and consumption on the oxygen contents in water could be estimated. A simple glass apparatus was built to extract gas from the water samples, and hereafter the N2/02-relations were determined by mass spectrometry. Most distributions of the oxygen anomaly show a negative oxygen balance which varies largely, probably due to strong mixing processes in the Iceland-Färö ridge area. The distribution of surface oxygen saturation values are of two different types. The values of the stations 260, 262 and 270 stem from mixed water and show homogeneous supersaturations, as can be found instantly when whitecaps appear. The values of 9 other stations are from water, sampled during calm periods which has been mixed and supersaturated before. They show a decreasing oxygen saturation towards the sea surface and often undersaturation in the upper decimeters up to 98% and even 91%. So at the air-sea interface even less initial oxygen saturation than 100% can be found after supersaturation during heavy weather periods.

Description: Records of currents and temperature on the upper edge of the continental slope off Sierra Leone show a significant energy peak between 0.3 and 2 cph in the bottom near layer. The fluctuations of temperature and velocity are interpreted as internal waves over a critical bottom slope. Since they seem to receive their energy mainly from the barotropic tide, the phenomenon is of interest in the dissipation cascade of tidal waves. The high frequency current amplitudes are occasionally strong enough to affect sediment deposition and related benthic processes. Inspection of current meter records from other regions of the NW-African continental slope reveal the similar effect of intensified bottom current fluctuations.

Description: A new technique for the harmonic analysis of current observations is described. lt consists in applying a linear band pass filter which separates the various species and removes the contribution of non-tidal effects at intertidal frequencies. The tidal constituents are then evaluated through the method of least squares. In spite of the narrowness of the fitter, only three days of data are lost through the filtering procedure and the only requirement on the data is that the time interval between samples be an integer fraction of one day. This technique is illustrated through the analysis of a few French current observations from the English Channel within the framework of INOUT. The characteristics of the main tidal constituents are given.

Description: 14C concentrations, as weil as 13C, hydrographic and nutrient data are reported for 5 hydrographic stations that form a transatlantic section near 40° N ("Meteor" cruise no. 23, 1971). Precision (for 14C ± 0.3% or better) and comparability with literature data are specified. A planned intercomparison with the US GEOSECS program within the Newfoundland Basin deep water failed because of variability of water characteristics. The observed 14C values decrease from about Δ 14C = + 80‰ at the surface to -70‰ at 2000 m depth. Deeper down, the values west of the Midatlantic Ridge remain similar, whereas those east of the ridge decrease further, to about -110‰. It is shown that bomb-14C is prominent down to about 1500 m depth. Beyond this depth the bomb 14C component is small and is negligible in the eastern basin below 2800 m. On the basis of the 14C-tritium correlation, the distribution of natural 14C below about 1500 m depth is derived from the observations. In the deep and bottom water east of the ridge the 14C-salinity relationship seemingly is non-linear. Contrary to expectation, the 14C concentration in the bottom water is not lower than found on an US GEOSECS station near 10° N. Apparently, lateral concentration differences in the Northeast Atlantic bottom water as well as nonlinearity of the 14C-salinity relationship at 40°N do not exceed 10‰ in Δ 14C.

Description: The grazing of different copepodite stages of Calanus finmarchicus on natural phytoplankton populations was measured at different times of day and night during the Fladen Ground Experiment (FLEX), from the end of May to the beginning of June 1976, at the central position of the "FLEX box" (58° 55' 00" N, 0° 32' 05" E), on board of the R.V. "Meteor". A big difference between nocturnal and diurnal food intake was found, particularly for the stages V & IV, which at night ingest 4 to 10 times more than during daytime. The maximal daily food intake (24 hours), taking into account the different feeding rates at the different times of the day and expressed as percent of own carbon weight, was found to be 31 %, 83 %, 115 % and 148 % for the copepodite stages V, IV, III, II and I together, respectively, with an initial feeding threshold at about 50-60 µg C · l-1. The total grazing for the upper 40 m depth layer was calculated for each sampling time; a very pronounced grazing rhythm was found, due to the higher ingestion rates at night combined with the vertical migrations. Maximal night ingestions were 100-200 mg C/m2/hour at the end of May to 300-400 mg C/m2/hour at the beginning of June, compared with 1-20 mg C/m2/hour at midday. Making a balance of the positive influence of particulate primary production and the negative influence of grazing on the stock of particulate carbon, we could show that the main cause of the decline of the phytoplankton bloom in this period was Calanus grazing. Other zooplankton activities, namely respiration, production and faecal pellets excretion as measured by four other authors are in balance with our results of ingestion.

Description: "Auftrieb 75" was a joint cruise of R.V. "Meteor" and R.R.S. "Discovery" performed in the area 21-26° N off the northwest African coast during January-March, 1975. Current meter observations from six moorings and CTD/STD observations from three repeatedly covered sections of the cruise are analysed in order to describe the distribution of the water masses and its variability with the changes in the current system. The Canary Current is seen to pass through the northwestern corner of the expedition area, carrying with it a geostrophic eddy with a period in excess of 30 days. The eddy is probably another example of the type generally found in the open ocean circulation. Further south, offshore currents display large variations in strength and direction with a typical time scale of 10-14 days which are believed to reflect largescale mixing processes along the boundary of the Canary Current and the poleward flow of the coastal region, involving North Atlantic Central Water (NACW) and South Atlantic Central Water (SACW). The coastal upwelling undercurrent has been observed along the shelf edge but undergoes large variations in response to the wind and to variations in the horizontal divergence of the offshore currents. On the shelf the circulation responds to the local longshore wind to some extent but is also strongly affected by variations of the currents at the shelf edge. The distribution of water masses at intermediate depth ( 100-800 m) is analysed quantitatively based on the assumption that mixing between NACW and SACW is effective along surfaces of constant density only. lt is shown that most intense mixing occurs at about 22-23° N and is still very important further south. At 25-26° N SACW has been absorbed into the surrounding NACW water mass to a high degree, even in the undercurrent. Isolated bodies of water are found in the southern part of the expedition area, some of which are carried north in the undercurrent. The large variability in the water mass distribution at the source level of the upwelling probably has important consequences for the variations in the efficiency of biological production of the upwelling region.

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: The monthly mean meteorologically induced circulation of the North Sea for the period 15 March to 15 April 1976 (JONSDAP '76 INOUT period) is computed using two numerical models. One has a fine grid resolution, is two-dimensional, comprehensively non-linear and covers the North Sea. The other has a coarser grid resolution, is three-dimensional, and linear except for the inclusion of quadratic bottom friction. The depth variation of the two horizontal components of current in this model is accomplished using an expansion of time and horizontally dependent coefficients and depth dependent functions. The three-dimensional modelling technique presented here is sufficiently flexible to allow an arbitraty space and time variation of vertical eddy viscosity, although still retaining a continuous representation of current in the vertical, and allowing for variable bottom topography. Preliminary results presented here for the meteorologically induced circulation of the North Sea during JONSDAP '76 agree weil with present knowledge of the circulation of the North Sea. Comparing surface and bottom currents computed with the 3 D shelf model, it is evident that the windinduced flow varies considerably in both magnitude and direction between sea surface and sea bottom. The distribution of depth mean current computed with the 3 D shelf model over the North Sea is nearly identical to that computed with the 2 D North Sea model. This is particularly encouraging since the 3 D shelf model does not contain the advective terms, which are present in the 2 D model, and has a coarser resolution.

Description: The ecology of the lower marine fungi, namely the thraustochytrids, in the Fladen Ground area (FLEX box) and other parts of the North Sea was studied during 5 cruises in 1975 and 1976. The number of fungi/liter and the number of species showed seasonal fluctuations in the surface water samples from all the stations. A high number was found in September 1976 and a low number in March 1976. These numbers, however, revealed no seasonal fluctuations in the underlying sediments. In both the surface waters and the sediments, a consistently low number of fungi was recorded for certain stations and a high number of fungi for others, the reason for this being unknown. The sediments revealed a very high number of fungi/liter. Observations on the distribution of various species are presented. Certain species occurred more frequently at some stations than at others; certain species occurred more in the water column, e. g. Ulkenia minuta, and still others in the sediments, e. g. Thraustochytrium multirudimentale.

Description: In the framework of the Fladen Ground Experiment 1976, zooplankton samples were taken during the phytoplankton spring bloom in April-May and after the bloom in June. The plankton was collected with two samplers, a towed multiple high-speed sampler and a newly developed swing net for local sampling. The results of both methods are compared. The mean number and dry weight per m3 are given for the common species, as weil as the density of fecal pellets. The calanoid copepod Calanus finmarchicus formed 63 %, resp. 90 % of the biomass. The population composition, distribution, dry weight/length relationship and productivity of this species is studied in more detail. The high abundance of fecal pellets, eggs and young stages during the spring bloom indicate a high zooplankton activity in this period. The low density of these indicators and the apparent descent of the older Calanus stages to deep water layers in June signify the dependency of the zooplankton activity on the phytoplankton density. The estimated daily production of Calanus during the phytoplankton bloom was 20 mgC/m2. The significance of the seasonal vertical migration and the role of zooplankton in the northern North Sea ecosystem is discussed. lt is concluded that the Zooplankton could have checked the low algal density in May-June after the spring bloom, but it is far from certain that it stopped the phytoplankton outburst at the end of April and early May.

Description: During the culmination of the phytoplankton spring bloom in the Fladen Ground area in April-Mai 1976, gross primary production was between 1500 and 2000 mg particulate C m-2 day-1, at a crop density (mainly diatoms of the genus Chaetoceros) of about 1500-3500 mg C m-2. Estimates of the C : chlorophyll a ratio in living cells were much lower than those reported in the literature, possibly because part of what is measured as "chlorophyll a" by the common fluorometric method is associated with particles that are not reported as cells. Most of the dark 14C fixation during the bloom's climax was due to abiotic processes. Excretion of 14C-labeled carbohydrates did not account for a significant fraction of the total photosynthetic rate. The low crop after the bloom period, in June, corresponded with nutrient depletion of the euphotic zone. The low photosynthetic efficiency in June may have been a gross underestimate. The presence of relatively high concentrations of chlorophyll derivatives signifies that the algal crop was consumed by heterotrophs, but at a lower rate in April/May than during the June cruise when particularly high molar ratios of phaeophorbide a and phaeophytin a relative to chlorophyll a were found. The high respiratory rate relative to autotrophic production in June manifested itself also in high dark 14C fixation values. The high concentration of phaeophorbide a in the upper 40 m and its scarcity below this depth during the spring bloom climax in April/May implies that copepod grazing at that time took place principally in the euphotic zone. The remarkably high concentration of chlorophyllide a in the surface layer during the bloom period indicates that the part of the crop that was destroyed by the grazers while eating was occasionally as high as the part that was actually ingested.

Description: During the Fladen Ground Experiment (FLEX, March 26-June 6, 1976) quantitative investigations of herbivorous zooplankton were performed. For that purpose 1785 water samples (5 or 10 l) were taken with a rosette sampler at the central station (pos. 58° 55' N, 0° 32' E) from nine to ten standard depths and filtered through 30 µm gauze filters. The development of the most important Zooplankton groups at the central Station is presented in depth-integrated time series (0-100 m) of individuals per m2. The number of individuals of Calanus finmarchicus was converted to biomass (dry weight). At the end of the sampling at the central station the standing stock of Calanus finmarchicus showed about 18 g dry weight per m2. Numerical values for the time lags between different plankton groups are calculated with the aid of the cross-correlation function. The time lag between the diatom ad copepod egg peaks is only up to 2.75 days; that between diatoms and the larvae of bottom invertegrates is 5 days. Between the copepod eggs and the maximum number of nauplii (N I-N VI) there is a time lag of 10.75 days. Another 10.25 days lie between the maximum numbers of nauplii and copepodites (C I-C VI). Considering the depth-integrated time series of the abundance of Calanus finmarchicus copepodites, a succession of the Stages seems to exist. Nevertheless, numerical values for the time lags between the different developmental stages cannot be calculated unambiguously by the cross-correlation technique. This is probably caused by extreme simultaneous fluctuations, especially of the numbers of all stages of Calanus finmarchicus in the last phase of the sampling at the central station.

Description: The third phase of the cooperative data collection program JONSDAP begun in 1970 by the countries bordering on the North Sea was planned to include for the first time biological and chemical measurements in 1976, as well as physical ones. Intensive measurement programs were performed, one concentrating on the currents flowing into and out of the open boarders of the North Sea (INOUT) for 40 days in March/ April and one in which the dependence of the spring plankton bloom on the vertical temperature structure was studied in the Fladen Ground area for 100 days from March to June (FLEX). Around 90 % of the planned program with moored systems and 75 % of the measurements from moving ships were able to be carried out successfully. The large quantities of data required the establishment of two data centers. The current data were collected in Liege, all data from the FLEX box in Hamburg. A cooperative JONSDAP format was agreed on for the exchange of data. Graphic presentations of the data have been compiled in the two-volume Draft FLEX/IN OUT Atlas and distributed to all JONSDAP '76 participants, one of the main purposes of which being the facilitation of interdisciplinary evaluations, now that the intradisciplinary data processing has almost been completed - as presented in this volume.

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.

Description: Since both German research vessels „Meteor" played a major role in G. Dietrich's work, it seemed appropriate to present his bibliography in this series. An assessment of his scientific achievements was given at an earlier date (H. U. ROLL 1973: In memoriam GüNTER DIETRICH 1911-1972. - ,,Meteor" Forsch.­ Ergebn. A, No. 12: V-X).

Description: Vertical velocity spectra can be determined by three different indirect methods: Following isopycnal surface displacements, following isothermal surface displacements, or calculating water particle displacements from temperature time series at fixed pressure levels, with the mean vertical temperature gradient used for the conversion factor. This third method is the easiest to perform. Data from GATE 1974, obtained by CTD profiling onboard R. V. "Meteor" and by temperature measurements on moorings, are used to check whether the three methods are equivalent. lt is shown that autospectra do not differ significantly within the 95 % confidence intervals, and either method can be applied. This does not infer an equivalence with respect to the actual data points since individual events were found in the low-passed time series with deviations occurring between displacement curves obtained by the different methods. These events were apparently due to the advection of another water mass.

Description: The research programmes of the German groups in JASIN 1978 are summarized, comprising projects that concern the planetary boundary layer, the radiation budget, the oceanic mixed layer and thermocline and the trace element exchange. Lists of the participating scientists and technicians are included. Brief descriptions of the field activities on board the three ships and the aircraft are given, including maps and stations lists.

Description: Biological, hydrographical and chemical parameters were analysed from surface survey maps, drogue experiments and tracks in the region between Cap Blanc and Cap Timiris off NW Africa between January and March 1972 during the "Meteor"­ Expedition "Auftrieb '72". The chemical data measured included the nutrients: nitrate, nitrite, ammonia, silicate and phosphate as well as oxygen, particulate organic carbon and particulate organic nitrogen. In the area under investigation three different watermasses could be defined by nutrient content and salinity: namely "South Atlantic Central Water" (SACW), "Old Surface Water" and water from the Banc d' Arguin ("Bankwater"). The nutrient content and salinity of the fresh upwelled water at the surface showed that it consisted mainly of SACW that had always been mixed with one of the other watermasses. Mixing between Bankwater and SACW probably takes place close to the seabed on the shelf edge where cells of Bankwater were found several times. The surface survey maps show active upwelling only on the onshore ends of shelfedge canyons. This spatial heterogenity together with the discontinuities in the upwelling processes might explain the fact that no processes with time could be followed during buoyed parachute drogue experiments. The atomic ratio of nutrient uptake was found to be about N: Si: P = 15: 12 : 1 for the first few days of phytoplankton uptake in fresh upwelled water. From a comparison of the original concentration of the nutrients in fresh upwelled water and the calculated uptake, it follows that silicate might pose as a limiting factor after some days. Two sets of data from drogue experiments indicate that biological oxygen production as estimated from nitrate uptake, is sufficient to explain the oxygen input to fresh upwelled water. Thus physical solution of oxygen from the air appears to be slight.

Description: During the International ICES Expedition "Overflow '73" a total of 174 samples from 18 stations were collected by R. V. "Meteor" in the waters of the Iceland-Faroe Ridge area. They were filtered on board ship (through 0.4 µm "Nuclepore" filters), then stored in 500 cm3 quartz bottles (at -20°C) and analyzed in air-filtered laboratories on land for zinc and cadmium by means of the differential pulse anodic stripping voltammetry technique and copper and iron by flameless atomic absorption spectrometry. The overall averages of 1.9 µg Zn l-1, 0.07 µg Cd l-1, 0.5 µg Cu l-1 and 0.9 µg Fe l-1 are in good agreement with recent "baseline" studies of open-ocean waters. The mixture of low salinity water masses from the North Iceland Shelf/Arctic Intermediate Waters seem to maintain distinctly lower concentration of Cd, Cu and Fe than the waters from the North Atlantic and the Norwegian Sea where quite similar mean values are found. There is only little evidence for the assumption that overflow events on the ridge are influencing the concentrations of dissolved metals in the near-bottom layers.

Description: This paper presents a compilation of the data sets obtained by CTDs and profiling current meters on board the ships "Meteor" and "Planet" during GATE in the B- and C-Scale Areas (7°-10 °N, 22°-25°W, June 17 to September 24, 1974). The bulk of the CTD data is displayed in the form of isopleths. Selected sets of profiles, outlining special phenomena observed, and profiles of the mean and standard deviation of temperature and salinity are given additionally. Besides examples of actual current profiles, isopleths of the 25 hour mean current components, and isopleths of the vertical shear are presented. The mean current components and their standard deviations are also displayed. Time series presented are suitable for comparison with moored current measurements. The presentation of the data is preceded by a summary of the editing procedures and by a discussion of the data quality.

Description: A first survey of the entire temperature data base from the central station is presented. The development and the changes of the sea surface temperature, the thermocline, and the heat content due to meteorological forces, are described.

Description: A description is given of part of the data on residual currents which were obtained during the INOUT phase of JONSDAP '76. This current measuring programme was the result of a concerted effort of North Sea bordering countries and was aimed at a better understanding of residual water movements in the North Sea. One of the first results of INOUT is the possibility to compare estimates of simultaneously occurrmg inflow/outflow through several North Sea boundary sections. It appears that major inflow/outfow occurs in the neighbourhood of the Norwegian Trench. Estimates for other boundaries are significantly lower. Matching the objectives of INOUT several charts are presented showing measured residual water movements under influence of some "persistent" winds that is to say, during situations with spatial homogeneous windfields not changing too rapidly in time. Under such conditions it is possible to identify residual current systems. However, as can be expected, in cases of spatially inhomogeneous winds and/or winds changing rapidly in time it is harder to interpret the current measurements. In those cases it is necessary to use mathematical North Sea models with the proper wind field input. The Royal Netherlands Meteorological Institute (KNMI) took care that these windfields were stored on magnetic tape during INOUT for this purpose.

Description: Recordings were made of the voltage differences between the ends of two submarine cables crossing the Pentland Firth; the recordings covered the period from February to October 1976 and thus included the period of the JONSDAP '76 oceanographic experiment in the North Sea. The noise level on these recordings was found to be greater than for similar recordings on cables crossing the Dover Strait and the North Channel of the Irish Sea; reasons for this increased noise level are discussed. Tidal analyses of the recordings were made for six discrete sets of recordings, each of 29 days duration; these analyses produced consistent results for the five major semi-diurnal constituents, namely N2, V2, M2, S2 and K2. However, an examination of the propagation of the M2 tidal constituent in this region showed that the phase of M2, as calculated from the cable recordings, did not obviously aeeord with the ove1·all pattern of propagation of that constituent. Tentatively it was concluded that cable measurements represent the integrated effect of flow over an area surrounding the Pentland Firth where this flow varies widely in both phase and direction. A calibration coefficient for the cable, relating voltage to flow, was calculated by equating the annual variation in the amplitude of the M2 constituent (measured by the cable) with the annual variation in the conduetivity of sea water in the region. The residual component of cable voltage was compared with residual components of (a) the sea surface elevation at Wick and (b) currents derived from current meter measurements at a nearby location in the North Sea; also with wind recordings at Wick. These comparisons indicated that there was neither a significant wind-driven flow through the Pentland Firth, nor a seasonally varying residual flow. It is suggested that a significant component of both the residual flow (as measured by the cables and by the current meters) and the residual elevations at Wick is associated with the propagation of "external surges" into this region.

Description: A simple model is used to simulate the dynamics of phytoplankton and phosphate from April 19 to May 16 during the Fladen Ground Experiment. The model describes the development of vertical profiles in time. lt allows changes of phytoplankton standing stock by turbulent diffusion, sinking of cells, primary production, respiration, mortality and grazing, and changes of phosphate concentration by turbulent diffusion, nutrient uptake and remineralization. The model is used as a means of checking the consistency of the biological assumptions made with the observed phosphate concentration, phytoplankton cell counts and primary production. Local turbulent diffusion coefficients, underwater light climate and Zooplankton standing stock in terms of total copepods are given quantities, the former from a physical upper layer model, the latter two from data. Simulations show that if phytoplankton standing stock and primary production are reproduced fairly well, then phosphate is still too high and vice versa. lt appears that the conversion factor expressing the amount of phosphate necessary to produce l g carbon is crucial. Relating this ratio to the observed decrease of phosphate and the primary production the simulation reproduces the exponential growth phase weil but fails for the rest. This indicates the need of a variable conversion factor in the model, depending on the status of the bloom. lt can be shown that turbulent diffusion is indispensable for the development of the spring bloom. Further it is shown that as a consequence of the assumptions made about two thirds of primary production are taken up by zooplankton. An estimate of potential grazing of copepods shows that copepods starve or have other food sources than living phytoplankton.

Description: The figures contain section data of S, t, total P, N03, chlorophyll a, total particulate P and total phytoplankton. The data indicate that primary production had started only along Norway, probably due to the high stability caused by the presence of water of Baltic origin. Three runs were made; differences between them are discussed in relation to results of current measurements.

Description: Tracking a balloon with a single ship-based theodolite, is a method which has been used for a long time to determine the wind profile over the sea. There are two main sources of error: (a) the incorrect estimate of the height of the balloon and (b) the pitch and roll motions of the ship. In this paper the effects of both errors are investigated. The ship's motion is simulated with use of a transformation from a fixed (earth) to a moving (ship) coordinate system. Some examples are presented to illustrate the magnitude of these effects.

Description: From 8 April to 4 May 1976 chemical changes in the marine environment and primary production were studied in the area of the northern North Sea (Fladen Ground). During most of the observation time, when the ship was keeping close to the central position, the influence of patchiness and advection by currents was relatively small. Under such favourable conditions it was possible to follow the temporal changes and processes in the water during the first phase of the spring phytoplankton bloom. After 19 April a distinct thermocline was established. At the same time the nutrient and C02 concentrations in the surface water began to decrease, due to the uptake by the growing phytoplankton. Before the start of the phytoplankton bloom the ratios (by atoms) were N : Si : P = 14 : 6.5 : 1.0. The ratios of nutrient and C02 uptake into the phytoplankton were ΔC : ΔN : ΔSi : ΔP = 120 : 19 : 9 : 1.0. During periods with high irradiance a remarkable diurnal rhythm of temperature and 02 concentration in the surface water could be observed. From the pH, temperature, salinity und alkalinity data the mean net primary production during the first 12 days of the phytoplankton bloom ( 19 April to 1 May) was calculated. lt was about 2.0 ± 0.4 gC · m-2 • d-1. The same result was obtained from the phosphate data.

Description: During the 1971 "Meteor" survey of the Mediterranean Outflow, seven current meter moorings were deployed and several hydrographic stations executed. The time series data from almost all the current meters revealed a solitary increase in temperature with an amplitude of ≃ 1 °C and a duration of 2-4 days. The present analysis of the event shows that it was due to a thickening of the Mediterranean Outflow and an increase in the volume transport. The origin of the event is traced to the source of the Outflow from where it propagated with a speed of 16 cm s-1. Coinciding with the time at which the event passed the Strait of Gibraltar, the cross channel water level difference revealed an anomalous variation of about 8-cm amplitude and 3-day duration. Through conversion the magnitude of this fluctuation is now shown to simply a significant increase in the Outflow volume transport. An investigation of the reigning meteorological conditions indicates that, simultaneously, an impulse of water in the Alboran Sea was transported westwards by the wind. Through a qualitative and quantitative approach, the atmospheric forcing of the Western Mediterranean is thus linked to a large variation in the Outflow structure.

Description: Measurements by CTDs (Multisonde, Bathysonde) and current profilers were carried out onboard the research vessels "Meteor" and "Planet" during the Joint Air-Sea Interaction Project (JASIN) in 1978. Data from these observations are presented in the form of mean distributions with their standard deviations, as time series and as profiles during the "multiship experiments". Selected time series of terms derived from the data are added: current shear, Vaisala frequency and Richardson Number. The text also contains information concerning instrument calibration and data processing.

Description: The three Federal German research vessels "Planet", "Meteor" and "Poseidon" participated in the Second Multiship Experiment during JASIN 1978 as stationary ships with CTD yo-yo profiling. The analysis is concerned mainly with the weakly stratified layer between the seasonal thermocline and the turbulent mixed layer. The thermoclinic structure of a front in that layer and its tidal/inertial displacement is described and is shown to be in accordance with current meter data from the H2 mooring. It is shown that the CTD yo-yos cannot be treated as pure time-series but that the movement of the ships relative to the seabed and relative to the front has to be taken into account. The method of isopycnic analysis was used to eliminate the effect of internal waves. Temporal coordinates can be converted to spatial coordinates allowing for the tidal/inertial movements. Thus high resolution sections through the front can be given. The thermohaline structure is described on density levels in the seasonal thermocline and in the weakly stratified layer above it.

Description: On a cruise from the eastern into the western Mediterranean Sea in November/December 1978 a total of 126 samples were collected from 8 vertical profiles and 7 coastal stations for trace metal analysis. The sampling, processing and analysis was performed under strict "clean room" conditions. The concentration of the open-sea samples are close to oceanic results gathered under similar conditions. The grand averages from all profiles ( ± st. dev. of the individual samples) of 0.40 ± 0.16 µg l-1 Zn, 17.4 ± 7.4 ng l-1 Cd, 0.21 ± 0.07 µg l-1 Cu, 0.21 ± 0.13 µg l-1 Mn and 0.25 ± 0.09 μg l-1 Fe indicate that a "metal problem" does not exist in the open Mediterranean. A biologically mediated depletion in surface waters or correlation with nutrients have not been observed under the conditions established on this cruise. This is probably due to low primary production and seasonal advection processes prevailing in this sea. The data for manganese show generally higher values in the surface layer (0-75 m) than in deep waters. This could evidently proved in the nearshore profile indicating a terrigenous source for manganese.

Description: We present field measurements of air-sea gas exchange by the radon deficit method that were carried out during JASIN 1978 (NE Atlantic) and FGGE 1979 (Equatorial Atlantic). Both experiments comprised repeated deficit measurements at mixed position over periods of days or longer, using a previously described precise and fast-acquisition, automatic radon measuring system. The deficit time series exhibit variations that only partly reflect the expected changes in gas transfer. By evaluating averages over each time series we deduce the following average gas transfer velocities (average wind velocity and water temperature in parentheses): JASIN phase 1: 1.6 ± 0.8 mid (at -6 mis, 13 °C) JASIN phase 2: 4.3 ± 1.2 mid (at -8 mis, 13 °C) FGGE: 1.2 ± 0.4 mid (at -5 mis, 28 °C) 0.9 ± 0.4 mid (at -7 mis, 28 °C) 1.5 ± 0.4 mid (at -7 mis, 28 °C) The large difference between the JASIN phase 2 and FGGE values despite quite similar average wind velocity becomes even larger when the values are corrected to a common temperature. Both values are, however, fully compatible with the range of gas transfer velocities observed in laboratory experiments and the conclusion is suggested that their difference is caused by the highly different wind variability in JASIN and FGGE. We conclude that in gas exchange parameterization it is not sufficient to consider wind velocity only. A comparison of our observations with laboratory results outlines the range of variation of air-sea gas transfer velocities with wind velocity and sea state. We also reformulate the radon deficit method, in the light of our observed deficit variations, to account explicitely for non-stationarity and horizontal inhomogeneity in the near-surface radon deficit layer (i.e., mixed-layer and upper thermocline). We show that neglection of non-stationarity and horizontal inhomogeneity in previous radon work introduces considerable uncertainty in deduced gas transfer velocities. We furthermore discuss the observational requirements that have to be met for an adequate exploitation of the radon deficit method, of which an observation area of minimum horizontal inhomogeneity and monitoring of the remaining inhomogeneities are thought to be the most stringent ones.

Description: In general the natural aerosol reacts very sensitively to the change of relative humidity. This behaviour could be observed from August to September during the Atlantic "Meteor" -Expedition 1965, but not during the periods January to May 1969 and July to August 1974. There are some reasons for the assumption that this is an effect of organic material in the surfaces of the particles. But we do not know if this is an effect of different seasons or of increasing pollution of the atmospheric aerosol.

Description: Data from two current meter moorings and thermosa�linograph records from the Scotia Sea are presented. Results from the first mooring site demonstrate the ex�change of Antarctic Bottom Water between the northern Scotia Sea and the Argentine Basin. The sec�ond current data set illustrates the permanent deep counter current on the continental rise of the southern Drake Passage. Surface temperature and salinity rec�ords describe the position of the Polar Front and the Weddell-Scotia-Confluence during early austral sum�mer 1980/81.

Description: From 27 Janua1y to 23 June 1979 R. V. "Meteor" surveyed the central equatorial Atlantic on a section along 22° W from 3° N to 2° S. During the observation period, a hydrographic section down to 600 m was repeated ten times with a continuous "Howaldt-Bathysonde" CTD and a rosette sampler. The station distance was 10 to 15 nm. The water samples were used to recalibrate salinity and to determine oxygen, nutrients and chlorophyll a. An undulating CTD system ("Delphin") was towed on 11 sections. A profiling distance of one to two nautical miles and a profile depth of 90 m was obtained. Five current meter arrays were moored along 22° W between 3° N and 1° S from January to March 1979. In May and June two moorings were installed at 2° N and at the equator. On the buoys measurements of wind speed and direction were obtained. At 43 stations a wire-guided Aanderaa profiling current meter was successfully lowered. Drifting buoy experiments were repeated three times with clusters of 5 to 10 buoys. A fourth experiment took place in 1978 in the Gulf of Guinea. On the way from and to port XBT sections were carried out. The data sets obtained by these instruments are presented in this data report.

Description: The tropical circulation exhibits a prominent two-layer structure in the vertical: a moist-unstable lower layer (the "trade layer") with an ITCZ-ward directed mass transport, and a stable upper layer. The aerolo�gical measurements of the German research vessel "Meteor" in Nov.-Dec. 1965 over the Eastern Atlantic (19° W) show that this mean structure is valid even in actual meridional sections, if disturbances are absent. It follows that vertical averages over each of the two layers are appropriate to characterize the tropical atmosphere. In this paper only the trade layer is studied. Its upper boundary is defined by (a) the vertical minimum of static energy; (b) the vertical extreme value of various physical quantities such as temperature and humidity gradients; ( c) constant surfaces of a quantity c which proved useful for the data evaluations. All these definitions are more or less equivalent. The boundary surface is permeable for vertical property transports which are parameterized in terms of the hot tower- and subsidence-process (RIEHL & MALKUS). It is not possible, however, to calculate these fluxes, since meridional profiles of the horizontal mass and energy transport divergence cannot be inferred from the "Meteor" data. The main results are: (1) the static energy surface (a) is always parallel to, but systematically several 100 meters above, the surfaces (b ). (2) The sea surface pressure is practically independent of the trade layer thickness. (3) The components of the horizontal transport of momentum and energy are practically uncorrelated in the vertical; this demonstrates the Hadley-like character of the trade layer. (5) Water vapour plays with 〉 50% contribution the dominant role in the horizontal energy transport. ( 6) In the diabatic forcing function the flux of latent heat across the sea surface contributes the biggest part.These results show that vertically integrated two-layer models represent the gross features of the tropical circulation. Such formulations are thus a good approach towards simple and straightforward models for numerical experiments.

Description: The size distribution of sulphate containing particles over the North Atlantic was determined for particles with radii larger than 0.18 µm. It is compared with the size distributions of the total aerosol, the hygroscopic and the insoluble parts in the maritime aerosol. From mass concentrations of sulphate and sodium, it can be concluded that only a fraction of sulphate originates from the ocean. The sulphate mass distribution separated into its sea salt sulphate and excess sulphate components is compared with a continental distribution.

Description: During the "Atlantic Trade Wind Experiment (ATEX)" from Feb. 6th to 23rd, 1969, an intensive aerological programme and detailed measurements near the sea surface were carried out simultaneously from three ships in the Atlantic northeast trade. From these data the kinematics, the dynamics and the kinetic energy budget of the trade wind flow in the lowest 3 km are investigated in this paper. The vertical shear of the horizontal wind vector is small in the mixed layer (lowest 600 m); a weak maximum is indicated at 400 m. Below about 1OOO m the large-scale horizontal flow is always divergent. Consequently, a large-scale sinldng motion of 300 to 500 m per day is observed through that level; sinking motion is also present at the trade wind inversion (1400 m). A considerable weakening of the divergence is noted during a period when the intertropical convergence zone (ITCZ) overrides the southern portion of the ATEX triangle. The northward displacement of the ITCZ is accompanied with a low pressure system approaching from the middle latitudes. The thermal wind vector is constant below the inversion and directed almost opposite to the surface geostrophic wind vector. Consequently, the magnitude of the geostrophic wind decreases rapidly with height while its direction remains nearly constant. The difference between the actual and the geostrophic wind vanishes at about 1200 m. Convective motions contribute to the small-scale vertical momentum transport. At the wind maximum the convective momentum transport amounts to about 30% of the surface stress. In a layer extending 300 m above the wind maximum the momentum is transported downward against the vertical gradient of the mean motion. The kinetic energy of the mean motion generated by the large-scale pressure gradient within the lowest 1OOO m primarily serves to balance the loss of mean kinetic energy due to conversion into turbulent kinetic energy in the surface boundary layer (lowest 20 m). In order to provide a reasonable description of the turbulent kinetic energy budget below the inversion the effects of condensation and evaporation within the cloud layer have to be taken into account.

Description: This paper describes measurements from shortwave radiation radiosonde ascents done at the Atlantische Expedition 1969. Using the results from a total of 67 ascents mean components of the shortwave radiation budget of the atmospheric layer between the ocean surface and the top of the ascent are discussed. The influence of clouds on the radiation balance is shown by dividing the ascents in classes of cloudiness and cloud altitude. Thereby the albedo of the ocean surface is increasing with increasing amount of cloudiness. Similar the albedo of the troposphere increases involving an increased heating rate of the atmospheric layer.

Description: This paper presents the components of the radiation balance and the balance itself, which are measured from "Meteor" during A TEX from January 1 to March 2, 1969 in the Atlantic Ocean. For "Planet", also engaged in ATEX, measurements of the global radiation are shown for the period of February 4 to February 28, 1969. From the results obtained by "Meteor" the albedo of the sea surface has been calculated and is presented for two exemplary days.

Description: In the tropics mean diurnal courses of air pressure and wind system show many similarities. To test the well known theoretical considerations data of three Atlantic "Meteor" expeditions are used: The "Meteor Expedition 1925 /27", the "Atlantic Expedition 1965 (IQSY)" and the "Atlantic Trade Wind Experiment (ATEX) 1969". The results show the response of the atmosphere to the semi-diurnal pressure oscillation. The diurnal oscillation of the wind system cannot be described by simple models. The influence of the continents upon the diurnal pressure wave seems to be dominant. The measurements close to the Intertropical Convergence Zone point to a diurnal variation of the inflow into the ITCZ.

Description: During the driftage of R. V. "Meteor" within the "Atlantic Trade Wind Experiment (ATEX) 1969" time series of wind velocity, air and sea temperature and humidity were measured on a buoy drifting windward of the disturbed zone of the ship. Using the profile method, vertical fluxes of momentum and sensible and latent heat were calculated. Time variations in the periodic range from 2.5 minutes to 5 days are analysed. Within the 18 days period the vertical fluxes of latent heat and momentum vary by a factor of 5 because of long period wind variations. For wind velocity, flux of momentum and flux of latent heat the variations in the range of periods greater than one day contribute most of spectral energy (65-85%) to total variance, while for air and water temperature, humidity and sensible heat flux the variations with periods smaller than one day represent more than 50% of total variance. For most of the mentioned variables the contribution of diurnal and semi-diurnal oscillations to total variance is small (3%), only for pressure, air and water temperature it is about 30% . The measurements during rain showers point out that even weak or moderate showers influence the surface layer right down to the sea surface. The amplitudes of the diurnal courses depends on the distance of the measurements to the air-sea interface. The diurnal course of water temperature follows the variation of incoming solar radiation, with increasing depth its amplitude is reduced and the phase is lagged. Applying the equation of diffusion to the diurnal harmonic water temperature oscillation down to 50 m depth, a coefficient of thermal diffusivity in water of K = 0.0525 - 0.00075 z (m2/s), decreasing with depth, was calculated. The diurnal variation of air temperature is influenced by the diurnal course of sea surface temperature. A semi-diurnal oscillation is superimposed by the semi-diurnal pressure wave because of adiabatic warming. The observed increase of the amplitude with height is caused by absorption of solar radiation. The stability of density stratification also shows a marked diurnal variation with a maximum of lability at night. This effects directly the variation of sensible heat flux. Humidity mainly shows a diurnal variation, the reason may be a diurnal variation of the divergence of vertical water vapor transport.

Description: The hydrodynamic roughness of the sea surface at low wind speeds (u10 〈 5 ms-1) is investigated according to the aerodynamic profile method. The wind, temperature, and humidity profiles were measured during GATE in 1974. In some earlier publications on this subject the density stratification has not been considered. Therefore apparent roughness parameters are found, which are smaller than those for a hydrodynamic smooth flow. In this paper the density stratification was determined from 10 m-values of wind, temperature, and humidity. From more than 1 OOO 10 min-profiles an average drag coefficient reduced to neutral stability of CD,N10 = (1.10 ± 0.32) · 10-3 for u10 〈 5 ms-1 is obtained. As the slight decrease of CD,NlO with increasing wind speed is not significant, CD,NlO can be regarded as independent of the wind speed. In the range of low wind speeds (1.75 ms-1 〈 t110 〈 5 ms-1) the sea surface is hydrodynamically rough. The validity of the Charnock formula z0 = u*2/ag cannot be verified. An influence of wind waves on the wind profile can be shown even for wave heights less than 0.75 m up to a level of 2 m above the sea surface. Therefore the drag coefficient was determined from wind values above 2 m height.

Description: During GATE 37 flights with radiometersondes to measure the infrared radiation were made from R.V. "Meteor" at 7.8° N, 22.1° W. This position was close to the ITCZ, very often high reaching convective clouds dominated. The profiles of the irradiances are dominating influenced by clouds. Examples are given, one showing the dependence on cirrus clouds, another that on dense altostratus and nimbostratus clouds. The goal of the measurements was to obtain mean profiles of infrared radiative heating rates, but due to the high variability of the clouds and due to the difficulty to assign the flights to distinct clouds, only three mean profiles could be calculated: - Average of all 37 flights, - Clear skies, - Skies overcast with medium clouds.

Description: The net flux of all irreversible fluxes of radiation and heat crossing the ocean surface is determined for phase III of GATE at position no. 27 (WFS "Planet", FRG). The radiation fluxes have been measured directly, while the heat fluxes have been parameterized with the bulk formula however with bulk coefficients depending on stability. The heat loss of the ocean due to warming of the cooler precipitation is included for the determination of the net flux at the ocean surface. Some examples of hourly mean values of different fluxes during different weather conditions are additionally shown.

Description: Spectral analysis of time series for hourly and three minutes surface observations of potential temperature, specific humidity and wind speed show significant differences between spectra for disturbed and undisturbed conditions in the period range between one and five days and 30 and 120 minutes. The spectrum of pot. temperature which was found to be a good indicator of convective activity showed that these differences are mainly caused by enhanced convection during disturbed conditions, as the cloud and subcloud layer are strongly coupled by updrafts and downdrafts. This convective mixing influences the near surface fields of pot. temperature, wind velocity, and to a lesser extent 0£ specific humidity. For moderate to depressed convection the cloud and subcloud layers are less coupled. The diurnal radiative forcing then determines the spectra. Convection seems not to be distinctly organized, while during enhanced convective activity, the individual clouds are organized on a larger scale, forming what is commonly called cloud clusters. Two modes are found in the long period range which could be determined with a certain significance. The first one in the range of 4 to 5 days the second one in the range of 30 to 40 hours. The analysis of the high resolution buoy measurements at "Meteor" shows a further maximum due to convective influences for periods of about 40 minutes.

Description: With a 6-channel integrating nephelometer spectral scattering properties of the atmospheric aerosol have been measured during the third part of the Atlantic Expedition 1969. A meridional cross section of light scattering integrals in the wavelength range 0.475 µm to 0.924 µm was recorded reaching from 10° S to 60° N along 30° W. With a new algorithm the time series of hourly scattering spectra was inverted yielding a first meridional cross section of the median radius of the number size distribution in situ. Three air mass regimes could be distinguished in the course of the experiment, the first one being the extremely clean air of the SE-trade south of the ITC. An abrupt increase in light scattering marked the hemispheric change when the ship entered the NE-trade which was heavily loaded with Sahara dust. North of the trade region the ship sailed through maritime North Atlantic air masses with highly variable light scattering and a slow decrease in median radius with latitude.

Description: One main point of our atmospheric-electric measurements over the Atlantic Ocean 1973 was the investigation of the air-earth current density above the sea. In addition to direct measurements at the water surface with a floating net, we calculated the air-earth current density from the electric field and the air conductivity measured simultaneously on board of the ship and during particular ascents in the free atmosphere. During all five ascents the air-earth current density did not change with altitude. For pure maritime air-conditions, the mean air-earth current density was found to be 2.9 pA/m2. The mean hourly air-earth current density over the Atlantic shows nearly the same 24-hour pattern as measured by COBB (1977) at the South Pole at the same time. When dust-loaden air masses of African origin reached the ship as well as under continental influence the mean air-earth current density was reduced to 2.1pA/m2. The global 24-hour pattern was modified by this continental influences. Finally, it is shown that the values of the air conductivity measured on board R. V. "Meteor" during our earlier expeditions have been influenced by the exhaust of the ship and must therefore be corrected. With this correction, our new mean values of the air-earth current density over the Atlantic are 2.6 pA/m2 in 1965 and 2.0 pA/m2 in 1969. From all measurements, the global air-earth current is estimated to be about 1250 A.

Description: The fluxes of momentum, heat, and water vapour have been obtained by the aerodynamic profile method. Within the frame work of GATE variation of fluxes with disturbed conditions are of special interest. The time traces of surface layer parameters repeatedly showed definite instationarities marked by a sudden drop of temperature by a few degrees centigrade. For these pronounced instationarities, equilibrium state of the profiles was regained after a few minutes, in agreement with scale considerations. For fluxes properly nondimensionalized in terms of surface layer parameters, no systematic deviations have been found under disturbed conditions compared with undisturbed conditions. Due to systematic variations of parameters, the energy exchange between sea and atmosphere was enhanced by about 30 % under disturbed conditions. From the above evidence it is concluded that for larger scale investigations reliable determination of fluxes from surface layer mean variables is possible.

Description: The Aitken particle size distribution in background aerosols was measured with a newly developed Diffusion Analyzer System. The measuring system and the inversion method is discussed critically. The several hundreds of measurements indicate that several maxima in the size distribution are present. Particles as small as 10-3 µm in radius are constantly observed. Measurements of other authors indicate similar results.

Description: Size distributions of Aitken nuclei were measured in the middle and western part of the North Atlantic between 38 through 22° N and 36 through 63° W. The apparatus comprised diffusion batteries and an especially designed condensation nuclei counter. The measurements cover the size range from about 3·10-1 through to 1·10-5 cm aerodynamically equivalent particle radius. There are some indications on the trend of particle numbers above 1·10-5 cm but no reliable number distributions. The size spectra were bimodal in the north eastern part of the cruise. Closer to the Caribbean the contribution of very small particles was enhanced and the peaks shifted to larger sizes to a certain extent.

Description: On board of the German research vessels "Meteor" and "Anton Dohrn" the components of shortwave and longwave radiation budgets have been measured over the Fladenground area during a short period in 1975 (13.-19. August) and the Fladenground-Experiment (FLEX, 25 March 1976-13 June 1976). The data show that in spring and in the beginning of summer, when the ocean water is still cool, the daily incident solar radiation exceeds the net thermal radiation loss of the water to the atmosphere. In August, however, the water emission has increased to such a level that on disturbed days the daily mean radiation balance is negative. The monthly averages of the radiation budget and the global radiation derived from the shipborn measurements agree surprisingly well with those derived by several authors from climatological data. A simple scheme has been developed to parameterize the global radiation with respect to the observed cloudiness.

Description: The CaC03-contents and the fractions 〉 40 μm have been analysed from 5 kastenloten, one piston core and two kastengreifer taken between Senegal and Cape Verde Islands. Numerous benthonic and planktonic organisms and different terrigenous components have been distinguished. The four cores off Senegal reach middle Würm sediments; cores 29 and 72 (see Fig. 1) reach the V-zone and core 31 the X-zone (Eem); the two kastengreifer contain sediments of Holocene age. Correlation of the cores has been made (see Fig. 8). Holocene sedimentation rates decrease from the shallow cores (6-11 cm/1000 years) to the deep-sea (1-2 cm/1000 years) (see Table 2). The following climatic variations could be deduced from the sediments off the Senegal (Fig. 9): during Holocene climate was in general as today, the Senegal river transporting fine grained material to the sea. The upper Würm was arid with no river influence but with red dune sand transported to the continental slope. During middle Würm the climate was humid again. The deep-sea cores (Fig. 10) have been influenced by eolian material from arid regions during glacial and interglacial periods, indicated by relatively high "Wüstenquarz-numbers". However, during Würm "Wüstenquarz-numbers" are higher than during Holocene and Eem, indicating that more intensely red coloured sediment was exposed to wind activity on the continent during this period. Varying amounts of terrigenous material and CaC03-contents indicate varying wind strengths (lower in Holocene and Eem than during Würm). The boundary between humid and arid Würm climate was at approximately 20° N. Influence of upwelling is difficult to establish in the sediments off Senegal, because river influence, while increasing fertility also dilutes the diatoms which are typical for upwelling. High amounts of organic carbon, low plankton/benthos ratios of foraminifers and low plankton foraminifer/radiolarian ratios in Holocene sections might be interpreted as influenced by upwelling. Turbidites occur in cores 72 and 31 and at the Holocene/Pleistocene boundary of core 29. Their composition indicates provenance from the continental shelf of the Cape Verde Islands for core 31 and the continental shelf and slope off Senegal for core 72. Volcanic material, rare in the normal pelagic sediment of core 31 is more frequent in the turbidites. Nests in core 45 show an enrichment of shells, mainly pteropods, benthonic molluscs and vertebrate debris compared to the surrounding sediment. Their mode of formation is not clear.

Description: Plankton pump samples and plankton tows (size fractions between 0.04 mm and 1.01 mm) from the eastern North Atlantic Ocean contain the following shell- and skeleton-producing planktonic and nectonic organisms, which can be fossilized in the sediments: diatoms, radiolarians, foraminifers, pteropods, heteropods, larvae of benthic gastropods and bivalves, ostracods, and fish. The abundance of these components has been mapped quantitatively in the eastern North Atlantic surface waters (Fig. 4) in October - December 1971. More ash (after ignition of the organic matter, consisting mostly of these components) per cubic meter of water is found close to land masses (continents and islands) and above shallow submarine elevations than in the open ocean. Preferred biotops of planktonic diatoms in the region described are temperate shallow water and tropical coastal upwelling areas. Radiolarians rarely occur close to the continent, but are abundant in pelagic warm water masses, even near islands. Foraminifers are similar to the radiolarians, rarer in the coastal water mass of the continent than in the open ocean or off oceanic islands. Their abundance is highest outside the upwelling area off NW Africa. Molluscs generally outnumber planktonic foraminifers, implying that the carbonate cycle of the ocean might be influenced considerably by these animals. The molluscs include heteropods, pteropods, and larvae of benthic bivalves and gastropods. Larvae of benthic molluscs accur more frequently close to continental and island margins and above submarine shoals (in this case mostly guyots) than in the open ocean. Their size increases, but they decrease in number with increasing distance from their area of origin. Ostracods and fish have only been found in small numbers concentrated off NW Africa. All of the above-mentioned components occur in higher abundances in the surface watet than in subsurface waters. They are closely related to the hydrography of the sampled watet masses (here defined through temperature measutements). Relatively warm water masses of the southeastern branches of the Gulf Stream system transport subtropical and southern temperate species to the Bay of Biscay, relatively cool water masses of the Portugal and Canary Currents carry transitional faunal elements along the NW African coast southwards to tropical regions. These mix in the northwest African upwelling area with tropical faunal elements which are generally assumed to live in the subsurface water masses and which probably have been transported northwards to this area by a subsurface counter current. The faunas typical for tropical surface water masses are not only reduced due to the tongue of cool water extending southwards along the coast, but they are also removed from the coastal zone by the upwelling subsurface water masses carrying their own shell and skeleton assemblages. Tropical water masses contain much more shelland skeleton-producing plankters than subtropical and temperate ones. The climatic conditions found at different latitudes control the development and intensity of separate continental coastal water mass with its own plankton assemblages. Extent of this water mass and steepness of gradients between the pelagic and coastal environment limit the occurrence of pelagic plankton close to the continental coast. A similar water mass in only weakly developed off oceanic islands.

Description: 54 miliolid species of 129 samples from the Persian Gulf have been described and illustrated. Some of the most common species have been plotted in depth frequency diagrams, important groups proportionally in triangular diagrams. The fequency of most species generally increases with water depth, with decreasing sedimentation rate and increasing grain size, respectively and has maximum values at water depths between 50 and 75 m. The frequency of some species decreases with water depth. A consideration of the proportions of three selected groups gives an indication of water depth. Text-fig. 19 summarizes the results in a block diagram.

Description: Living and dead benthic Foraminifera of 26 sediment surface samples from the East Atlantic continental margin (off Portugal) are studied. The stations are located on two profiles off Cape Mondego and off Cape Sines, ranging in water depth from 45 to 3905 meters. The highest values of standing crop are on the shelf (200 m) (up to 420 specimens/10 cm3). Below 1000 m watet depth standing crop is low (5-24 specimens/10 cm3). 151 species and species groups are distinguished; 41 species are described and partly illustrated. The Figures 13-18 show the relative frequencies and the depth distributions (living and dead) of the most important species. Most of the living species do occur in a wide depth range. Faunal depth boundaries are at 50/100 m, at 600/800 m, and at 1000 m (Fig. 19). Results published from the North Atlantic and the East Mediterranean do not differ from those obtained in samples off Portugal. The Mediterranean outflow probably does not influence the benthic foraminiferal fauna off Portugal. Depth of water (e. g. hydrostatic pressure) or another factor being controlled by depth (e. g. limitation of food supply) seems to be the most important factor of the benthic foraminiferal distribution.

Description: Six soft sediment cores, up to and over 9 m in length, and additional surface samples were selected for study of their planktonic foraminifera to provide information on the Holocene and Pleistocene stratigraphy of the West African continental margin south of the present boundary of the Sahara. The material was collected mainly by the German research vessel "Meteor" during Cruise 25 in 1971. One piston core has been selected from the material provided by the Trans-Atlantic Geotraverse project of thc U. S. National Oceanic and Atmospheric Administration (NOAA ship "Discoverer"). The residues larger than 160 microns were determined, counted and statistically evaluated (Fig. 11 ). Stratigraphical correlations with trans-Atlantic regions are given by the occurrence of Truncorotaloides hexagonus and Globorotalia tumida flexuosa which mark the last interglacial stage (Fig. 2). According to the climatic record the two deep-sea cores extend down to the V-zone, considered here as equivalent to the Mindel-Riss-interglacial time, as there are three distinctly warm and two cold periods indicated in the cores by planktonic foraminiferal faunas. Z-zone = Holocene is present in all cores, Y-zone = Würmian glacial can be divided into five sections, three cold and two warm stages; the X-zone can be divided into three warm stages, separated by two cool periods. The earliest warm stage is indicated to be the warmest one. There are excellent correlations to the Camp century ice core from Greenland, to the Mediterranean, to the Carribbean and to the tropical Atlantic as weil as to the Barbados stages (Fig. 27). The W-zone was correlated to the Riss-glacial. V-zone is a warm period, the upper limit of which being not sufficiently defined, which contains also some cool sections. Increasing sedimentation rates from the deep-sea to the upper slope reveal climatic and regional details in Holocene and Late Pleistocene history of the continental margin. These were based mainly on different parameters of planktonic foraminiferal thanatocoenoses (Figs. 2-10, 15- 26) which are the main components of the size fraction 〉 160 microns of the pelagic cores. They become increasingly diluted by other faunal and terrigeneous components with decreasing slope depths (Figs. 11, 14). Estimates of absolute abundances (Fig. 14), ranging from 25000 specimens/gm of sediment in the deep sea to less than 100, indicate various sedimentary processes at the continental margin. An ecological correlation by dominant species (Fig. 15) is possible. Readily computed temperature indices of different scales (Figs. 20-26) are presented which indicate, for instance, three distinctly cold sections within the last glacial and several warm sections within the last interglacial time. These are used for estimates of sedimentation rates. During cold periods sedimentation rates are higher than during warmer periods. Stratigraphie correlation and faunal record, combined with absolute abundances and sedimentation rates, indicated that in the deep sea turbidity currents not only cause high sedimentation rates for short periods of time, but also that material is occasionally eroded. Effects of upwelling may be detected in the surface sediment samples as well as in late Pleistocene and early Holocene samples of the slope by planktonic foraminiferal data which are not influenced by sedimentary processes.

Description: By critical examination of the stratigraphical methods and interpretations applied to Eastern Mediterranean Quaternary sediments, "endemic" (Mediterranean) and "foreign" (non-Mediterranean) data are separated. Basing on the "endemic" data, cores of various authors are correlated by lithology as well as by Foraminifera frequency curves. Using "cycles" (containing a basal warm and the following cold period) a chronological interpretation of Foraminifera frequency curves, similar to that of PARKER (1958) is given. lt is applicable to curves of all authors.

Description: In the sediments of the NW African continental margin the mainly biogenic carbonate constituents become increasingly diluted with terrigenous material as one approaches the coast, as indicated by the carbonate-C02 content, the Al20a/Si02-ratios, and the presence of ammonia fixed to alumino-silicates, predominantly to illites. In the northern area of investigation - off Cape Blanc and Cape Bojador - the terrigenous constituents are mainly quartz from the Sahara Desert, whereas in the south - off Senegal - more alumino-silicates as clay minerals are admixed with the carbonate constituents. The organic carbon content of the continental slope sediments off Senegal is higher than in samples of the continental rise or of the shelf, indicating optimal conditions for the preservation of organic matter as a result of high production and relatively rapid sedimentation. The zone of manganese-oxide enrichment follows the redox potential of + 330 m V from the surface (0-5 cm) into the sediments (20-30 cm deep) at 2000-3000 m and 3700 m of water depths, respectively. At shallower water depths, low redox potentials preclude deposition of manganese oxides and cause their mobilization from the sediments. About 1/3 of the total sedimentary Zn and 1/4 of the Cu is associated with the carbonate mineral fraction, probably in calcium phosphate overgrowths as a result of the mineralization of phosphorus-containing organic matter. Besides the precipitation of calcium phosphate, the mineralization of organic matter mediated by bacterial sulfate reduction also results in calcium carbonate precipitation and the exchange of ammonia for potassium on illites. Because of these simultaneous reactions, the depth distribution of all mineralization constituents in the interstitial water can be determined using the actual molar carbon-to-nitrogen-to-phosphorus ratios of the sedimentary organic matter. The amount of sulfide sulfur in this process indicates the predominance of bacterial sulfate reduction in the sediments off NW Africa. This process also preferentially decomposes nitrogen- and phosphorus-containing organic compounds so organic matter deficient in these elements is characteristic for the rapidly accumulating sediments. During the last glacial stage there were more biogenic carbonates and organic matter accumulating in the sedimcnts than today, indicating there was increased production of organic carbon compounds and more favorable conditions for their preservation. During the last interglacial times conditions were similar to those of today. This differentiation with time has also been observed in sediments from thc Argentine Basin and from the slope off South India indicating perhaps world-wide environmental changes throughout Late Quaternary times.

Description: The cruises "Valdivia" 10 and "Meteor" 39/1975 had geological and geophysical investigations as focal points. They covered the northwest African continental margin between Morocco (33.5° N) and the southernmost Senegal (12° N) with the purpose: 1) to fill gaps from previous "Meteor" cruises, 2) to contribute to post-site surveys for DSDP Leg 41 (sites 367-370) and 3) to provide pre-site surveys for DSDP Legs 47 and 51 and IPOD crustal site 7 area around 21° N/32° W. The equipment used was similar to "Meteor" cruise 25/1971 with the main exceptions being the new multi-channel, digital seismic system of the BGR (Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover) (Meteor 39-1), refraction seismic buoys, the Kiel multisonde for measuring physical oceanographic parameters (Meteor 39-2) and continuous television observations from a slowly moving ship (Valdivia 10-3). The activities are summarized in Table 1. The scien1ific goals, cruise log, equipment used, participants, profiles and station lists as well as some preliminary results form the contents of the report.

Description: Sediment cores from the continental slope off NW Africa (20-27° N) have been investigated by means of an analysis of clay minerals, of grajn size distribution of terrigenous material and of coarse fractions and CaC03 -contents. Deductions concerning Late Quaternary climatic variations could be made from the obtained results. The interglacial periods X and Z (stage 1 and 5 after SHACKLETON & OPDYKE 1973) had an arid climate, characterized by: a) presence of chlorite and attapulgite in noticeable amounts, these fragile minerals being preserved from weathering in dry climatic conditions, b) small grain size of terrigenous material, c) high desert quartz numbers, high CaC03-amounts of total sediment, small terrigenous input and low transport energy. The glacial periods Y and W (stage 2-4 and 6) had a humid climate. This is suggested by: a) the absence or rareness of chlorite and attapulgite and increasing amounts of mixed-layer minerals, b) high amounts of coarse-grained terrigenous material, indicating greater transport energy, c) low or disappearing desert quartz numbers, low CaC03-content and high terrigenous input. The cores from 27 and 20° N do not fit into this general scheme, because they are situated at climatic boundaries, the northern core lying at the actual boundary of mediterranean humid and arid climate, the southern core lying at the Würm boundary between humid and arid climate. Results of 40-63 μm sized desert quartz and amount of 〈6 respectively 20-63 μm fraction show sharp boundaries between stratigraphic zones, revealing rapid changes in climate. Clay mineralogical changes are less rapid, showing the progressive changes in soil formation and soil destruction. The origin of the clay minerals is exclusively detrital. Their quantitative variations show a differential settling with distance from coast, and a latitudinal zonation parallel to terrestrial soils.

Description: Sedimentological and biostratigraphic investigations of 15 cores (total length: 88 m) from the vicinity of Great Meteor Seamount (about 30° N, 28° W) showed that the calcareous oozes are asymmetricaly distributed around the seamount and vertically differentiated into two intervals. East and west of the seamount, the upper "A"-interval is characterized by yellowish-brown sediment colors and bioturbation; ash layers and diatoms are restricted to the eastern cores. On both seamount flanks, the sediments of the lower "B"-interval are white and very rich in CaC03 with a major fine silt (2-16 μ) mode (mainly coccoliths). Lamination, manganese micronodules, Tertiary foraminifera and discoasters, and small limestone and basalt fragments are typical of the "B"-interval of the eastern cores only. The sediments contain abundant displaced miaterial which was reworked from the upper parts of the seamount. The sedimentation around the seamount is strongly influenced by the kind of displaced material and the intensity of its differentiated dispersal: the sedimentation rates are generally higher on the east than on the west flank (e.g. in "B" : 0.9 cm/1000 y in the W; 3.1 cm/1000 y in the E), and lower for the "A" than for the "B"-interval. The lamination is explained by the combination of increased sedimentation rates with a strong input of material poor in organic carbon producing a hostile environment for benthic life. The CaC03 content of the cores is highly influenced by the proportion of displaced biogenous carbonate material (mainly coccoliths). The genuine in-situ conditions of the dissolution fades are only reflected by the minimum CaCOs values of the cores (Fig. 23; CCD = about 5,500 m; first bend in dissolution curve = 4,000 m; ACD = about 3,400 m). The preservation of the total foraminiferal association depends on the proportion of in-situ versus displaced specimens. In greater water depths (stronger dissolution), for example, the preservation can be improved by the admixture of relatively well preserved displaced foraminifera. Carbonate cementation and the formation of manganese micronodules are restricted to microenvironments with locally increased organic carbon contents (e.g. pellets; foraminifera). The ash layers consist of redeposited, silicic volcanic glass of trachytic composition and Mio-Pliocene age; possibly, they can be derived from the upper part of the seamount. Siliceous organisms, especially diatoms, are frequent close to the ash layers and probably also redeposited. Their preservation was favoured by the increase of the Si02 content in the pore water caused by the silicic volcanic glass. The cores were biostratigraphically subdivided with the aid of planktonic foraminifera and partly also coccoliths. In most cases, the biostratigraphically determined cold- and warm sections could be correlated from core to core (Fig. 21). Almost all cores do not penetrate the Late Pleistocene. All Tertiary fossils are reworked. In general, the warm/cold boundary W2/C2 corresponds with the lithostratigraphic A/B boundary. Benthonic foraminifera indicate the original site of deposition of the displaced material (summit plateau or flanks of the seamount). The asymmetric distribtttion of the sediments around the seamount east and west of the NE-directed antarctic bottom current (AABW) is explained by the distortion of the streamlines by the Coriolis force; by this process the current velocity is increased west of the seamount and decreased east of it (Fig. 25). The different proportion of displaced material within the "A" and "B" interval is explained by changes of the intensity of the oceanic circulation. At the time of "B" the flow of the AABW around the seamount was stronger than during "A"; this can be inferred from the presence of characteristic benthonic foraminifera. The increased oceanic circulation implies an enhanced differentiation of the current velocities, and by that, also of the sedimentation rates, and intensifies the winnowing processes on the seamount plateau. The winnowed sediment material was transported downslope by turbid layers into the deep-sea, incorporated into the current system of the AABW, and asymmetrically deposited around the seamount.

Description: The 60 km wide shelf off Mauritania is cut by several submarine canyons. Its water-circulation is controlled by the cool Canary current and upwelling. Its Recent sediments show faunal assodations remarkably related to the grain size distribution which in water depths between 40 and 80 m is strongly influenced by reworldng of older coarse sand or sandstone. In this depth range a mixed biofades originating from Pleistocene and Recent material is encountered. The present lateral faunistic and sedimentological fades change, including horizons of mixed provenance, can be recognized in vertical sequences taken by vibro-coring. This correlation combined with 14C-datations on molluscs enable the reconstruction of the history of the last gladal regression and transgression. Due to the arid climate, the emerging calcareous shelf sediments are indurated and, therefore, protected from subaerial and submarine erosion. During low sea level eolian sand migrates over the shelf, but only about l/10 of this material remains there and is later incorporated into the sandy shelf sediments. The calculated average rate of total sedimentation during Holocene is 15 cm, and the production rate of carbonate is 5 cm/1000 years.

Description: In March 1974 combined refractional and reflectional seismic experiments were performed in the Cretan Sea. A total of 141 shots were fired along two lines, one parallel to the main structure striking nearly E-W between Karpathos and the SE-Peloponnese, the other perpendicular to it between Crete and Santorin (Thira). The shots were observed at 13 sites on land and by four buoy stations at sea. The seismic data reduced to time-distance plots and evaluated by direct and inverse ray theory methods revealed that: The Cretan Sea builds an E-W elongated dome of the upper mantle with maximum crustal attenuation at its central part and a thickness of nearly 20km. The vertical distribution of the P wave velocity is that of a continental crust that has been subjected to attenuation. The present distribution of sediments is mainly confined to the zone: SE-Peloponnese-Kithera-Antikithera-Crete-Karpathos, and also to small depressions within the central basin. In general they do not exceed 2 km in thickness. The uneven distribution of the sediments indicates the possibility of a two phase subsidence of the Cretan Sea. Areas with no or very thin sedimentary cover belong to the youngest tectonic phase. The morphology of the crystalline basement has been formed by intensive fragmentation, consisting mainly of normal faults, typical for tensional tectonism. The northern border of the Cretan Sea exhibits intensive volcanism along the line : Methana-Milos-Santorin-los. This zone is partly mobilized and intruded by surplus masses from the upper mantle as shown in the case of Santorin.

Description: This paper is a dcscription of the shallow structure of the Cretan Trough in the Aegean Sea as illustrated by continuous seismic profiles obtained by R. V. "Meteor" (1600 n.m., 1974), and R. R. S. "Shackleton" (1000 n.m., 1972, 1974). Study of this data shows an erosional unconformity between indurated rocks and sediments which over most of the Cretan Trough corresponds to erosion after the main Alpine orogeny and prior to the Upper Tortonian and in some places to the Upper Pliocene transgression. Thick sediments of up to 1.5 km have collected in local basins. Strong vertical movements on normal faults were responsible for the formation of the Cretan Trough and subsequently controlled the sedimentation. Sediments within the Trough have been deformed by Upper Pliocene/Pleistocene faulting and folding. Quaternary intrusions of volcanic? material are sporadically observed over the whole width of the Cretan Trough and do not suggest active seafloor spreading. Extensional processes are seen to be the dominant f eature in the tectonics of this area since ca. 10 m. y. A geodynamic process responsible for the observed structural data - mantle diapirism or subduction induced back-arc spreading - could not be derived from the reflection seismic data.

Description: Sediments sampled in three lateral traverses from the outer continental shelf to the continental rise off the Sahara Desert were analysed for their grain size distribution and composition. The carbonate content of the shelf and upper slope sediments increases from about 10-15 % in the south to about 50-90 % in the north and changes to about 40-45 % in deeper water. The high carbonate content in the north generally reflects the high proportion of relict material in the sediments. The main change in the composition of the sediments - defined mostly as hemipelagic - from the outer shelf to the rise is in an increase of coccoliths and clays and a decrease of quartz. The cumulative grain size curves indicate that each of the samples is a mixture of different proportions of two approximately log normal populations. The size of the truncation point between the populations, the proportion between the coarse and fine populations and the mean, sorting, skewness and kurtosis decrease with increasing depth. Correlations between the parameters indicate that the moments express mainly the mixture proportions of the two populations. The two populations may, however, indicate an artificial effect of deflocculation during sample treatment rather than reflecting some hydraulic factor. The cumulative grain size distribution curves of eolian dust collected on ship's surface during cruises along the Saharan shelf and that of other published data is divided into a two-population and a onepopulation type. The two populations may be attributed to either gravitational settling of larger dust particles and normal dust fall or to disaggregation effect. The moment statistics of the dust differ mainly from those of the marine sediments in that they have a lower standard deviation. The composition and the textural parameters, combined with modal analysis of the dust and the separated soluble and insoluble components of the sediments indicate that the downslope transportation of the coarser sediment particles is a result of marine currents rather than of wind. The distribution pattern of the relict material in the northern outer shelf and upper slope is attributed to an extinct current regime which was stronger than the present one. The gravitational settling of coarse dust, mainly over the shelf, most probably accounts for the principal input of sediment that is transported further downslope by marine currents. Part of the fine, as well as a small portion of the coarse terrigenous material may be derived from direct settling of dust over the open sea. The recent sedimentation process results in a continental margin prograding off the Sahara Desert. In the south sedimentation occurs on the outer shelf, slope and rise, whereas in the north main sedimentation occurs on the lower slope and rise. The deflection of the Canary current away from the Cape Blanc coast is proposed as an explanation for the apparent reduced deposition rate over the outer shelf and upper slope in the northern area.

Description: The Th content of the sediment samples from "Meteor" core 12310 (3080 m water depth, off NW Africa) on a carbonate-free basis lies around the average of 12.4 ppm and is similar to the average content of the earth crust. On the contrary, uranium was found to be up to 3.5-fold enriched in the core section between 60 and 330 cm (within the Würm Glacial) where reducing conditions occur, due to deposition of authigenic uranium (9 µg/cm2 1000 yrs.). The authigenic uranium content is correlated to the organic matter content (U/Corg ratio = 6 · 10-4). On the basis of the uranium content of the oxidized section uranium was split into a detritic and an authigenic component and the amount of supported ionium was calculated. From the profile of the specific I0.excess act1v1ty Io-total - Io-supported) with depth, average sedimentation rates of 3.3 ± 0.6 cm/1000 yrs. for the warmer stages and of 5 ± 1 cm/1000 yrs. for the cooler periods were estimated.

Description: A rapid procedure for Io (Th230) dating of sediments with accumulation rates in the range of several cm/1000 years is described. Studying of large sample populations with very small Io-excess activity is possible as the counting time (around 1500 min/sample) are 2 to 5 times shorter than with the standard Io-excess method. Improved sensitivity of the Io-excess measurement is achieved by: 1) extraction (~90%) of the authigenic Io-excess with EDTA, with minor leaching (~30%) of the allogenic Th232 and Io-supported, 2) processing samples as large as 10 g or more. The procedure was applied to sediments from the Caribbean (V 12-122) and from the Ionian Sea (22M48 and 17M17). In the case of the standard core V 12-122 our results are in good agreement with previous time-consuming Io determinations. The resulting average accumulation rates of 2.0 ± 0.3 cm/1000 years for the Ionian Sea cores are close to the average derived from magnetic reversal studies of a nearby core.

Description: A preliminary study was carried out on the ostracode fauna obtained from marine sediments off the Sahara Desert. The ostracodes are divided into two distinct associations: Association A - shallow water (100-483 m); Association B - deep water (470-2859 m). The deep water association differs from that of the shallow water by its low diversity and by the predominance of somewhat larger "blind" ostracodes in it. The depth of the boundary between the two associations corresponds closely to the general universally recognized 500 m boundary, below which psychrospheric conditions prevail and dictate the appearance of typical deepwater ostracode fauna.

Description: The pollen record of three marine late Quaternary cores off Senegal shows a juxtaposition of Mediterranean, Northern Saharan, Central Saharan elements, which are considered transported by the trade winds from a winter-rainfall area, and Sahelian, Soudanese, Soudano-Guinean elements, considered transported both by winds and mostly by the Senegal River, and coming from the monsoonal, summer tropical rainfall area of southern West Africa. Littoral vegetation is either the edaphically dry and saline Chenopodiaceae from sebkhas at the time of the main regression, or the warm tropical humid mangrove with Rhizophora during the humid optimum period. Four stratigraphic zones reflect, from basis to top: Zone 4. A semi-arid period with a balanced pollen input. Zone 3. A very arid period with the disappearance of monsoonal pollen, probably from the disappearance of the Senegal River, a very saline littoral plain with Chenopodiaceae, a larger input of northern Saharan pollen from intensified trade winds. Zone 2. A quite humid period, much more so than today, very suddenly established, with a northward extension of the monsoonal areas, a rich littoral mangrove, and weakening of the trade winds. Zone 1. A slow and steady evolution toward the present semi-humid conditions with regression of the mangrove, and of the monsoonal areas toward the south. Tentative datations and correlations with the Tchad area suggested: zone 4: 22,500 to 19,000 years BP; zone 3: 19,000 to 12,500 years BP; zone 2: 12,500 to 5,500 years BP; zone l: 5,500 years BP to top of core. Dinoflagellate cysts display a tropical assemblage wwith mostly estuarine neritic elements and also a weak oceanic component, mostly in the lower slope core 47. Cosmopolitan taxa dominate the assemblage and only a few species point to more specialized environments. Quantitative variations of the assemblage are the basis of stratigraphy which is not similar to the pollen stratigraphy, and an inshore-outshore gradient has to be taken into account to correlate the three cores.