ALBERT

Description: The first expedition planned for 1970 was conducted in the ocean area between the Iberian and West African coasts (north of 15 ° N and 30 ° W, see map). The first three sections of the expedition were devoted mainly to biological questions. The fourth and last cruise-section was concentrated on geological and geophysical problems relating to the exploration of the Iberian shelf and shelf margin. Since the activation of R.V. "Meteor" in 1964, biological work has predominantly centred round two questions: a) comparative studies on nutrient dynamics in poor and rich areas and b) communities in the open ocean and their diurnal periodic migrations. It was the purpose of the Canaries Basin expedition to supplement the data collected during previous research cruises, particularly the Atlantic Seamount cruises ("Meteor" cruise 8 and 9) in 1967 and the West African expedition ("Meteor" cruise 13) in 1968. Research work in the various disciplines of marine biology was carried out simultaneously with the collecting of chemical and physical data indispensable for the understanding of productivity, transport and decomposition of organic matter as well as affording an opportunity to observe biogenic sedimentation. In planning the cruise, special emphasis was laid on ensuring as close a coordination as possible between the individual working programmes; it was decided that of the vast number of problems presently confronting marine science, particularly in the biological field, only a few should be selected and these approached from diverse sides. Each cruise section was directed at one focal point, around which other investigations were grouped. Cruise section I. Nutrient dynamics in an upwelling water body off the West African coast. Cruise section II. Communities and environmental conditions in the region of the Great Meteor Seamount. Cruise section III. Metabolism and communities on the Iberian deep-sea bed. Cruise section IV. Testing of geophysical gear. Moreover, investigations on two important questions that for a considerable length of time have occupied the attention of planktologists and geologists at various German institutes covered several cruise sections: a) The structure of communities in the oceanic deep scattering layers and at the sea surface; an insight into the feeding migrations of these organisms is essential for an understanding of the vertical transport of organic matter in the open sea. b) The origin of sediments in the deep sea and on the Iberian shelf in relation to organic productivity and climatic and oceanographic fluctuations. The Canaries Basin expedition 1970 inaugurated the "Cooperative Investigations of the Northeastern Central Atlantic" (CINECA), a programme coordinated by the International Council for the Exploration of the Sea (ICES) on the recommendation of the FAO and IOC.

Description: The Persian Gulf situated in the arid climate region of the northern hemisphere shows special conditions in its hydrochemistry. The high evaporation, the lack of large rivers, and the exclusion of deep water from the Indian Ocean governs the nutrient cycle. At 95 stations in the deeper part of the Persian Gulf (Iran side), in the Strait of Hormuz, and in the Gulf of Oman determinations of dissolved oxygen, dissolved inorganic phosphate, silicate, and pH were carried out. The data are compiled in the data report (BRETTSCHNEIDER, GRASSHOFF, KOSKE & v. TREPKA 1970). The ammonia, nitrite and nitrate data from 30 stations are added to this report. On 4 selected transverse profiles for phosphate, and dissolved oxygen and on 1 length profile for phosphate, silicate, oxygen, and pH the distribution of these components is shown and the in- and outflow is characterized. It is also pointed out that the nutrients on their way into the Persian Gulf are diminished and that temporary replenishment supply from a layer of about 100 m depth in the Indian Ocean follows. On one horizontal map the phosphate distribution in the surface and 30 m layer gives reference to biological activity. One diagram where nitrogen components are plotted against phosphate shows that nitrate is a limiting factor for productivity. 02/P04-P and P04-P/S‰ diagrams enable the different waterbodies and mixed layers to be characterized.

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: 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: 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: 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 atmospheric space from 11° N to 5° S along the Somali-coast of East-Africa over the western part of the Arabian Sea has been investigated making use of the aerological measurements, gained during the International Indian Ocean Expedition (IIOE) 1964/65. On the basis of the analyses obtained, an attempt is made to compute a heat budget for this space. In particular the following components have been taken into account: the net-radiation flux in the atmosphere (GN), the turbulent flux of sensible heat (Qs) and of latent heat (QL) from ocean to the atmosphere above, the potential (P), the sensible (I) and the latent energy (E). The vertical velocity component (ω) has been carefully determined making use of the adiabatic method but considering nonadiabatic effects of various kind lateron. From the vertical divergence of the net-radiation flux the cooling by long wave radiation was computed. Maximum effect of this process was obtained in the monsoon inversion (-5.4°C/day). Above the tropical tropopause the atmosphere shows maximum warming of 1.8°C/day. The intensity of the turbulent flux of sensible and latent heat is mainly determined by the windfield and by the local differences in the watertemperature. Maximum values are for Qs = 12·10-4 cal cm2 sec-1 and for QL = 140·10-4 cal cm2 sec-1 (Bowen-ratio R = Qs/QL = 8.5%, mostly not more than 4-5%). The computation of the vertical velocity rests besides the thermodynamic method (adiabatic) on a consideration of various non-adiabatic effects such as radiation, flux of sensible and latent heat. The following distribution has been obtained: Below the monsoon inversion a rising motion (maximum -30·10-4 mb/sec ≈ +2.8 cm/sec) and above a sinking motion (maximum +20·10-4 mb/sec ≈ -3.4 cm/sec) upwards to the tropical tropopause (near 90 mb). Above the tropopause weak rising motion (-2·10-4 mb/sec ≈ +1.3 cm/sec) was obtained. An attempt to compute various terms (in total 7) of the heat budget equation shows, that horizontal advection of various energy forms are only of importance in the monsoon layer (below the inversion) and above the tropical tropopause. In all height-intervalls considered the vertical advektion of the energy forms is dominant. The results of the budget-computation are presented in graphical form.

Description: During the Atlantic Expedition 1965 (IQSY) with the research vessel "Meteor" an extensive aerological programme was performed in order to investigate the lower trade wind regime. In this study energy and mass transport in the atmospheric layer below the top of the trade inversion was estimated on the basis of 4 to 8 radiosonde and radar wind measurements. The experiment took place on an anchoring station at the intersection of the Equator and 30° W longitude from September 12 to October 11, 1965. With the aid of simple model assumptions a mean sinking rate through the inversion of 540 m/d was derived. This value is determined mainly by the net radiative cooling and the prerequisite of no heating due to condensation. From the temporal variations of the daily averages of the thermal energy content within the inversion layer and the height of its boundaries it seems to be evident that changes of a quasi-equilibrium of mean subsidence and turbulent mixing at the inversion base are compensated by vertical motions of the inversion. The effect of strong mixing at the inversion base is supported by the fact that remarkable turbulent upward transport of latent heat is required at this level.

Description: The records of the potential gradient over the ocean obtained during the Atlantic Expedition of the research vessel "Meteor" in 1965 show a strong fluctuation of the values. Their frequency behaviour has been investigated. First a separation of different types of fluctuation has been made with regard to visual impression. Then power spectra of selected records were calculated. They show a F-5/3-range (F = frequency) in the interval of periods between 0.2 and 10 minutes for the most frequent visual type. For longer periods the ascent becomes more flat. This result can be explained by the assumption that the fluctuations are effected by the convective vertical air exchange over the sea.

Description: Siliceous skeletons were investigated in two core profiles (9 cores ), one off Cap de Sines, Portugal and the other off Cap de Mazagan, Morocco. Total number of skeletons was determined per gram of dried sediment at different core depths of the fraction 〉 21 μ. Results are compared with a core profile from the Arabian Sea. Diatoms are of four roups: (A) marine-planktonic, (B) marine-benthic, (C) freshwater and (D) Tertiary species (Trinacria e. g.). Species from groups (B), (C) and (D) are redeposited in all cores taken at a water depth of greater than 100 m. Small numbers of Silicoflagellates and Radiolarians were found throughout the cores from the Ibero-Moroccan shelf. In the Arabian Sea core, Radiolarians were concentrated in distinct horizons in which Tertiary material was redeposited (40-50, 140-150, 250-260 cm). The number of siliceous skeletons per gram of dried sediment decreases more or less rapidly with increasing depth in all cores. Whereas about 2500 skeletons were found in sediments close to the surface, approximately 100 skeletons only were found in deeper (〉40 cm) layers. Deeper horizons with more than 100 specimens were interpreted as redeposited material. This sediment contained robust skeletons, resistant against dissolution, as well as benthic and Tertiary material. The decrease of siliceous skeletons relative to core depth depends upon the sedimentation rate. Where the sedimentation rate is high, the opal dissolution zone extends down to 30-60 cm, where the sedimentation rate is low, it is located at 10-30 cm. Below these depths opals disappears. These zones also have approximately the same age (4000 years) everywhere. Siliceous skeletons dissolve differentially, first the Silicoflagellates disappear, second the Diatoms, third the Radiolarians, and fourth the Sponge Spicules. Surface structure of skeletons from near the opal dissolution zones are similar to those of skeletons treated with NaOH. Tertiary diatoms ( Trinacria e. g.) and benthic diatoms (Campylodiscus e. g.) dissolve less rapidly than skeletons of modern planktonic diatoms (Coscinodiscus e. g.). The time control of the opal dissolution zones appeared rather independent of various oceanic influences. No evidence was found for effects from upwelling either off Portugal or off Morocco. No difference in dissolution rates was recorded between the abyssal plains lying off these two areas. Likewise, there was no change in solution rates from Pleistocene to Holocene within either one of the abyssal plains. The Mediterranean outflow, which is enriched in dissolved silica, apparently had 110 effect on dissolution rates of siliceous skeletons in the sediment.

Description: This is a report about a joint scientific venture of German and Norwegian Institutes in an area between φ = 66° 45' N and 68° 30' N and λ 10° E to 7° 30' W. The chief scientist's report gives an outline of the cruise. The preliminary contributions by the scientists deal with results of gravity at sea, magnetic and geothermic measurements, the seismic shooting, results of continuous seismic reflection work, some refraction seismic results and with the observations of the ship's weather station.

Description: The benthic foraminiferal populations along three traverses across the Northwest African continental margin were analyzed on the base of ea. 60 surface sediment samples. Depth ranges of 213 species were established and the main trends of vertical distribution are compared with those known from adjacent regions. Main faunal breaks occur at 100/200 m and 1OOO/ 1500 m depth of water. Some species show latitudinal distribution boundaries and the same applies to population density (standing stock), reflecting the regional distribution of nutrients supply by river discharge and upwelling processes. - High proportions of Bolivina tests at the lower slope indicate extended downslope transport.

Description: Surface sediments from the continental slope and rise off North-West Africa between the Canary Islands and the Cape Verde Islands are mainly composed of silt-sized material (2-63 µm). A number of sampling profiles were run normal to the coast and the composition of the silt fraction was determined quantitatively by scanning electron microscope analysis. The carbonate portion of the sediment was found to be nearly exclusively of biogenic origin. The most important contributors are planktonic foraminifers and coccoliths with minor contributions derived from pteropods. Plankton-produced biogenic opal such as diatoms and radiolarians play a very minor role. The high production rates of opal-silica plankton which exists in the surface waters of the NW-African upwelling system does not give rise to corresponding increases of opal accumulation in the bottom sediment. Benthic producers consist mainly of foraminifers and molluscs but the entire input from benthic producers is extremely small. An exception to this occurs in the prodelta sediments of the Senegal river. Downslope particle transport is indicated by the occurrence of shallow-water coralline algae, ascidian sclerites and cliona boring chips and can be traced as far down as the continental rise. The non-carbonate silt fraction mostly consists of quartz which is derived as eolian dust from the Sahara desert by the Harmattan and the NE-Trade-wind system. The percentage of carbonate in the surface sediments directly indicates the relative proportions of autochthonous biogenic components and terrigenous allochthonous quartz particles.

Description: Water depth zonation of fifty nine benthonic foraminiferal species in marine sediment surfaces has been described. Some species are combined to groups which mark particular depth zones: an upper and lower shelf-fauna, an upper and lower slope fauna, and a shelf-slope fauna. Dependence on latitude could be ascertained for Textularia panamensis) and submergence effects for Hyalinea balthica.

Description: During cruise VA 18 of R.V. "Valdivia" an area of 15 X 18 km, lying on a horst within the Clarion fracture zone south-southeast of Hawaii at 14° N and 153° W was studied in detail by reflection seismic measurements and geological sampling. The horst lies between two fracture-zone-parallel grabens. Its top displays a typical abyssal hill topography which is a result of block faulting within the oceanic crust, with faults parallel to the fracture zone and in north-southerly directions. It is assumed that the horst represents an already faulted block of oceanic crust which was included into the fracture zone when it tectonically developed into a system of horsts and grabens upon its transform stage. The surveyed horst differs from its neighbouring grabens by reduced sediment-accumulation rates and hiatuses. Its basement relief has led to a further differentiation of the internal sedimentary pattern. The northward-tilted horse block shows on its southern, more elevated part, frequently signs of erosion or reduced sedimentation, whereas the low lying part is characterized by an increased sediment accumulation. In the area of low accumulation rates and erosion volcanic ash layers with manganese-oxide crusts occur at or near the surface of the sediment layer. Also manganese nodules occur in this area. In the area of high accumulation rates the volcanic ash layers were observed with increased thicknesses in deeper sections of the cores. Crusts and nodules were not found here. This is also the case for the graben south of the horst, where high accumulation rates prevented the formation of manganese crusts and nodules. The reduced accumulation in the southern part of the horst has favored the dissolution of radiolarians as well as the authigenic formation of zeolites and manganese micronodules. The correlation between the reflectors seen in the 3.5 kHz subbottom profiler records and the lithostratigraphic boundaries found via geological sampling was generally good. It allowed the determination of the areal distribution of sedimentary sequences and magmatic rock outcrops.

Description: Along the Sierra Leone continental shelf edge, bedded rocks, presumably mostly calcareous sandstone, calcarenites and siltstones form exposures up to 10 km long in water depths ranging from 80 to 110 m. These outcrops are found in a 6 km broad zone along the shelf edge; landward they get covered by recent shelf sands. Their apparent strike direction parallds the shelf edge indicating nearly horizontal bedding which locally is interrupted by faulting. On the middle shelf, a terrace is well developed at a water depth of 56 m. Ripples, megaripples, pockmarks 1-5 m in diameter, and canyon-heads form other significant features of the shelf.

Description: The sediments of a 10.67 m long piston core recovered from the Sierra Leone Rise ("Meteor" Core 13519) have been analysed for their paleomagnetic properties. Using detailed demagnetization techniques, the geomagnetic Brunhes/Matuyama boundary could be identified between 9.81 and 9.89 m sub-bottom. This is in excellent agreement with the oxygen isotope stratigraphy by SARNTHEIN et al., this volume. Down to this level, therefore, the average apparent accumulation rate amounts to 13.5 m/m.y. assuming an age of 0.73 m.y. for the reversal boundary (BERGGREN et al. 1983). A second transition in magnetization polarity was recognized between 10.51 and 10.54 m sub-bottom. According to its magnetic signature it was tentatively correlated to the beginning of the Jaramillo event (0.98 m.y.). This would imply that in the lowermost part of the core the apparent accumulation rate decreases to less than 20% of that found in the upper sequences. However, as obviously only a small portion of the Jaramillo event is recorded in the sediment column, a more plausible solution is to keep the overall sedimentation rate about constant by introducing a hiatus of some 2·105 years shortly after the lower Jaramillo/Matuyama reversal boundary. Alternative interpretations are also discussed.

Description: From a 10.7 m long gravity core from the Sierra Leone Rise (5° 39,5' N, 19° 51'W) a detailed oxygen and carbon isotope record of both planktonic and benthonic foraminifera species was obtained extending from the Recent to the Jaramillo event. The analysis yielded six major results. 1. Benthos oxygen isotopes varied by 1.8-2.2‰ from interglacial to glacial times and may indicate a synglacial cooling of North Atlantic Deep Water at 2800 m depth by 1-3° C. 2. Variable anomalies between the benthos and plankton δ18 O record indicate a cooling of sea-surface temperatures (SST) by up to 6° C during some glacial stages. 3. Southerly trade winds and equatorial upwelling may exert the primary control of SST variations, in particular of extreme values of cold and warm stages and of the abrupt character of climate transitions and their leads and lags, and finally, of variable sedimentation rates. 4. The benthos δ13C record correlates well with the flux and preservation of organic matter. 5. A new time scale, CARPOR, was established from the assumption that terrigenous sediment supply was ± constant but CaC03 varied considerably. When applied to the δ18O record, three major and numerous short-term variations of sedimentation rates (0.8 to 4.0 cm/kyr) can be distinguished. 6. The climatic record was modified by bioturbation much more strongly during cold than during warm stages.

Description: Planktonic foraminiferal tests of the spinose species Orbulina universa, of the non-spinose Globorotalia tumida-menardii complex, and of a mixed species assemblage (grain size fraction 200-400 μm) were isolated from Sierra Leone Rise core 13 519-2 and analyzed for free, total, and bound (by difference) amino acids to study the isoleucine epimerization mechanism in fossil foraminiferal tests and to define empirical calibration curves for dating deep-sea sediments over the past 900,000 years. Total isoleucine epimerization curves typically separate into three "linear" segments of decreasing apparent rates with increasing time and exhibit a pronounced "species effect". The degree of epimerization attained at time is considerably lower in 0. universa than in G. tumida-menardii while the mixed species results scatter between the limits delineated by the two monospecific curves. Total allo/iso ratios are closely related to the proportion of free to total isoleucine accumulating in the tests indicating that the rate of hydrolysis of matrix proteins and peptides controls the overall epimerization reaction. The results are consistent with experimental evidence (KRIAUSAKUL & M1TTERER 1978, 1980 a, b) whereupon isoleucine epimerizes at a rapid rate in terminal positions but at slow rates in interior positions as well as in the free state. Notwithstanding free isoleucine exhibits the highest degree of epimerization due to preferential hydrolysis of extensively epimerized terminal isoleucine. Species-specific hydrolysis and epimerization rates are maintained until about 50% of bound isoleucine have been hydrolyzed to the free state corresponding to a total allo/iso ratio of about 0.5. Remaining peptide units appear to be more resistent against hydrolysis and separate species then show the same apparent epimerization rate dominantly controlled by the slow conversion rate in the free state until equilibrium is achieved in Miocene samples under deep-ocean temperature conditions (KING & HARE 1972 a). The degree of epimerization attained at comparable time in separate species will, however, remain different due to different initial rates of hydrolysis. Selective leaching of free isoleucine from the tests results in a lowering of total allo/iso ratios and apparent rate constants when significant amounts have been generated by diagenetic hydrolysis. Comparison with results based on Pacific core V 28-238 (KING & NEVILLE 1977) indicates an inverse relationship between the intensity of surficial carbonate dissolution and post-depositional leaching. Tests deposited under less corrosive conditions (Atlantic core 13519-2) will more significantly deviate from a closed system during diagenesis than those deposited in more corrosive bottom waters (Pacific core V 28-238). Carbonate dissolution removes proteinaceous lamellae from more external shell structures, which otherwise - if preserved during deposition - will preferentially be subject to leaching of free amino acids during diagenesis. This effect may qualify the applicability of empirical epimerization calibration curves to different depositional environments although the general agreement of the epimerization curves obtained for both sites is promising for future research. Identical apparent epimerization rates in G. tumidamenardii tests younger than 120,000 years (when leaching is stiH insignificant) at both Atlantic and Pacific sites are not consistent with the presently different bottom water temperatures in these regions. It is concluded that glacial North Atlantic Deep Water was cooler than at the present at the Sierra Leone Rise.

Description: Eine neue Art der zentrale Diatomeengattung Thalassiosira wird aus dem Auftriebsgebiet vor Kap Blanc, Afrika, beschrieben. Die Art ist durch die Ausbildung von gallertigen Tuben charakterisiert, die sich zusammenlagern und Zellaggregate bilden. A new species of the centric diatom genus Thalassiosira is described from upwelling waters near Cap Blanc, Africa. The species is charcterised by living in gelatinous tubes which are packed together and form large aggregates.

Description: 1. The new species Umbellula thieli, found in the Horseshoe deep-sea basin near Madeira, has only one single, big autozooid (="polyp"). Thus the species represents the ultimate point of an evolutionary series in some Pennatularian groups, characterised by the reduction of the number of autozooids. - This sea-pen, even it is a colony of polyps, appears as a solitary organism. 2. During the intensive investigations with trawls, dredges and cameras no sea-pen was found on the plateau of the Josephine Seamount and the Great Meteor Seamount. Pennatularians seem to lack in these biotopes.

Description: During the German "Meteor"-Canaries-Basin-Expedition, 1970, a total of 1577 meso- and bathypelagical fishes were caught by means of the IKMT and the Agassiz-Trawl in stratified or oblique hauls on 18 stations (Fig. 1). Some few fishes were selected from catches with the Bongo-Net. Stratified hauls were only made on the first six IKMT-stations (1000-700, 700-400 and 400-0 m), using an exchanging-container-system. Since this proved not to work satisfactorily the method was abandoned in favour of oblique hauls from 1000, 700 or 650 m to the surface. The material splits up into 31 fish families, 72 genera and 134 species. Nearly one third (35%) of the total of fish is yielded by the large family of Myctophidae, which is followed by the Gonostomatidae (31%), the Sternoptychidae (15%) and the Chauliodontidae (8%). All the remaining 26 families are of minor importance and represented, in general, each by less than 0,5%. No species new to science were found, but several are first records for this area. Since the circumstances of catch (gear, duration and depths) on the single stations were distinct, considerations on the qualitative and quantitative composition of the pelagic fish population, as well as their vertical distribution within the investigated area, seem not to be admissible. Fot this reason, only an annotated check-list is given. A new genus of myctophid fishes, Paralampanyctus, is erected, comprising the Lampanyctus ater-lineatus-niger-complex which is clearly separated from the remaining Lampanyctus-species. Otoliths, valuable diagnostic characteristics, are figured from the majority of the fish species discussed.

Description: Two aphyonids were caught in 1968 by the R.V. "Meteor" off Southwest Europe. One specimen, a male, belongs to Meteoria erythrops of which only a female and a juvenile were known. The other is referred to Nybelinella erikssoni hitherto found at two localities, north of Madagascar and in the tropical Atlantic Ocean. Nybelinella nom. nov. is proposed as a substitute for the preoccupied Nybelinia.

Description: In the subtropical NE Atlantic 337 neuston samples had been collected simultaneously in the 0-10 cm surface layer and in the adjacent 10-25 or 38-53 cm strata with a modified DAVID neuston catamaran. At a permanent station additional vertical stepwise hauls had been made down to 200 m with a Helgoland Larvae Net with a changing bucket device. Invertebrate neuston and other plankton was analysed in order to taclde the following problems: horizontal and vertical micro- and macrostratification, diurnal vertical migration, abundance, and feeding of species and their ontogenetical stages. Three ecological groups are described: 1. euneuston, living permanently in the uppermost layer (0-10 cm) by day and night; 2. facultative neuston, migrating into the surface layer mainly at crepuscular time and at night, or during certain phases of its early life history; 3. pseudoneuston, inhabiting with its highest concentration deeper layers, and reaching the immediate surface by relatively few specimens. - Contrary to the Black and Caspian Seas, the surface layer of the subtropical NE Atlantic is poor in nutrition compared with deeper layers. In the surface layer the total amount of invertebrates was only half of that in the adjacent strata of 10-25 and 38-53 cm, whereas the average concentration of Zooplankton in the 0-30 m macrolayer was eight times higher than in the surface layer. During daytime, particularly at noon, the average number of the invertebrate neuston diminished to 25 specimens/100 m3, and macrophages, i.e. mainly carnivores, represented about 75% of all the specimens, giving evidence of extreme scarcity of food at the sea surface. - The existence of a neuston biocoenoses in the subtropical NE Atlantic is discussed. The increase of the total number of invertebrates in the surface layer during dim light and at night, caused by facultative and pseudoneuston species, has to be regarded as an exchange of food between two communities: the biocoenoses of euneuston und pleuston on one hand and that faunal association on the other hand which is living in other habitats than at the very surface. Because of biological reasons and of terminological considerations the uppermost 5 to 10 cm thick layer at the sea surface should be called "pleustal".

Description: 1. On the cruises 3 and 15 of R.V. "Meteor" 6 grab samples, and 6 hauls with the 6 m Agassiztrawl were taken and at 2 stations the deep sea camera was lowered. This material gave quantitative results on the meiofauna and minimum counts of the macrofauna. 2. The nematodes constitute nearly 95% of the meiofauna, the copepoda only 2%, With increasing sediment depth the density of animals decreases gradually. In the uppermost centimeter of sediment (layer A) 42.6% of the meiofauna are found while only 3.7% live in layer G (tab. 6). Meiofauna weight ranges from 0.6-5.7 mg/25 m2 sediment surface i.e. 0.24-2.8 g/m2. 3. Mean numbers of individuals (tab. 3) and weights (tab. 5 for nematodes) show standard errors of 20-30%. As an approximate average value for further considerations the weight of the meiofauna in the area was taken as 1 g/m2. 4. Quantitative information on the macrofauna is derived from the trawls and the photographs for the actinia Chitonanthus abyssorum only, which is found in the rate of 1 individual/36-72 m 2, but seems to be less abundant generally. 5. Animal density does not decrease steadily from nearshore to offshore biocoenoses, i.e. generally with increasing depth. The decrease is more pronounced for macro- than for meiofauna. For the deep sea the weight proportion of macrofauna : meiofauna is of the order of 1 : 1. 6. With the assumption, that adaptation of metabolism to deep sea conditions is similar in macro- and meiofauna total metabolism of invertebrates is ascribed to meiofauna to more than 80%. 7. The structure of the biocoenosis of the deep sea floor is characterized by the meiofauna living on and in the sediment and by the dominance of sediment feeders in the macrofauna. 8. Considering the large numbets and high partition rates of bacteria a comparative large part of the metabolism in the deep sea sediment must be ascribed to bacteria. This favours the hypothesis, that with increasing depth and decreasing addition of organic material to the sediment, the importance of meiofauna and microorganisms for total metabolism increases. 9. Considering the different modes of food transport to the deep sea environment, i.e. sinking of dead particles, transport by vertical migration of organisms, aggregation of organic particles, adsorption of dissoloved organic substance to inorganic particles, and heterotrophy, the sediment may be assumed to contain more food for invertebrates than the water above the bottom. 10. Suspensionfeeders of macrofauna are fixed to hard substrates in the sediment surface. Same of them are shown to bend themselves down to the bottom in underwater photographs. This suggests the idea that some deep sea suspension feeders partly depend on food from the sediment surface, on which they feed directly.

Description: The genus Desmopterus (Pseudothecosomata, Gastropoda) includes two species. They are D. papilio Chun 1889 and D. gardineri T esch 1910. Both are tropical species having widespread distribution between 40° N and 40° S. D. papilio is common in occurrence, but D. gardineri is very rare. The present study on Zooplankton collections of the International Indian Ocean Expedition (IIOE) reveals that D. papilio is abundant in the area off the Somali coast, Gulf of Aden, South Arabian coast, Gulf of Oman, West coast of Pakistan, South-West coast of India, northern and Western Bay of Bengal, Southern Andaman Sea and North-West Australian Sea. The highest abundance was noticed in the area off Cochin. D. gardineri is relatively common in the Bay of Bengal, equatorial Zone and North-West Australian Sea. The seasonal Variation in spatial abundance shows that D. papilio is distinctly more abundant during the period dominated by the North-East Monsoon in the North Indian Ocean. Along 110° E two maxima were found, one during April—August between 9° and 11° S and another during November—February between 17° and 23° S. D. gardineri occurs mainly between April and August. The distribution in relation to the thermocline shows that D. papilio is almost uniformly abundant above and below the thermocline during day and night. But D. gardineri was almost absent above the thermocline. Therefore the thermocline appears to be a barrier for the distribution of D. gardineri.

Description: 1. Morphological characters of Ellisella flagellum were studied. The population of the plateau of the Josephine Seamount was compared with that of the Great Meteor Seamount. 2. The calcareous spicules of the colonies occur in several types (Fig. 1). The spicules of the cortex are uniform in all colonies, those of the calyx wall show differences between colonies. 3. The percentage of each spicule type of the calyx wall varies from colony to colony (Figs. 2-3). The range of variation is large (Fig. 4). 4. Differences between the two populations: a) Size: The colonies are bigger on the plateau of Great Meteor Seamount than those of the Josephine Seamount. b) Coloration: About one fourth of the specimens from Josephine Seamount are orange-red, on Meteor Seamount all colonies are white. c) Spicules: The average percentage of some spicule types show significant differences (see Table 1). 5. These results point to the morphological differentiation of E. flagellum in its area, probably favoured by the isolation of the seamounts and of the isles. The two different populations are preliminarily considered as infraspecific forms without nomenclatural state.

Description: 1. The three species of the Gorgonarian family Ellisellidae occurring in the eastern North Atlantic and the Mediterranean are described and compared with similar western Atlantic forms. 2. Material examined: a) the Gorgonarians obtained during the cruises of R.V. "Meteor" (Octocorallia now in the Senckenberg Museum, Frankfurt am Main), b) the Gorgonarians of the museums in Amsterdam, Leiden, London, Monaco and Paris. These collections contain the original material of classical expeditions and of the chief works on the east Atlantic and Mediterranean Gorgonarian fauna (WRIGHT, STUDER, KÜKENTHAL, THOMSON, STIASNY). 3. Ellisella paraplexauroides is found only in the African shelf, Ellisella jlagellttm on the seamounts and near the islands, Nicella granifera in both regions. 4. Ellisella flagellum is the most frequent species of the big benthic forms living on the plateaus of the Great Meteor Seamount and the Josephine Seamount. 5. The three species are quite distinct in their morphological characters. For each of these three east Atlantic species there can be found a similar species in the west. The colonies are similar in form but differ slightly in the structure of spicules. Ellisella flagellum / E. barbadensis, Ellisella paraplexauroides/ E. elongata and Nicella granifera/ N. guadalupensis can be spoken of as east-west-atlantic pairs. (This does not exclude that there are probably morphologically similar species in the Indo-Pacific). 6. Bach species has several types of spicules. The percentage of each spicule type varies from colony to colony, at least in Ellisella flagellum and in Nicella granifera. 7. The population of Ellisella jlagellttm of the Josephine Seamount and that of the Great Meteor Seamount show differences in coloration, average size of the colonies and significant differences in the average percentage of some spicule types.