ALBERT

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: 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.