ALBERT

Description: We present a plate kinematic evolution of the South Atlantic which is based largely on the determination of the equatorial fracture zone trends between the African and South American continental margins. Four main opening phases are dated by oceanic magnetic anomalies, notably MO, A34, and A13, and are correlated with volcanism and tectonic events on land around the South Atlantic Ocean. The Ceara and Sierra Leone rises are probably of oceanic origin and were created 80 m.y. ago or later in their present-day positions with respect to South America and Africa.

Description: This paper concerns the linear response of the ocean to forcing at a specified frequency and wave number in the absence of mean currents. It discusses the details of the forcing function, the general properties of the equations of motion, and possible simplifications of these equations. Two representations for the oceanic response to forcing are described in detail. One solution is in terms of the normal modes of the ocean. The vertical structure of these modes corresponds to that of the barotropic and baroclinic modes; their latitudinal structure corresponds to that of inertia‐gravity and Rossby waves. These waves are eigenfunctions of Laplace's tidal equations (LTE) with the frequency as eigenvalue. The description in terms of vertically standing modes is particularly useful if the forcing is nonlocal, because only these modes can propagate into undisturbed regions. The principal result is that it is extremely difficult for baroclinic (but not barotropic) disturbances to propagate horizontally away from a forced region. Instabilities of the Gulf Stream excite disturbances that are confined to the immediate neighborhood of the current; disturbances due to instabilities of equatorial currents do not propagate far latitudinally. A second representation of the oceanic response to forcing is in terms of vertically propagating, or vertically trapped, latitudinal modes. These modes are eigenfunctions of LTE with the equivalent depth h (not the frequency) as eigenvalue. Both positive and negative eigenvalues h are necessary for completeness. The modes with h 〉 0 consist of an infinite set of inertia‐gravity waves and a finite set of Rossby waves which either propagate vertically or form vertically standing modes. The latitudinally gravest modes are equatorially trapped and have been observed in the Atlantic and Pacific oceans. The modes with h 〈 0 are necessary to describe the oceanic response to nonresonant forcing. In the vertical this response attenuates with increasing distance from the forcing region. Because of the shallowness of the ocean the large eastward traveling atmospheric cyclones in mid‐latitudes and high latitudes force a response down to the ocean floor. Interaction with the bottom topography will result in smaller‐scale disturbances and will affect the frequency spectrum of the response when bottom‐trapped waves are excited.

Description: A tsunami earthquake is defined as a shock which generates extensive tsunamis but relatively weak seismic waves. A comparative study is made for the two recent tsunami earthquakes, and a subduction mechanism near a deep-sea trench is discussed. These two earthquakes occurred at extremely shallow depths far off the coasts of the Kurile Islands and of eastern Hokkaido on October 20, 1963, and on June 10, 1975, respectively. Both can be regarded as an aftershock of the preceding larger events. Their tsunami heights and seismic wave amplitudes are compared with those of the preceding events. The results show that the time constants involved in the tsunami earthquakes are relatively long but not long enough to explain the observed disproportionality between the tsunamis and the seismic waves. The process times are estimated to be less than 100 s. The spatio-temporal characteristics of the two events suggest that they represent a seaward and upward extension of the rupture associated with a great earthquake which did not break the free surface at the coseismic stage. The amplitude and phase spectra of long-period surface waves and the long-period P waveforms indicate that this extension of the rupture did not take place entirely along the lithospheric interface emerging as a trench axis. It rather branched upward from the interface in a complex way through the wedge portion at the leading edge of the continental lithosphere. This wedge portion consists in large part of thick deformable sediments. A large vertical deformation and hence extensive tsunamis result from such a branching process. A shallowest source depth, steepening of rupture surfaces, and a deformable nature of the source region all enhance generation of tsunamis. The wedge portion ruptured by a tsunami earthquake is usually characterized by a very low seismic activity which is presumably due to ductility of the sediments. We suggest that this portion fractures in a brittle way to generate a tsunami earthquake when it is loaded suddenly by the occurrence of a great earthquake and that otherwise it yields slowly. Upward branching of the rupture from the lithospheric interface produces permanent deformation of the free surface which is relative uplift landward and relative subsidence trenchward of the zone of surface break. This surface break zone geomorphologically corresponds to the lower continental slope between the deep-sea terrace and the trench. Such a mode of permanent deformation seems to be consistent with a rising feature of the outer ridge of the deep-sea terrace and a depressional feature of the trench. This consistency implies a causal relationship between great earthquake activities and geomorphological features near the trench.

Description: A tsunami earthquake is defined as a shock which generates extensive tsunamis but relatively weak seismic waves. A comparative study is made for the two recent tsunami earthquakes, and a subduction mechanism near a deep-sea trench is discussed. These two earthquakes occurred at extremely shallow depths far off the coasts of the Kurile Islands and of eastern Hokkaido on October 20, 1963, and on June 10, 1975, respectively. Both can be regarded as an aftershock of the preceding larger events. Their tsunami heights and seismic wave amplitudes are compared with those of the preceding events. The results show that the time constants involved in the tsunami earthquakes are relatively long but not long enough to explain the observed disproportionality between the tsunamis and the seismic waves. The process times are estimated to be less than 100 s. The spatio-temporal characteristics of the two events suggest that they represent a seaward and upward extension of the rupture associated with a great earthquake which did not break the free surface at the coseismic stage. The amplitude and phase spectra of long-period surface waves and the long-period P waveforms indicate that this extension of the rupture did not take place entirely along the lithospheric interface emerging as a trench axis. It rather branched upward from the interface in a complex way through the wedge portion at the leading edge of the continental lithosphere. This wedge portion consists in large part of thick deformable sediments. A large vertical deformation and hence extensive tsunamis result from such a branching process. A shallowest source depth, steepening of rupture surfaces, and a deformable nature of the source region all enhance generation of tsunamis. The wedge portion ruptured by a tsunami earthquake is usually characterized by a very low seismic activity which is presumably due to ductility of the sediments. We suggest that this portion fractures in a brittle way to generate a tsunami earthquake when it is loaded suddenly by the occurrence of a great earthquake and that otherwise it yields slowly. Upward branching of the rupture from the lithospheric interface produces permanent deformation of the free surface which is relative uplift landward and relative subsidence trenchward of the zone of surface break. This surface break zone geomorphologically corresponds to the lower continental slope between the deep-sea terrace and the trench. Such a mode of permanent deformation seems to be consistent with a rising feature of the outer ridge of the deep-sea terrace and a depressional feature of the trench. This consistency implies a causal relationship between great earthquake activities and geomorphological features near the trench.

Description: Published geological and geophysical data are reviewed. The Walvis Ridge is a complex linear feature made up of three parts of unequal lengths and differing basement morphologies: an eastern sector composed of rugged, subparallel basement ridges; a low-lying central sector with subdued basement morphology; and a western sector consisting of seamounts and guyots (including Tristan da Cunha and Gough islands). Rock samples and geophysical data suggest that the Ridge is composed of alkali basalt which becomes progressively older eastwards. Gravity data indicate that at least parts of the ridge are in local isostatic equilibrium. A mantle plume mechanism of formation is rejected in favour of a centre of abnormally high volcanic activity on the spreading ridge axis. The location of this centre, whose relative movement has been southwards, is determined by fracture zones crossing the spreading ridge axis.

Description: Projekte: a) Erosionsbeobachtung im Bereich der Veisnäs-Rinne b) Geräteerprobungen für die Reise JASIN

Description: Observations of the temporal and spatial distribution of N2O in solution are not yet sufficient to permit quantitative assessment of the role of the ocean in the budget of atmospheric N2O. Consideration of the global nitrogen cycle suggests that the land should be the primary source of N2O. The gas is removed in the atmosphere by photolysis and by reaction with O(1D), and there may be additional sinks in the ocean.

Description: One hundred and five new heat flow measurements in the Gulf of California support the premise that conductive heat loss is not the only mode by which heat is lost from a sea floor spreading center, even in an area with thick sediment cover. Theoretical estimates suggest that the average heat flow in the Guaymas and Farallon basins should be at least 11 μcal/cm2 s (HFU) (325 mW/m2). Outside a 30-km-wide zone centered on the central troughs, the heat flow values measured are reasonably uniform but average only 4.3±0.2 HFU (180±10 mW/m2). Although the high sedimentation rate may depress the measured heat flow, the effect probably does not exceed 15%. Some heat, particularly in the smaller basins, may be lost to the adjacent cooler continental blocks. The discrepancy between the measured and predicted heat losses, which is at least 30%, may be due to the discharge of thermal waters, through the thinner sediment cover in the central troughs or along active faults.

Description: The Cape Verde Islands are emerged portions of a Mesozoic-Cenozoic volcanic accretion in the form of a westward-opening horseshoe along fracture zones converging from the mid-Atlantic ridge toward Africa. An interior abyssal plain slopes westward, increasing in depth from 2.7 to 4.5 km. The plain is underlain by low relief on acoustic basement that is associated with a 300-gamma negative magnetic anomaly. The flanks of the Sal-Maio ridge appear bounded by large-displacement normal faults; superficial slumping is common. The trends of magnetic anomalies are linear N-S north of the islands and less linear within the islands and may change coincident with E-W bathymetric trends south of the islands. A triangular pattern of reversed refraction lines 200–250 km long along the north and east ridges and NW-SE across the interior abyssal plain indicated 2–3 km of semiconsolidated sediments underlain by 3–6 km of basalt and 6–8 km of plutonic rocks. The depth of the Moho is between 16 and 17 km. A deep NW-SE trending fault intersects the Sal-Maio ridge near Boa Vista. The consistent depth to Moho and the regional Bouguer anomaly indicate lack of local relief at the base of the crust. The crustal load of the entire archipelago is regionally adjusted.

Description: An intensive three-dimensional survey of the Antarctic Polar Front was made in the Drake Passage in March 1976. The front, which was imbedded within one of the high-velocity cores of the circumpolar current, is viewed as a water mass boundary demarking the northern extent of near-surface antarctic waters. Within the front, water masses are observed to intrude, one above the other, with characteristic vertical scales of 50–100 m. The intrusions are horizontally anisotropic, being elongated in the alongstream direction and constrained primarily to the upper 800 m of the front. The spatial and temporal persistence of the variability is examined through the analysis of continuous vertical profiles of horizontal velocity, temperature, salinity, and oxygen with discrete sampling of nutrients. Analysis of the velocity data showed the mean current flowing to the NNE with speeds of the order of 30–40 cm s−1 in the upper 600 m, with temporal variability over a 28-hour ‘yo-yo’ due primarily to internal gravity waves. The thermohaline variability was not internal wave induced but rather was associated with nearly isentropic advection of different water masses across the front. Cold fresh and warm salty intrusions did not conserve potential density, however, and double-diffusive transfers are strongly suggested as being crucial to an understanding of the dynamics of the intrusions. Applying a model (Joyce, 1977) for lateral mixing we estimate poleward temperature and salinity fluxes due to interleaving of 0.086°C cm s−1 and 0.069‰ cm s−1, respectively. If these values are typical, interleaving could play a significant role in large-scale balance of salt and, to a lesser extent, heat for the Southern Ocean.

Description: The structural evolution of the northwestern Iberian margin has been reconstructed from the results of IPOD drill site 398, as well as from numerous dredgings and a dense network of seismic profiles. During the Mesozoíc the margin first underwent two consecutive extensional phases interpreted as the result of two episodes of rifting in the Atlantic. Then during Eocene, subsidence was interrupted by compression and related deformation caused by subduction of oceanic sea floor of the Bay of Biscay beneath the Iberian Peninsula. Present day marginal banks are interpreted as blocks of the older passive margin uplifted during early Tertiary as a result of that subduction. Fault escarpments provide opportunities to sample older sediments and basement by dredging.

Description: A model for interstitial silica concentrations is derived, incorporating biological mixing of sediments. This model predicts concentrations and gradients and can account for the observed geographical variations in interstitial silica on the basis of a dynamic balance between solution of silica particles and diffusion from the sediments. The flux of particulate biogenous silica into the sediments is confirmed as an important parameter controlling interstitial silica concentrations. Biological mixing of sea floor sediments also has an important influence on interstitial composition by modifyirig the depth at which dissolving particles react. Faster mixing raises the interstitial concentration. The rate at which siliceous particles dissolve also plays a role; the slower they dissolve, the greater the interstitial silica concentration. Measurements on near‐bottom waters of the Atlantic show no consistent gradients in dissolved silica, but antarctic bottom water seems significantly more variable in the benthic boundary layer than in the water mass above or in the benthic zone of North Atlantic deep water.

Description: Biological mixing in deep‐sea sediments is described in terms of a time‐dependent eddy diffusion model where mixing takes place to a depth L at constant eddy diffusivity D. The differential equation that describes this model has been solved for an impulse source of tracer delivered to the plane surface that forms the top of the mixed layer. The solution then serves as a Green's function, which can be used to determine the distribution of tracer in depth and in time for a surface input of tracer specified as any arbitrary function of time. The characteristic properties of the solution are dependent on the dimensionless parameter D/Lυ, where υ is the sedimentation rate. If D/Lυ is greater than 10, the surface layer becomes homogeneous, and the model is identical to the homogeneous layer model proposed by Berger and Heath (1968). If D/Lυ is less than 0.1, little mixing can take place before the sediments are buried, and so the surface concentration propagates downward into the sediments with little dispersion. For all values of D/Lυ the weighted mean depth of the concentration distribution is the depth at which an impulse source would be found in the sediment if no mixing had taken place. The microtektite data of Glass (1969, 1972) and Glass et al. (1973) indicate that abyssal sediments are mixed from the surface to a maximum mixing depth that ranges between 17 and 40 cm below the surface. Mixing occurs at rates between 1 and 100 cm2 kyr−1. Higher mixing rates may occur nearer the surface, but microtektite distributions cannot be used to estimate these rates in the presence of the deeper, slower mixing. Estimates for D based on dimensional analysis of sediment reworking rates for nearshore organisms (103–106 cm2 kyr−1) are used to predict abyssal mixing rates between 1 and 103 cm2 kyr−1 by invoking the assumption that mixing is proportional to biomass. Plutonium distributions in deep‐sea sediments (Noshkin and Bowen, 1973) indicate abyssal mixing rates ranging from 100 to 400 cm2 kyr−1.

Description: Deep‐sea drilling in the Antarctic region (Deep‐Sea Drilling Project legs 28, 29, 35, and 36) has provided many new data about the development of circum‐Antarctic circulation and the closely related glacial evolution of Antarctica. The Antarctic continent has been in a high‐latitude position since the middle to late Mesozoic. Glaciation commenced much later, in the middle Tertiary, demonstrating that near‐polar position is not sufficient for glacial development. Instead, continental glaciation developed as the present‐day Southern Ocean circulation system became established when obstructing land masses moved aside. During the Paleocene (t = ∼65 to 55 m.y. ago), Australia and Antarctica were joined. In the early Eocene (t = ∼55 m.y. ago), Australia began to drift northward from Antarctica, forming an ocean, although circum‐Antarctic flow was blocked by the continental South Tasman Rise and Tasmania. During the Eocene (t = 55 to 38 m.y. ago) the Southern Ocean was relatively warm and the continent largely nonglaciated. Cool temperate vegetation existed in some regions. By the late Eocene (t = ∼39 m.y. ago) a shallow water connection had developed between the southern Indian and Pacific oceans over the South Tasman Rise. The first major climatic‐glacial threshold was crossed 38 m.y. ago near the Eocene‐Oligocene boundary, when substantial Antarctic sea ice began to form. This resulted in a rapid temperature drop in bottom waters of about 5°C and a major crisis in deep‐sea faunas. Thermohaline oceanic circulation was initiated at this time much like that of the present day. The resulting change in climatic regime increased bottom water activity over wide areas of the deep ocean basins, creating much sediment erosion, especially in western parts of oceans. A major (∼2000 m) and apparently rapid deepening also occurred in the calcium carbonate compensation depth (CCD). This climatic threshold was crossed as a result of the gradual isolation of Antarctica from Australia and perhaps the opening of the Drake Passage. During the Oligocene (t = 38 to 22 m.y. ago), widespread glaciation probably occurred throughout Antarctica, although no ice cap existed. By the middle to late Oligocene (t = ∼30 to 25 m.y. ago), deep‐seated circum‐Antarctic flow had developed south of the South Tasman Rise, as this had separated sufficiently from Victoria Land, Antarctica. Major reorganization resulted in southern hemisphere deep‐sea sediment distribution patterns. The next principal climatic threshold was crossed during the middle Miocene (t = 14 to 11 m.y. ago) when the Antarctic ice cap formed. This occurred at about the time of closure of the Australian‐Indonesian deep‐sea passage. During the early Miocene, calcareous biogenic sediments began to be displaced northward by siliceous biogenic sediments with higher rates of sedimentation reflecting the beginning of circulation related to the development of the Antarctic Convergence. Since the middle Miocene the East Antarctic ice cap has remained a semipermanent feature exhibiting some changes in volume. The most important of these occurred during the latest Miocene (t = ∼5 m.y. ago) when ice volumes increased beyond those of the present day. This event was related to global climatic cooling, a rapid northward movement of about 300 km of the Antarctic Convergence, and a eustatic sea level drop that may have been partly responsible for the isolation of the Mediterranean basin. Northern hemisphere ice sheet development began about 2.5–3 m.y. ago, representing the next major global climatic threshold, and was followed by the well‐known major oscillations in northern ice sheets. In the Southern Ocean the Quaternary marks a peak in activity of oceanic circulation as reflected by widespread deep‐sea erosion, very high biogenic productivity at the Antarctic Convergence and resulting high rates of biogenic sedimentation, and maximum northward distribution of ice‐rafted debris.

Description: The olivine melilitite diatemes of the Swabian Alb, frequently compared with kimberlite diatremes, are discussed in terms of hydrogeological setting, internal structure and juvenile fraction. The hydrogeological conditions of the Swabian Alb at the time of diatreme emplacement were characterized by copious amounts of groundwater within the sedimentary cover of the basement. Subsequently to the eruptions groundwater accumulated within the maars of the larger diatremes forming fresh‐water lakes as also happened nearby in the Steinheim and Ries impact craters. The diatremes reveal subsidence structures composed of large wall‐rock blocks, subaerially deposited pyroclastic beds, and well‐bedded reworked pyroclastic debris which accumulated on the floor of the fresh‐water crater lakes. The latter fact implies availability of groundwater at the time the diatremes formed. The juvenile fraction is developed in the shape of spherical to ovoid nucleated autoliths of ash to lapilli size that are macroscopically nearly devoid of vesicles. The autoliths are interpreted as the product of water vapor explosions which took place when rising olivine melilitite magma contacted groundwater and was fragmented into magma droplets. The droplets were rapidly chilled and thus preserved their shape. Because of the hydrogeological data, the diatreme structure, and the chilled nature of the autoliths a phreatomagmatic origin of the Swabian diatremes is suggested.

Description: The olivine melilitite diatemes of the Swabian Alb, frequently compared with kimberlite diatremes, are discussed in terms of hydrogeological setting, internal structure and juvenile fraction. The hydrogeological conditions of the Swabian Alb at the time of diatreme emplacement were characterized by copious amounts of groundwater within the sedimentary cover of the basement. Subsequently to the eruptions groundwater accumulated within the maars of the larger diatremes forming fresh‐water lakes as also happened nearby in the Steinheim and Ries impact craters. The diatremes reveal subsidence structures composed of large wall‐rock blocks, subaerially deposited pyroclastic beds, and well‐bedded reworked pyroclastic debris which accumulated on the floor of the fresh‐water crater lakes. The latter fact implies availability of groundwater at the time the diatremes formed. The juvenile fraction is developed in the shape of spherical to ovoid nucleated autoliths of ash to lapilli size that are macroscopically nearly devoid of vesicles. The autoliths are interpreted as the product of water vapor explosions which took place when rising olivine melilitite magma contacted groundwater and was fragmented into magma droplets. The droplets were rapidly chilled and thus preserved their shape. Because of the hydrogeological data, the diatreme structure, and the chilled nature of the autoliths a phreatomagmatic origin of the Swabian diatremes is suggested.

Description: Fünf Dinoflagellatenarten aus der Nordsee werden eingehend beschrieben und abgebildet. Eine der beschriebenen Arten ist neu für die Wissenschaft, eine andere wird vom Niveau einer Varietät zur eigenen Art erhoben, zwei weitere Arten werden als Synonym zu einer anderen Art gestellt.

Description: Die Inkorporation von (14C) - Glukose in Konzentrationen von 1µg C/l durch größenfraktioniertes natürliches Plankton wurde in Wasserproben aus der Kieler Förde bestimmt. Die Größenfraktionierung wurde durch Filtration mit Nuclepore-Filtern abgestufter Porengröße durchgeführt. Organismen, deren Durchmesser weniger als 1 µ betragen, waren in erster Linie (zu mehr als 69%) an der Aufnahme der Glukose beteiligt. Hierbei handelt es sich zweifellos um Bakterien. Von den größeren Fraktionen wurde relativ wenig Substrat heterotroph aufgenommen. Durch mikroskopische Untersuchungen und durch Kulturverfahren konnte nachgewiesen werden, daß auch in diesen Größenklassen die Glukose-Aufnahme durch Bakterien (auf Detritus) anteilmäßig beträchtlich ist. Die Beobachtungen führen zu dem Schluß, daß zumindest bei natürlichen Substratkonzentrationen die Aufnahme der gelösten organischen Verbindungen fast ausschließlich auf Bakterien zurückzuführen ist.

Description: An mehreren Makrobenthosarten der westlichen Ostsee und des Kattegat wurde der Sauerstoffverbrauch in Abhängigkeit vor der Sauerstoffspannung gemessen. Die untersuchten Bewohner sauerstoffarmer Weichböden haben eine niedrige Stoffwechselgröße und die Fähigkeit, die Atmung bis zu einem kritischen Partialdruck von unter 10% zu regulieren. Bei Arten aus besser belüfteten Biotopen nimmt die Stoffwechselgröße zu und die Fähigkeit zur Atemregulation ab. Bei zunehmender Mobilität einer Art wächst die Stoffwechselgröße; eine große Fähigkeit zur Atemregulation kann dabei bestehen bleiben. The oxygen consumption of several macrobenthic species of the western Baltic and Kattegat was measured in dependence of oxygen tension. The examined inhabitants of soft sediments, poor in oxygen demonstrate low metabolic rates and an ability, to regulate oxygen consumption down to critical partial pressures of less than 10%. In species of well aerated biotopes, metabolic rates increase and the ability of respiratory regulation is reduced. With increasing mobility animals increase their metabolic rates. The ability of respiratory regulation needs not to be affected by this.

Description: 1. Haddebyer und Selker Noor am inneren Ende der Schlei werden als Beispiele oligohaliner Lebensräume hydrographisch-physikalisch, chemisch und biologisch untersucht. 2. Auf Grund der gemessenen abiotischen Faktoren werden beide Noore als hypertrophe, homohaline und oligohaline "Stillwasserbuchten" charakterisiert. 3. Eine genauere Untersuchung der aus der Literatur zusammengestellten Artenliste beider Noore und der Vergleich mit dem benachbarten Schleigebiet sowie dem inneren Randersfjord in Dänemark ergibt eine gute Übereinstimmung mit dem von REMANE (1934) gegebenen Schema der Artenverteilung in Abhängigkeit vom Salzgehalt. Das Haddebyer Noor wird als Gebiet des Artenminimums bestimmt, von dem aus nach beiden Seiten des Salinitätsspektrums die Zahl der Arten wieder ansteigt. 4. Dies wird durch die während des Untersuchungszeitraums gefundenen Arten bestätigt. 5. Die quantitativen Ergebnisse vermitteln eine Vorstellung davon, daß die Artenarmut begleitet wird von einer Massenentwicklung der noch vorhandenen Arten. 6. Die floristischen und faunistischen Ergebnisse zeigen deutliche Veränderungen gegenüber den Ergebnissen NEUBAURs und JAECKELs (1935, 1936 u. 1937). Das Phytoplankton wird in der Hauptsache von Cyanophyceen gebildet, die Bivalvier fehlen fast vollständig, Chironomiden treten mit sehr hohen Individuenzahlen auf. 7. Diese Veränderungen werden auf die anthropogene Verschmutzung durch die in die Schlei geleiteten Abwässer zurückgeführt.

Description: Es wird eine einfache Methode beschrieben, die das Erkennen und Auszählen von Bakterienzellen mit aktivem Elektronentransportsystem in Wasser- und Sedimentproben ermöglicht. Sie beruht auf der Reduktion eines Tetrazoliumsalzes (INT) zu rotgefärbtem Formazan. Anhand von 3 Beispielen werden die Anwendungsmöglichkeiten der Methode diskutiert. A simple method is described whereby it is possible to recognize and count bacteria cells with active electron transport system in samples of water and sediment. lt is based on the reduction of a tetrazoliurn salt (INT) to a red colored formazan. By means of 3 examples the uses of the method are discussed.

Description: The present paper describes an improved method for the semicontinuous culture of bacterial populations on Nuclepore membrane filters. The filters, placed on swimming rings, are incubated in direct contact with the water surface of the flow system, and examined by fluorescence microscopy. The growth activity of both, pure cultures and natural bacterial populations, measured in the flow system is compared to the activity measured in a conventional culture system (incubation of membrane filters on the surface of paper disc saturated with incubation medium). The flow system increases the number and the spectrum of colony forming cells. The reasons for the superiority of the flow system are discussed.

Description: Bei marinen Mollusken, die in der Gezeitenregion der gemäßigten Breiten überwintern, nimmt die Gefrierresistenz in der Reihenfolge Littorina saxatilis, L. littorea, Mytilus edulis, Mya arenaria und Macoma baltica ab. Die Littorina-Arten ertragen noch mehrstündige Exposition bei -15°C zu einem hohen Prozentsatz. Primärschäden durch Gefrieren bei -10° und -15°C werden im Laufe längerer Hälterung nach der Kälteexposition verstärkt. Im Sommer ist die Gefrierresistenz stark verringert. Tiergröße sowie die Außenbedingungen am Fundort (Salzgehalt etc.) modifizieren die Überlebensfähigkeit bei Frosteinwirkung. Marine mollusks overwintering in the tidal zone of the temperate latitudes show decreasing freezing resistance in the following order: Littorina saxatilis, L. littorea, Mytilus edulis, Mya arenaria and Macoma baltica. The Littorina species even resist some hours exposure at -15 °C with a high degree of survival. Primary injuries caused by freezing at -10° and -15°C are enhanced during longer keeping subsequent to freezing exposure. From spring to autumn freezing resistance is strongly reduced. Size of the animals and environmental factors of the habitat (salinity etc.) modify survivability during exposure to frost.

Description: In the tropical brackish water lagoon Cienaga Grande de Santa Marta the change of the bacterial population was studied during a period of dropping salinity from September to December 1973. Plate counts on ZoBell's Medium 2216 E with different salinities were made from a series of 11 sections through the lagoon, and compared with the salinity, temperature, and pH of the water. Following the decrease of salinity, a mass development of halophilic bacteria can be observed. They decrease again at a salinity about 3‰ , while the fresh water bacteria reach their maximum. This group made up only 0,1-3,7% of the bacterial flora in the salinity range above 10‰. Among he halophilic bactcria a brown pigmented organism occurs, which resembles Agrobacterium stellulatum, the most common brackish water bacterium of the Baltic Sea. Before the maximal increase of the fresh water bacteria, a pink coloured population of halotolerant aquatic bacteria temporarily appears. 41 brown and 14 pink isolations are maintained in the Institut für Meereskunde in Kiel for further investigations. As in the lagoon, the fresh water inflow influences the salinity and bacterial content in the adjacent coastal region. On a profile from the mouth of the Cienaga seaward the number of halophilic bacteria in the surface layer decreases within 11 nautical miles from 90000 cfu/ml to 60-70 cfu/ml, that of fresh water from 2100 cfu/ml to 20-50 cfu/ml. The fresh water originates mainly from the Rio Magdalena. Between the mouth of the Magdalena and Santa Marta the surface samples show a terrestrial influence. The halophilic bacteria are most numerous with the shallow stations of high nutrient content and decrease with increasing distance from the coast. With the water of the river Magdalena halotolerant fresh water bacteria are transported to the surface layer of the bight, especially the pink organism which was found to be frequent in the Cienaga. In the surface water of Santa Marta the plate counts on sea water agar range from 390 to 20500 cfu/ml, those on fresh water agar from 68 to 12000 cfu/ml. The highest numbers coincide with the inflow of fresh water. The bacterial counts of the 10 metre samples make up about 10% of the surface values.

Description: Kleine Exemplare des Seesterns Asterias rubens (5-10 mm Armradius) sind drucktoleranter als große (25-40 mm Armradius). Die Drucktoleranz nimmt bei dieser Art bei Erhöhung der Temperatur von 5 auf 15°C zu. Durch den Druck verursachte reversible Schädigungen werden bei der höheren Temperatur schneller „repariert". Irreversibel geschädigte Tiere sterben bei 15°C schneller ab als bei 5°C. Die Aktivität des Enzyms Lactat-Dehydrogenase von Asterias rubens wird mit abnehmender Temperatur und steigendem Druck zunehmend gehemmt. Small specimen of the starfish Asterias rubens (radius: 5-10 mm) tolerate higher hydrostatic pressures than larger ones (radius: 25-40 mm). Pressure tolerance of this species increases with rising temperature from 5 to 15°C. Pressure induced reversible injuries are "repaired" more quickly at higher temperatures. Irreversible damaged starfishes die more quickly at 15°C than at 5°C. With decreasing temperature and augmenting hydrostatic pressure the activity of the enzyme Lactate-dehydrogenase of Asterias rubens is increasingly inhibited.

Description: Für den Wasseraustausch in der westlichen Ostsee sind die Transportvorgänge im Fehmarnbelt von sehr großer Bedeutung. Die vorliegende Untersuchung ist ein Versuch, die Änderungen des Wassertransports durch den Fehmarnbelt in Zeitskalen von einigen Tagen als Wirkung des Windfeldes über der westlichen Ostsee zu erklären und Ansätze für eine Vorhersage zu finden. In der Zeit vom 24.7. bis 7.8.1972, in der die zugrunde liegenden Strömungsmessungen im Fehmarnbelt und bei Gedser durchgeführt werden, ist die Großwetterlage durch ein sommerliches Hochdruckgebiet über Mitteleuropa gekennzeichnet, das nur geringfügig, aber in regelmäßiger Folge durch flache, ostwärts ziehende Tiefs abgeschwächt wird. Die Schichtung von warmem Ostseewasser geringen Salzgehalts über salzreichem Nordseewasser bleibt im ganzen Meßzeitraum erhalten. Die Gezeiten, die durch Kelvin-Wellen beschrieben werden können, erfassen die gesamte Wassersäule gleichmäßig stark, während sich die beobachteten Strömungsschwankungen mit Perioden im Bereich von 50 bis 60 und 100 bis 120 Stunden auf die Oberschicht beschränken. Ein Vergleich der gemessenen mit der aus dem lokalen Windschub berechneten Strömung ergibt, daß der über dem Fehmarnbelt wehende Wind nicht als Ursache der dort auftretenden Strömung in Frage kommt. Die Differenzen zwischen den Wasserständen bei Korsör und bei Gedser und die daraus resultierende Gefälleströmung lassen sich nicht durch statische Reaktion der Oberfläche auf Unterschiede in den Luftdruckschwankungen über Nord- und Ostsee erklären. Aus den Veränderungen des großräumigen Windfeldes, dargestellt mit Hilfe des zeitlichen Verlaufs horizontaler Luftdruckdifferenzen, geht hervor, daß die Windverhältnisse über dem Kattegat sowie der Kieler und Mecklenburger Bucht als Ursache für die Strömung durch den Fehmarnbelt ausscheiden. Zwischen der Ost-West-Komponente des berechneten Windes über der westlichen Ostsee und den langperiodischen Strömungskomponenten durch den Fehmarnbelt besteht dagegen eine lineare Beziehung. Die zwei- und fünftägigen Schwankungsperioden des Windfeldes erzeugen in der Ostsee erzwungene stehende Wellen. Mit Hilfe der Differenzen zwischen den Wasserständen bei Rödby und Puttgarden und bei Korsör und Slipshavn werden effektive Strömungsquerschnitte abgeschätzt, um Transportraten zu bestimmen. Der Vergleich mit dem berechneten, windgetriebenen Transport im Arkona-Becken bestätigt, daß die langperiodischen Strömungsänderungen im Fehmanrbelt durch die Bewegungsvorgänge in der sommerlichen Deckschicht der westlichen Ostsee bestimmt werden. Die Dichtesprungschicht neigt sich im Fehmarnbelt immer aufwärts in Richtung der Strömung in der Oberschicht, so daß in der Unterschicht ein entgegengesetzter horizontaler Druckgradient entsteht, der bewirkt, daß die Oberflächenneigung keinen Einfluß auf die Bodenströmung hat. Die vorliegenden Untersuchungen, auch wenn sie unter sommerlichen Verhältnissen durchgeführt worden sind, zeigen, daß für eine Vorhersage des langperiodischen Ein- oder Ausstromtransports durch den Fehmarnbelt die Luftdruckdifferenzen zwischen Kopenhagen und Helgoland und zwischen Gotland und Gelingen herangezogen werden können, während mit Hilfe der Wasserstandsdifferenz zwischen Rödby und Puttgarden der gerade herrschende Transport abgeschätzt werden kann.

Description: Die Untersuchung von Muschelbruchsand aus Gezeitentümpeln eines bei East London (Südafrika) gelegenen Riffs erbrachte 21 Harpacticoiden-Arten, unter denen sich eine mit einer Art vertretene neue Gattung, 11 neue Arten und eine neue Unterart befanden, nämlich Caligopsyllus primus n. gen., n. sp., Paradactylopodia hexarticulata n. sp., Psyllocamptus (Langpsyllocamptus) longisetosus n. subgen., n. sp., Psyllocamptus (Langpsyllocamptus) quadiospinosus n. subgen., n. sp., Ameiropsis australis n. sp., Sarsameira elegantula n. sp., Karllangia tertia n. sp., Parapseudoleptomesochra dubia n. sp., Phyllopodopsyllus langi n. sp., Phyllopodopsyllus paraborutzkyi n. sp., Mesochra bodini n. sp., Laophonte spinifer n. sp. und Typhlamphiascus lamellifer SARS capensis n. ssp. Als Untergattung von Psyllocamptus wird die neue Untergattung Langpsyllocamptus begründet. Beim Vergleich mit Untersuchungen aus anderen Gebieten ergaben sich Ähnlichkeiten mit der Besiedlung von Muschelbruchsand aus der Gezeitenzone der kalifornischen Küste.

Description: 1. An Gammarus salinus und Idotea baltica wurde der Einfluß einer mehrstündigen Beschichtung mit Rohölen auf Überlebensfähigkeit und Atmung der Tiere untersucht. 2. Bei Gammarus salinus betrug die mittlere Überlebenszeit nach Überschichtung mit einer 0,1 mm dicken Ölschicht 1-2 Tage und nahm in folgender Reihe zu: Iran-Rohöl 〈 Libyen-Rohöl 〈 Venezuela-Rohöl. Der Kontrollwert betrug 31 Tage. 3. Bei Idotea baltica lag die mittlere Überlebenszeit bei 41 Tagen für Iran-Rohöl, 48 Tagen für Venezuela-Rohöl und 51 Tagen für Libyen-Rohöl. Der Kontrollwert betrug 56 Tage. 4. Der Sauerstoffverbrauch bei 15‰ S und 15°C sank durch die Überschichtung mit Rohöl aus dem Iran bei Gammarus salinus auf etwa 40% des Normalwertes, bei Idotea baltica auf etwa 70%. The influence of crude oil from Venezuela, Libya and Iran was observed with respect to Idotea baltica and Gammarus salinus. Prior to the measurements the animalsspread out on sand were exposed to a 0,1 mm layer of crude oil for four hours. After this period they were transferred back into sea water of 15‰ S and 15°C. The mean time of survival for Gammarus salinus varied between one and two days: Iran oil 〈 Libya oil 〈 Venezuela oil (control value: 31 days). Idotea baltica showed a greater resistance. The mean time of survival was 41 days for Iran oil, 48 days for Venezuela oil and 51 days for Libya oil (control value: 56 days). At 15‰ S and 15°C the oxygen consumption of Gammarus salinus was reduced owing to the influence of Iran crude oil down to 40% of the normal value, in Idotea baltica to 70%.

Description: Prolonged in situ observations of the behaviour of the pelagic amphipod Hyperia galba MONTAGU were carried out in the Baltic Sea in August 1974. On 8 consecutive days, for a definite period of time at dusk and at the first light of dawn, the Hyperia galba which appeared in front of a searchlight were collected. The collections were made by a saturation diver from the underwater laboratory "Helgoland". Analysis of the fixed animals in the laboratory yielded the following results: 1. The females come from the surface to the bottom earlier and return later than the males. Presumably the males and females have a different threshold of stimulation with regard to light. 2. Sinking of the animals to the bottom is not exclusively connected with light, as indicated by diminished catches after development of a thermocline 4-5 m above the bottom. 3. An investigation of the Hyperia galba population in the jellyfish Aurelia aurita showed that 62,5% of the animals taken from Aurelia were females, almost all of them carrying eggs in various stages of development. The Hyperia galba which were caught in front of the searchlights showed that 58,1 % were males.

Description: Ziel dieser Arbeit war es, einen Beitrag zur Klärung des Problems der Selbstreinigung von Gewässern unterschiedlichen Salzgehaltes zu liefern. An Hand verschiedener Parameter wurde in geeigneten Versuchsgefäßen der Abbau von häuslichem Abwasser in Süßwasser und in Ostseewasser verglichen, um festzustellen, wie sich der Salzgehalt auf die Dekomposition der Schmutzstoffe auswirkt. Es konnte festgestellt werden, daß dieser im Ostseewasser anfangs nicht langsamer verläuft als im Süßwasser. Erst nach 3-4 Tagen setzt eine Verzögerung ein, die sich vor allem in einer verlangsamten Nitrifikation bemerkbar macht und möglicherweise auf den im Brackwasser stärkeren Rückgang der Abwasser- und Süßwasserbakterien zurückzuführen ist. Die bakterizide Wirkung tritt anfangs infolge der hohen Nährstoffkonzentration zurück und macht sich erst nach einigen (1-3) Tagen bei Abnahme der Nährstoffe bemerkbar. In der Anfangsphase scheint sich der Salzgehalt des Ostseewassers in vitro eher günstig auf den Abbau auszuwirken, wobei vielleicht der höhere osmotische Wert eine Rolle spielt. Die Übertragung dieser in vitro gewonnenen Ergebnisse auf die natürlichen Verhältnisse ist zwar nicht ohne weiteres möglich bei Berücksichtigung der Ergebnisse von Standortuntersuchungen im Bereich der Abwassereinleitung der Stadt Kiel in die Ostsee bei Bülk ergibt sich jedoch, daß die Selbstreinigungskraft des Brackwassers so groß ist, daß es von Vorteil sein kann, Küstengewässer an Stelle von benachbarten Binnengewässern als Vorfluter zu verwenden.

Description: 1. Versuche zur Vermehrung und Einwanderung von Colibakterien ins Sediment erfolgten mit dem Teststamm E. coli K.12. Dessen Verhalten wurde in Labor- und Freilanduntersuchungen überprüft und in Abhängigkeit vom Salz-, Nährstoff- und Schwefelwasserstoffgehalt diskutiert. 2. Einwanderung und Vermehrung von E. coli K 12 im Sediment konnte im Laborversuch in speziell dafür konstruierten Säulen beobachtet werden. Im sterilisierten Schlicksediment wurde aktive Einwanderung von E. coli K 12 mit recht gleichmäßiger Geschwindigkeit festgestellt. Im unsterilisierten Sediment erfolgte die Einwanderung mit erheblich höherer Geschwindigkeit. Dieses kann auf einen passiven Transport der Bakterien durch Würmer oder andere schlickbewohnende Tiere zurückzuführen sein. 3. Eine Vermehrung von E. coli K 12 wurde im Laborversuch nur in sterilisiertem Brackwassersediment festgestellt. In allen anderen Proben starben die Keime mehr oder weniger schnell ab. 4. Freilanduntersuchungen im Watt der Nordsee zeigten, daß unter natürlichen Verhältnissen das Absterben von E. coli im Sediment erheblich langsamer erfolgt als im Seewasser gleichen Salzgehaltes.

Description: Die Untersuchung über die benthonische Ostracodenfauna im Oligohalinikum des Haddebyer und Selker Noores und der Vergleich mit der Selker Au (Süßwasser) haben folgendes ergeben: Von 13 gefundenen Arten sind 9 den Nooren (incl. der Selker Au) gemeinsam, 2 sind auf das Haddebyer, 2 auch auf das Selker Noor beschränkt. Neu für das Haddebyer Noor sind 9, für das Selker Noor 6 Arten. 3 von anderen Autoren gefundenen Arten konnten nicht mehr nachgewiesen werden. Die Selker Au zeigt - mit Ausnahme 1 Brackwasserart - die gleiche artenmäßige Besiedlung wie das Selker Noor. Die hauptsächlich für die Süßwasserarten bekannte "Anpassungsstärke" gegenüber den physiographischen Faktoren wird im Untersuchungsgebiet analysiert. Die Besiedlungsdichte schwankte im Jahresgang zwischen 800 und 418000 Ind./m2. Es wird versucht, diese Schwankungen mittels der Faktoren Salinität, Temperatur, Sauerstoff und Substrat zu erklären. Für das Haddebyer Noor (Station B) konnte das für diesen Salinitätsbereich bekannte Artenminimum festgestellt werden. Zum Selker Noor (geringere Salinität) steigt die Artenzahl an; der Höchstwert wird in der Selker Au (Süßwasser) erreicht. Erwartungsgemäß war die durchschnittliche Besiedlungsdichte in der Selker Au am geringsten. Die Besiedlungsdichte und ihre Schwankungen lassen sich mit dem prozentualen Anteil von Cyprideis torosa an der Artengemeinschaft korrelieren. Die Massenentwicklung aller Arten bei Station H wird auf die Art des Substrates zurückgeführt. Die Zusammensetzung der Artengemeinschaften wird prozentual aufgeschlüsselt. Die Änderungen in der Zusammensetzung (z.B. Monokulturen) werden hauptsächlich mit dem Salinitätsgradienten und dem Konkurrenzdruck durch Cyprideis torosa erklärt. Die marine Faunenkomponente fehlt im Untersuchungsgebiet völlig. Die Noore werden hauptsächlich durch euryöke (euryplastische) Süßwasserarten besiedelt, deren Anteil zum Selker Noor zunimmt, während der Anteil der genuinen Brackwasserarten im Haddebyer Noor stärker ausgeprägt ist. Für Cyprideis torosa konnten die Ergebnisse VESPER's (1972) bezüglich der Größenreduktion und der Buckelbildung im Brackwasser für Haddebyer und Selker Noor als oligohaline Lebensräume bestätigt werden.

Description: Es wird eine Unterwasserfernsehanlage beschrieben, die aus Fernsehkamera, Mikrophon und Video-Recorder besteht, die jeweils in entsprechende Gehäuse eingebaut sind. Damit sind Aufnahmen von 20 min Dauer bis zu Tiefen von 50 m möglich. An underwater TV-set is described which consists of TV-camera, microphone and Videorecorder in separate housings. 20 min-recordings down to 50 m are possible.

Description: In the scope of our investigations on the basic processes in a soft-bottom macrobenthos community, as a preliminary test, a series of five 1 m2 metal boxes filled with sterilized sediment from the surrounding habitat was exposed in an enclosed area in the western Kiel Bight at a depth of 20 m from September 1972 until July 1975. The establishment and succession of the soft bottom association in the boxes was followed and compared to the association on the surrounding sea floor by monthly to bimonthly sampling by the diving group of SFB 95. While the number of species increases continuously until a final level of about 20 per 0.1 m2 is reached in January 1974, the values of total biomass (the starfish excluded) fluctuate seasonally being high in autumn and early winter and low in March and April. In a late experimental stage in January 1975, before or just in the beginning period of the regression of the bivalve populations, the association in the boxes (80g wet wt./m2) has only reached 50% of the biomass of the assemblage outside where large long-lived and slowly growing bivalve species contribute 75% of macrobenthos weight. The data of total specimen number fluctuate widely due to oxygen deficiency in late 1973 followed by a high colonization activity by opportunistic spionid species immediately after. According to the dominance in specimen numbers of the major taxononomic groups, three phases can be distinguisted: crustacea (mainly Diastylis rathkei) - sedentary polychaetes (spionids, Pectinaria koreni) - bivalves (Abra alba) together with errant polychaetes (Nepthys spp.). In terms of biomass, however, there is an additional phase of echinoderm prevalence (Asterias rubens) during the last five months. The starfish obviously utilize the bivalve production to a high extent: between 94 and 75 % mortality for the three most abundant bivalve species within six months. For the last six months of the experiment, the net production of all bivalve species is calculated as 24g wet wt./m2, i.e. 0.61 g organic carbon of living tissue, most of which is produced by only three species (Abra alba, Cardium fasciatum and Mya truncata: 22g wet wt/m2.) lt is suggested that predators are of eminent importance in controlling succession and production of the new association. The effects of the experimental conditions on the findings is discussed, and a design for extended interdisciplinary in situ experiments to be carried out from 1976 on, based on the experiences of this first test, is presented.

Description: The intention was to study recruitment of benthic macrofauna to an exposed shore. Two mesh-sizes (1.0 and 0.5 mm) were used. The additional abundance and biomass in the finer sieve show both temporal and spatial variations. Maximum values were found in the autumn and at the shallowest station (5 m). The reasons for this are discussed.

Description: In 1975 and 1976 at two stations in the Arkana and the Bornholm Sea the dynamics of the plankton development were studied. The annual course of the measured biological parameters shows peaks of phytoplankton productivity in spring and summer, and of zooplankton in summer. In spring also the phytoplankton biomass reaches a maximum while in August only low chlorophyll values could be observed. In summertime the pelagic system is characterized by an equilibrium state. In autumn after a possible autumnal bloom of phytoplankton all biological parameters sink down to a winter level.

Description: Nitrogen fixation measurements carried out in 1974 and 1975 in the Baltic Sea showed that heterocyst fixed nitrogen c. 3.5 pg (2)-1. According to our preliminary calculations the amount of nitrogen fixed in 1974 in the northern and central Baltic proper was c. 100000 tons.

Description: In 1970/1971 zooplankton was collected monthly at 33 stations in Kiel Bay by means of a Bongo net equipped with 300 µm gauze. Adult copepods were separated into species and sexes. Eleven species were found of which seven were dominant. A succession between winter-spring species (Temora longicornis, Pseudocalanus sp., Acartia bifilosa) and summer-fall species (Centropages hamatus, Paracalanus parvus, Acartia longiremis, A. tonsa) took place. Total abundance varied considerably between the stations. Usually female copepods were more frequent than mal es (up to 85%), with the exceptions of Temora longicornis and Centropages hamatus, which showed a sex ratio of about 1: 1. The sex ratios of Acartia bifilosa and A. longiremis were related to the concentration of the population.

Description: Solutions of detergent or crude oil of 10 ppm, 50 ppm, and 100 ppm after 48-96 hours of exposure induce significant changes in the ionic composition of the hemolymph of the shrimp Crangon crangon and the crab Rhithropanopeus harrisi. The concentrations of sodium, calcium, and chloride ions decrease, whereas the concentration of potassium increases in both species exposed to both pollutants. - The magnesium ion concentration decreases in the hemolymph of the shrimp incubated in solutions of detergent and in the crab incubated in the water containing crude oil. - lt is suggested that changes of the ionic composition of the hemolymph of the studied shrimps and crabs under influence of both pollutants are possibly brought about by alteration of cell membrane permeability and action on some enzyme activities.

Description: The filtration, feeding and assimilation rates of the zooplankton consisting largely of copepods in a shallow eutrophic bodden south of the Darß-Zingst Peninsula (salinity: 5-7‰) were determined under field conditions with the help of 14 C-labelled phytoplankton. During the zooplankton maximum in May (biomass: 2.13 mg dry weight/l), the feeding rate was up to 53.63% of the primary production. The zooplankton production calculated from the experimentally determined assimilation rates was not more than 6.5% of the primary production. The continuously available substantial amounts of detritus resulted in an extraordinarily low grazing rate. 0.39-3.63% of the seston present were removed from the water body daily by filtration. The studies show that the zooplankton also plays an important role in the ecosystem, at least part of the time, even in severely eutrophic landlocked coastal waters.

Description: Kassari Bay is of a specific character, a relatively isolated, sheltered and shallow sea area where the sediment mainly consists of clay and sandy clay. The main communities are the association of the loose-lying red algae Furcellaria fastigiata and Phyllophora brodiaei f. angustissima and the association Zosteretum marinae and its variant which is rich in red algae. Areas with dense vegetation alternate with areas almost without vegetation, or where only single tufts of red algae or some charophytes and phanerogames are found. The floristic list contains 24 taxa, 5 of them are phanerogames. Sphacelaria radicans is a new taxon for the Estonian flora.