ALBERT

Description: Zur Unterstützung einer lithostratigraphischen Neugliederung der Rotliegend- Sedimente der Saar-Nahe-Senke wurden im Donnersberg-Raum zwei Bohrungen niedergebracht. Durch diese konnten Aufbau und Mächtigkeiten mehrerer lithostratigraphisch wichtiger Einheiten aus dem mittleren Teil der Nahe-Gruppe erfaßt werden.

Description: Abstract: Two 300 and 392 m deep holes where drilled to gain detailed Information on the Rotliegend-stratigraphy in the Donnersberg-area, which is part of the Permocarboniferous Saar-Nahe-Basin (SW-Germany). The results lead to a better knowledge of lithostratigraphic important units from the upper part of the Rotliegend (the Nahe-Group).

Description: research

Description: Vertical phytoplankton distribution, temperol fluctuations and sedimentation rates were studied in the central Baltic Sea during the "Baltic Sea Patchiness Experiment 1986" (PEX'86). Vertical particle flux was measured with free sediment traps deployed at 30 and 60m depth for ten April/May 1986 within the PEX grid (20 x 40 nautical drifting days in miles). In the vicinity of one drifting trap water samples were collected in 10-12 depths down to 70m and vertical profiles of temperature, salinity, beam attenuation and light intensity were measured at three hour intervals. Water samples were analyzed for Chl.a, POC and PON content, dry weight and nutrients. Particulate parameters including the activity of 137 Cs were measured in trap samples. Suspended and sedimented particulates were counted under an inverted microscope. Precision and accuracy of the microscopical counts are discussed and confidence limits are calculated for different spec1es and applied counting schemes. Errors in all cases were smaller than the observed in situ variability. A general description of spring blooms in the central Baltic is given and the particular situation of spring 1986 is summarized. Within the station grid of PEX'86 an anticyclonic eddy was observed in which this study was conducted. Here the phytoplankton had reached peak concentrations and mass sedimentation of diatoms was about to start. The bloom was dominated by Thalassiosira levanderi and Chaetoceros spp. (lOµm size). Achnantes taeniata, Mesodinium rubrum, Gonyaulax catenata and an autotrophic Gymnodinium species (26-30µm) were also abundant. Horizontal patchiness and advection caused greater variability in the distribution of phytoplankton biomass blooms as well as temperature and attenuation during the first days than during the latter half of the investigation period. In four different areas within the PEX grid different developed independently. On still smaller time and space scales, the phytoplankton species composition also changed. The degree of patchiness was different for different species. General concepts explaining vertical distribution patterns of phytoplankton by physical and biological mechanisms are discussed. The species-specific distribution of selected diatoms, dinoflagellates and of the funktionally autotrophic ciliate M.rubrum are described. None of the species were homogeneously distributed although no vertical density stratification was observed. Whereas the diatoms and M.rubrum were present within the whole trophogenic layer, the dinoflagellates were only found in the upper 30m. The vertical distribution was different for concentrations were encountered each at species and different maximum depths respectively. Mechanisms affecting species-specific distribution of mobile and non-mobile phytoplankters in isopycnal layers are discussed in light of the particular situation of this study. Diurnal vertical migration is shown for two dinoflagellates and the phytociliate and triggering factors are discussed. All three species migrated upwards during the day and downwards at night. In its detail, however, the migratory behaviour differed between species and also within single populations. Different strategies of adaptation of phytoplankton to changing environmental conditions are suggested: Wheras diatoms adapt to fluctuations of the light climate by physiological adaptations, mobile organisms have the possibility to stay in an isolume layer. The significance of turbulence, of chainformation and of resting stages in the life cycles of phytoplankton is also evaluated. Trap deployments reveiled that only T.levanderi and Chaetoceros spp. sedimented. Their daily relative sedimentation rates (losses as % of standing stocks) increased over time and were species-specific (for T.levanderi max. 50%). Since part of the T.levanderi population was actively dividing (20% of the standing stock was found as paired cells) their suspended concentration decreased slower than that of Chaetoceros spp., although the daily sedimentation of the latter species was only about 30% of the standing stock. T.levanderi occured in chains in the water column but only single cells were found in sedimented material and paired cells were never found in the trap samples. Chaetoceros spores were rare in the water column and only sporadically collected by the sediment traps. The relative sedimentation rate of all other species was less than 5% per day. The settling velocity of the cells was estimated in different independent ways to be about 40-60m/d. This high sinking speed was attributed to aggregate formation. The results indicate that aggregate formation is not only species-specific but also differs between life-stages within one species. Variability of sedimentation rates on a timescale of hours was high, suggesting a diurnal pattern. Sedimentation did not change the vertical distribution patterns, indicating that cells were sinking with similar rates from all depths. The advantages of a Lagrangian sampling strategy (time series measurements 1n the vicinity of a free drifting buoy) for investigating phytoplankton development in time are evaluated and compared to a sampling at a moored station (Eulerian approach). In an environment that exhibits an intense patchiness even at spatial scales of lOOm, as encountered in this study, the influence of advection and patchiness on a time-series with a resolution of hours to days can not be neglected even if the Lagrangian approach is followed. Furthermore, in this study the variability of var1ous parameters measured in an Eulerian mode was not generally higher than that following the Lagrangian one, as one would have expected.

Description: The book is devoted to investigations of benthic fauna and geology of the Southern Atlantic Ocean. These works have been carried out in terms of exploring biological structure of the ocean and are of great importance for development of this fundamental problem. They are based on material collected during Cruise 43 of R/V Akademik Kurchatov in 1985-1986 and Cruise 43 of R/V Dmitry Mendeleev in 1989. Problems of quantitative distribution, group composition and trophic structure of benthos in the Southern Scotia Sea, along the east-west Transatlantic section along 31°30'S, and offshore Namibia in the area of the Benguela upwelling are under consideration in the book. Authors present new data on fauna of several groups of deep-sea bottom animals and their zoogeography. Much attention is paid to analysis of morphological structure of the Scotia Sea floor considered in terms of plate tectonics. Bottom sediments along the Transatlantic section and facial variation of sediments in the area of South Shetland Islands and of the continental margin of Namibia are under consideration.

Description: The Milankovitch theory of climate change predicts that variations of the climate system should match the dominant frequencies of the orbital forcing in the 41 and 23 kyr**-1 frequency bands. Such a linear theory would predict that the amplitude variations of the climate response in these bands should match amplitude variations in orbital forcing. Here we compare amplitude variations of the marine oxygen isotope record with orbital forcing in these bands over the last 700,000 years and find systematic changes through time. We express these amplitude mismatches as variations in the glacial response time, a measure of the climate system's sensitivity to orbitally induced insolation changes. Variations in the glacial response time occur in all frequencies bands without strong concentration of variance in any given band, and have a 'red' spectrum with larger variations at the longer periods. The response time is coherent with delta18O at periods of 100 and 41 kyr, which suggests that the variations in glacial response time in part reflect internal feedback mechanisms of the global climate system. The phase relationship between the estimated glacial response time and the delta18O (ice volume) record is very different at these two frequencies, which suggests at least two separate feedback mechanisms. The first mechanism enhances the 100,000-year climate cycle by increasing rates of change during major glacial terminations. Candidates for this feedback include lithospheric depression and rebound, enhanced ice calving from large marine based ice sheets, and possibly others. A second set of mechanisms, which is detected in the response to the 41,000-year orbital cycle of Earth's obliquity, accelerates ice growth events and slows glacial melting. Some models which include feedbacks between ice sheets, sea ice, and deep ocean temperatures predict early rapid ice growth, followed by slower growth, and this general feature is consistent with our analysis. While we can not at present identify the specific feedbacks leading to asymmetry of growth and decay rates at different frequency bands, the finding of this ice-growth acceleration mechanism in the 41,000-year frequency band suggests that high-latitude processes, where insolation varies most strongly at this rhythm, may be involved. Our finding of systematic changes in climate sensitivity has implications for orbitally tuned chronologies in Pleistocene sediments. Instead of a constant phase shift within a frequency band between orbital forcing and glacial response, as has been assumed in the past, we suggest a variable phase. The largest changes in age estimates for isotopic events are at the glacial terminations, which in our chronology are as much as 3500 years older that estimated previously.

Description: Variations in the contribution of North Atlantic Deep Water (NADW), relative to North Pacific Deep Water (NPDW), to the Southern Ocean, are assessed by comparing delta13C records from the mid-depth North Atlantic, deep Southern Ocean, and deep equatorial Pacific Ocean. In general, the relative contribution of NADW was greater during interglaciations than glaciations of the past 550,000 years. An increase in the NADW flux to the Southern Ocean since the last glaciation was proposed to have resulted in higher atmospheric CO2 in the Holocene (Broecker and Peng, 1989, doi:10.1029/GB003i003p00215). Glacial-interglacial variations in the proportion of NADW in the Southern Ocean may have also influenced atmospheric CO2 levels over the past 550,000 years. The greatest relative flux of NADW to the Southern Ocean occurred during interglacial stage 11. Faunal data suggest that the North Atlantic polar front and southern Indian Ocean subtropical convergence zone were located farthest poleward during stage 11. Warmth in these locations and a strong southward flux of NADW during stage 11 may be causally linked by the NADW formation process/warm water return route (Gordon, 1986, doi:10.1029/JC091iC04p05037). Time series analysis indicates that delta13C variations in the deep Southern Ocean occur at the same frequencies as the Earth's orbital variations and are coherent and in phase with delta18O. At most, 50% of the glacial-interglacial delta13C amplitude in the Southern Ocean is due changes in the contribution of NADW. The remainder is probably due to mean ocean delta13C changes.

Description: The high-resolution delta18O and delta13C records of benthic foraminifera from a 150,000-year long core from the Caribbean Sea indicate that there was generally high delta13C during glaciations and low delta13C during interglaciations. Due to its 1800-m sill depth, the properties of deep water in the Caribbean Sea are similar to those of middepth tropical Atlantic water. During interglaciations, the water filling the deep Caribbean Sea is an admixture of low delta13C Upper Circumpolar Water (UCPW) and high delta13C Upper North Atlantic Deep Water (UNADW). By contrast, only high delta13C UNADW enters during glaciations. Deep ocean circulation changes can influence atmospheric CO2 levels (Broecker and Takahashi, 1985; Boyle, 1988 doi:10.1029/JC093iC12p15701; Keir, 1988 doi:10.1029/PA003i004p00413; Broecker and Peng, 1989 doi:10.1029/GB003i003p00215). By comparing delta13C records of benthic foraminifera from cores lying in Southern Ocean Water, the Caribbean Sea, and at several other Atlantic Ocean sites, the thermohaline state of the Atlantic Ocean (how close it was to a full glacial or full interglacial configuration) is characterized. A continuum of circulation patterns between the glacial and interglacial extremes appears to have existed in the past. Subtracting the deep Pacific (~mean ocean water) delta13C record from the Caribbean delta13C record yields a record which describes large changes in the Atlantic Ocean thermohaline circulation. The delta13C difference varies as the vertical nutrient distribution changes. This new proxy record bears a striking resemblance to the 150,000-year-long atmospheric CO2 record (Barnola et al., 1987 doi:10.1038/329408a0). This favorable comparison between the new proxy record and the atmospheric CO2 record is consistent with Boyle's (1988a) model that vertical nutrient redistribution has driven large atmospheric CO2 changes in the past. Changes in the relative contribution of NADW and Pacific outflow water to the Southern Ocean are also consistent with Broecker and Peng's (1989) recent model for atmospheric CO2 changes.

Description: In vielen naturwissenschaftlich-technischen Disziplinen zeigt es sich immer wieder, daß es sehr lohnend sein kann, eine schon als abgeschlossen betrachtete Fragestellung mit neuen methodischen Ansätzen wieder aufzunehmen. So bemerkt man in den technischen Anwendungen eine regelrechte Renaissance der Variationsrechnung, da die damit durchgeführten Computersimulationen helfen, einen Teil der Entwicklungskosten für z.B. Automodelle im Maßstab 1:1 einzusparen. Die topographischen Reduktionsrechnungen, welche als geradezu klassisches Gebiet der Gravimetrie gelten, werden in dieser Arbeit analog dem oben angeführten Gesichtspunkt erneut diskutiert. Dabei werden in den einleitenden Betrachtungen diejenigen Verfahren in einem sehr kurzen historischen Abriß vorgestellt, die sich durch ihre Anwendungsbreite und ausreichende Genauigkeit auszeichnen. Der entscheidende Gesichtspunkt für die erneute Entwicklung von Reduktionsverfahren sind die gerade jetzt im Entstehen begriffenen Höhendatenbanken. Die dort in geeigneter Weise abgespeicherten Daten ersparen dem Gravimetriker in Zukunft die enorm zeitaufwendige Kartendigitalisierung. Ausführlich werden in der Arbeit die beiden neuesten Rechenschemata das • Sideris-Verfahren , das die schnelle Fourier-Transformation (FFT) benutzt, und • eine Methode, die auf der Basis einer Polyeder-Approximation des Geländes arbeitet, erläutert und an synthetischen Beispielen getestet. Eine kritische Gewichtung der Arbeitsresultate hinsichtlich der Verwendung dieser Verfahren und ihrer Weiterentwicklung ergibt folgendes Bild: • Die Verwendung der FFT nach Sider is liefert zwar ein überragend schnelles Verfahren, ist aber durch seine physikalische Äquivalenz zur Massenlinienmethode für die angewandte Gravimetrie zu ungenau. • Die Polyeder -Methode ist von einer exakten Darstellung des Geländes (zumindest in unmittelbarer Stationsumgebung) abhängig und erleidet bei der Anwendung auf Datensätze mit mittleren Höhen einen Genauigkeitsverlust. Die zukünftig verfügbaren Datenbanken, die so oder ähnlich wie das mit TIN bezeichnete Abspeicherungsschema auf gebaut sind, werden für die Polyeder -Methode in idealer Weise verwendbar sein. Denn diese Höhendatenbanken verwenden nicht nur exakte Punkthöhen zur Geländebeschreibung, auch die sehr rechen zeitaufwendige Dreiecksbildung würde damit entfallen. Bis zur Verfügbarkeit solcher Datenbanken kann man aber mit dem in der Arbeit als "kombiniertes System" vorgestellten Kompromiß arbeiten: Die Schnelligkeit der FFT-Methode wird für den Stationsfernbereich ausgenutzt und die Genauigkeit der Polyeder -Methode in der Stationsnähe. Mit diesem Verfahren lassen sich Fehler von weniger als einem Milligal mit durchaus vertretbarem Aufwand erzielen. In den Anwendungen der entwickelten Methoden auf reale Gegebenheiten werden im Falle des Westharzes die oben genannten Eigenschaften bestätigt. Dabei kann man als Ergebnis der Simulation eines TIN -Höhenmodells davon ausgehen, daß die Polyeder -Methode ohne Kompromisse auch auf sehr große Datensätze anwendbar ist, wenn die Dreiecksbildung entfällt. Das Beispiel aus Zimbabwe zeigt, daß man sich mit modernen digitalen Methoden solch ein TIN-Höhenmodell selbst erstellen kann (Digitalisiertablett und angeschlossener PC). Die dann im weiteren diskutierten, modellgebundenen Anwendungen der topographischen Massenreduktionen wurden in erster Linie durch die einfache morphologische Situation des Gebietes provoziert.

Description: In most natural sciences and technology it is sometimes profitable to tackle an old problem which seems to be solved once more with new powerful tools. In finite element computer simulations one can find optimization methods which are based on a very old mathematical discipline called variational calculus. These methods can be used in the automobile industry for instance, for reducing the costs in motor car development. Analogously, in this work, the classical subject of topographic reduction calculations has been tackled with modern algorithmic techniques. Firstly a brief historical overview gives insight into topographical algorithms which are precise enough in calculating and flexible to use. Some remarks about data bases of topographic heights serve as an introduction into geographical information systems. Such systems may be of great help in future topographical work, as they eliminate the time consuming digitalization of topographic maps by hand. The topographical reduction method of Sideris using the fast fourier transform algorithm and a new developed reduction scheme based on an exact polyhedron algorithm and a triangulization of the topography are discussed in detail and tested. The calculations of synthetic topographic models gave varied results: • The method of Sideris works with an enormous speed but as it is physically equivalent to the massline method it is not precise enough for applied gravimetry. • The algorithm using polyhedral bodies needs exact topographical point heights especially in the near surroundings of the gravimetrical station. In future there will be a data base of topographical heights stored in a triangular fashion (triangulated irregular network) called a TIN data base. With TIN the topographical reduction method using the polyhedron formula will be fast enough to handle even big topographical models. As such data bases are not available at present one can use a method developed in this work which combines the positive attributes of both algorithms: The heights far away from the station are calculated with FFT while those in the immediate surroundings with the algorithm using the polyhedron formula. This combined system gives results which are better than 1 mGal and take a considerable short CPU-time. All algorithms are tested with real topographical models of the Harz mountains of West Germany and the Zambezi escarpment of Zimbabwe.

Description: thesis

Description: DFG, SUB Göttingen

Description: In der vorliegenden Arbeit wird das Schwerefeld in den südlichen zentralen Anden in Hinblick auf die Vorgänge an einem aktiven, konvergenten Plattenrand untersucht. Es können wesentliche Randbedingungen für die Strukturen und den Stoffbestand der Lithosphäre abgeleitet werden. Die Grundlage dieser Interpretationen bildet die Bearbeitung der gravimetrischen Meßdaten in drei Schritten: • Erstellung einer homogenen, regionalen Datenbasis unter besonderer Berücksichtigung der Vernetzung der Schweredaten und der topographischen Reduktion • Numerische Analyse des Schwerefeldes mit Hilfe von Filterungen, isostatischen Berechnungen und Massenabschätzungen • Durchführung 2-dimensionaler und 3-dimensionaler Modellrechnungen Die wesentlichen Ergebnisse der Bearbeitung des Schwerefeldes der andinen Subduktionszone sind in der Reihenfolge von den tieferen zu den höheren Stockwerken: • Die subduzierte Nazca Platte hat einen maximalen gravimetrischen Effekt von 55 mGal. • Thermische isostatische Prozesse nach Froidevaux ir Isacks (1984) haben einen minimalen Einfluß auf das Schwerefeld. • Die Berechnung regionaler isostatischer Modelle nach Banks et al. (1977) ergibt eine Biegesteifigkeit der Kruste von 1 ∙ 1023 Nm im W-E Segment zwischen 20° S und 22° S und 5 ∙ 1022 Nm im Segment zwischen 22° S und 26° S. • Die Kruste - Mantel - Grenze zeigt entlang der Hochkordillere einen strukturierten Verlauf mit einer maximalen Tiefe von 63 km bei 67.5° W, 23° S. • In dem Gebiet zwischen 23.5° S bis 24.5° S und 68.5° W bis 69.5° W wird im Bereich der Moho eine anomale Geschwindigkeit - Dichte Beziehung registriert. • Die kombinierte Interpretation seismologischer, refraktionsseismischer, gravimetrischer und petrophysikalischer Untersuchungen deutet auf eine Mächtigkeit der kontinentalen Kruste im küstennahen Bereich von 30 - 33 km und einer zunächst mit einem sehr geringen Abtauchwinkel subduzierten ozeanischen Lithosphärenplatte hin. • Die kontinentale Unterkruste zeigt im Untersuchungsgebiet eine geringe Änderung in der Streichrichtung der Anden. • Die Ostgrenze der aus refraktionsseismischen Messungen abgeleiteten, stark aufgegliederten Unterkruste mit sehr geringen Durchschnittsgeschwindigkeiten kann mit Hilfe des Schwerefeldes kartiert werden. Ihre Übereinstimmung mit der Ostgrenze des neogenen bis holozänen Vulkanismus deutet auf einen direkten Zusammenhang zwischen dieser Unterkrustenstruktur und dem rezenten Magmatismus hin. • Die gravimetrisch geforderte Mittelkruste mit Dichten um 2.9 g/cm3 unter der Hochkordillere könnte zum überwiegenden Teil aus Gesteinen einer präandinen Unterkruste bestehen. • Die gravimetrische Modellierung der Schichten mit schon oberflächennah sehr hohen Geschwindigkeiten im Bereich Küstenkordillere und Längstal in Kombination mit Massenabschätzungen zeigt, daß nur der obere maximal 5 km mächtige Teil der modellierten Körper für die Anomalien im Residualfeld verantwortlich ist. Die tieferliegenden Massen erzeugen zusammen mit der Unterkrustenstruktur im wesentlichen den regionalen Trend im Schwerefeld. • Die bedeutendste Struktur im residualen Schwerefeld, das langgestreckte Maximum südöstlich von Calama, ist vermutlich ein relativ einheitlicher, paläozoischer Gesteinskomplex in 10 bis 20 km Tiefe. • Modellrechnungen und Massenabschätzungen im Bereich des rezenten magmatischen Bogens lassen auch aufgrund des Schwerefeldes die Anwesenheit von kleineren, partiell geschmolzenen Magmenreservoiren in der oberen Kruste möglich erscheinen. • Im andinen Vorland ist im Schwerefeld deutlich zwischen dem SANTA BARBARA SYSTEM und dem fold and thrust belt zu unterscheiden. Auf der Basis des regionalen Schwerefeldes konnten bisher unbekannte Krustenstrukturen aufgezeigt werden. Trotz der Einschränkungen, die sich aus den mangelnden oder nicht existenten Randwerten ergeben, konnte ein plausibles Strukturmodell des Untergrundes des Andenorogens erstellt werden.

Description: The present work deals with the gravity field in the Southern Central Andes in regard to the processes at an active convergent margin. Substantial boundary conditions can be deduced for the structure and the material parameters of the lithosphere. This interpretation is based on the processing of the gravity data in three steps: • Preparation of a homogeneous, regional data base considering especially the connection of the different gravity networks and the topographic reduction. • Numeric analysis of the gravity field with the aid of filtering procedures, isostatic calculations and excess mass estimations. • Realization of 2-dimensional and 3-dimensional model calculations. The main results of the analysis of the gravity field at the Andean subduction zone considered from the lower to the higher levels are: • The subducted Nazca slab has a gravity effect not exceeding 55 mGal. • Processes of the thermal compensation model by Froidevaux fc Isacks (1984) have an insignificant effect on the gravity field. • The calculation of regional isostatic models according to Banks et al. (1977) results in a crustal flexural rigidity of 1 • 10 23 Nm in the W - E segment between 20° S and 22° S, and 5 • 10 22 Nm between 22° S and 26° S. • The crust - mantle boundary shows undulations along the High - Cordillera with a maximum depth of 63 km at 67.5° W, 23° S. • In the region between 23.5° S - 24.5° S and 68.5° W - 69.5° W a level with a anomalous velocity - density relationship exists near the M – discontinuity. • The combined interpretation of seismological, refraction seismic, gravimetric and petrophysical investigations points to a thickness of the continental crust near the coast of 30 - 33 km. There the dip of the subducted plate seems to have a very low angle. • In the area under investigation the lower continental crust shows only little variations in the general strike direction of the Andean orogen. • According to the seismic investigations the lower Andean crust is highly structured and has a small mean velocity. The easternmost limit of this lower crust can be mapped with the aid of the gravity field. Its agreement with the limit of the neogene to holocene volcanism points to a direct relation between this structured lower crust and the recent, magmatism. • The postulated crustal layer with densities about 2.9 g/cm 3 beneath the High - Cordillera, which is necessary for the gravity fitting, may consist mainly of rocks of a preandean lower crust. • The 3D - modelling of the layers with high velocities near the surface under the Coast Range and the Longitudinal Valley in combination with mass estimations shows, that only the uppermost 5 km of the modelled structure are relevant for the anomalies seen in residual gravity fields. The deeper masses produce, in combination with the structure of the lower crust, mainly the regional trend of the gravity field. • The most important feature in the residual gravity fields, the pronounced regional maximum southeast of Calama, is presumably a relatively homogeneous, paleozoic rock complex in the depth range of 10 to 20 km. • The results of modelling and mass calculations in the area of the recent magmatic arc could possibly account for smaller, partly molten magma reservoires in the upper crust. • The gravity field distinguishes well between the Santa Barbara System and the Bolivian fold and thrust belt along the Andean Foreland. Based on the regional gravity field new structures in the lithosphere were detected. Besides the restriction of the limited boundary constraints it was possible to establish a plausible structural model of the Andean orogen.

Description: thesis

Description: DFG, SUB Göttingen

Description: Es wurden moderne Methoden auf ihre Eignung zur Bestimmung von Fischlarven untersucht. Als Vorbereitung auf die Bestimmung wurden Formen und proportionales Wachstum von Fischlarven der Nordsee und angrenzender Gebiete untersucht. Dazu wurden an 831 Fischlarven aus 33 Arten und 18 Familien die folgenden Messungen durchgeführt: Standardlänge, Präanallänge, Präorbitallänge, Präpektorallänge, Augendurchmesser, Orbitalhöhe, Pektoralhöhe, Analhöhe, Pektoralbreite und Analbreite. Aus den Messungen wurde das Volumen der Larven errechnet. Die Formen von Larven mit einem Volumen zwischen 3 und 5 μl wurden verglichen. Es ergaben sich vier deutlich getrennte Formgruppen: "eel-like", "fusiform", "deep + compressed" und "tadpole-like". Bis auf die Gruppe "fusiform" zeigten alle Gruppen allometrisches Wachstum bei bestimmten Körperproportionen. Die mögliche ökologische Bedeutung dieser Gruppen wird diskutiert. Es wurden drei computergestützte Bestimmungssysteme entwickelt und getestet: Ein numerisches System, ein Expertensystem und eine moderne Datenbank. Als Beispiel einer Methode der numerischen Taxonomie wurde die Quadratische Diskriminanzanalyse untersucht. Dazu wurden aus den durchgeführten Messungen die Diskriminanzfunktionen errechnet und unbekannte Larven zunächst einer Formgruppe und dann einer Art innerhalb der Formgruppe zugeordnet. Die richtige Zuordnung bei dieser Methode betrug 82 % . Die numerische Taxonomie scheint damit zur Bestimmung von Fischlarven grundsätzlich geeignet zu sein. Allerdings ist zweifelhaft, ob genügend Fischlarven (30 - 100 pro Art) zum Aufbau des Systems erhältlich sind. Aufbauend auf dem HALBEISEN-Schlüssel zur Bestimmung von Fischlarven der Nordsee und angrenzender Gebiete wurde das Expertensystem IDEXSYS entwickelt. Es kann als moderne Form traditioneller Bestimmungsschlüssel betrachtet werden. Expertensysteme erweisen sich damit als gut geeignet zur Bestimmung von Fischlarven. Mit einem modernen Datenbankprogramm wurde ein Such- und Eingabeformular mit etwa 80 Merkmalen entwickelt. Alle in der Nordsee und den angrenzenden Gebieten vorkommenden 126 Fischlarvenarten wurden auf diese Merkmale überprüft und in die Datenbank eingegeben. Der Test des Systems ergab, daß durchschnittlich nur drei Merkmale zur Bestimmung einer Fischlarve erforderlich waren. Bei einem Vergleich der Methoden wird für die Bestimmung von Fischlarven dem Datenbanksystem der Vorzug gegeben.

Description: Major-element compositions (Cl-, SO4[2-], Ca2+, Mg2+ , Li+ , K+, Na+ , Sr2+) of interstitial waters obtained from sediment cores along the ODP Leg 110 transect across the Northern Barbados accretionary prism have shown that a complex set of geochemical processes are of importance in this area. In the volcanic ash-rich Pleistocene-Pliocene sediments, alteration reactions involving volcanic ash lead to depletions of Mg2+ and K+. This process is confirmed by the much lower than contemporaneous seawater values of the 87Sr/86Sr ratios of dissolved strontium. In the deeper sediments recovered below the zone of decollement (Sites 671 and 672) large increases in Ca2+ and gradual decreases in Mg2+ , Na+, and d18O (H2O) indicate a potential contribution to the interstitial water chemistry by exchange with underlying basement rocks. This process has been hard to confirm because the drill holes were terminated well short of reaching basement. However, the concentration gradient pattern is consistent with observations in a large number of DSDP drill holes. Finally, but most importantly, low Cl- concentrations in the decollement zone and underlying sand layers, as well as in fault zones at Sites 673 and 674, indicate dilution of interstitial waters. The potential origins of the low Cl- concentrations are discussed, though we are not able to distinguish any mechanism in particular. Our evidence supports the concept of water migration along the decollement and through the underlying sandstones as well as along recent fault zones in the accretionary complex. Interstitial water concentration depth profiles are affected by faulting, thrusting, and overturn processes in the accretionary prism. These processes have caused a diminished diffusive exchange with the overlying ocean, thus explaining increased depletions in Mg2+ and SO4[2-] in sites farther onto the accretionary prism.

Description: Die anthropogene Entwicklung vom Torf zum Moorboden führt in den eutrophen Niedermooren nach Entwässerung und Nutzung sehr schnell zu Degradationsstadien mit zunehmend unbefriedigender Wasser- und Nährstoffdynamik sowie unsicheren Erträgen. An die Erfolge der Rekultivierung gealterter Hochmoore mittels Besandung und Tiefumbruch anknüpfend, werden in zunehmendem Maße auch flachgründige Niedermoore analog melioriert trotz der ungünstigen Erfahrungen mit den alten RIMPAUschen Moordammkulturen. Durch neue Auflagen im Rahmen von Boden- und Gewässerschutz erhalten derartige bodentechnologische Maßnahmen aktuelle Bezüge. Durch torfkonservierende Tiefpflugsanddeckkulturen oder maschinelle Besandungen werden der weitere Torfschwund und die damit verbundene Nitratfreisetzung minimiert. Ein gemeinsames Forschungsprogramm im Rahmen der deutsch-deutschen Vereinbarung zur wissenschaftlich-technischen Zusammenarbeit mit der Akademie der Landwirtschaftswissenschaften, Forschungszentrum Bodenfruchtbarkeit, Müncheberg/Mark, DDR, wird dargestellt.

Description: After drainage and agricultural use of fens the anthropogeneous development of peat to humus soil leads very fast to degradation states with increasing unsatisfactory dynamics of water and nutrients. From the successful results gathered from recultivating older raised bogs with sand-covering and deep-ploughing, shallow fens are also increasingly improved in analogue fashion despite the unfavourable experiences made by the old fen-soil sand-cover cultivation according to von RIMPAU. Up to date such soil technological measures are becoming new restrictions in soil and water protection. Further peat losses and subsequent release of nitrate are minimized by means of fen peat-conservation deep-plough recultivation and mechanical sand-covering. A research programme since 1988 in co-operation with the Academy of Agricultural Sciences, Research Centre for Soil Fertility, Müncheberg/Mark, GDR, which run under a joint agreement of the two German States to collaborate on science and technology is presented here.

Description: research

Description: DFG, SUB Göttingen

Description: Am 10.04.1970, also vor nunmehr 20 Jahren, waren 38 Moor- und Torfexperten‚einer Einladung von Prof. LÜTTIG folgend,zur Gründungsversammlung der DGMT im Niedersächsischen Landesamt für Bodenforschung in Hannover zusammengekommen. Seit dieser Zeit hat Prof. LÜTTIG dieser wissenschaftlich-technischen Vereinigung bis zur letzten Mitgliederversammlung 1989 in Neuburg/Donau als ihr 1.Vorsitzender gedient. Einem inzwischen auch älteren DGMT-Gefährten seit dieser Zeit ist es deshalb mehr als eine Pflicht, diese Daten zum Anlaß zu nehmen, um im Namen aller inzwischen 284 DGMT-Mitglieder Herrn Kollegen LÜTTIG mehr als den üblichen Dank für diesen engagierten Einsatz im Organ unserer Gesellschaft auszudrücken und damit für eine Chronik festzuhalten. [...]

Description: editorial

Description: DFG, SUB Göttingen

Description: Physical and sedimentological investigations were carried out on a 14 m long gravity core and a 0.5 m long box core from 4440 m water depth off Queen Maud Land, East-Antarctica. Strongly bioturbated hemipelagic muds of predominantly terrigenous origin and a very small biogenic part build up the 'Normal-Facies'. Several sandy to silty layers are inserted in the 'Normal-Facies'. These layers are seperated by lithology, structure and the investigated parameters of this study and are interpreted as turbidites. The source area for the turbidity currents is supposed to be at the uppermost continental margin, close to the shelf break and there is evidenee for this gravity transport within the erosive Ritscher-Canyon, which extends close to the core position. The distribution of biogenic components indicates an age of 1.3 million years or more, with an average sedimentation rate of about 1 cm/1000 years. Early diagenetic proeesses caused water loss by compaction, errosion and dissolution of biogenic components and precipitation and recrystallization of manganese micronodules. Cyclic fluctuations of the sediment-parameters within the 'Normal-Facies' enable the distinction of a 'Glazial'- and an 'Interglazial'-Facies. The 'Glazial'-Facies reflects glacial sedimentary conditions and shows a dark olive gray colour, high susceptibility, low silt/clay-ratios, only a few biogenic components and the regular occurence of interrelated turbidite layers. In contrast, the 'Interglazial'-Facies is dominated by a light olive or olive-brown colour, low susceptibility, high silt/clay-ratios and an increased number of biogenic components. This facies corresponds to interglacial conditions. Three main processes are supposed to have been responsible for the observed facies changes: (1) the bottom water mass circulation, (2) the gravity transport by turbidity currents and (3) the biogenic surface production. These processes are related to the quaternary climatic changes. The extension of the ice shelves directed the gravity transport to the deep sea and the formation of Antarctic Bottom Water, which in turn influenced the silt/clay-ratios in the sediment record. Fluctuations in sea ice coverage controlled the biogenic surface production.

Description: Gel electrophoretic techniques were used to analyse patterns of variation at 12 genetic loci within and among species of the Ectoedemia subbimaculella group from western Europe. Geographically separated conspecific populations were similar to one another genetically, with the exception of E. subbimaculella where the malate dehydrogenase locus exhibited clinal variation. Genetic differences among species often concerned loci that were monomorphic or slightly polymorphic within populations. Three of the species could not be diagnosed by their allozyme content; allele distribution patterns at some loci suggest that speciation took place recently and did not involve a genetic bottleneck. Phylogenetic trees constructed from allozyme data paralleled closely the phylogeny based on morphology.

Description: Site 716 is a continuous sequence (upper Miocene to Holocene) of periplatform oozes and chalks from the Maldives Ridge, Indian Ocean. Mineralogical and geochemical studies of these carbonate sediments indicate that submarine burial diagenesis has played an important role in the induration of sediments at this site. Metastable carbonates, high-magnesium calcite (HMC) and aragonite, convert to low-magnesium calcite (LMC) rapidly, within 1.1 and 6.0 Ma, respectively. Strontium concentrations in carbonate decrease with depth as the result of the burial diagenesis of calcium car- bonate, primarily aragonite, with excess strontium being expelled into pore waters. The formation of celestite at depth indicates that sufficient diagenesis of carbonate sediments has occurred to saturate or supersaturate pore waters with re- spect to this authigenic mineral. Sodium also decreases monotonically with depth as a result of the burial diagenesis of calcium carbonate. Magnesium and carbon and oxygen isotopic curves are remarkably similar. Carbon isotopic compositions record inputs of 13C-enriched components from shallow carbonate banks. Magnesium concentrations vary widely, recording enhanced episodes of cementation by LMC with slightly elevated magnesium contents. Positive shifts in oxygen isotopic composition also record episodes of cementation during burial diagenesis. Intervals with increased accumulation rates of metastable components have undergone more rapid diagenesis than intervals with predominately pelagic deposition.

Description: This report presents the results of a study of the stable isotopic and chemical composition of secondary carbonate minerals precipitated within basalts at Ocean Drilling Program Sites 707 and 715. At Site 715, the secondary carbonates are all composed of calcite and display a narrow range of carbon and oxygen stable isotope ratios, with values ranging from -2.75 per mil to 1.95 per mil PDB and -0.27 per mil to 2.86 per mil PDB, respectively. Strontium, iron, and manganese values of the samples are generally low. The geochemistry of Site 715 samples indicates that they precipitated from seawater-domi- nated fluids, at low temperatures, as is typical of secondary carbonates from most Deep Sea Drilling Project sites. In contrast, at Site 707, aragonite, siderite, and manganese-rich calcite occur as secondary carbonates in addition to calcite. The carbon isotopes of the Site 707 carbonates of all rock types are depleted in 13C. Values range from -2.79 per mil to -16.43 per mil PDB. Oxygen isotope values do not show a wide variation, ranging from -1.78 per mil to 1.17 per mil. The strontium contents of the samples range from 5200 to 8100 ppm for aragonites, and from 145 to 862 ppm for calcites. Iron and manganese contents are high in calcites and siderites and low in aragonites. Site 707 carbonates precipitated at low temperatures in a fairly closed system, in which basalt-seawater interaction has greatly influenced the chemistry of the pore fluids. The reactions occurring within the system before and in conjunction with secondary carbonate precipita- tion include oxidation of isotopically light methane, derived from fluids circulating within the basalts, and reduction of substantial amounts of iron and manganese oxides from the basalts.

Description: Stable isotopic and minor element compositions were measured on the fine fraction of pelagic carbonate sediments from Ocean Drilling Program Site 709 in the central Indian Ocean. This section ranges in age from 47 Ma to the present. The observed compositional variations are the result of either paleoceanographic changes (past oceanic chemical or temperature variations) or diagenetic changes. The CaCO3 record is little affected by diagenesis. From previous work, carbonate content is known to be determined by the interplay of biological productivity, water column dissolution, and dilution. The carbon isotopic record is generally similar to previously published curves. A good correlation was observed between sea-level high stands and high 13C/12C ratios. This supports Shackleton's hypothesis that as the proportion of organic carbon buried in marine sediments becomes larger, oceanic-dissolved inorganic carbon becomes isotopically heavier. This proportion appears to be higher when sea level is higher and organic carbon is buried in more extensive shallow-shelf sediments. The strontium content and oxygen isotopic composition of carbonate sediments are much more affected by burial diagenesis. Low strontium concentrations are invariably associated with high values of d18O, probably indicating zones of greater carbonate recrystallization. Nevertheless, there is an inverse correlation between strontium concentration and sea level that is thought to be a result of high-strontium aragonitic sedimentation on shallow banks and shelves during high stands. Iron and manganese concentrations and, to a lesser extent, magnesium and strontium concentrations and carbon isotopic ratios are affected by early diagenetic reactions. These reactions are best observed in a slumped interval of sediments that occurs between 13.0 and 17.5 Ma. As a result of microbial reduction of manganese and iron oxides and dissolved sulfate, it is hypothesized that small amounts of mixed-metal carbonate cements are precipitated. These have low carbon isotopic ratios and high concentrations of metals.

Description: Een nieuwe combinatie in Glyceria \xe2\x80\x94 Zoals door M. Kergu\xc3\xa9len in Buil. Soc. Bot. Fr. 125 (1978): 113\xe2\x80\x94120 is uiteengezet, moet de plant die tot dusver als Glyceria plicata Fries bekend stond, de (oudere) naam Glyceria notata Chevallier krijgen. Beschouwt men Glyceria declinata en G. notata als ondersoorten van \xc3\xa9\xc3\xa9n soort (de argumenten hiervoor zullen over enige tijd in Gorteria worden gepubliceerd), dan dient ook G. declinata een nieuwe naam te krijgen. Zij heet dan Glyceria notata Chevallier subsp. declinata (Br\xc3\xa9bisson) Weeda, comb. nov. (basionym: Glyceria declinata Br\xc3\xa9bisson, Fl. Normandie, ed. 3, 1859: 354).

Description: De internationale natuurbeschermingsorganisatie I.U.C.N. begon in de jaren zeventig met de publicatie van soortenlijsten van in hun voortbestaan bedreigde organismen, de zogenaamde \xe2\x80\x98Red Data Books\xe2\x80\x99. Voor planten dateert de meest recente lijst voor Europa uit 1983.\xc2\xb9 Naast lijsten voor in Europa bedreigde soorten werden in Belgi\xc3\xab\xc2\xb2, Groot-Brittanni\xc3\xab\xc2\xb3 en Duitsland 4 ook nationale Rode Lijsten samengesteld. De huidige publicatie is bedoeld als een voorlopige eerste Rode Lijst van in Nederland bedreigde (vaat-)planten.\nNationale Rode Lijsten ontlenen hun waarde voor toepassingen op het terrein van natuurbeheer, -beleid en -bescherming uitsluitend aan de mate van betrouwbaarheid van de achterliggende gegevens. Hun betekenis is des te groter, naarmate onder deskundigen een grotere eensgezindheid over de inhoud van de Rode Lijst bestaat. De publicatie van de thans gepresenteerde Rode Lijst heeft dan ook vooral tot doel om allen die deskundig zijn op het gebied van de Nederlandse flora in de gelegenheid te stellen de Lijst op zijn merites te beoordelen. Het is de wens van de samenstellers dat deze Lijst in discussie komt, zodat eind 1990 of begin 1991 tot het maken van een tweede versie van de Rode Lijst kan worden overgegaan.

Description: Anonymus, Cruydt-Hoeck: De dikke zadenlijst, Postbus 1414, 9701 BX Groningen, 1990, 212 pag., te bestellen door overmaking van \xc6\x92 5 op giro 4058000 t.n.v. Cruydt-Hoeck, Groningen. \xe2\x80\x94 Een zeer informatieve catalogus voor wie een fraaie tuin of plantsoen wil maken met inheemse en goed geselecteerde uitheemse planten. * Anonymus, Inventarisatie van planten in het park Westerveld en de Steenen Kamer, Gemeente Arnhem, Dienst PeBReM, Blankenweg 22, 6827 BW Arnhem, 1989, 66 pag.

Description: J. Barkman, Groeivormen van planten in Nederland, Wetenschappelijke Mededeling KNNV nr, 196, 1990, 32 pag., ISBN 90-5011-037-1, \xc6\x92 19 (voor leden \xc6\x92 15, te bestellen via gironummer 13028, Stichting Uitgeverij KNNV, Hoogwoud). \xe2\x80\x94 Barkman onderscheidt 87 architectuur-typen waarin Nederlandse planten (van algen tot bomen) zich kunnen voordoen. Speciaal bedoeld voor studie van de structuur van vegetaties.\nS. Castroviejo, M. Lanz, G. L\xc3\xb3pez Ganz\xc3\xa1lez, P. Montserrat, F. Mu\xc3\xb1os Garmendia, J. Paiva & L. Villar (ed.), Flora Iberica. Plantas vasculares de la Pen\xc3\xadsula Ib\xc3\xa9rica e Islas Baleares, Vol. 2: Platanaceae \xe2\x80\x93 Plumbaginaceae, Real Jard\xc3\xadn Bot\xc3\xa1nico, C.S.I.C., Madrid, 1990, 897 pag., ca. \xc6\x92 75, ISBN 84-00-07034-8. \xe2\x80\x94 Het tweede deel van de eerste wetenschappelijke, fraai ge\xc3\xafllustreerde flora van het Iberisch schiereiland.

Description: C. Bas, Th. W. Kuyper, M.E. Noordeloos & E.C. Vellinga (red.), Flora Agaricina Neerlandica, Critical monographs on families of agarics and boleti occurring in the Netherlands, Volume 2, Pleurotaceae by T. Boekhout, C. Bas & M.E. Noordeloos, Pluteaceae by E.C. Vellinga & T. Boekhout; (1): tribus Hygrocybeae and Tricholomataceae tribus Hygrophoreae by E.J.M. Arnolds & C. Bas, A. A. Balkema, Rotterdam/Brookfield, 1990, 137 pag., \xc6\x92 58,30 (ISBN 90-6191-972-X: gebrocheerd), \xc6\x92 79,50 (ISBN 90-6191- 971-1: gebonden). \xe2\x80\x94 Het tweede deel van de op kritisch taxonomisch onderzoek gebaseerde \xe2\x80\x98paddestoelen\xe2\x80\x99- Flora van Nederland [zie de eerdere korte bespreking in Gorteria 14 (6), 1988: 148]. * A. Corporaal, De Loire en de Kievitsbloem, Consulentschap NMF-Overijssel, Postbus 10051, 8000 GB Zwolle, 1990, ongepag. \xe2\x80\x94 Bevat beschijvingen van de groeiplaatsen van Fritillaria meleagris in het Franse rivierengebied van de Loire, uitgevoerd ten behoeve van beheer van Nederlandse vindplaatsen van deze bedreigde soort.

Description: Vom 9. Juli bis zum 16. August 1987 wurden im Rahmen der "Polarstern"-Expedition ARK IV/3 zwischen 81°30'N und 86°N entlang zweier Schnitte durch das Nansen-Becken auf zwölf Stationen Vertikalfänge (500-0 m) mit einem Mehrfachschließnetz (Maschenweite: 300 μm) durchgeführt. Die Probennahme fand in dichtem Packeis statt. Das Untersuchungsgebiet umfaßte drei hydrographische Zonen: den 1) Bereich des atlantischen Randstromes im Süden, den 2) zentralen Beckenbereich und den 3) Bereich des nördlichen Randstromes an der Südflanke des Nansen-Gakkel-Rückens. Im zentralen Nansen-Becken befand sich auf 83°N eine ausgeprägte ozeanographische Front. Alle in den fixierten Fangproben enthaltenen Metazooplankter wurden soweit als möglich bestimmt. Neben den Abundanzen wurden mit Hilfe selbst erstellter Längen-Gewichts-Beziehungen für den größten Teil der Arten Biomassebestände und -konzentrationen berechnet. Bei vier dominanten Copepodenarten wurden alle Copepoditstadien einzeln erfaßt und Weibchen auf ihre Ovarienreife hin untersucht. Für nicht zu den Copepoden gehörende dominante Arten wurde die Längenverteilung innerhalb des Untersuchungsgebietes detailliert dargestellt. Anhand der Clusteranalyse und der Multidimensionalen Skalierung wurde die räumliche Zonierung der Planktonfauna und die Ähnlichkeit von Verteilungsmustern einzelner Arten untersucht. Insgesamt konnten 47 Arten und acht nicht bis zur Art bestimmte Taxa im Probenmaterial identifiziert werden. Die Mehrzahl der Organismen war mit Großen zwischen 0,5 und 20 mm dem Mesozooplankton zuzurechnen. Mehr als die Hälfte der Arten kam auf allen Stationen vor, die höchste Artenzahl (34-38 Arten/Station) wurde im Bereich der ozeanographischen Front bei 83°N festgestellt. Im Polaren Oberflächenwasser traten deutlich weniger Arten auf als in der Atlantischen Schicht, zwischen 500 und 200 m waren bis auf eine Ausnahme alle Arten vertreten. Knapp ein Drittel aller Arten gehörte der Arktischen Fauna an. Der durchschnittliche Individuen- und Biomasse-Gesamtbestand war auf den südlichsten, schelfnahen Stationen mit ca. 34000 n/m2 bzw. 5 g/m2 mehr als fünfmal bzw. dreimal höher als im nördlich von 83°N gelegenen zentralen Teil des Nansen-Beckens. Die höchsten durchschnittlichen Individuen- und Biomassekonzentrationen traten innerhalb der obersten 25 m auf, zwischen 500 und 200 m wurden nur noch 20 bzw. 10% dieser Werte festgestellt. Der Schwerpunkt der Biomasseverteilung verlagerte sich mit steigendem Abstand zum Schelfabhang der Barentssee in geringere Wassertiefen. Zwischen 81° 30'N und 82°N lag knapp die Hälfte des gesamten Biomassebestandes unterhalb von 200 m in der Schicht des Atlantischen Wassers vor, nördlich von 85°N konzentrierten sich zwei Drittel der Biomasse oberhalb von 50 m in der Schicht des Polaren Oberflächenwassers. Copepoden dominierten im gesamten Untersuchungsgebiet, ihr durchschnittlicher Anteil an der Artenzahl lag bei knapp 50%, die Anteile am Individuen- und Biomasse-Gesamtbestand erreichten 85%. Calanus finmarchicus übertraf mit einem durchschnittlichen Anteil am Individuen- und Biomassebestand von 20% bzw. 35% alle anderen Arten deutlich. Mehr als 90% aller Individuen hielten sich südlich von 83° N auf. Die drei Calanus-Arten C. finmarchicus, C. glacialis und C. hyperboreus stellten zusammen zwei Drittel des gesamten Biomassebestandes. Im nördlichen Teil des Nansen-Beckens herrschten Metridia longa und C. hyperboreus nach der Häufigkeit und Biomasse vor. Darüber hinaus nahm dort die Bedeutung bathypelagischer Arten erheblich zu. Chaetognathen und Ostracoden stellten nach der Häufigkeit und Biomasse die wichtigsten Tiergruppen auBerhalb der Copepoden dar. Bei vielen Arten zeigte sich mit steigender Entfernung vom Schelfabhang der Barentssee eine Abnahme des Anteiles an Jungtieren. C.finmarchicus kann sich im zentralen und nördlichen Nansen-Becken wahrscheinlich nicht erfolgreich fortpflanzen, junge Copepodite und reife Weibchen fehlten dort nahezu vollständig. Auch für die Ostracodenart Conchoecia elegans und die Chaetognathenart Sagitta elegans stellt das zentrale Nansen-Becken vermutlich nur noch ein steriles Zerstreuungsgebiet dar. Die Ergebnisse der Gemeinschaftsanalyse wiesen insgesamt auf eine graduelle Wandlung der Planktonfauna von Süden nach Norden hin, lediglich im Bereich der ozeanographischen Front bei 83° N machten sich deutlichere Veränderungen bemerkbar. Die Gemeinschaft des südlichen Nansen-Beckens stand unter dem Einfluß des Atlantischen Randstromes und glich in der Zusammensetzung dem Zooplankton der weiter östlich gelegenen Gebiete des eurasischen Kontinentalabhanges. Nördlich der Front prägte vorallem der Transpolare Driftstrom den Charakter der Gemeinschaft, die bereits eine nahe Verwandtschaft zur Planktonfauna des zentralen Nordpolarmeeres und des Ostgrönlandstromes erkennen ließ. Der Anteil subarktisch-borealer Arten am Individuen- und Biomassebestand war deutlich vermindert, omnivore Arten stellten mehr als die Hälfte aller Individuen. Zwischen 82 und 83° N überschnitten sich die Gemeinschaften des südlichen und nördlichen Nansen-Beckens. Die südliche Gemeinschaft erstreckte sich im Oberflächenwasser bis in den Frontenbereich, die nördliche Gemeinschaft war in größeren Tiefen auch südlich der Front nachweisbar. Anhand der horizontalen und vertikalen Verteilungsmuster der einzelnen Arten lieBen sich mit Hilfe der Clusteranalyse drei Hauptgruppen unterscheiden: 1) Arten mit einem im Süden gelegenen und flachen Verteilungsschwerpunkt, 2) Arten mit einem im Süden gelegenen und tiefen Verteilungsschwerpunkt sowie 3) Arten mit einem im Norden gelegenen und tiefen Verteilungsschwerpunkt. Subarktisch-boreale Arten gehörten vorwiegend den Gruppen 1 und 2 an, weitverbreitete und kosmopolitische Arten der Gruppe 3. Die arktischen Arten ließen sich dagegen keinem bestimmten Verteilungsmuster zuordnen. In der Diskussion wird die Verteilung arktischer, subarktisch-borealer und weitverbreiteter Arten wahrend ARK IV /3 mit Angaben zur Biologie und Verbreitung dieser Arten in anderen Teilen des Arktischen Ozeans und angrenzenden Meeresgebieten verglichen. Viele Arten, die sich im zentralen Nordpolarmeer bevorzugt innerhalb des Polaren Oberflächenwassers aufhalten, kamen im südlichen Nansen-Becken in größeren Tiefen vor und wiesen damit deutlich auf eine Beziehung zum Einstrom des Atlantischen Wassers hin. Ungewöhnlich hoch für die normalerweise von herbivoren Arten dominierten polaren Meeresgebiete war der Anteil omnivorer Arten am Individuenbestand. Die Individuen- und Biomassebestände des Mesozooplanktons im südlichen Nansen-Becken waren in der Größenordnung mit denen der östlichen FramstraBe vergleichbar. Die im zentralen und nördlichen Nansen-Becken festgestellten Biomassewerte lagen höher als die meisten der bisher bekannten Angaben für das Eurasische und Kanadische Becken. Eine auf den Flußraten des Ostgrönland- und Westspitzbergen-Stromes basierende Bilanzierung des Zooplanktonaustausches ergab, daß jährlich ca. 0,1-0,2 Millionen Tonnen Trockengewichtsbiomasse aus der Framstraße in das Nordpolarmeer (Netto-Import) transportiert werden, der Anteil dieses Eintrages am Gesamtbestand des Metazooplanktons im Nordpolarmeer liegt in der Größenordnung von 5-10%.

Description: Stable isotope measurements on the planktonic foraminifer Globigerinoides ruber (white) have been carried out on a number of selected deep-seas sediment cores from the South Lau and Norlh Fiji Basins. The d18O-curves show good correlation with the inter-ocean oraphic correlation composite d18O-record of the standard reference section (Prell et al. 1986), which, in combination with the chronostratigraphic classifications of Herterich & Sarnthein (1984, modified) and Imbrie et al. 1984), allows a detailed dating of the sedimentary sequences. The deepest layers in core no. 119 (southern Lau Basin) could be assigned to Isotope Stage 24. Measurements made on bulk carbonate in two cores show a much higher glacial-interglacial amplitude, allowing the general identification of the conventional oxygen isotope stages. The d13C-values of the benthic foraminifer Cibicidoides wuellerstorfi show progressively lighter values northwards reflecting an increasing contribution of the isotopically lighter CO2 from the remineralisation of organic matter during the general northward movement of the deep water masses. Cyclicities in the sedimentation rates were observed in core nos. 117 and 119 (both southern Lau Basin) where the interglacials exhibit higher levels than the glacials. Calculated new or export paleoproductivity show that the glacials had higher productivity in the euphotic zone. From the oxygen isotope stratigraphy, the five ash layers in core nos. 117 and 119 could be dated as about 530 ka B.P. in Stage 14, 695 ka B.P. in Stage 18, 775 ka B.P. in Stage 21, 790 ka B.P. and 825 ka B.P. in Stage 22. Carbonate dissolution occurred during stages 5, 8 and 10 to 12.

Description: The first experiment of the ECOMARGE programme (ECOsystèmes de MARGE continentale) was initiated in 1983-1984, in the Gulf of Lions (northwestern Mediterranean Sea). The objectives of the ECOMARGE-I experiment were: to quantify the transfer of particulate matter, in general, and of organic carbon, in particular, from its introduction to and formation in the waters of the continental shelf-to its consumption or sedimentation on the shelf or its transfer to the slope and deep sea; and to understand the processes involved in that transfer, consumption and sedimentation together with their variability in space and time. The results of that experiment, from 1983 to 1988, are presented in this Special Issue. The highlights of the results are summarised in this paper. These results indicate that, of the particles formed in the waters of the continental shelf and those introduced by rivers, some are deposited as sediments on the shelf. A portion is transported offshore, however, to the slope and deep sea. The Rho^ne River, in the northeastern part of the study area, is the major source of continental material; this is transported to sea in a benthic nepheloid layer and, mostly, alongshore to the southwest. Here, it largely leaves the shelf through the canyons, especially the Lacaze-Duthiers Canyon. In the offshore waters, particle concentrations and distributions show surficial, intermediate and benthic nepheloid layers. These turbid structures increase towards the southwest, corresponding to the seaward shift of the front between the coastal waters and the Liguro-Provençal cyclonic gyre, a major forcing function in the Gulf of Lions. Considering the source and fate of particles (largely biogenic from the euphotic zone and abiogenic from deeper waters) a layered system is described, which is emphasized by the concentrations of natural and artificial elements and compounds. Of the flux of particles to the Lacaze-Duthiers Canyon, on a decadal scale, about 30% (as a minimum) is estimated to be stored as sediment; the remainder is transported down-canyon, towards the deep sea. The temporal variability of processes affecting this net seaward transport, of both biogenic and abiogenic material, is from hours, days to seasonal, and probably interannual, time scales. The response of the system to these variations is rapid, with pulses of increased discharge of particles from the adjacent shelf being detected in sediment traps in the Lacaze-Duthiers Canyon in less than 16 days (the temporal resolution of the traps). Based upon the study of tracers of particulate matter and environmental factors (i.e. river discharge and climatic conditions), it appears that the contribution from the Rho^ne River and its adjacent area is maximal during the winter; at this time, the flow of the Liguro-Provençal Current also increases. In contrast, the maximum relative contribution of the adjacent southwesterly area to the flux in the Lacaze-Duthiers Canyon occurs in summer, during storm events.

Description: The terrains in the South China Sea were apart of the Southeast China continent, and their rift-departing process dominated the formation and evolution of the South China Sea. The survey results of topography and paleoenvironment of the northern South China Sea during SO-49 cruise demonstrate that the terrains rift-departed from the South China continent before early Eocene.

Description: A series of novel long-chain 3,4-dialkylthiophenes (C36–C54) was identified in a number of sediments ranging from Pleistocene to Cretaceous. The identifications were based on mass spectral characterisation, desulphurisation and mass spectral data of synthesised model compounds. These organic sulphur compounds are probably formed by sulphur incorporation into mid-chain dimethylalkadienes with two methylenic double bonds. These putative precursor lipids are unprecedented and may be considered rather unusual. The distribution of 3,4-dialkylthiophenes in sediments varies considerably with the depositional palaeoenvironment, indicating that these compounds have a potential as molecular markers reflecting changes in palaeoenvironment.

Description: Unter Einsatz eines Vielkammer-Dialysebrettes wurde im Friihjahr 1990 ein Porenwasserprofil eines ungestörten Elbwatt-Sediments gewonnen. Die Porenwässer wurden mit Hilfe von polarographischen, voltammetrischen und einigen weiteren chemischen Methoden bezüglich der Mobilität und Bindungsformen von Spurenmetallen untersucht. Die Durchführung thermodynamischer Gleichgewichtsrechnungen ermöglichte eine Abschätzung von Mineralisations- und Lösungsprozessen im Sedimentkörper. Aufgrund der Beobachtung von Fällungsprodukten am Dialysebrett und infolge der durchgeführten Messungen konnte eine Horizont-Differenzierung des Sedimentkörpers in oxisches Milieu, wechselnd oxisch / postoxisches Milieu und permanent postoxisches Milieu vorgenommen werden. Diese Milieu-Einteilung wurde durch die thermodynamischen Gleichgewichtsrechnungen bestätigt. Besonderes Augenmerk wurde auf die Bindungsformen und Mineralisationsprozesse im postoxischen Sedimentmilieu gerichtet. Das oxische Milieu beschränkt sich in den Sedimenten des Heuckenlocks auf den oberen cm. Indikatoren hierfür waren eine stark vermehrte Freisetzung der Spurenmetalle Cadmium, Kupfer und auch Blei aus der mineralisierten organischen Substanz sowie das Fehlen von Fe(II) im Porenwasser und die Ausbildung besonders kräftiger Oxidhydratkrusten am Dialysebrett. Die Spurenmetall-Konzentrationen werden in der oxischen Zone also durch die Freisetzung aus der organischen Substanz und die Adsorption an den frisch gebildeten Oxidhydraten kontrolliert. Das periodisch oxisch / postoxische Milieu ist während der sauerstoffbeeinflußten Phasen von starker Oxidhydratbildung gekennzeichnet. Diese werden unter anaeroben Bedingungen nicht vollständig wieder gelöst. Die Spurenmetall-Konzentrationen liegen unter denen der oxischen Zone. Die Kontrolle der Konzentration erfolgt über die Adsorption der Metalle (Cd, Cu) an den Oxidhydraten und die Bildung inerter Komplexe. Ebenso kann die Fällung von Metallsulfiden eine Rolle spielen. Die Sulfidgehalte liegen jedoch unter der Bestimmungsgrenze von ca. 100 nM und konnten trotz des Einsatzes sehr empfindlicher polarographischer Meßmethoden nicht detektiert werden. Die wechselnd oxisch / postoxische Schicht (und auch die oxische Schicht) sind an Fe-Sulfid und Eisenphosphat deutlich untersättigt. Gleiches gilt für Mangansulfid und -phosphat. Dies beruht auf der Oxidation des Sulfids und der Adsorption des Phosphat-Anions an den Oxidhydraten. Im permanent postoxischen Milieu zeigen die thermodynamischen Gleichgewichtsrechnungen, daß die Konzentrationen der Spurenmetalle über die Bildung von Metallsulfiden kontrolliert werden. Schon bei Sulfidkonzentrationen von 100 nM kommt es zur massiven Bildung von sulfidischen Mineralen. Die von WALLMANN (1990) in Suspensionsversuchen gemachte Beobachtung, daß im postoxischen Milieu bereits eine Fällung von Sulfidmineralen bei Sulfidkonzentrationen unter 1 μM (BERNER 1981) stattfindet, konnte erstmals in einem Geländeversuch verifiziert werden. Es gelang zusätzlich, die Bestimmungsgrenze für Sulfid in natürlichen Porenwässern mit Hilfe polarographischer Meßmethoden auf 0.1 μM zu senken. Die Konzentrationen der Spurenmetalle in der Lösung waren etwa vergleichbar mit denen der wechselnd oxisch / postoxischen Schicht. Die starke Übersättigung in den unteren Profilbereichen zeigt an, daß neben dem (steigenden) Sulfidgehalt vor allem inerte organische Komplexe und Kolloide die Spurenmetall-Konzentrationen in der Lösung kontrollieren. Die permanent postoxische Zone ist ebenfalls durch Sättigung an Eisenphosphat gekennzeichnet. Übersättigung gilt für das gesamte Profil an Eisen- und Mangankarbonat; die Bildung dieser Minerale ist offensichtlich kinetisch gehemmt. Ein weiterer Ansatz dieser Arbeit bestand darin, das Meßverfahren und die Meßparameter an der rotierenden Quecksilberfilmelektrode für Spurenmetall-Bestimmungen im unteren ppt-Bereich (ng/l) zu modifizieren. Die Rotel-Elektrode erwies sich als sehr leistungsfähig; so konnten die Bestimmunggrenzen für Cadmium und Blei unter den gegebenen Laborbedingungen auf 5-15 ppt gesenkt werden. Im Zuge der Messungen zeigten sich jedoch Metall-Konzentrationen in den Porenlösungen, die einen weiteren Einsatz der rotierenden Quecksilberfilmelektrode nicht ratsam erscheinen ließen. Dennoch ist der Einsatz dieser Methode bei entsprechender Einarbeitung des Benutzers und Qualität der Meßapparaturen als probates Meßverfahren in der Spurenanalytik zu betrachten.

Description: Four new octocoral species, Telestula stocki, Telestula batoni, Telestula verseveldti, and Telestula kuekenthali are described and illustrated and a redescription is given of Telesto humilis Thomson, 1927. All the species mentioned were collected during expeditions by Prince Albert Ier of Monaco in the Eastern Atlantic during the period 1896-1912.

Description: A new species of the tropical-subtropical genus Monanchora Carter, 1883, is reported from S\xc3\xa3o Tiago (Cape Verde Islands) and Ascension Island. The new species, M. stocki n. sp., is compared with related Atlantic and Indo-Pacific species, viz. Caribbean M. arbuscula (Duchassaing & Michelotti, 1864) (senior synonym of Echinostylinos unguiferus De Laubenfels, 1953, and Monanchora barbadensis Hechtel, 1969), and Indo-Pacific M. unguiculata (Dendy, 1922). The new species stands out among Monanchora species by the longer and more pointed teeth of its spatulate-unguiferate chelae, which in extreme cases almost meet. The structure of the chelae of Monanchora species of various parts of its range are compared with that found in some other (? related) genera, leading to critical remarks on current familial classifications of the Poecilosclerida.

Description: According to electrophoresis and erythrocyte size the genotypes of 756 waterfrogs, collected during 1986\xe2\x80\x941988 in 54 localities in The Netherlands, were classified as belonging to 5 different genotypes: 331 diploid R. lessonae (LL), 5 triploid R. lessonae (LLL), 250 diploid R. kl. esculenta (LR), 133 triploid R. kl. esculenta (LLR), and 37 diploid R. ridibunda (RR).\nThe occurrence of triploid R. kl. esculenta in The Netherlands is reported for the first time and triploid R. lessonae has not yet been reported previously. There are indications that LL gametes could be produced by LLR triploids and LL diploids. R. kl. esculenta in R. kl. esculenta and R. ridibunda \xe2\x80\x94 R. kl. esculenta populations of the western regions seems to be exclusively triploid, whereas the percentage of triploid R. kl. esculenta in R. lessonae \xe2\x80\x94 R. kl. esculenta populations of the eastern regions is about 1%.\nBiometrical differences were neither found between R. kl. esculenta triploid and diploid, nor between R. lessonae triploid and diploid.

Description: Several Conus species of the coast of Oman are revised. Conus stocki n. sp. is described from Mas\xc3\xafrah Island. For C. ardisiaceus Kiener, 1845, a neotype is designated. A lectotype is selected for C. luctificus Reeve, 1848. C. lischkeanus tropicensis Coomans & Filmer, 1985, has a disjunct range in the Indian Ocean. The recorded distribution of C. parvatus sharmiensis Wils, 1986, is enlarged from the Red Sea to the coast of Oman. c. quasimagnificus Da Motta, 1982, is provisionally considered a subspecies of C. pennaceus Born, 1778.

Description: Lovenula (Neolovenula) alluaudi is widespread on Lanzarote, where it occurred at 22 of the 105 stations. On Fuerteventura it was found at only 2 of the 53 stations, both in the extreme northwest part of the island. It was also found in a reservoir on the south side of the small island of Alegranza. Samples collected at several hundred stations in the other Canary Islands failed to yield a single calanoid, supporting the belief that the eastern islands are fragments of the African continent that drifted to deeper waters.\nMales outnumbered females in about 2/3 of the samples, often heavily.

Description: Burrington Baker (1924) states that Cura\xc3\xa7ao can be divided into three distinct faunal areas. Stock (1977) mentions the occurrence of three subspecies of hadziid amphipods almost exclusively confined to different parts of Cura\xc3\xa7ao. The results of a study of the distribution on this island of various subspecies of the gastropods Cerion uva, Brachypodella raveni, Tudora megacheilos and T. rupis, however, do not support the hypothesis of a tripartite Cura\xc3\xa7ao.

Description: Mantra speciosa Leigh-Sharpe, 1934 (ex Poecilostomatoida), collected during the Siboga Expedition is redescribed on the basis of the holotype female. The 15-segmented antennule and the gnathostomous nature of the mouthparts exclude the Mantridae from the Poecilostomatoida and point to a relationship with the tunicate-infesting families Ascidicolidae, Notodelphyidae and Archinotodelphyidae (Cyclopoida). Nearchinotodelphys indicus Ummerkutty, 1960 (ex Archinotodelphyidae) is transferred to the Mantridae. It is suggested that the bivalveinhabiting mantrids have diverged from the ascidicolous lineage leading to the Notodelphyidae and Ascidicolidae.

Description: In many copepod species adult males clasp females for an extended period before transferring spermatophores. Clasping juvenile females (first to fifth copepodid inclusive) is interpreted as mate guarding and is shown to be widespread among podoplean copepods. It is distinct from copulation, which takes place only between adults and is often distinguishable from mate guarding by a difference in clasping posture.

Description: Genetic differentiation of morphologically variable members of the G. pulex-group in northwestern Europe was investigated by electrophoresis at 20 enzyme loci. Five recently described related forms were examined with reference to the \xe2\x80\x9cclassical\xe2\x80\x9d species G. pulex, G. wautieri and G. fossarum. G. pulex and G. wautieri were shown to be genetically homogeneous and clearly distinct species. In the other species, morphologically similar forms were shown to be genetically distant, and inter-areal intraspecific genetic differentiation may warrant recognition of subspecies or sibling species. In some cases, levels of reproductive isolation of the forms involved could be assessed by cross-breeding experiments. To estimate dispersal capabilities, gene flow levels were indirectly estimated from gene frequency data. Gene flow levels are generally low and fluctuating population sizes may enhance the occurrence of stochastic processes. Dendrograms derived from genetic distances were compared with zoogeographical and paleoclimatological evidence. The distribution areas of the species involved correspond to patterns predicted by these data.

Description: The critical function is an important aspect of the science of taxonomy. Every classification is built upon a critical evaluation and emendation of a previously existing one. Ultimately, this reaches back to pre-scientific classifications which are, like scientific ones, hierarchically structured. The critical function is strongly developed in phylogenetic systematics in which some time-honoured taxa are no longer considered natural groups. Rejection of paraphyletic taxa has given rise to opposition against the phylogenetic methodology. It is suggested that paraphyletic taxa may be retained for administrative reference, but not for scientific evaluation of biogeography and evolutionary differentiation.

Description: Recently the scientific correspondence of the Dutch zoologist P.P.C. Hoek (1851\xe2\x80\x941914) turned up in the Artis Library. This collection contains three hitherto unpublished letters from Charles Darwin. It appears that Charles Darwin recommended Hoek to the favour of Sir Charles Wyville Thomson upon Hoek\xe2\x80\x99s request for duplicates of Pycnogonida collected by the Challenger Expedition. This led to Hoek\xe2\x80\x99s participation in the publication of the scientific results of the Challenger Expedition. Hoek\xe2\x80\x99s report on the Pycnogonida was published in 1881 and those on the Cirripedia in 1883 (Systematic Part) and 1884 (Anatomical Part). In a letter to Hoek dated November 23, 1881 Charles Darwin praises Hoek\xe2\x80\x99s contribution on the Pycnogonida as a magnificent piece of work with admirable plates.

Description: A new family Cristacoxidae is proposed to accommodate the monotypic genera Cristacoxa gen. nov., Noodtorthopsyllus Lang (ex Canthocamptidae) and Cubanocleta Petkovski (ex Laophontidae). Cristacoxa petkovskii gen. et spec. nov. is described on the basis of a single male collected from coralline sand of Bonaire, West Indies. N. psammophilus Noodt and C. noodti Petkovski are redescribed and refigured on the basis of new material from the Gal\xc3\xa1pagos (Isla Santa Cruz), the West Indian Islands (Cura\xc3\xa7ao, Klein Cura\xc3\xa7ao, Bonaire) and the Canary Islands (El Hierro, Tenerife). The new family is characterised by the presence of an outer spinous process on the first antennular segment, the absence of the antennary exopod, the uniramous mandibular palp, the presence of conspicuous cristae on the precoxa and coxa of leg 1 and the elongation of the apical exopodal spines of P2 to P4. The Cristacoxidae are unique in having an equal number of setae/spines on the P5 in both sexes. Examination of the ontogeny of this leg in males and females of Orthopsyllus spec. gives strong evidence that the cristacoxid P5 has undergone neotenous evolution. Males of Cristacoxidae are readily recognisable by their extremely long spermatophores. The new family is allocated to the superfamily Laophontoidea T. Scott, together with the Laophontidae T. Scott, the Laophontopsidae Huys & Willems, the Orthopsyllidae Huys and the Adenopleurellidae Huys. A phylogenetic analysis of the relationships within the superfamily is presented, and as a result Por\xe2\x80\x99s (1986) concept of the Laophontoidea is refuted. Instead, it is concluded that the superfamily can be defined on the basis of the following apomorphies: (1) antennules with outer spinous process on segment 2; (2) antenna with allobasis bearing 1 seta; (3) antennary exopod quadrisetose; (4) P1 exopod without inner seta on exp-2 and 4 setae/spines on exp-3; (5) P1 endopod 2-segmented with elongated enp-1 and 2 elements on enp-2; (6) P2\xe2\x80\x94P4 with 2-segmented endopods; exp-1 without inner seta; (7) sexual dimorphism of P3 endopod; (8) P6 bisetose with one member fused to somite. There is no close relationship neither with the Normanellidae Lang, nor with the Ancorabolidae T. Scott. The Laophontidae are considered the first offshoot in the evolution of the Laophontoidea because of the retention of the 8-segmented antennule in both sexes and the ancestral seta formulae on P2\xe2\x80\x94P4. The other families can be assigned to two clades: the Adenopleurellidae and the Laophontopsidae-Cristacoxidae-Orthopsyllidae-grouping. The Laophontopsidae and the Cristacoxidae are sister groups because of the shared sexual dimorphism of the P3 endopod (advanced type), and the fusion of antennular segments distal to the geniculation in the male. Emphasis is placed on the postembryonic development in the Laophontoidea of the male P3 endopod and P6 and on their homologies in the female. A reconstruction of the hypothetical ancestor of the Laophontoidea is presented.

Description: Two calanoid copepods were collected from groundwaters in Spain by the University of Amsterdam Expeditions in 1983\xe2\x80\x9484 and 1985. Copidodiaptomus numidicus was found in southwestern Spain, in provincias Huelva and Sevilla. Mixodiaptomus laciniatus, previously known in Spain only from the Pyrenees, was collected in the Cantabrian Mountains.

Description: The appendages of Limnoria stephenseni are redescribed on the basis of newly collected specimens from Marion Isl. These specimens are compared with type material and some other specimens. The variation and distribution of the species is given.

Description: Om een tentoonstelling aan de preparateur P .L. Steenhuizen te kunnen wijden, \nmoest voor het Zo\xc3\xb6logisch Museum te Amsterdam eerst meer informatie over \nSteenhuizen verzameld worden. Tijdens het bijeenzoeken van informatie bleek \nniet over alle aspecten van het leven en werk van Steenhuizen evenveel bekend \nte zijn. Dit heeft tot gevolg, dat in de navolgende biografie niet op alle aspecten \neven gedetailleerd ingegaan kan worden. Uit het materiaal is gebleken, dat de \nkeuze van het museum om een tentoonstelling aan Steenhuizen te wijden een \nzeer goede is, want Steenhuizen heeft duidelijk zijn sporen achtergelaten in de \ngeschiedenis van Artis en het Zo\xc3\xb6logisch Museum. \nIn de tijd, dat Steenhuizen bij Artis werd aangesteld, was in vele natuurhistorische musea de taxonomische opstelling ten dienste van de wetenschapper nog gebruikelijk. Heimans & Thijsse trachtten echter de natuurbeleving en \nde veldbiologie populairder te maken bij het grote publiek. Wat zij veelal met \nboeken en artikelen in kranten en tijdschriften deden, poogde Steenhuizen te \nbewerkstelligen met zijn eigen werk: vogelgroepen, diorama\'s en vogelfoto\'s. \nSteenhuizen had ook de unieke gelegenheid zijn hobby (vogels) ten dienst te \nmaken aan zijn museumwerk. De kennis over vogels, die hij tijdens zijn vele \ntochten opdeed, verwerkte hij in zijn prepareerwerk. De bezoekers van de \nverschillende instellingen, waar zijn werk te zien was, profiteerden daar op \nhun manier ook weer van. Hoewel natuurlijk met instemming van zijn \nsuperieuren, kreeg Steenhuizen de gelegenheid met zijn vogelgroepen een \noverheersend stempel te drukken op het zogeheten Museum Fauna \nNeerlandica. \nDe uitdrukking "wie schrijft, die blijft" is op Steenhuizen als volgt van \ntoepassing: Heimans & Thijsse hebben veel geschreven, zodat zij ook nu nog \nnaamsbekendheid genieten; Steenhuizen schreef niet, zijn prepareerwerk \ndoorstond de tand des tijds maar ten dele, zodat hij nu tot de rang der \nonbekenden behoort. Van het kaliber Heimans & Thijsse was hij niet, maar hij \nverdient meer dan anonimiteit. De tentoonstelling van het Zo\xc3\xb6logisch Museum \n is een poging om hem daarvoor te behoeden. \nHoewel volledigheid is nagestreefd, blijven aanvullingen mogelijk. \nDe samensteller staat open voor alle op- en aanmerkingen, correcties, \naanvullingen etcetera, die lezers na het lezen van de navolgende biografie \nzouden kunnen hebben. Mogelijke bijdragen worden wellicht in een herziene \n(en eventueel uitgebreide) versie verwerkt . \nWanneer in het navolgende verhaal sprake is van Artis wordt of het Koninklijk \nZo\xc3\xb6logisch Genootschap "Natura Artis Magistra" of de door dit genootschap \nbeheerde diergaarde bedoeld. Tenslotte bedankt de samensteller iedereen, die op \nwat voor manier dan ook heeft bijgedragen aan de samenstelling van de \nnavolgende biografie.

Description: Characters in male genitalia suggest that several New Guinean and Australian genera of the family Tibicinidae form a monophyletic taxon, indicated here as the \xe2\x80\x9c Baeturia and related genera complex\xe2\x80\x9d. A new genus, Aedeastria, forms part of this complex and is erected for two New Guinean species: Aedeastria cobrops n. sp. from Sorong (Cendrawasih) and Aedeastria sepia n. sp. from Cendrawasih, Roon Island and north New Guinea. The phylogenetic position of Aedeastria is discussed and some remarks are made on the biogeography of this genus in relation to the geologic origin of Cendrawasih.

Description: Deux esp\xc3\xa8ces d\xe2\x80\x99 Orchomene aveugles appartenant aux communaut\xc3\xa9s benthiques abyssales sont d\xc3\xa9crites. O. kaikoi a \xc3\xa9t\xc3\xa9 r\xc3\xa9colt\xc3\xa9 dans le grand bivalve Calyptogena (Ectenagena) phaseoliformis provenant des fosses de subduction du Japon. O. stocki provient du lavage d\xe2\x80\x99\xc3\xa9pong\xc3\xa9s du genre Cladorhiza r\xc3\xa9colt\xc3\xa9es aux Barbades avec d\xe2\x80\x99autres Calyptogena. Les deux esp\xc3\xa8ces sont compar\xc3\xa9es aux autres esp\xc3\xa8ces d\xe2\x80\x99 Orchomene s. l. profondes.

Description: The worldwide distribution of Euphausiacea is related to differences in character states found in the genera belonging to this order. An area cladogram is composed. The vicariant events postulated in this study made it possible to distinguish between different \xe2\x80\x9chydroplates\xe2\x80\x9d of the \xe2\x80\x9chydrotectonic (cf. Nelson, 1986) system\xe2\x80\x9d on the basis of general trends in distribution of these genera.

Description: Lithoxus stocki, a catfish species new to science from the Maroni River drainage in French Guiana and Surinam is described. A lectotype is designated for Lithoxus bovallii. Morphometric and meristic characters of the six species of the genus are provided. Paralithoxus, originally proposed as a subgenus of Lithoxus, is relegated to the synonymy of Lithoxus.

Description: Area cladistics suffer from the fact that areas have various \xe2\x80\x9chistories\xe2\x80\x9d, as such dictated by different groups of taxa. Consequently, a generalized area cladogram has not or hardly any biological meaning. Conflicting area cladograms may be derived from even the same species, when their ranges in different geological periods are used. This is a consequence of the individuality of species.

Description: A brief survey is given of current literature in comparison with former studies. Since the 18th century phenotypic diversity of Labridae is a matter of argument. At first in dribs and drabs, yet last decades at a rapid rate, dichromatic adult morphs are synonymized. There are few monochromatic species.\nWrasses are protogynous hermaphrodites. Most species are described as monandric, but a minority (of slightly or extremely dichromatic) species is diandric, with both primary and secondary males. Terminal males reproduce with single females, but initial phase males spawn in aggregations. Some species are haremic, and large males are permanently or temporarily territorial. Last decades insight in the various social factors has greatly increased, resulting in theoretic models to explain the evolution of the typical, diverse modes of labrid reproductive biology.

Description: The new genus and species, Dicrotrichura tricincta, is described from deep mud (1220 m) in the Ligurian Sea (western Mediterranean). It is the first tantulocaridan not found to be attached to a crustacean host but free living in the sediment. It is assigned to the Deoterthridae on the basis of the absence of a rostrum, the abdominal segmentation and the characteristic cephalic pore pattern. It can be distinguished from all known tantulocaridans in the presence of peculiar, bi-articulated caudal setae and the difference in thoracopodal setation between leg 2 and legs 3-5. Some new structures located on the attachment disc are described for the first time. D. tricincta is the second tantulocaridan to be recorded from the Mediterranean.

Description: A survey is presented of the status of species boundaries in nontropical Northern Hemisphere owls in order to investigate the reality of the biological and geographical species concept applied to these owls in current handbooks. At the same time the practicability of evolutionary systematics as opposed to phylogenetic synthesis is elaborated on.