Geochemistry of surface sediments from the German Bight

Im Rahmen dieser Arbeit wurden sedimentologische und geochemische Untersuchungen an Oberflächensedimenten der Deutschen Bucht NW von Helgoland durchgeführt. Die chemischen Analysen zeigten, daß in den Pelitfraktionen der fein sandigen bis mittelsandigen Sedimente z. T. erhöhte Schwermetallkonzentrationen anzutreffen sind. Diese Anreicherungen sind auf die Einbringung von Dünnsäure ins Meerwasser als Abfallprodukt der Titandioxidgewinnung zurückzuführen, wie Korrelationen einzeln untersuchter Elemente zeigen.

German Bight bedform reconstructions

Bodenformen an der Sohle von Flüssen, Küstenzonen und flachen Schelfen sind wichtige skalenübergreifende Elemente der Küstendynamik in ihren Eigenschaften als Transportkörper von Sedimenten und ihrer Wirkung auf die Strömungsdynamik als Rauheitselemente. Neben vielen neueren Studien über die Entstehung, Gestalt und Dynamik von Bodenformen in vergleichsweise kleinen Untersuchungsgebieten ist die Arbeit von ULRICH (1973) über die Verteilung von Bodenformen in der Deutschen Bucht bis heute die einzige verfügbare zusammenhängende Darstellung für die deutsche Nordseeküste. Die analogen Karten und die Darstellung der Klassifizierung in Buchstabenkürzeln macht sie für heutige quantitative Analysen schwer zugänglich. Hier wurden diese Karten digitalisiert und Eigenschaften der Bodenformen rekonstruiert und interpretiert. Das Ergebnis ist eine Zusammenstellung digitaler Karten eines vollständigen - und eines auf steile, hydrodynamisch wirksame Bodenformen reduzierten Datensatzes der Minimal, Maximalund Mittelwerte von Höhen, Längen und Steilheiten von Bodenformen in der Deutschen Bucht. Die Datensätze stehen der Allgemeinheit in der Datenbank Pangaea zur Verfügung. Bedforms in rivers, coastal zones and shallow shelf seas are important cross-scale elements of coastal dynamics in their function as sediment transport agent and in their effect on the flow dynamics as roughness elements. In addition to many recent studies on the origin, shape and dynamics of bedforms in relatively small study areas the work of ULRICH (1973) on the classification of bedform types in the German Bight is until today the only available coherent representation of the spatial distribution of bedforms for the whole German coastal sea. The analogue maps and the coded classification makes them difficult to access for quantitative analyses. Here these maps were digitized and properties of the bedforms were reconstructed and interpreted. Resulting digital maps of the whole and a reduced dataset on steep bedforms contain minimum, maximum and average values of heights, lengths and steepness of bedform types in the German Bight. The data sets are available to the public in the database Pangaea.

Compilation of maximum ingestion and maximum clearance rate data for marine pelagic organisms

The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size within taxa is related to the inherent decrease in feeding efficiency of any particular feeding mode. The transitions between feeding mode and simultaneous transitions in clearance and respiration rates may then represent adaptations to the food environment and be the result of the optimization of tradeoffs that allow sufficient feeding and growth rates to balance mortality.

Compilation of growth rate data for marine pelagic organisms

The metabolic rate of organisms may either be viewed as a basic property from which other vital rates and many ecological patterns emerge and that follows a universal allometric mass scaling law; or it may be considered a property of the organism that emerges as a result of the organism's adaptation to the environment, with consequently less universal mass scaling properties. Data on body mass, maximum ingestion and clearance rates, respiration rates and maximum growth rates of animals living in the ocean epipelagic were compiled from the literature, mainly from original papers but also from previous compilations by other authors. Data were read from tables or digitized from graphs. Only measurements made on individuals of know size, or groups of individuals of similar and known size were included. We show that clearance and respiration rates have life-form-dependent allometries that have similar scaling but different elevations, such that the mass-specific rates converge on a rather narrow size-independent range. In contrast, ingestion and growth rates follow a near-universal taxa-independent ~3/4 mass scaling power law. We argue that the declining mass-specific clearance rates with size within taxa is related to the inherent decrease in feeding efficiency of any particular feeding mode. The transitions between feeding mode and simultaneous transitions in clearance and respiration rates may then represent adaptations to the food environment and be the result of the optimization of tradeoffs that allow sufficient feeding and growth rates to balance mortality.

Location and ages of terrestrial peatlands located on continental shelves and in coastal sediments

This synthesis dataset contains records of freshwater peat and lake sediments from continental shelves and coastal areas. Information included is site location (when available), thickness and description of terrestrial sediments as well as underlying and overlying sediments, dates (when available), and references.

Table 1: Densities of nitrate-dissimilating and nitrite-dissimilating bacteria in surface sediments in the German Bight, North Sea

At 24 stations in the Weser Estuary and the German Bight the Most Probable Numbers (MPN/g dry wt. sediment) of nitrate-dissimilating (= denitrifying) and of nitrate plus nitrite-dissimilating bacteria were recorded. The numbers of nitrite-dissimilating bacteria, i. e. denitrifiers not capable of reducing nitrate to nitrite, were calculated by subtraction of the MPN for nitrate-dissimilating from the MPN of nitrate plus nitrite-dissimilating bacteria. By determining the percentages of these bacteria in relation to the number of the heterotrophs, the ecological importance of denitrification, especially the nitrite dissimilation, was estimated. The results showed the MPN of nitrate-dissimilating bacteria to be in the range of 0-156 (up to 0.8 % of heterotrophic bacteria). An exception was the sediment of one station with a MPN of 1849, or 5.2 % of the heterotrophs. The amounts of nitrite-dissimilating bacteria were between 0 and 2352 (up to 13 % of heterotrophic bacteria). In the estuary the numbers of nitrate-dissimilating and of nitrite-dissimilating bacteria showed a decreasing tendency with distance from Bremerhaven. The highest numbers were found in the Weser off Bremerhaven and also at 3 stations in the German Bight, south of the Isle of Helgoland.

Characteristics of samples obtained during Pokhodsk 2012-2013 campaigns in the joint Russian-German POLYGON Project

Polygonal tundra, thermokarst basins and pingos are common and characteristic periglacial features of arctic lowlands underlain by permafrost in Northeast Siberia. Modern polygonal mires are in the focus of biogeochemical, biological, pedological, and cryolithological research with special attention to their carbon stocks and greenhouse-gas fluxes, their biodiversity and their dynamics and functioning under past, present and future climate scenarios. Within the frame of the joint German-Russian DFG-RFBR project Polygons in tundra wetlands: state and dynamics under climate variability in Polar Regions (POLYGON) field studies of recent and of late Quaternary environmental dynamics were carried out in the Indigirka lowland and in the Kolyma River Delta in summer 2012 and summer 2013. Using a multidisciplinary approach, several types of polygons and thermokarst lakes were studied in different landscapes units in the Kolyma Delta in 2012 around the small fishing settlement Pokhodsk. The floral and faunal associations of polygonal tundra were described during the fieldwork. Ecological, hydrological, meteorological, limnological, pedological and cryological features were studied in order to evaluate modern and past environmental conditions and their essential controlling parameters. The ecological monitoring and collection program of polygonal ponds were undertaken as in 2011 in the Indigirka lowland by a former POLYGON expedition (Schirrmeister et al. [eds.] 2012). Exposures, pits and drill cores in the Kolyma Delta were studied to understand the cryolithological structures of frozen ground and to collect samples for detailed paleoenvironmental research of the late Quaternary past. Dendrochronological and ecological studies were carried out in the tree line zone south of the Kolyma Delta. Based on previous work in the Indigirka lowland in 2011 (Schirrmeister et al. [eds.] 2012), the environmental monitoring around the Kytalyk research station was continued until the end of August 2012. In addition, a classical exposure of the late Pleistocene permafrost at the Achchaygy Allaikha River near Chokurdakh was studied. The ecological studies near Pokhodsk were continued in 2013 (chapter 13). Other fieldwork took place at the Pokhodsk-Yedoma-Island in the northwestern part of the Kolyma Delta.