Lead and cadmium in the Weser Estuary and the German Bight: Correlations between bacteria populations, heavy metals and organic carbon

Organic carbon, lead and cadmium contents of 20 sediments were determined and compared with the colony counts of anaerobic heterotrophic, anaerobic nitrogen fixing, chitinoclastic and cellulolytic bacteria. Organic carbon content, which is dependent on the sediment type, was positively correlated with lead and cadmium as well as with colony counts of all 4 physiological groups of bacteria. Even the sediments with the highest concentrations of 251.7 ppm Pb and 3.1 ppm Cd showed no reduction in their colony counts. From 2 different sediment sampIes with lead contents of 140 ppm and 21 ppm lead tolerance of the aerobic heterotrophic bacteria was investigated. However, no significant difference in lead tolerance of the 2 heterotrophic populations was found. Water from 6 stations was analysed for dissolved and particulate organic carbon, lead and cadmium. Dissolved lead concentrations were in the range of 0.2-0.5 µg/l and the particulate lead contents were between 0.05 and 4.3 µg/l. The concentrations of total lead for the stations off-shore were only one order of magnitude from the concentrations of the near-shore stations. The same phenomenon was observed for dissolved cadmium (0.02 - 0.25 µg/l) and particulate cadmium (0.003 - 0.15 µg/I) concentrations. Correlations between dissolved (1.6 - 10.8 mg/I) and particulate organic carbon (0.25 - 1.53 mg/I) with dissolved and particulate lead or cadmium were not found.

Sulfur concentrations and isotope ratios in sediments from Kiel Bay, western Baltic Sea

The isotope-ratios of sulfur-components in several sedimentologically different cores of recent marine sediments from Kiel Bay (Baltic Sea) were investigated. In addition, quantitative determinations were made on total sulfur, sulfate, sulfide, chloride, organic carbon, iron and watercontent in the sediment or in the pore-water solution. The investigations gave the following results: 1. The sulfur in the sediment (about 0.3 -2 % of the dry sample) was for the most part introduced into the sediment after sedimentation. This confirms the results of Kaplan et al. (1963, doi:10.1016/0016-7037(63)90074-7). The yield of Sulfur from organic material is very small (in our samples about 5-10% of the total sulfur in the sediment). 2. The sulfur bound in the sediment is taken from the sulfate of the interstitial water. During normal sedimentation, the exchange of sulfate by diffusion significant for changes in the sulfur-content goes down to a sediment depth of 4-6 cm. In this way the sulfate consumed by reduction and formation of sulfide or pyrite is mostly replaced. The uppermost layer of the sediment is an partly open system for the sulfur. The diagenesis of the sulfur is allochemical. 3. The isotope-values of the sediment-sulfur are largely influenced by the sulfur coming into the sediment by diffusion and being bound by bacteriological reduction. Due to the prevailing reduction of 32S and reverse-diffusion of sulfate into the open sea-water, an 32S enrichment takes place in the uppermost layer of the sediment. delta34S-values in the sediment range between -15 and -35 ? while seawater-sulfate has +20 ?. No relationship could be established between sedimentological or chemical changes and isotope-ratios. In the cores, successive sandy and clayly layers showed no change in the delta-values. The sedimentation rate, however, seems to influence isotope-ratios. In one core with low sedimentationrates the delta34S-values varied between -29 and -33 ?, while cores with higher sedimentationrates showed values between -17 and -24 ?. 4. As sediment depth increases, the pore-water sulfate shows decreasing concentrations (in a depth of 30-40 cm we found between 20 and 70 % of the seawater-values), and increasing delta 34S-values (in one case reaching more than +60 ?). The concentration of sulfide in the pore-water increases with sediment-depth (reaching 80 mg S/l in one case). The (delta34S-values of the pore-water-sulfide in all cores show increases paralleling the sulfate sulfur, with a nearly constant delta-distance of 50-60 ? in all cores. This seems to confirm the genetic relationship between the two components.

Abundance and biomass of in- and epibenthic invertebrate macrofauna in the German Bight from 1969 to 2000

In order to examine the long-term development of offshore macrozoobenthic soft-bottom communities of the German Bight, four representative permanent stations (MZB-SSd, -FSd, -Slt, -WB) have been sampled continuously since 1969. Inter-annual variability and possible long-term trends were analysed based on spring-time samples from 1969 until 2000. This is part of the ecological long-term series of the AWI and is supplemented by periodic large-scale mapping of the benthos. The main factors influencing the development of the benthic communities are biological interactions, climate, food supply (eutrophication) and the disturbance regime. The most frequent disturbances are sediment relocations during strong storms or by bottom trawling, while occasional oxygen deficiencies and extremely cold winters are important disturbance events working on a much larger scale. Benthic communities at the sampling stations show a large inter-annual variability combined with a variation on a roughly decadal scale. In accordance with large-scale system shifts reported for the North Sea, benthic community transitions occurred between roughly the 1970ies, 80ies and 90ies. The transitions between periods are not distinctly marked by strong changes but rather reflected in gradual changes of the species composition and dominance structure.

Observations of plankton production in Kiel Bay 1957 to 1975

This data volume presents a series of planktological observations carried out over a 19-year-period in Kiel Bight in the Western Baltic Sea. Three fixed stations were visited at monthly intervals, and the planktion standing stock was investigated in relation to depth and environmental factors, employing a standard observation programme. This consisted in the measurements of temperature, salinity, density, oxygen, phosphorus, seston, protein and chlorophyll a. Additional measurements comprised in the caloric content of seston, particulate organic carbon and nitrogen, as well as dry weight and organic matter of plankton, sampled by vertical hauls of three plankton nets of different mesh size.

Sedimentology on surface sediments of Porcupine Bay/Gollum Channel

Das Gollum Channel System mit dem untersuchten Kanal gc1 liegt in der Por- cupine Bucht südwestlich vor Irland. Während der ersten Messung im Jahr 2000 (ANT-XVII/4) fielen vier Kanalabschnitte mit markanten Rückstreuungen ins Au- ge. Diese Bereiche weisen eine abwechselnd starke und schwache Rückstreuinten- sität auf. Da der Schwerpunkt der Expedition ANT-XVII/4 auf der Erforschung der carbonate mounds lag, wurde eine genauere Untersuchung des Kanals während der Expedition ARK-XIX/3 (2003) nachgeholt. Mit dieser zweiten Messung wur- den die vier unterschiedlich rückstreuenden Sektoren bestätigt. Zusätzlich wurden Sedimentproben entnommen und Videos der Meeresbodenoberfläche aufgezeichnet. (ff siehe Diplomarbeit)

Macrofauna abundance and sediment characteristics during R/V Senckenberg cruise west of Sylt in september 2010

The continuously influence of human impacts on the seafloor and benthic habitats demands the knowledge of clearly defined habitats to assess recent conditions and to monitor future changes. In this study, a benthic habitat dominated by sorted bedforms was mapped in 2010 using biological, sedimentological and acoustic data. This approach reveals the first interdisciplinary analysis of macrofauna communities in sorted bedforms in the German Bight. The study area covered 4 km², and was located ca. 3.5 km west of island of Sylt. Sorted bedforms formed as sinuous depressions with an east west orientation. Inside these depressions coarse sand covers the seafloor, while outside predominantly fine to medium sand was found. Based on the hydroacoustic data, two seafloor classes were identified. Acoustic class 1 was linked to coarse sand (type A) found inside these sorted bedforms, whereas acoustic class 2 was related to mainly fine to medium sands (type B). The two acoustic classes and sediment types corresponded with the macrofauna communities 1 and 2. The Aoinides paucibranchiata-Goniadella bobretzkii community on coarse sand and the Spiophanes bombyx - Magelona johnstonii community on fine sand. A transitional community 3 (Scoloplos armiger - Ophelia community), with species found in communities 1 and 2, could not be detected by hydroacoustic methods. This study showed the limits of the used acoustic methods, which were unable to detect insignificant differences in the fauna composition of sandy areas.

(Table 1) Composition of manganese-iron accumulates in the Kiel Bay, western Baltic Sea

Manganese-iron accumulates in the Kiel Bay were investigated with regard to their occurence, chemical composition and formation. Three morphologically different types were identified: a) growth on mussels, b) spherical nodules (ca. 1-3 cm) and c) disshaped symetrical and asymetrical nodules (up to 10 cm). Average values from 110 accumulates representing the three types were: Mn 29.3%, Fe 10.0%, Co 77 ppm, Ni 97 ppm, Cu 21 ppm and Zn 340 ppm. Accumulates on mussels showed the highest trace metal concentrations. A growth rate of ca. 0.6 mm/yr for type (a) was estimated. Heavy metal concentrations were determined in ca. 60 sediment and 30 pore water samples, and in 110 Baltic sea water samples. During certain periods, large increases in Mn values (up to 400 (µg/l) were found in the deeper waters. These concentrations develop during periods of strong stagnant conditions in the sediments where dissolution of Mn oxides, and diffusion mobilizes the Mn into the overlying waters. The manganese is then reprecipitated close to the boundary of the O2-enriched surface waters. This critical O2-concentration was found to be 40% saturation. In the Kiel Bay, Mn-Fe-accumulates are found in a zone which marks the upper limit sometimes reached by the deep waters of lower O2-concentration. Additionally, the availability of larger particles (especially stones or mussels) on the sediment surface is necessary. These conditions are met in the Kiel Bay in a water depth of 20-28 m at several places.

Contextual classification of full waveform lidar data in the Wadden Sea

The classification of airborne lidar data is a relevant task in different disciplines. The information about the geometry and the full waveform can be used in order to classify the 3D point cloud. In Wadden Sea areas the classification of lidar data is of main interest for the scientific monitoring of coastal morphology and habitats, but it becomes a challenging task due to flat areas with hardly any discriminative objects. For the classification we combine a Conditional Random Fields framework with a Random Forests approach. By classifying in this way, we benefit from the consideration of context on the one hand and from the opportunity to utilise a high number of classification features on the other hand. We investigate the relevance of different features for the lidar points in coastal areas as well as for the interaction of neighbouring points.