(Tables 1-3) Silicon dioxide, Corg and trace element concentrations in sediments of the outer Eckernfoerder Bay, Western Baltic Sea

The main question, posed in the work scheme before laboratory analysis was started, was expressed as follows: Do marked seasonal fluctuations occur in trace element content of the sediment surface, and what are the probable influences of factors such as changing hydrographical parameters, plankton sequence etc. ? Special attention was paid to elements known as pollutants, for example mercury. Within this framework samples have been analysed for their contents of manganese, iron, zinc, lead, and mercury. The amounts of silica and organically-bound carbon serve in most cases as reference values for the trace element content. On sand temporary conditions of increased C org content raise the concentrations of all determined elements. Especially the values reached for mercury in July are worth nothing. It is concluded that Zn, Pb, and Hg tend to enrich with respect to C org as the decomposition of organic matter progresses. On mud-sand flocculation and precipitation of Mn/Fe-hydroxides probably represent an additional concentrating factor for the other elements as the relationship of the results for zinc and manganese shows. Manganese may indicate a seasonally related concentrating cycle at the sediment surface.

(Table 1) Radiocarbon ages of core AB01/94 obtained in the Tromper Wiek, western Baltic Sea

In the Tromper Wiek northeast of Rügen, acoustical investigations using Air Gun, Boomer, Chirp Sonar and Sediment-Echosounder were carried out. Together with sediment core information, it allowed the identification of five seismostratigraphic units (E1 to E5). Conventional and AMS-14C-datings supported their chronostratigraphical classification. The uppermost till (E1) was incised by late glacial channels filled with glaciolacustrine sediments (E2) of the early Baltic Ice Lake stages. These were regionally overlain with a sharp unconformity by a thick (locally >20 m) sedimentary complex (E3) of acoustically laminated silts of freshwater origin. This lower part of the E3-complex (E3a) is overlain by fluvial to coastal silty fine sands (E3b) deeper towards the Arkona Basin. Fine plant debris in the uppermost part of sub-unit E3a yielded ages of 10,100 and 10,500 14C-years B.P., representing the final phase of the Baltic Ice Lake. The fine sands of sub-unit E3b were deposited after the final drainage of the Baltic Ice Lake. In the shallower central part of the bay, the silts of sub-unit E3a were covered by a younger unit (E4) of fine sand with plant debris. A sedge peat occurring at the basis of unit E4 yielded an age of 9,590 14C-years B.P. The fine sands overlying the unit E3 in the central part of Tromper Wiek were deposited in the Ancylus Lake. Their position at about 20 m below present sea level (b.s.l.) reflects the maximum highstand in this area. The character and distribution of the Early Holocene deposits at greater depth suggest a lake water level at about 30 m b.s.l. after this highstand. Below 25 m b.s.l. muddy Littorina Sea sediments are observed. The thickness of these muds and sandy muds increases gradually towards the Arkona Basin. Locally, they are found in a channel-like structure immediately north of Jasmund.

Trace metal investigations in the fjords of Kiel Bight, Western Baltic Sea - data report of 1977/78

This data report includes the analytical results of about 220 water wamples collected at 33 stations in the Fjords of Kiel ,...

Impacts of seawater acidification on mantle gene expression patterns of the Baltic Sea blue mussel: implications for shell formation and energy metabolism, link to supplementary material

Marine organisms have to cope with increasing CO2 partial pressures and decreasing pH in the oceans. We elucidated the impacts of an 8-week acclimation period to four seawater pCO2 treatments (39, 113, 243 and 405 Pa/385, 1,120, 2,400 and 4,000 µatm) on mantle gene expression patterns in the blue mussel Mytilus edulis from the Baltic Sea. Based on the M. edulis mantle tissue transcriptome, the expression of several genes involved in metabolism, calcification and stress responses was assessed in the outer (marginal and pallial zone) and the inner mantle tissues (central zone) using quantitative real-time PCR. The expression of genes involved in energy and protein metabolism (F-ATPase, hexokinase and elongation factor alpha) was strongly affected by acclimation to moderately elevated CO2 partial pressures. Expression of a chitinase, potentially important for the calcification process, was strongly depressed (maximum ninefold), correlating with a linear decrease in shell growth observed in the experimental animals. Interestingly, shell matrix protein candidate genes were less affected by CO2 in both tissues. A compensatory process toward enhanced shell protection is indicated by a massive increase in the expression of tyrosinase, a gene involved in periostracum formation (maximum 220-fold). Using correlation matrices and a force-directed layout network graph, we were able to uncover possible underlying regulatory networks and the connections between different pathways, thereby providing a molecular basis of observed changes in animal physiology in response to ocean acidification.

Sediment and pore water chemistry and physical oceanography of samples obtained during Baltic Sea research cruises

Sediment samples from approximately 40 stations in the Western, middle and eastern Baltic Sea were investigated for manganese and iron content. In a series of interstitial water samples and numerous deep and surface water samples, the manganese content was likewise determined. A strong enrichment of these elements in the basin sediments was shown. In many instances, several percent manganese were present. As a maximum value, 13% was found in a 1 mm thick layer. Furthermore, a distinct decrease in manganese content with increasing sediment depth was shown in the upper 10 to 20 cm of the Sediment at almost all stations. Both phenomena may be explained by the release of manganese from the Sediment through diffusion. In the flat parts of the Baltic and those parts having good bottom water circulation, this diffusion progresses especially vigorously as a result of a steep gradient of the Mn++ concentration in the interstitial water-deep water interface. The manganese which hereby passes into the water overlying the bottom (manganese contents between 10 and 100 y Mn/l were determined in numerous deep water samples) is partly reprecipitated on the Sediment surface, and partly carried by currents into the deeper basins where it is finallv deposited. It is bound there as a manganese-rich mixed carbonate, the composition of which can be proved chemically and by x-ray methods. Iron is likewise of higher content in the basinal sediments, however, the extent of its enrichment is far less since it is less soluble than manganese under the reducing conditions in the sediments. The fine bands of manganese- and iron-rich layers in the basin sediments may likewise be explained as a result of diffusion.

(Table1) Frequency of well defined bioturbation in sediments of the Eckernförder Bay, Western Baltic Sea

The lamination and burrowing patterns in 17 box cores were analyzed with the aid of X-ray photographs and thin sections. A standardized method of log plotting made statistical analysis of the data possible. Several 'structure types' were established, although it was realized that the boundaries are purely arbitrary divisions in what can sometimes be a continuous sequence. In the transition zone between marginal sand facies and fine-grained basin facies, muddy sediment is found which contains particularly well differentiated, alternating laminae. This zone is also characterized by layers rich in plant remains. The alternation of laminae shows a high degree of statistical scattering. Even though a small degree of cyclic periodicity could be defined, it was impossible to correlate individual layers from core to core across the bay. However, through a statistical handling of the plots, zones could be separated on the basis of the number of sand layers they contained. These more or minder sandy zones clarified the bottom reflections seen in the records of the echograph from the area. The manner of facies change across the bay, suggests that no strong bottom currents are effective in the Eckernförde Bay. The marked asymmetry between the north and south flanks of the profile can be attributed to the stronger action of waves on the more exposed areas. Grain size analyses were made from the more homogeneous units found in a core from the transition-facies zone. The results indicate that the most pronounced differences between layers appear in the silt range, and although the differences are slight, they are statistically significant. Layers rich in plant remains were wet-sieved in order to separate the plant detritus. This was than analyzed in a sediment settling balance and found to be hydrodynamically equivalent to a well-sorted, finegrained sand. A special, rhythmic cross-bedding type with dimensions in the millimeter range, has been named 'Crypto-cross-lamination' and is thought to represent rapid sedimentation in an area where only very weak bottom currents are present. It is found only in the deepest part of the basin. Relatively large sand grains, scattered within layers of clayey-silty matrix, seem to be transported by flotation. Thin section examination showed that the inner part of Eckernförder Bay carbonate grains (e. g. Foraminifera shells) were preserved throughout the cores, while in the outer part of the bay they were not present. Well defined tracks and burrows are relatively rare in all of the facies in comparision to the generally strongly developed deformation burrowing. The application of special measures for the deformation burrowing allowed to plot their intensity in profile for each core. A degree of regularity could be found in these burrowing intensity plots, with higher values appearing in the sandy facies, but with no clear differences between sand and silt layers in the transition facies. Small sections in the profiles of the deepest part of the bay show no bioturbation at all.

Geochemistry, carbon isotope ratio and radiocarbon ages of sediment core GIK1093-2 from Bornholm Basin, Baltic Sea

Concentrations of Cd, Pb, Zn, Cu, Co, Ni, Fe, and Al203, water content, the amounts of organic carbon, the ratio of 13C/12C and the 14C-activity of the organic fraction were determined with sediment depth from a 34 cm long box-core from the Bornholm Basin (Baltic Sea). The average sedimentation rate was 2.4 mm/yr. The upper portion of the core contained increasing amounts of 14C-inactive organic carbon, and above 3 cm depth, man-made 14C from atomic bomb tests. The concentrations of the heavy metals Cd, Pb, Zn, and Cu increase strongly towards the surface, while other metals, as Fe, Ni and Co remain almost unchanged. This phenomenon is attributed to anthropogenic influences. A comparison of the Kieler Bucht, the Bornholm and the Gotland Basins shows that today the anthropogenic addition of Zn is about 100 mg/m**2 yr in all three basins. The beginning of this excess of Zn, however, is delayed by about 20 years in, the Bornholm Basin and by about 40 years in the Gotland Basin. It is suggested that SW-NE transport of these anthropogenically mobilized metals may be related to periodic bottom water renewal in the Baltic Sea sedimentary basins.

(Table 1) Composition of lipids in particulate matter and bottom sediments of the Baltic Sea

Lipid contents in the upper layer of bottom sediments in the Baltic Sea range from 0.37 to 2.66 mg/g (1.2-25.8% Corg). It is shown that the main factors determining composition of lipids in bottom precipitates are relative roles of different sources of lipids in sediments and conditions of sediment accumulation. Runoff of the Daugava River into the Gulf of Riga contributes simple low-polarity lipids. Sterols and certain bound fatty acids originate in living organic matter. Polar lipids are formed by inheritance of complex phospholipids and glycolipids from plankton and/or by formation of polycondensates.