(Table1) Living and dead benthic foraminifera abundance in sediments of the Bottsand-Lagoon, Western Baltic Sea

Seasonal collections were made from 3 stations in a brackish lagoon near Kiel/Germany from December 1964 to June 1967. In addition 120 samples were taken in June 1966 to investigate the general pattern of distribution. Two species of the offshore fauna were found to dominate the lagoon (high population densities): Cribrononion articulatum and Miliammina fusca. The 'Vegetation zone' of the lagoon contains an assemblage of seven euryhaline arenaceous species. All of them were previously recorded from different regions of the world. - C. articulatum seems to prefer shallow water with a high daily range of water temperature (up to 30° Cels.). Population density and distribution show considerable differences between the different years. Size distribution curves of C. articulatum indicate main reproduction activity in spring and subsequent growth in uniform populations. Growth is terminated after six months but most of the specimens will either die in winter or reproduce the next spring; only a smaller amount is reproducing in summer or autumn. - Annual differences of the observed degree make it difficult to calculate foraminiferal productivity in a lagoonal environment and require seasonal observation over a period of at least 3 or 4 years.

(Table 2) Oxygen isotopic of composition of Pliocene to late Pleistocene planktonic foraminifera of the Mediterranean Sea

Stable isotopic and micropaleontological studies were made of selected sapropels (organic-rich sediments) deposited in the Mediterranean Sea during the last 5.0 m.y. to determine the processes responsible for their formation. Distinct isotopic and faunal changes occur across sapropels of late Pleistocene, early Pleistocene and latest Pliocene age, while smaller isotopic changes and more stable faunal assemblages are associated with the early and mid-late Pliocene sapropels. The large d18O depletions and euryhaline fauna associated with latest Pliocene-Pleistocene sapropels supports a density stratification model with a low salinity surface layer. In contrast, early Pliocene and mid-late Pliocene sapropels appear to have been formed as the result of sluggish circulation and low oxygen contents in bottom waters of the eastern Mediterranean due to the stable, warm climatic conditions of that time period.

Physical and chemical properties, 14C ages and palynology of sediment cores from the Western Baltic Sea

Sea level related radiocarbon, palynological and stratigraphical data from sediment cores in the Western Baltic have been tested against the existing sea level curves for the region. The relative sea level rise curves for the beginning of the Holocene show no significant deviations between the Kiel, Mecklenburg und Lübeck Bays and hence do not support the previously reported differences in the averaged regional subsidence rates for this time interval. Local subsidence and upheaval due to salt tectonics probably played a greater role than previously suspected in the region. The sea level possibly stagnated around -28 m during the early Holocene before rising very rapidly to -14 m. The submarine terraces at -30 m and perhaps also at -27 m were formed during the lacustrine phase of the Western Baltic when the water levels were controlled by the main thresholds in the Great Belt.

Sr- and Nd-isotopic composition of bulk lithogenic sediments from the Eastern Mediterranean Sea (Table 1)

In order to characterize the provenance of lithogenic surface sediments from the Eastern Mediterranean Sea (EMS), residual (leached) fraction of 34 surface samples have been analysed for their 143Nd/144Nd and 87Sr/86Sr isotope ratios. The sample locations bracket all important entrances of riverine suspended matter into the EMS as well as all sub-basins of the EMS. The combined analyses of these two isotope ratios provide a precise characterization of the lithogenic fraction of surface sediments and record their dilution towards the central sub-basins. We reconstruct provenance and possible pathways of riverine dispersal and current redistribution, assuming more or less homogenous isotopic signatures and flux rates of the eolian fraction over the EMS. Lithogenic sediments entering the Ionian Sea from the Calabrian Arc and the Adriatic Sea are characterized by high 87Sr/86Sr isotope ratios and low epsilon-Nd(0) values (average 87Sr/86Sr=0.718005 and epsilon-Nd(0)=-11.06, n=5). Aegean Sea terrigenous sediments show an average ratio of 87Sr/86Sr=0.713089 (n=5) and values of epsilon-Nd(0)=-7.89 (n=5). The Aegean isotopic signature is traceable up to the southwest, south, and southeast of Crete. The sediment loads entering the EMS via the Aegean Sea are low and spread out mainly through the Strait of Casos (east of Crete). Surface sediments from the eastern Levantine Basin are marked by the highest epsilon-Nd(0) values (-3.3, n=6) and lowest 87Sr/86Sr isotope ratios (average 0.709541, n=6), reflecting the predominant input of the Nile sediment. The influence of the Nile sediment is traceable up to the NE-trending, eastern flank of the Mediterranean Ridge. The characterization of the modern riverine dispersal and eolian flux, based on isotope data, may serve as a tool to reconstruct climate-coupled variations of lithogenic sediment input into the EMS.

Water chemistry and fluffy layer geochemistry and mineral content at four sites in the western Baltic Sea

The fluffy layer was sampled repeatedly during nine expeditions between October 1996 and December 1998 at four stations situated along a S-N-transect from the Oder Estuary to the Arkona Basin. Geochemical and mineralogical analyses of the fluff show regional differences (trends) in composition, attributed to provenance and to hydrographical conditions along their transport pathways. Temporal variability is very high at the shallow water station of the estuary, and decreases towards the deeper stations in the north. In the shallow water area, intensive resuspension of the fluff due to wind-driven waves and currents leads to an average residence time of only one to two days. Near-bottom lateral transport of the fluff is the main process that transfers the fine grained material, containing both nutrients and contaminants, from the coastal zone into the deeper basins of the Baltic Sea. Seasonal effects (e.g. biogenic production in relation to trace metal variation) are observed at the Tromper Wiek station, where the residence time of the fluffy material is in the scale of seasons. Thus, the fluffy layer offers suitable material for environmental monitoring programs.

Concentrations of floating plastic debris in northwestern Mediterranean Sea measured in summer 2013 during Expeditions MED cruise

Floating plastic debris sampled in surface waters of northwestern Mediterranean Sea during summer 2013. Geographical coordinates and dates of sampling are available in the dataset.

Concentrations of major and minor constituents of samples from the lower end of the cores from the eastern Mediterranean Sea (Table 2)

The pore water chemistry of mud volcanoes from the Olimpi Mud Volcano Field and the Anaximander Mountains in the eastern Mediterranean Sea have been studied for three major purposes: (1) modes and velocities of fluid transport were derived to assess the role of (upward) advection, and bioirrigation for benthic fluxes. (2) Differences in the fluid chemistry at sites of Milano mud volcano (Olimpi area) were compiled in a map to illustrate the spatial heterogeneity reflecting differences in fluid origin and transport in discrete conduits in near proximity. (3) Formation water temperatures of seeping fluids were calculated from theoretical geothermometers to predict the depth of fluid origin and geochemical reactions in the deeper subsurface. No indications for downward advection as required for convection cells have been found. Instead, measured pore water profiles have been simulated successfully by accounting for upward advection and bioirrigation. Advective flow velocities are found to be generally moderate (3-50 cm/y) compared to other cold seep areas. Depth-integrated rates of bioirrigation are 1-2 orders of magnitude higher than advective flow velocities documenting the importance of bioirrigation for flux considerations in surface sediments. Calculated formation water temperatures from the Anaximander Mountains are in the range of 80 to 145 °C suggesting a fluid origin from a depth zone associated with the seismic decollement. It is proposed that at that depth clay mineral dehydration leads to the formation and advection of fluids reduced in salinity relative to sea water. This explains the ubiquitous pore water freshening observed in surface sediments of the Anaximander Mountain area. Multiple fluid sources and formation water temperatures of 55 to 80 °C were derived for expelled fluids of the Olimpi area.

(Table 1) Ice station data during POLARSTERN expeditions ARK-XVIII/2 and ARK-XIX/1 to Fram Strait, the western Barents Sea and north of Svalbard

During two expeditions of the R.V. "Polarstern" to the Arctic Ocean, pack ice and under-ice water samples were collected during two different seasons: late summer (September 2002) and late winter (March/April 2003). Physical and biological properties of the ice were investigated to explain seasonal differences in species composition, abundance and distribution patterns of sympagic meiofauna (in this case: heterotrophs >20 µm). In winter, the ice near the surface was characterized by extreme physical conditions (minimum ice temperature: -22°C, maximum brine salinity: 223, brine volume: <=5%) and more moderate conditions in summer (minimum ice temperature: -5.6°C, maximum brine salinity: 94, most brine volumes: >=5%). Conditions in the lowermost part of the ice did not differ to a high degree between summer and winter. Chlorophyll a concentrations (chl a) showed significant differences between summer and winter: during winter, concentrations were mostly <1.0 µg chl a/l, while chl a concentrations of up to 67.4 µmol/l were measured during summer. The median of depth-integrated chl a concentration in summer was significantly higher than in winter. Integrated abundances of sympagic meiofauna were within the same range for both seasons and varied between 0.6 and 34.1×103 organisms /m**2 in summer and between 3.7 and 24.8×10**3 organisms /m**2 in winter. With regard to species composition, a comparison between the two seasons showed distinct differences: while copepods (42.7%) and rotifers (33.4%) were the most abundant sea-ice meiofaunal taxa during summer, copepod nauplii dominated the community, comprising 92.9% of the fauna, in winter. Low species abundances were found in the under-ice water, indicating that overwintering of the other sympagic organisms did not take place there, either. Therefore, their survival strategy over the polar winter remains unclear.