Mercury concentrations in waters of the Atlantic Ocean and Mediterranean Sea

Total mercury concentration in waters of the Atlantic Ocean and Mediterranean Sea measured in January-April 1982 varied from 0.007 to 0.192 µg/l. Particulate form was 1.6-16% of dissolved form. Inorganic mercury accounted for 16-67% of dissolved mercury. Total mercury concentration in the surface film was 0.74-1.85 µg/l, 10-40 times higher than in seawater. Concentration of particulate form in the film was from 100 to 400 times higher than in seawater.

Paleoenvironmental changes in the western Mediterranean since the last glacial maximum: High resolution multiproxy record from the Algero-Balearic basin

The present study uses a multiproxy approach in order to further understand the evolution of climate responses in the western Mediterranean as of the Last Glacial Maximum. Sediments from ODP Site 975 in the Algero-Balearic basin have been analysed at high resolution, both geochemically andmineralogicallly. The resulting data have been used as proxies to establish a sedimentary regime, primary marine productivity, the preservation of the proxies and oxygen conditions. Fluctuations in detrital element concentrations were mainly the consequence of wet/arid oscillations. Productivity has been established using Ba excess, according to which marine productivity appears to have been greatest during cold events Heinrich 1 and Younger Dryas. The S1 time interval was not as marked by increases in productivity as was the eastern Mediterranean. In contrast, the S1 interval was first characterized by a decreasing trend and then by a fall in productivity after the 8.2 ky BP dry-cold event. Since then productivity has remained low. Here we report that there was an important redox event in this basin, probably a consequence of the major oceanographic circulation change occurring in the western Mediterranean at 7.7 ky BP. This circulation change led to reventilation as well as to diagenetic remobilization of redox-sensitive elements and organic matter oxidation. Comparisons between our paleoceanographic reconstruction for this basin and those regarding other Mediterranean basins support the hypothesis that across the Mediterranean there were different types of responses to climate forcing mechanism. The Algero-Balearic basin is likely to be a key area for further understanding of the relationships between the North Atlantic and the eastern Mediterranean basins.

Ingestion rate and egg production of copepods collected in the upper 100m in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The phytoplankton dataset is based on samples taken during March-April 2008 in Libyan Sea, Southern Aegean Sea and Northern Aegean Sea. Ingestion rates were estimated from experiments performed at all the third priority stations during the cruise according to DoW of Sesame project. Copepods for the experiments were obtained with slow non-quantitative tows from the upper 100 m layer of the water column using 200 µm mesh size nets fitted with a large non-filtering cod end. For the grazing experiments we used the following copepod species: Calanus helgolandicus and Centropages typicus according to the relevant reference (Bamstedt et al. 2000). Copepod clearance rates on ciliates were calculated according to Frost equations (Frost 1972). Ingestion rates were calculated by multiplying clearance rates by the initial standing stocks (Bamstedt et al. 2000). Egg production rates of the dominant calanoid copepods were determined by incubation of fertilised females (eggs/female/day) collected in the 0-100m layer. Copepod egg production was measured for the copepods Eucalanus monachus, Centropages typicus and Calanus helgolandicus. On board experiments for the estimation of copepod egg production were taken place. For the estimation of copepod production (mg/m**2/day), lengths (copepods and eggs) were converted to body carbon (Hopcroft et al., 1998) and production was estimated from biomass and weight-specific egg production rates, by assuming that those rates are representative for juvenile specific growth rates (Berggreen et al., 1988).

Weather conditions and phosphorus speciation in waters of the Western Sargasso Sea in October-November 1977

Forms of phosphorus were determined for the first time in the area under study. Based on the ratio between organic and inorganic forms of phosphorus, it is concluded that sorption processes in the thin surface layer and photosynthetic processes in surface water are of the same intensity. Extremely high values of total phosphorus in the thin layer may be indicators of water pollution.

Radiocarbon datings of Upper Quaternary bottom sediments from the Mediterranean Sea

Bottom sediment samples were collected in the Central Mediterranean, Southern Adriatic, Tyrrhenian, Algerian-Provencal, and Alboran basins of the Mediterranean Sea. Fifty-six datings were done for 12 sediment cores. The lowest sedimentation rates during Holocene were found on the abyssal plain of the Algerian-Provencal basin (2.4-4.0 cm/ky). In the Southern Adriatic, Tyrrhenian, and Alboran basins sedimentation rates were somewhat higher (6-12 cm/ky). On slopes of the Southern Adriatic and Tyrrhenian basins during Late Würm glaciation rates of "normal" sedimentation were within the range 11.8-26.8 cm/ky.

Physical/chemical properties and stable oxygen and carbon isotope records of Holocene to late Pleistocene sediments in the Gela Basin, central Mediterranean Sea

The Holocene Twin Slides form the most recent of recurrent mass wasting events along the NE portion of Gela Basin within the Sicily Channel, central Mediterranean Sea. Here, we present new evidence on the morphological evolution and stratigraphic context of this coeval slide complex based on deepdrilled sediment sequences providing a >100 ka paleo-oceanographic record. Both Northern (NTS) and Southern Twin Slide (STS) involve two failure stages, a debris avalanche and a translational slide, but are strongly affected by distinct preconditioning factors linked to the older and buried Father Slide. Core-acoustic correlations suggest that sliding occurred along sub-horizontal weak layers reflecting abrupt physical changes in lithology or mechanical properties. Our results show further that headwall failure predominantly took place along sub-vertical normal faults, partly through reactivation of buried Father Slide headscarps.

(Table 1) Time series of ostracod population density off Bokniseck shore ('Hausgarten'), western Baltic Sea

Seasonal distributions of ostracode species from the Bay of Kiel, western Baltic Sea (Bokniseck, 'Hausgarten') were studied at seven observation stations located between 6 - 23.5 m water depth. During the period from December 1973 to March 1975, 175 samples were taken every two weeks from the sediment surface at each station. Environmental factors were measured simultaneously with sampling. Most of the ostracode species were present in all of the samples throughout the year; four species were found to be seasonal. On the other hand, the population densities of each of the examined ostracode species, as revealed by countings, indicate marked seasonal variations. These variations are attributed to changes in length rate and timing of the reproductive cycles of the different ostracode species, effected mainly by food supply. Maxima in the abundance of the ostracode species with short (1/2 - 1 month) life cycles, occurred simultaneously with peaks of food supply in spring and autumn, whereas the maxima abundance of ostracodes with longer (10 - 12 months) life cycles was delayed.

Ciliates abundance in the eastern Mediterranean Sea in March and April 2008 during SES_GR1

The dataset is based on samples collected in the framework of the project SESAME, in the Ionian, Libyan and Aegean Sea during March- April 2008. For ciliate identification and enumeration, 100-3000 ml samples were left for 24h-4d for sedimentation and then observed under an inverted microscope. Ciliates were counted, distinguished into size-classes and major taxonomic groups and identified down to genus or species level where possible (Pitta et al. 2005).