Sulphur compounds, methane, and phytoplankton during SONNE cruise SO202/2 (Transbrom Sonne)

Here we present results of the first comprehensive study of sulphur compounds and methane in the oligotrophic tropical West Pacific Ocean. The concentrations of dimethylsuphide (DMS), dimethylsulphoniopropionate (DMSP), dimethylsulphoxide (DMSO), and methane (CH4), as well as various phytoplankton marker pigments in the surface ocean were measured along a north-south transit from Japan to Australia in October 2009. DMS (0.9 nmol/l), dissolved DMSP (DMSPd, 1.6 nmol/l) and particulate DMSP (DMSPp, 2 nmol/l) concentrations were generally low, while dissolved DMSO (DMSOd, 4.4 nmol/l) and particulate DMSO (DMSOp, 11.5 nmol/l) concentrations were comparably enhanced. Positive correlations were found between DMSO and DMSP as well as DMSP and DMSO with chlorophyll a, which suggests a similar source for both compounds. Similar phytoplankton groups were identified as being important for the DMSO and DMSP pool, thus, the same algae taxa might produce both DMSP and DMSO. In contrast, phytoplankton seemed to play only a minor role for the DMS distribution in the western Pacific Ocean. The observed DMSPp : DMSOp ratios were very low and seem to be characteristic of oligotrophic tropical waters representing the extreme endpoint of the global DMSPp : DMSOp ratio vs. SST relationship. It is most likely that nutrient limitation and oxidative stress in the tropical West Pacific Ocean triggered enhanced DMSO production leading to an accumulation of DMSO in the sea surface. Positive correlations between DMSPd and CH4, as well as between DMSO (particulate and total) and CH4, were found along the transit. We conclude that both DMSP and DMSO serve as substrates for methanogenic bacteria in the western Pacific Ocean.

Major ion concentrations in rain water and atmospheric moisture above the Atlantic Ocean

Concentratios of Cl-, Mg2+, Ca2+, and HCO3- ions were studied in rain waters and condensed atmospheric moisture above the Atlantic Ocean. Maximal number of samples was collected in the eastern tropical North Atlantic. Concentration of chloride ions ranged from 1 to 28 mg/l in rain waters (average 4.3 mg/l) and ranged from 0.3 to 2 mg/l in condensed atmospheric moisture with the average about one order of magnitude less than that for rain waters. Chloride normalized concentrations of magnesium and calcium are greater in rain waters and condensed atmospheric moisture than in ocean water due to more intensive subtraction of these ions as compared to chloride ions. Chloride normalized HCO3- concentration is one order of magnitude greater in atmospheric moisture than in seawater, possibly because of volatile component CO2 taking part in exchange between the ocean and the atmosphere.

Data on multidisciplinary research in the Tajura Rift (Gulf of Aden) during Cruise 7 of R/V Akademik Mstislav Keldysh in winter 1983-1984

In the collective monograph results of geological and geophysical studies in the Tadjura Rift carried out by conventional outboard instruments and from deep/sea manned submersibles "Pisces" in winter 1983-1984 are reported. Main features of rift tectonics, geology, petrology, and geochemistry of basalts from the rift are under consideration. An emphasis is made on lithology, stratigraphy, and geochemistry of bottom sediments. Roles of terrigenous, edafogenic, biogenic, and hydrothermal components in formation of bottom sediments from the rift zone are shown.

Major and rare earth element contents and their speciations in ferruginous nodules and host sediments from the Barents Sea

Contents of Fe, Mn, Al, P, and rare earth elements (REE) in ferruginous nodules and host sediments of the eastern Barents Sea were studied. A direct Fe-P correlation in reactive components of the sediments and nodules was found. The nodules were shown to be formed through Fe(II) oxidation in the surface layer of sediments and cementation of terrigenous fraction of sediments by Fe(III) oxyhydroxides. The latter accumulate phosphorus due to processes of sorption - co-precipitation, by forming Fe(III) hydrophosphates. REE composition in the sediments and nodules normalized to NASC contents is characterized by increased proportion of light REE that may be caused by regional features of their sources. Due to significant share of terrigenous matter in the Fe nodules (up to 65% for Nd), REE composition of bulk samples is similar to that of host sediments. A negative cerium anomaly in composition of reactive REE may result from REE sorption from seawater. REE bulk composition of a ferruginous crust is closer to that of seawater than one of the ferruginous nodules from the sediments because of essentially lower content of diluent terrigenous matter.