Boron isotopes, pH and pCO2 calculation for one Fiji coral specimen Porites (1898-1998), 2012

delta11B results and deduced pH, pCO2 and omega values obtained for a tropical coral specimen Porites collected in 1998 at Yasawa (16°48'S- 177°27'E) on the western side of the Fiji archipelago, location in the north western part of the Pacific Warm Pool. Such Porites specimen grew during the XXth century (1898-1998). Boron isotopes results allowed the reconstruction of surface ocean acidification in the vincinity of Fiji Islands with strong interdecadal influence of the ENSO at regional scale. pHT calculation parameters (Hönisch et al., 2007): a=0 PER MIL; alpha=0.9804; delta11B=39.5 PER MIL; salinity=35.02; pKB from Dickson (1990). pCO2 and omega calculation parameters: TA= 2350 µM; Ca= 10.2 mM; Dickson et al.(2007); Mucci 1983.

Mineralogic, elemental, and stable isotopic composition of bulk carbonate sediments from ODP Leg 166 sites

An intensive mineralogic and geochemical investigation was conducted on sediments recovered during Ocean Drilling Program Leg 166 from the western Great Bahama Bank at Sites 1006, 1008, and 1009. Pleistocene through middle Miocene sediments recovered from Site 1006, the distal location on the Leg 166 transect, are a mixture of bank-derived and pelagic carbonates with lesser and varying amounts of siliciclastic clays. A thick sequence of Pleistocene periplatform carbonates was recovered near the platform edge at Sites 1008 and 1009. Detailed bulk mineralogic, elemental (Ca, Mg, Sr, and Na), and stable isotopic (d18O and d13C) analyses of sediments are presented from a total of 317 samples from all three sites.

Abundance and biomass of dinoflagellates and ciliates at time series station Helgoland Roads, North Sea, 2007-2009

A monitoring programme for microzooplankton was started at the long-term sampling station ''Kabeltonne'' at Helgoland Roads (54°11.30' N; 7°54.00' E) in January 2007 in order to provide more detailed knowledge on microzooplankton occurrence, composition and seasonality patterns at this site and to complement the existing plankton data series. Ciliate and dinoflagellate cell concentration and carbon biomass were recorded on a weekly basis. Heterotrophic dinoflagellates were considerably more important in terms of biomass than ciliates, especially during the summer months. However, in early spring, ciliates were the major group of microzooplankton grazers as they responded more quickly to phytoplankton food availability. Mixotrophic dinoflagellates played a secondary role in terms of biomass when compared to heterotrophic species; nevertheless, they made up an intense late summer bloom in 2007. The photosynthetic ciliate Myrionecta rubra bloomed at the end of the sampling period. Due to its high biomass when compared to crustacean plankton especially during the spring bloom, microzooplankton should be regarded as the more important phytoplankton grazer group at Helgoland Roads. Based on these results, analyses of biotic and abiotic factors driving microzooplankton composition and abundance are necessary for a full understanding of this important component of the plankton.

Chemical and isotopic compositions of ocean authigenic carbonates

Oceanic authigenic carbonates are classified according to origin of the carbonate carbon source using a complex methodology that includes methods of sedimentary petrography, mineralogy, isotope geochemistry, and microbiology. Mg-calcite (protodolomite) and aragonite predominate among the authigenic carbonates. All authigenic carbonates are depleted in 13C and enriched in 18O (in PDB system) that indicates biological fractionation of isotopes during carbonate formation. Obtained results show that authigenic carbonate formation is a biogeochemical (microbial) process, which involves carbon from ancient sedimentary rocks, abiogenic methane, and bicarbonate-ion of hydrothermal fluids into the modern carbon cycle.

Minerals, native metals, and intermetallides in bottom sediments of the Markov Deep, Mid-Atlantic Ridge

Bottom sediments of the Markov Deep contain rather large (>0.1 mm) grains of native minerals and intermetallides of noble and nonferrous metals that can be concentrated in placers. Intermetallides of Pt and Fe are likely to be derivates of the gold-hematite-barite assemblage that forms at late (low-depth) stages of hydrothermal massive sulfide formation. Mineral association of native forms of lead, tin, and copper with Zn-bearing copper may be related to hydrothermal transformation of ultrabasic and basic rocks accompanied by massive sulfide copper mineralization. The association of these minerals of native elements in bottom sediments can also serve as a prospecting guide for sulfide mineralization both at the Sierra Leone site, in particular, and on the seafloor, in general.

(Table 2) Mineralogy, stable isotopes, and mineral percentages of the carbonate fraction of samples from the South China Sea

Chemoherm carbonates, as well as numerous other types of methane seep carbonates, were discovered in 2004 along the passive margin of the northern South China Sea. Lithologically, the carbonates are micritic containing peloids, clasts and clam fragments. Some are highly brecciated with aragonite layers of varying thicknesses lining fractures and voids. Dissolution and replacement is common. Mineralogically, the carbonates are dominated by high magnesium calcites (HMC) and aragonite. Some HMCs with MgCO3 contents of between 30-38 mol%-extreme-HMC, occur in association with minor amounts of dolomite. All of the carbonates are strongly depleted in d13C, with a range from -35.7 to -57.5 per mil PDB and enriched in d18O (+ 4.0 to + 5.3 per mil PDB). Abundant microbial rods and filaments were recognized within the carbonate matrix as well as aragonite cements, likely fossils of chemosynthetic microbes involved in carbonate formation. The microbial structures are intimately associated with mineral grains. Some carbonate mineral grains resemble microbes. The isotope characteristics, the fabrics, the microbial structure, and the mineralogies are diagnostic of carbonates derived from anaerobic oxidation of methane mediated by microbes. From the succession of HMCs, extreme-HMC, and dolomite in layered tubular carbonates, combined with the presence of microbial structure and diagenetic fabric, we suggest that extreme-HMC may eventually transform into dolomites. Our results add to the worldwide record of seep carbonates and establish for the first time the exact locations and seafloor morphology where such carbonates formed in the South China Sea. Characteristics of the complex fabric demonstrate how seep carbonates may be used as archives recording multiple fluid regimes, dissolution, and early transformation events.

Radiocarbon dating, sedimentation rate, granulometry and organic carbon content of ODP Leg 182 sites

This data report presents sedimentological (grain size) and geochemical (X-ray diffraction, total organic carbon, accelerator mass spectrometry radiocarbon, and percent carbonate) information obtained from the western transect (Sites 1132, 1130, and 1134) and the eastern transect (Sites 1129, 1131, and 1127) in the Great Australian Bight during Leg 182. The purpose is to quantify changing rates of sediment accumulation and changes in sediment type from the late Pleistocene and Holocene, in order to relate these changes to the well-known sea level curve that exists for this time frame. Ultimately, these data can be used to more effectively interpret lithologic variations deeper in the Pleistocene succession, which most likely represent orbitally forced sea level events.