Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 30 September 2009 Evgeniy, Yakushev , Svetlana, Pakhomova , Kai, Sørenson , Jens, Skei
The joint analysis of manganese species distributions (dissolved Mn, particulate Mn, and bound Mn) obtained in the Black Sea, the Baltic Sea (Landsort Deep) and Oslo Fjord (Baerumsbassenget), enabled common features to be revealed that demonstrate the similarity in the mechanisms of pelagic redox layer formation. Our investigations demonstrate that Mn bound in stable complexes with hypothetical P-containing compounds or organic matter (OM) is observed in the redox zones at significant (average: 0.5-1.0μM) concentrations and is likely present as Mn(III), an intermediate product of Mn(II) oxidation. This bound Mn(III) can explain phosphate distribution in redox interfaces and the formation [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 23 September 2009 Mauro, Mecozzi , Marco, Pietroletti , Veronica, Gallo , Marcelo Enrique, Conti
This study describes some specific aspects of the mechanisms of chemical reactions involved in the formation of marine mucilage aggregates obtained from several living organisms incubated in laboratory under static conditions in absence of water and air circulation. After appearance, the synthetic mucilages were sampled daily during the evolution of the aggregation process and for each sample infrared (FTIR) and ultraviolet visible (UV-VIS) spectra were collected. Then the spectra were examined by two-dimensional correlation analysis (2DCORR), a powerful tool for the study of the dynamic structural and compositional changes of a molecular system caused by any possible external perturbation. [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 22 September 2009 Luc, Tremblay , Jean-Pierre, Gagné
Dissolved and particulate organic matters from different stations and depths in the St. Lawrence estuarine system (Canada) were collected and extracted using humic substance (HS) fractionation protocols. The origin, composition, and fate of organic matter/HS were assessed by distribution characteristics, elemental and isotopic compositions, and infrared diffuse reflectance spectroscopy (DRIFTS). HS represented over 50% of dissolved organic matter in the Saguenay Fjord’s surface waters but this proportion decreased to 9 – 19% in the St. Lawrence Lower Estuary (SLLE). Fulvic acids were the dominant component (68 – 92%) of dissolved HS, especially in high salinity waters having very low [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 19 September 2009 Ralph N., Mead , Jeremy B., Morgan , G. Brooks, Avery Jr. , Robert J., Kieber , Aleksandra, Kirk , …
The first concentration data for the artificial sweetener sucralose (Splenda®) is presented for North American coastal and open ocean waters. Large volume water samples were collected and pre-concentrated using solid phase extraction followed by GC/MS analysis. The concentration of sucralose varied over several orders of magnitude in these environmental samples with the greatest abundance in a waste water treatment plant effluent (300nM). The concentration decreased in receiving waters of the Cape Fear River Estuary, NC (CFRE) where surface water concentrations at the mouth of the estuary were 0.94nM. Sucralose was also detected in the oligotrophic waters of the Gulf [...]
Abstract A comprehensive review is given of the theory and properties of nonrelativistic shocks in hot collisionless plasmas—in view
of their possible application in astrophysics. Understanding non-relativistic collisionless shocks is an [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 15 September 2009 Miguel, Caetano , Ricardo, Prego , Carlos, Vale , Hilda, de Pablo , Judith, Marmolejo-Rodríguez
The vertical distribution of trace and rare earth elements (REE) was studied in a sediment core from the Vigo Ria (NW Iberian Peninsula) where sedimentation patterns have changed during the last century. The depth profiles of Al, Ca and Corg (particulate organic carbon) point to three distinct sedimentary units: (a) the upper sediment unit that consists of fine grained material rich in organic matter (3-4% of Corg); (b) a transitional layer between 75 and 105cm where an almost linear decrease of Al and Corg content was observed; (c) a deep sediment unit composed of coarser material. Ratios of Fe, [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 15 September 2009 N.K., Bigalke , G., Rehder , G., Gust
The dissolution of in-situ generated methane hydrate in undersaturated, synthetic seawater (S=35) was investigated in a series of laboratory-based experiments at P-/T-conditions within the hydrate stability field. A controlled flow field was generated across the smooth hydrate surface to test if, in addition to thermodynamic variables, the dissolution rate is influenced by changing hydrodynamic conditions. The dissolution rate was found to be strongly dependent on the friction velocity, showing that hydrate dissolution in undersaturated seawater is a diffusion-controlled process. The experimental data was used to obtain diffusional mass transfer coefficients kd, which were found to correlate linearly with the [...]
Publication year: 2009 Source: Marine Chemistry, In Press, Accepted Manuscript, Available online 12 September 2009 A., Hirota , A., Ijiri , D.D., Komatsu , S.B., Ohkubo , F., Nakagawa , …
We found N2O enrichment of up to 157% saturation in continental shelf water columns in the Bering and Chukchi Seas at water depths less than 66m. The N2O enrichment exhibited a linear relationship with N* depletion. We also observed that the stable isotopic characteristics of N2O are an enrichment of 18O and a depletion of 15N relative to atmospheric N2O. We conclude that N2O in the area is primarily produced through denitrification in sediments. By using the observed instantaneous N2O emission rate, we estimated the annual emission rate from the surface to atmosphere in the area to be 0.097±0.065 [...]
Substance dependence is a complex environmental and genetic disorder that results in serious health and socioeconomic consequences. Many studies have reported and implicated genes associated with various substance dependence outcomes, including [...]
