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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/S0967-0637(99)00101-6 Byline: M Goutx, A Momzikoff, L Striby, V Andersen, J.C Marty, I Vescovali Keywords: Particle fluxes; High-frequency sampling; Particulate organic carbon; Proteins; Lipid classes; Northwestern Mediterranean Abstract: Sinking particles were collected every 4h with drifting sediment traps deployed at 200m depth in May 1995 in a 1-D vertical system during the DYNAPROC observations in the northwestern Mediterranean sea. POC, proteins, glucosamine and lipid classes were used as indicators of the intensity and quality of the particle flux. The roles of day/night cycle and wind on the particle flux were examined. The transient regime of production from late spring bloom to pre-oligotrophy determined the flux intensity and quality. POC fluxes decreased from, on average, 34 to 11 mg m.sup.-2 d.sup.-1, representing 6-14% of the primary production under late spring bloom conditions to 1-2% under pre-oligotrophic conditions. Total protein and chloroplast lipid fluxes correlated with POC and reflected the input of algal biomass into the traps. As the season proceeded, changes in the biochemical composition of the exported material were observed. The C/N ratio rose from 7.8 to 12. Increases of serine (10-28% of total proteins), total lipids (7-9 to 14-28% of POC) and reserve lipids (1-5 to 5-22% of total lipids) were noticeable, whereas total protein content in POC decreased (20-27 to 18-7%). N-acetyl glucosamine, a tracer of fecal pellet flux, showed that zooplankton grazing was a major vector of downward export during the decaying bloom. Against this background pattern, episodic events specifically increased the flux, modifying the quality and the settling velocity of particles. Day/night signals in biotracers (POC, N-acetyl glucosamine, protein and chloroplast lipids) showed that zooplankton migrations were responsible for sedimentation of fresh material through fast sinking particles (V=170-180md.sup.-1) at night. Periodic signatures of re-processed material (high lipolysis and bacterial biomass indices) suggested that other zooplankton fecal pellets or small aggregates, probably of lower settling velocities (V Article History: Received 6 October 1997; Revised 3 March 1999; Accepted 25 June 1999

Researchers at the DYFAMED permanent station in the northwestern Mediterranean Sea determined monthly vertical profiles of iodide, iodate and total free iodine in the area for a period of one year. Differential pulse polarography and cathodic stripping square wave voltammetry were used to determine dissolved iodate and iodide, respectively. The predominant species present was iodate while iodide was concentrated in surface waters. Total free iodine was slightly lower in surface waters than in deep waters.

Abstract: The kinetic parameters, namely the triplet activation energy E A, model function f(α) or g(α) and pre-exponential factor A of the oxidation of Constantan tapes in 1atm of oxygen have been determined from both isothermal and non-isothermal thermogravimetry. For isothermal experiments, with temperatures ranging from 650°C to 900°C, the results from direct conversion of the weight increase as a function of the time and curve fitting, are compared with the isoconversion method. For the non-isothermal experiments, with heating rates from 1°C/min to 20°C/min, comparison is made between the Friedman differential method and the integral methods of Kissinger, Ozawa and Li and Tang. All methods give apparent activation energies with relative standard deviations as low as 3%. The results converge to the identification of three stages in the oxidation behaviour. A parabolic law for reaction extents α below 15% with E A =246±7kJmol−1, ln A =14.3, is followed by two linear stages with E A =244±4kJmol−1 and ln A =15.3 for 0.18< α <0.35 and E A =228±15kJmol−1, ln A ≈13 for α >45%, respectively. [Copyright &y& Elsevier]