Simultaneous combustion preparation for mercury isotope analysis and detection of total mercury using a direct mercury analyzer.

Mercury (Hg) stable isotope signatures are widely used to understand Hg cycling in the environment. Sample preparation methods for determining Hg isotope ratios by CV-MC-ICP-MS vary widely among laboratory facilities and sample types. Here, we present a novel and rapid method for preparing solid samples prior to determining Hg isotope composition.

Updates to instrumentation and protocols for isotopic analysis of nitrate by the denitrifier method.

Rationale: The denitrifier method allows for highly sensitive measurement of the (15) N/(14) N (δ(15) N value) and (18) O/(16) O (δ(18) O value) of nitrate dissolved in natural waters and for highly sensitive δ(15) N measurement of other N forms (e.g., organic N) that can be converted into nitrate.

Bacterial diversity in hydrothermal sediment and epsilonproteobacterial dominance in experimental microcolonizers at the Mid-Atlantic Ridge.

We report here a molecular survey based on 16S rRNA genes of the bacterial diversity found in two deep-sea vent niches at the Mid-Atlantic Ridge: hydrothermal sediment (Rainbow site), and microcolonizers made of three different substrates (organic-rich, iron-rich and pumice) that were exposed for 15 days to a vent emission. Bacterial diversity in sediment samples was scattered through many bacterial divisions. The most abundant and diverse environmental sequences (phylotypes) in our libraries corresponded to the Gammaproteobacteria, followed by the Acidobacteria.