Anthropogenic Forcing of the Baltic Sea Thallium Cycle.

Anthropogenic activities have fundamentally changed the chemistry of the Baltic Sea. According to results reported in this study, not even the thallium (Tl) isotope cycle is immune to these activities. In the anoxic and sulfidic ("euxinic") East Gotland Basin today, Tl and its two stable isotopes are cycled between waters and sediments as predicted based on studies of other redox-stratified basins (e.

Fossilized giant sulfide-oxidizing bacteria from the Devonian Hollard Mound seep deposit, Morocco.

The giant sulfide-oxidizing bacteria are particularly prone to preservation in the rock record, and their fossils have been identified in ancient phosphorites, cherts, and carbonates. This study reports putative spherical fossils preserved in the Devonian Hollard Mound hydrocarbon-seep deposit. Based on petrographical, mineralogical, and geochemical evidence the putative microfossils are interpreted as sulfide-oxidizing bacteria similar to the present-day genus Thiomargarita, which is also found at modern hydrocarbon seeps.

Biological manganese-dependent sulfide oxidation impacts elemental gradients in redox-stratified systems: indications from the Black Sea water column.

The reduction of manganese oxide with sulfide in aquatic redox-stratified systems was previously considered to be mainly chemical, but recent isolation of the Black Sea isolate Candidatus Sulfurimonas marisnigri strain SoZ1 suggests an important role for biological catalyzation. Here we provide evidence from laboratory experiments, field data, and modeling that the latter process has a strong impact on redox zonation in the Black Sea. High relative abundances of Sulfurimonas spp.

Candidatus Sulfurimonas marisnigri sp. nov. and Candidatus Sulfurimonas baltica sp. nov., thiotrophic manganese oxide reducing chemolithoautotrophs of the class Campylobacteria isolated from the pelagic redoxclines of the Black Sea and the Baltic Sea.

Species of the genus Sulfurimonas are reported and isolated from terrestrial habitats and marine sediments and water columns with steep redox gradients. Here we report on the isolation of strains SoZ1 and GD2 from the pelagic redoxcline of the Black Sea and the Baltic Sea, respectively. Both strains are gram-stain-negative and appear as short and slightly curved motile rods.

Bubble-mediated transport of benthic microorganisms into the water column: Identification of methanotrophs and implication of seepage intensity on transport efficiency.

Benthic microorganisms transported into the water column potentially influence biogeochemical cycles and the pelagic food web structure. In the present study six gas-releasing vent sites in the Coal Oil Point seep field (California) were investigated, and the dislocation of microorganisms from the sediment into the water column via gas bubbles released from the seabed was documented. It was found that the methanotrophs transport efficiency was dependent on the volumetric gas flow, with the highest transport rate of 22.