Biogeochemical Niches of Fe-Cycling Communities Influencing Heavy Metal Transport along the Rio Tinto, Spain.

In the mining-impacted Rio Tinto, Spain, Fe-cycling microorganisms influence the transport of heavy metals (HMs) into the Atlantic Ocean. However, it remains largely unknown how spatial and temporal hydrogeochemical gradients along the Rio Tinto shape the composition of Fe-cycling microbial communities and how this in turn affects HM mobility. Using a combination of DNA- and RNA-based 16S rRNA (gene) amplicon sequencing and hydrogeochemical analyses, we explored the impact of pH, Fe(III), Fe(II), and Cl on Fe-cycling microorganisms.

Role of biogenic Fe(III) minerals as a sink and carrier of heavy metals in the Rio Tinto, Spain.

Oxidation of sulfide ores in the Iberian Pyrite Belt region leads to the presence of extremely high concentration of dissolved heavy metals (HMs) in the acidic water of the Rio Tinto. Fe(II) is microbially oxidized resulting in the formation of suspended particulate matter (SPM) consisting of microbial cells and Fe(III) minerals with co-precipitated HMs. Although substantial amount of HM-bearing SPM is likely deposited to river sediment, a portion can still be transported through estuary to the coastal ocean.

Radioprotective role of cyanobacterial phycobilisomes.

Cyanobacteria are thought to be responsible for pioneering dioxygen production and the so-called "Great Oxygenation Event" that determined the formation of the ozone layer and the ionosphere restricting ionizing radiation levels reaching our planet, which increased biological diversity but also abolished the necessity of radioprotection. We speculated that ancient protection mechanisms could still be present in cyanobacteria and studied the effect of ionizing radiation and space flight during the Foton-M4 mission on Synechocystis sp. PCC6803.

Turning cellulose waste into electricity: hydrogen conversion by a hydrogenase electrode.

Hydrogen-producing thermophilic cellulolytic microorganisms were isolated from cow faeces. Rates of cellulose hydrolysis and hydrogen formation were 0.2 mM L(-1) h(-1) and 1 mM L(-1) h(-1), respectively.