biogeochemistry
Environmental Microbiology | SpotlightEvidence for a Growth Zone for Deep-Subsurface Microbial Clades in Near-Surface Anoxic SedimentsMany studies show that the uncultured microbes that dominate global marine sediments do not actually increase in population size as they are buried in marine sediments; rather, they exist in a sort of prolonged torpor for thousands of years. This is because, although studies have shown biomass turnover in these clades, no evidence has ever been found that deeper sediments have larger populations for specific clades than shallower layers...
Geomicrobiology | SpotlightGenome-Resolved Metagenomics and Detailed Geochemical Speciation Analyses Yield New Insights into Microbial Mercury Cycling in Geothermal SpringsLittle is currently known about biogeochemical mercury cycling in geothermal systems. The manuscript presents a new conceptual model, supported by genome-resolved metagenomic analysis and detailed geochemical measurements. The model illustrates environmental factors that influence mercury cycling in acidic springs, including transitions between solid (mineral) and aqueous phases of mercury, as well as the interconnections among mercury...
GeomicrobiologyPerformance of a Geosynthetic-Clay-Liner Cover System at a Cu/Zn Mine Tailings ImpoundmentMining activities are accompanied by significant environmental and financial liabilities, including the release of acid mine drainage (AMD). AMD is caused by accelerated chemical and biological oxidation of sulfide minerals in mine wastes and is characterized by low pH and high concentrations of sulfate and metal(loid)s. Microorganisms assume important roles in the catalysis of redox reactions. Our research elucidates linkages among the...
Genetics and Molecular BiologyAxenic Biofilm Formation and Aggregation by Synechocystis sp. Strain PCC 6803 Are Induced by Changes in Nutrient Concentration and Require Cell Surface StructuresMicrobes can exist as suspensions of individual cells in liquids and also commonly form multicellular communities attached to surfaces. Surface-attached communities, called biofilms, can confer antibiotic resistance to pathogenic bacteria during infections and establish food webs for global nutrient cycling in the environment. Phototrophic biofilm formation is one of the earliest phenotypes visible in the fossil record, dating back over...
- Environmental Microbiology | SpotlightFilamentous Giant Beggiatoaceae from the Guaymas Basin Are Capable of both Denitrification and Dissimilatory Nitrate Reduction to Ammonium
Whether large sulfur bacteria of the family Beggiatoaceae reduce NO3− to N2 via denitrification or to NH4+ via DNRA has been debated in the literature for more than 25 years. We resolve this debate by showing that certain members of the Beggiatoaceae...
- Environmental Microbiology | SpotlightThe Tale of a Neglected Energy Source: Elevated Hydrogen Exposure Affects both Microbial Diversity and Function in Soil