Water table fluctuations regulate the transformation and fate of nitrogen (N) species in groundwater near streams, particularly in Mediterranean catchments with dry conditions interrupted by wet seasons. To understand N dynamics at the interface between soils and groundwater, a 1-m-long soil column was constructed and filled with riparian soil with elevated organic matter content, retrieved from an experimental site in Font de...

Summary About 60% of natural gas production in the United States comes from hydraulic fracturing of unconventional reservoirs, such as shales or organic‐rich micrites. This process inoculates and enriches for halotolerant microorganisms in these reservoirs over time, resulting in a saline ecosystem that includes methane producing archaea. Here, we survey the biogeography of methanogens across unconventional reservoirs, and rep...

Aim To test whether within‐species and among‐species patterns of abundance and latitudinal range in marine bacteria resemble those found for macro‐organisms, and whether these patterns differ along latitudinal clines. Location Global pelagic marine environments. Methods Taxon‐specific sequence abundance and location were retrieved from the open‐access V6‐ rRNA pyrotag sequence data base VAMPS ( http://vamps.mbl.edu/ ), which h...

Summary Deep sequencing of PCR amplicon libraries facilitates the detection of low‐abundance populations in environmental DNA surveys of complex microbial communities. At the same time, deep sequencing can lead to overestimates of microbial diversity through the generation of low‐frequency, error‐prone reads. Even with sequencing error rates below 0.005 per nucleotide position, the common method of generating operational taxon...

Summary PCR‐based surveys of microbial communities commonly use regions of the small‐subunit ribosomal RNA (SSU rRNA) gene to determine taxonomic membership and estimate total diversity. Here we show that the length of the target amplicon has a significant effect on assessments of microbial richness and community membership. Using operational taxonomic unit (OTU)‐ and taxonomy‐based tools, we compared the V6 hypervariable regi...