Methane fueled lake pelagic food webs in a Cretaceous greenhouse world.

Methane (CH) is a potent greenhouse gas but also an important carbon and energy substrate for some lake food webs. Understanding how CH incorporates into food webs is, therefore, crucial for unraveling CH cycling and its impacts on climate and ecosystems. However, CH-fueled lake food webs from pre-Holocene intervals, particularly during greenhouse climates in Earth history, have received relatively little attention.

Sustained and intensified lacustrine methane cycling during Early Permian climate warming.

Lakes are a major emitter of the atmospheric greenhouse gas methane (CH); however, their roles in past climate warming episodes remain poorly understood owing to a scarcity of geological records. Here we report the occurrence of sustained and intensified microbial CH cycling in paleo-Lake Junggar in northwestern China, one of the largest known Phanerozoic lakes, during Early Permian climate warming. High-precision U-Pb geochronology refines the age of the upper Lucaogou Formation to the Artinskian, which marks a major glacial-to-postglacial climate transition.

Comparative metagenomic analysis of plasmid encoded functions in the human gut microbiome.

Background: Little is known regarding the pool of mobile genetic elements associated with the human gut microbiome. In this study we employed the culture independent TRACA system to isolate novel plasmids from the human gut microbiota, and a comparative metagenomic analysis to investigate the distribution and relative abundance of functions encoded by these plasmids in the human gut microbiome.

Results: Novel plasmids were acquired from the human gut microbiome, and homologous nucleotide sequences with high identity (>90%) to two plasmids (pTRACA10 and pTRACA22) were identified in the multiple human gut microbiomes analysed here.