Methane is the most abundant hydrocarbon in the atmosphere, and it is an important
greenhouse gas, which has so far contributed an estimated 20% of postindustrial global …

Life at high salt concentrations is energetically expensive. The upper salt concentration limit
at which different dissimilatory processes occur in nature appears to be determined to a …

A committee of the Mars Exploration Program Analysis Group (MEPAG) has reviewed and
updated the description of Special Regions on Mars as places where terrestrial organisms …

Microbes are difficult to culture. Consequently, the primary source of information about a
fundamental evolutionary topic, life's diversity, is the environmental distribution of gene …

Archaea and Bacteria constitute a majority of life systems on Earth but have long been
considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic …

Deep-sea ecosystems represent the largest biome of the global biosphere, but knowledge of
their biodiversity is still scant. The Mediterranean basin has been proposed as a hot spot of …

Competition between microbial species is a product of, yet can lead to a reduction in, the
microbial diversity of specific habitats. Microbial habitats can resemble ecological …

Highlights•Metagenomics permitted a better knowledge of the microbial diversity of
hypersaline habitats.•Cellular life in hypersaline habitats is dominated by prokaryotes …

Measurements of the N 2 produced by denitrification, a better understanding of non-
canonical pathways for N 2 production such as the anammox reaction, better appreciation of …

Background Several unicellular organisms (prokaryotes and protozoa) can live under
permanently anoxic conditions. Although a few metazoans can survive temporarily in the …