SYSTEMS BIOLOGY: Footprints in the Oceans

Laboratory research works well in identifying the responses of individual organisms to a series of environmental changes; it is rather more difficult, however, to carry out analogous studies of how community structure and function are influenced by the environment and by interactions among ecosystem residents. Gianoulis et al. have documented the

metabolic adaptations of microbial communities using metagenomic data culled from the Global Ocean Survey, which has sampled sites in the Atlantic and Pacific Oceans. Analytical approaches enabled them to examine the effects of multiple environmental factors (including temperature, salinity, sample depth, and average chlorophyll content) on metabolic pathways. Some pathways were associated with particular environments, providing what could be called a metabolic footprint. In contrast, some amino acid biosynthetic pathways varied with the environment, yet others did not. Rather than reflecting the energetic potential of the environment, this variation may indicate the presence or absence of valuable metals, such as cobalt, that are used to make catalytic cofactors. Potentially, metabolic footprints might be used as sensitive detectors of environmental change. -- BJ

Proc. Natl. Acad. Sci. U.S.A. 106, 1374 (2009).