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Accueil > Actualités > Metagenomics of Antarctic Peninsula Picoplankton in Light of Ecosystem Ecology

Jeudi 10 Juin, 14h - Bat. Mendel, 4e étage, Campus la Doua, Villeurbanne

Metagenomics of Antarctic Peninsula Picoplankton in Light of Ecosystem Ecology

Alison E. Murray, Ph.D., Earth and Ecosystem Sciences, Desert Research Institute, 2215 Raggio Parkway, Reno NV 89512

Comparative metagenomics is opening doors to the study of marine microbial ecology through providing unprecedented access to the underlying genomic capacity of marine microbial communities. This information encodes the biogeochemical capabilities, adaptive traits, abilities for nutrient acquisition, self defense, and other functions that comprise the basis for an interacting network of microorganisms. How these networks interact and are influenced by variation in space, time, depth, or in response to mesoscale oceanic features, or large ecosystem shifts such as climate change are poorly understood in ocean ecosystems. It is therefore essential to study microbial life on gradients and scales appropriate to the ecosystem in order to understand the intimate relationships between structure and function of the organism-ecosystem interaction. We have recently undertaken a study to investigate the dynamics of marine picoplankton in the Antarctic Peninsula, a region undergoing rapid regional climate change. We have conducted seasonal surveys to describe the community structure and shifts in biological diversity flanked by detailed metagenomic analysis of two samples collected at the height of austral summer secondary productivity and in the dark of austral winter. Differences in diversity are mirrored by differences in the summer and winter metagenomes, which was evident even by comparing G+C content bins of the end sequences from each library. Overall, the two libraries share a large pool of common cogs, yet differences in winter only or summer only functions are evident. From this analysis we hypothesize that bacteria and archaea, and potentially picoeukaryotes including Ostreococcus., have developed alternate strategies to thrive in austral winter when pressures from light-driven ecosystem ecology (i.e. competition and predation) are reduced, resulting in high bacterioplankton diversity with enhanced metabolic capabilities. These types of conclusions are only possible through community-wide comparative analyses and stand to reshape our understanding of ocean ecosystems.

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