Fungi in the future: interannual variation and effects of atmospheric change on arbuscular mycorrhizal fungal communities

Understanding the natural dynamics of arbuscular mycorrhizal (AM) fungi and their response to global environmental change is essential for the prediction of future plant growth and ecosystem functions. We investigated the long-term temporal dynamics and effect of elevated atmospheric carbon dioxide (CO2) and ozone (O3) concentrations on AM fungal communities. Molecular methods were used to characterize the AM fungal communities of soybean (Glycine max) grown under elevated and ambient atmospheric concentrations of both CO2 and O3 within a free air concentration enrichment experiment in three growing seasons over 5 yr. Elevated CO2 altered the community composition of AM fungi, increasing the ratio of Glomeraceae to Gigasporaceae. By contrast, no effect of elevated O3 on AM fungal communities was detected. However, the greatest compositional differences detected were between years, suggesting that, at least in the short term, large-scale interannual temporal dynamics are stronger mediators than atmospheric CO2 concentrations of AM fungal communities. We conclude that, although atmospheric change may significantly alter AM fungal communities, this effect may be masked by the influences of natural changes and successional patterns through time. We suggest that changes in carbon availability are important determinants of the community dynamics of AM fungi

Preface: Mechanistic links between biodiversity and ecosystem functioning

International audienc

Root associated fungal communities from the Wageningen long term biodiversity-productivity experiment

Species-rich plant communities are more productive than species-poor plant communities but the reasons behind this relationship are currently unclear. We characterised the fungal communities associated with plant roots from the Wageningen biodiversity experiment to explore the effect of plant species identity, abundance and diversity on root associated fungal communities. Briefly, the Wageningen biodiversity experiment consisted of plant communities comprised of the following plant species: Agrostis capillaris L., Anthoxanthum odoratum L., Festuca rubra L., and Holcus lanatus L., Centaurea jacea L., Leucanthemum vulgare Lamk., Plantago lanceolata L., and Rumex acetosa,.These were grown either in monocultures or 2,4 or 8 plant species mixtures. 3cm diameter soil cores were taken from this experiment in 2010 and divided into two depth increments: (0-5, 20-35 cm). Roots from each depth were washed and their fungal communities characterised using 454 GS FLX pyrosequencing of amplicon libraries of the internal transcribed spacer (ITS1) region using primers ITS1F (Gardes & Bruns 1993) and ITS2 (White et al. 1990

Contrasts between the cryoconite and ice-marginal bacterial communities of Svalbard glaciers

Cryoconite holes are foci of unusually high microbial diversity and activity on glacier surfaces worldwide, comprising melt-holes formed by the darkening of ice by biogenic granular debris. Despite recent studies linking cryoconite microbial community structure to the functionality of cryoconite habitats, little is known of the processes shaping the cryoconite bacterial community. In particular, the assertions that the community is strongly influenced by aeolian transfer of biota from ice-marginal habitats and the potential for cryoconite microbes to inoculate proglacial habitats are poorly quantified despite their longevity in the literature. Therefore, the bacterial community structures of cryoconite holes on three High-Arctic glaciers were compared to bacterial communities in adjacent moraines and tundra using terminal-restriction fragment length polymorphism. Distinct community structures for cryoconite and ice-marginal communities were observed. Only a minority of phylotypes are present in both habitat types, implying that cryoconite habitats comprise distinctive niches for bacterial taxa when compared to ice-marginal habitats. Curiously, phylotype abundance distributions for both cryoconite and ice-marginal sites best fit models relating to succession. Our analyses demonstrate clearly that cryoconites have their own, distinct functional microbial communities despite significant inputs of cells from other habitats