• Arbuscular mycorrhizal community structure on co-existing tropical legume trees in French Guiana

      Brearley, Francis Q.; Elliott, David R.; Iribar, Amaia; Sen, Robin; Environmental Sustainability Research Centre, College of Life and Natural SciencesUniversity of Derby (Springer, 2016-02-10)
      Aims We aimed to characterise the arbuscular mycorrhizal fungal (AMF) community structure and potential edaphic determinants in the dominating, but poorly described, root-colonizing Paris-type AMF community on co-occurring Amazonian leguminous trees. Methods Three highly productive leguminous trees (Dicorynia guianensis, Eperua falcata and Tachigali melinonii were targeted) in species-rich forests on contrasting soil types at the Nouragues Research Station in central French Guiana. Abundant AMF SSU rRNA amplicons (NS31-AM1 & AML1-AML2 primers) from roots identified via trnL profiling were subjected to denaturing gradient gel electrophoresis (DGGE), clone library sequencing and phylogenetic analysis. Results Classical approaches targeting abundant SSU amplicons highlighted a diverse root-colonizing symbiotic AMF community dominated by members of the Glomeraceae. DGGE profiling indicated that, of the edaphic factors investigated, soil nitrogen was most important in influencing the AMF community and this was more important than any host tree species effect. Conclusions Dominating Paris-type mycorrhizal leguminous trees in Amazonian soils host diverse and novel taxa within the Glomeraceae that appear under edaphic selection in the investigated tropical forests. Linking symbiotic diversity of identified AMF taxa to ecological processes is the next challenge ahead.
    • Sampling and Describing Glacier Ice

      Toubes-Rodrigo, Mario; Cook, Simon J.; Elliott, David R.; Sen, Robin; University of Derby; Manchester Metropolitan University (British Society for Geomorphology, 2016-02-02)
      Determination of the physical, chemical and biological properties of glacier ice is essential for many aspects of glaciology and glacial geomorphology. In this chapter, we draw principally on examples of the description and sampling of the basal zone of glaciers where the ice is in direct contact with its substrate, and hence is where a great deal of geomorphological work is achieved. Whilst a pre-determined sampling strategy is essential to inform sampling equipment requirements, flexibility in data collection is necessary because of the dynamic nature of glaciers, and variability of ice exposure. Ice description is best achieved through stratigraphic logging, section drawing and photography. Detailed description can include a variety of information about the nature of layering, structures and sediment distribution; the size, shape and roundness of included debris; ice crystallography; and bubble content. It is common practice to categorise descriptively different ice types into cryofacies, so that comparisons can be made between studies. Sample extraction may be required for more detailed analyses of the physical, chemical and microbiological composition of the ice. We outline the use of a number of tools for ice sample extraction, including chainsaws, ice axes, chisels and ice screws.