HR: 11:05h
AN: B12B-04 INVITED     [Abstracts]
TI: Relating species and functional diversity using stable isotope probing
AU: * Prosser, J I
EM: j.prosser@abdn.ac.uk
AF: University of Aberdeen, School of Medical Sciences Institute of Medical Sciences Foresterhill, Aberdeen, AB25 2ZD United Kingdom
AU: Rangel-Castro, J I
EM: i.rangel@abdn.ac.uk
AF: University of Aberdeen, School of Medical Sciences Institute of Medical Sciences Foresterhill, Aberdeen, AB25 2ZD United Kingdom
AU: Mahmood, S
EM: s.mahmood@abdn.ac.uk
AF: University of Aberdeen, School of Medical Sciences Institute of Medical Sciences Foresterhill, Aberdeen, AB25 2ZD United Kingdom
AU: Nicol, G
EM: graeme.nicol@abdn.ac.uk
AF: University of Aberdeen, School of Medical Sciences Institute of Medical Sciences Foresterhill, Aberdeen, AB25 2ZD United Kingdom
AU: Meharg, A A
EM: a.meharg@abdn.ac.uk
AF: University of Aberdeen, School of Biological Sciences Cruickshank Building St Machar Drive, Aberdeen, AB24 3UU United Kingdom
AU: Killham, K S
EM: k.killham@abdn.ac.uk
AF: University of Aberdeen, School of Biological Sciences Cruickshank Building St Machar Drive, Aberdeen, AB24 3UU United Kingdom
AB: Microbial communities play an essential role in biogeochemical cycles and analysis of laboratory cultures has provided much information on biochemical processes and physiological characteristics of functional groups of microorganisms responsible for these processes. However, the majority of microorganisms cannot be grown readily in laboratory culture and cultivation-independent molecular techniques are required for analysis of community structure and diversity. These techniques have demonstrated considerable microbial diversity in natural communities and have revealed the existence of abundant microorganisms belonging to novel, previously unsuspected microbial groups. Molecular analysis of natural communities typically provides little information on links between specific microorganisms and the biogeochemical processes that they carry out. We are therefore ignorant of the significance of microbial diversity for ecosystem processes and of the ecosystem function of uncultivated, but abundant microbial groups. Stable isotope probing enables identification of which members of a community are involved in the utilisation of specific substrates, particularly carbon substrates. It involves amendment of environmental samples, or field application with 13C-labelled carbon substrates and, after a period of exposure, extraction of nucleic acids and separation of 13C-labelled (heavy) and 12C-labelled (light) nucleic acid pools by density gradient centrifugation. The heavy nucleic acid pool will be derived only from organisms assimilating the labelled substrate.Molecular analysis of this pool provides information on identity and relative abundance of active members of the community. The technique therefore enables in situ functional analysis of microbial groups without the requirement for laboratory cultivation. Stable isotope probing has been used to determine which organisms are involved in the degradation of specific organic substrates, including recalcitrant compounds, and has been used, in field studies, to determine microorganisms responsible for utilisation of plant root exudates under different environmental conditions. It has the potential to increase greatly our understanding of the links between diversity and ecosystem function and identification of the role of novel, previously uncharacterised microbial functional groups.
DE: 1030 Geochemical cycles (0330)
DE: 1615 Biogeochemical processes (4805)
DE: 0330 Geochemical cycles
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting