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Seasonal changes in the microbial community of a salt marsh, measured by phospholipid fatty acid analysis.

Keith-Roach, M. J. and Bryan, N. D. and Bardgett, Richard D. and Livens, F. R. (2002) Seasonal changes in the microbial community of a salt marsh, measured by phospholipid fatty acid analysis. Biogeochemistry, 60 (1). pp. 77-96. ISSN 0168-2563

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Abstract

Microbial activity within the environment can have distinct geochemicaleffects, and so changes in a microbial community structure can result ingeochemical change. We examined seasonal changes in both the microbialcommunityand the geochemistry of an inter-tidal salt marsh in north-west England tocharacterise biogeochemical processes occurring at this site.Phospholipid fatty acid (PLFA) analysis of sediment samples collected atmonthly intervals was used to measure seasonal changes in microbial biomass andcommunity structure. The PLFA data were analysed using multivariate techniques(Ward''s method and the Mahalanobis distance metric), and we show that the useofthe Mahalanobis distance metric improves the statistical analysis by providingdetailed information on the reasons samples cluster together and identifyingthedistinguishing features between the separate clusters. Five clusters of likesamples were defined, showing differences in the community structure over thecourse of a year.At all times, the microbial community was dominated by PLFA associated withaerobic bacteria, but this was most pronounced in summer (August). Theabundanceof branched fatty acids, a measure of the biomass of anaerobes, started toincrease later in the year than did those associated with aerobes and thefungalbiomarker 18:26 showed a brief late-summer peak.The salt marsh remained mildly oxic throughout the year despite the increase inmicrobial respiration, suggested by the large increases in the abundance ofPLFA, in the warmer months. The conditions therefore remained most favourablefor aerobic species throughout the year, explaining their continual dominanceatthis site. However, as the abundance of PLFA synthesised by anaerobesincreased,increases in dissolved Mn concentrations were observed, which we suggest weredue to anaerobic respiration of Mn(IV) to Mn(II). Overall, the geochemicalconditions were consistent with the microbial community structure and changeswithin it.

Item Type: Article
Journal or Publication Title: Biogeochemistry
Uncontrolled Keywords: Element cycling - Mahalanobis - Phospholipid fatty acid - Salt marsh - Statistical analysis
Subjects: Q Science > QH Natural history > QH301 Biology
Departments: Faculty of Science and Technology > Lancaster Environment Centre
ID Code: 10284
Deposited By: Prof Richard Bardgett
Deposited On: 10 Jul 2008 16:42
Refereed?: Yes
Published?: Published
Last Modified: 17 Sep 2013 10:49
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/10284

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