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Highly dynamic iron-oxidizing bacterial community

Juanjuan Wang studied the diversity and distribution of iron-oxidizing bacteria from freshwater and brackish wetlands of circumneutral pH that differ with respect to the prevailing ecohydrological and geochemical conditions. Her work opens up new opportunities for using molecular tools to study microbial iron oxidation at circumneutral pH and contributes to the knowledge of iron cycling in redox-stratified environments. On 16 february she will defend her PhD thesis.

Highly dynamic bacteria community

The results implied temporal dynamics in community structure of iron-oxidizing bacteria. The abundance of iron-oxidizing bacteria was also observed to increase with elevation and, hence, decreasing flooding intensity and soil moisture content. Iron-oxidizing bacteria were found to have higher abundance and more sensitivity to moisture content than methane-oxidizing bacteria. A novel iron-oxidizing bacteria strain, Ferrocurvibacter nieuwersluisensis gen. nov., sp. nov., was isolated from an iron-rich grassland.

Gradient tubes

Gradient tubes were used to enrich and isolate iron-oxidizing bacteria. PCR-DGGE, cloning and real-time PCR (qPCR) were applied to study the distribution of these microorganisms. Specific probes and primers were developed and novel iron oxidizers were detected from three contrasting wetlands environments. A qPCR assay was developed to delineate the spatial and temporal distributions of iron-oxidizing bacteria.

Thesis title

Ecology of neutrophilic iron-oxidizing bacteria in wetland soils

Promotors: Prof. Dr. H.J. Laanbroek, Prof. Dr. P. Van Cappellen

Co-promotors: Dr. P.L.E Bodelier, Dr. G. Muyzer

Date: 16 February 2011

Time: 12.45 p.m.

Location: Academiegebouw, Domplein 29, Utrecht.

Darwin program 1030: The role of microbial activity in iron-deposition in wetland ecosystems
Darwin program 1034: Ecology of iron-oxidizing bacteria in wetland environments