Research
Theme 1 & 2
www.darwincenter.nl
Project 1031

Ecology of iron-oxidizing bacteria in wetland environments
Project leader: Prof. dr. H. J. Laanbroek
Researcher(s): Dr. J. Wang
Starting date: 1-nov-05

Abstract
Iron-oxidising bacteria play an important role in the oxidation of iron under conditions of oxygen limitation, a circumneutral pH and a sufficient supply of reduced iron; conditions that prevail in the root zone, and more specifically in the rhizosphere, of wetland plants. These plants are adapted to anoxia in waterlogged soils by the formation of aerenchyma in stems and roots, which allows transport of oxygen to anoxic parts. Some part of the transported oxygen is released in the rhizosphere where it creates small oxic zones. Activity of aerobic microorganisms, such as the iron-oxidising bacteria, is limited to these microenvironments, where they can oxidise reduced compounds from the otherwise anoxic environment. Aerobic bacteria involved in the oxidation of different reduced compounds have to compete with each other as well as with chemical oxidation processes, for limited amounts of oxygen. In contrast to reduction processes, hardly anything is known about the competitive abilities of the different microbial and chemical oxidation processes. With respect to this, the present project aims to study the competitive abilities of iron-oxidising bacteria isolated from the rhizosphere of wetland plants, by a combination of field work and experiments in laboratory systems, all in close collaboration with project 2.

Publications
Wang, J., Muyzer, G., Bodelier, P.L.E., Laanbroek, H.J. (2009). Diversity of iron oxidizers in wetland soils revealed by novel 16S rRNA primers targeting Gallionella-related bacteria . ISME Journal3 (6): 715-725.
Darwin Center authors: Bodelier P. L. E., Laanbroek H. J., Wang J.

Wang, J., Vollrath, S., Behrends, T., Bodelier, P.L.E., Muyzer, G., Meima-Franke, M., Oudsten, F.D., Van Cappellen, P., Laanbroek, H.J. (2011). Distribution and diversity of Gallionella-like neutrophilic iron oxidizers in a tidal freshwater marsh . Applied and Environmental MicrobiologyVolume 77, Issue 7: 2337-2344.
Darwin Center authors: Behrends T., Bodelier P. L. E., Laanbroek H. J., Van Cappellen P., Vollrath S., Wang J.

Juanjuan Wang (2011). Ecology of neutrophilic iron-oxidizing bacteria in wetland soils. February 2011.
Darwin Center authors: Wang J.

Wang J, Krause S, Muyzer G, Meima-Franke M, Laanbroek HJ, Bodelier PLE (2012). Spatial patterns of iron- and methane-oxidizing bacterial communities an in an irregularly flooded, riparian wetland. Frontiers in Microbiology3:
Darwin Center authors: Bodelier P. L. E., Laanbroek H. J., Wang J.