Iron-Oxidizing Bacteria in the Wetland Plant Rhizosphere: Characterization of a Novel Microbial Niche

Megonigal- DEB-9986981湿地植物生态圈中的铁氧化细菌：一种新型微生物生态位的表征湿地是铁在O2存在下从还原形式（Fe 2+）转变为氧化形式（Fe 3+）的地方。 我们知道这个过程发生在湿地植物的根部，因为它们通常有一个铁锈色的Fe 3+涂层。 大多数科学家认为铁氧化是自发的，它不涉及微生物。 然而，我们在湿地植物根部发现了氧化Fe 3+的细菌，我们怀疑它们控制着湿地土壤中的Fe氧化速率。 我们还怀疑这些生物产生的铁涂层比散装土壤中的铁还原微生物更容易获得。 我们将使用实验室和现场实验来验证这些假设。 这项工作很重要，因为铁循环会影响其他几种元素的行为，包括一些污染物。 特别令人感兴趣的是，铁循环可能会影响湿地释放的甲烷量;甲烷是一种主要的温室气体。

Megonigal- DEB-9986981Iron-Oxidizing Bacteria in the Wetland Plant Rhizosphere: Characterization of a Novel Microbial NicheWetlands are places where iron changes form a reduced form (Fe2+) to an oxidized form (Fe3+) in the presence of O2. We know this process occurs around wetland plant roots because they often have a rust-colored Fe3+ coating. Most scientists believe Fe oxidation is spontaneous and that it does not involve microorganisms. However, we discovered bacteria on wetland plant roots that oxidize Fe3+ for energy and we suspect they control Fe oxidation rates in wetland soils. We also suspect that the Fe coatings that these organisms produce are more available to Fe-reducing microbes than those in the bulk soil. We will use laboratory and field experiments to test these hypotheses. The work is important because Fe cycling affects the behavior of several other elements including some pollutants. Of particular interest is the fact that iron cycling may affect the amount of methane released from wetlands; methane is a major greenhouse gas.