Wetland Microbial Ecology and Biogeochemistry

In the original version of this chapter (Boon 2006), I noted the intellectual and practical gulfs that then existed between microbial ecology and metazoan-focused "mainstream" ecology. One reading of the information that has come out in the intervening period would suggest that the two fields still exist apart, perhaps are even irreconcilably separated. In even the most recent monographs on wetland ecology, for example, it is still rare for biogeochemistry to be discussed as a topic in its own right, and even rarer for microbial ecology to be considered in any context at all. A quite different conclusion, however, would be drawn from looking at textbooks that synthesize existing knowledge, and if we examine the primary literature directly. A quick look at recently published papers shows, for example, that biogeochemical processes are now acknowledged as a critical ecosystem service rendered by wetlands, especially in terms of improvements in water quality (Bateman et al. 2011; Zak et al. 2011); moreover, biogeochemical and microbial "maturity" is increasingly considered in assessments of the effectiveness of wetland and floodplain rehabilitation (Lamers et al. 2006; Ogram et al. 2011). More generally, there is also a growing recognition of the role that microbes play in the ecological structure and function in aquatic systems (Gutknecht et al. 2006; Logue et al. 2008; Newton et al. 2011), perhaps mirroring complementary developments that have taken place with non-aquatic ecosystems (e.g., Drenovsky et al. 2008). ... Significant advances have taken place in methods and in conceptual understandings since the original chapter of 2006. We now cover new material on viruses and on biofilms - the former because in the intervening years it has become clear how pivotal viruses are in aquatic systems (Jackson and Jackson 2008; Weinbauer et al. 2009); the latter because we needed to include and then update the periphyton section that the late Bob Wetzel covered in his contribution to the original book (Wetzel 2006). Although we have removed an explicit focus on hydrology, we do retain water regime as a fundamental, but this time implicit, principle that structures almost all aspects of wetland ecology. Because of space limitations, we focus on carbon processing and on nitrogen cycling, and do not consider in detail the cycling of other elements (e.g., phosphorus or silica).