Ecosystem succession in the earliest stages: Linking microbial community structure to ecological function

From the onset of ecosystem development, pioneering microorganisms are the engines that drive ecosystem processes by decomposing organic matter, mineralizing nutrients, and weathering primary minerals. Despite their importance, we know very little about how microbial assembly occurs during early ecosystem development, how it relates to environmental characteristics and function, what importance it has for aboveground plant communities, and whether it varies in different parts of the world. The overall objective of my dissertation research was to explore the processes and mechanisms of soil microbial succession along a series of actively retreating glacial chronosequences. I used three climatically, geographically, and geologically distinct glacial sites: Easton Glacier, Washington, USA, Mendenhall Glacier, Alaska, USA, and Puca Glacier, Peru. The chosen sites differed with regard to soil forming state factors (organisms, geology, climate) and rates of succession, providing the unique opportunity to test the generality of microbial succession across sites.