Chapter 9 Microbial Ecology 9.1 Microorganisms in nature ecosystem 9.2 Microbial population interactions 9.3 Biogeochemical cycles 9. 4 Plant-microbe interactions 9.5 Bioremediation9.1 Microorganisms in nature ecosystem 9.2 Microbial population interactions 9.3 Biogeochemical cycles 9.4 Plant-microbe interactions 9.5 Bioremediation Chapter 9 Microbial Ecology