Use of Nitrifiers As Biological Indicators of Soil Health to Assess Environmental Impact.

As researchers, we must determine which management practices meet current local and global demands for food fiber and energy without reducing our natural resource base. Advances in molecular microbiology and data analysis continue to foster the adoption of biological indicators as tools for environmental assessment. Biological indicators of soil health can be effectively employed to determine the environmental impact of a variety of management practices and materials, biological or xenobiotic across land use and ecosystems. This talk will address the value of utilizing the nitrification pathway to assess global climate change, nutrient cycling and remediation strategies. The biological indicators employed include: community composition of nitrifiers, amoA gene copy numbers of ammonia oxidizing bacteria (AOB) and archaea (AOA), AOA:AOB ratios, enzyme activity and nitrification rates. Research from five separate studies will be used to illustrate how differences in the growth and activity of the two overlapping nitrifier communities can be used to assess changes in edaphic properties, short and long-term management, land use, remediation strategies and biogeochemical processes contributing to global climate change. Current and future research will address the application of nitrifiers for rapid assessment of the impacts of nanoparticles (<100 nm) on air, soil and water quality.