Nitrification and nitrifying microbial communities in forest soils

Abstract

How nitrogen (N) cycling is regulated and how environmental change affects it are major study questions in forest ecology, because N availability often limits the primary production of plants in many forest ecosystems. These are being extensively highlighted because of growing concerns regarding chronic and elevated N deposition in forest ecosystems on a global scale. Until now, N cycling has been mainly documented in association with various environmental factors other than microbial communities. However, with the recent rapid development in culture-independent molecular-based techniques, microbial ecologists have discovered that alterations in N cycling are highly associated with alternations in microbial communities through changes in either resource supplies or processing rates. In this review, we describe nitrification as a key N cycling process and present general approaches to associate the nitrification process with the nitrifying community in forest soils. Furthermore, we briefly summarize currently available information about the relationship between the process and nitrifying community dynamics in soil. We suppose that linking N cycling processes with microbial community dynamics provides a deeper insight into the mechanisms regulating N cycling in forest ecosystems.

Keywords:

• Forest soil
• Microbial community
• Nitrification
• Nitrogen cycling
• Nitrogen saturation

Acknowledgments

This work was supported by the Mitsui and Company Ltd Environment Fund (R08-C108) and grants-in-aid for Scientific Research from the Ministry of Education, Culture, Sports, Science, and Technology, Japan (nos 19658060, 20780113, 21310008, 19310019, and 19201004) and the Grant for Projects for the Protection, Preservation, and Restoration of Cultural Properties in Japan by the Sumitomo Foundation. K.I. was supported by a Grant-in-Aid for JSPS fellows. K.K. was supported by the Program to Create an Independent Research Environment for Young Researchers from the Ministry of Education, Culture, Sports, Science, and Technology, Japan.