Patterns in N dynamics and N isotopes during primary succession in Glacier Bay, Alaska
The primary successional sequence in Glacier Bay, Alaska represents a 230-year record of the development of nitrogen (N) dynamics. Because of low inputs of N in precipitation and the absence of initial soil N pools, the pattern of N accumulation is strongly biologically controlled. The simple successional sequence at Glacier Bay is dominated by two main species (Alnus sinuata and Picea sitchensis), thus the influence these species have on N dynamics is more easily deduced than in more complex systems. Along a successional sequence in Glacier Bay, N mineralization rates, foliage and soil C:N, and foliage and soil values in six sites ranging in age from 20 to 225 years old were examined. It is concluded that: (1) Alnus sinuata and Dryas drummondii derived most of their N through the fixation of atmospheric N; (2) under conditions of high N availability, differences among species in plant preference for ammonium or nitrate can be deduced from values; (3) over time, organic soil N separates into two isotopically distinct pools which differ in their turnover rate; (4) the transition from an alder-dominated to a spruce-dominated system results in slower N cycling; and (5) previous site conditions are an important factor in explaining patterns in values.
Earth Systems Research Center
Digital Object Identifier (DOI)
Hobbie, E.A., S.A. Macko, and H.H. Shugart. 1998. Patterns in N dynamics and N isotopes during primary succession in Glacier Bay, Alaska. Chemical Geology 152:3-11.
© 1998 Elsevier Science B.V. All rights reserved.