Long-term measurements of microbial biomass and activity at the Hubbard Brook Experimental Forest, 1994 - present

Long-term monitoring of soil nitrate (NO3-) and
ammonium (NH4+) concentrations, microbial biomass carbon (C)
and nitrogen (N) content, microbial respiration, potential
nitrification and N mineralization rates, and denitrification
potential has been ongoing at the Hubbard Brook Experimental
Forest since 1994. Samples have been collected in the Bear
Brook Watershed (west of Watershed 6) beginning in 1994. In
1998, our sampling regime was extended to Watershed 1 in an
effort to monitor and quantify microbial response to a
whole-watershed calcium addition.
These data were gathered as part of the Hubbard Brook
Ecosystem Study (HBES). The HBES is a collaborative effort at
the Hubbard Brook Experimental Forest, which is operated and
maintained by the USDA Forest Service, Northern Research
Station.