Some Perspectives on Long-Term Biogeochemical Research From the Hubbard Brook Ecosystem Study

Integrated, long-term, ecological, hydrological, and biogeochemical studies have been done at the Hubbard Brook Experimental Forest since 1963 using the small watershed–ecosystem approach. Some biogeochemical results from these long-term studies, collectively called the Hubbard Brook Ecosystem Study, are described here, including approaches used for managing this large and complicated project. Some major biogeochemical findings of the Hubbard Brook Ecosystem Study are discussed briefly, including acid rain, and some biogeochemical research questions, opportunities, and challenges for the future are identified, including a recent whole-watershed addition of calcium silicate, weathering processes, and long-term trends in stream-water nitrate concentrations.