The Bear Brook Watershed in Maine (BBWM) is in its third decade of research on the response of these northern forested ecosystems to a changing chemical and physical climate. The emphasis of research has been, and continues to be, on decadal scale responses to whole ecosystem acidification, nitrogen enrichment, and climatic drivers as evident in events ranging from instantaneous episodic responses in
ecosystem processes to decadal scale trends.
Scientific questions have emphasized:
- Alterations to nitrogen dynamics throughout the ecosystem from bioindicators of change to terrestrial and aquatic biogeochemistry,
- Base cation decline, particulary emphasizing calcium, to these drivers of change,
- Factors governing carbon cycling and its alteration in these reference and nitrogen-enriched watersheds,
- Phosphorus controls on nitrogen cycling in terrestrial and aquatic ecosystems,
- Ecosystem response to decreasing ambient and sustained elevated treatment sulfate deposition,
- Alterations to forest growth and the importance of tree species in ecosystem response.
Several major initiatives are currently underway focusing on understanding nitrogen dynamics over the decadal-scale arc of ambient and experimental conditions, including the importance of an altered ecological stoichiometry between carbon, nitrogen, and phosphorus. This includes the use of stable isotope techniques and studies of soil and dissolved organic carbon composition and behavior.