There has been a long-term decline in nitrate (NO3−) concentration and export from several long-term monitoring watersheds in New England that cannot be explained by current terrestrial ecosystem models. A number of potential causes for this nitrogen (N) decline have been suggested, including changes in atmospheric chemistry, insect outbreaks, soil frost, and interannual climate fluctuations. In-stream removal of NO3− has not been included in current attempts to explain this regional decline in watershed NO3− export, yet streams may have high removal rates of NO3−. We make use of 40 years of data on watershed N export and stream N biogeochemistry from the Hubbard Brook Experimental Forest (HBEF) to determine (a) whether there have been changes in HBEF stream N cycling over the last four decades and (b) whether these changes are of sufficient magnitude to help explain a substantial proportion of the unexplained regional decline in NO3− export. Examining how the tempos and modes of change are distinct for upland forest and stream ecosystems is a necessary step for improving predictions of watershed exports.
How to translate text using browser tools
1 March 2005
Can't See the Forest for the Stream? In-stream Processing and Terrestrial Nitrogen Exports
EMILY S. BERNHARDT,
GENE E. LIKENS,
ROBERT O. HALL,
DON C. BUSO,
STUART G. FISHER,
THOMAS M. BURTON,
JUDY L. MEYER,
WILLIAM H. MCDOWELL,
MARILYN S. MAYER,
W. BRECK BOWDEN,
STUART E. G. FINDLAY,
KATE H. MACNEALE,
ROBERT S. STELZER,
WINSOR H. LOWE
ACCESS THE FULL ARTICLE
It is not available for individual sale.
This article is only available to subscribers.
It is not available for individual sale.
It is not available for individual sale.
BioScience
Vol. 55 • No. 3
March 2005
Vol. 55 • No. 3
March 2005
ecosystem change
HBEF
nitrate
nutrient retention
stream ecosystems