DETERMINANTS OF SUMMER NITRATE CONCENTRATION IN A SET OF ADIRONDACK LAKES, NEW YORK

摘要

Following reductions in the emission and deposition of sulfur compounds in the past decade, atmospheric deposition of nitrogen has become a focus of concern. Identification of water- shed characteristics that mediate the effect of atmospheric nitrogen deposition can help evaluate the sensitivity of lakes to chronic and episodic nitrogen addition. Twenty four lakes in the southwestern portion of the Adirondack Park, New York, U.S.A., were classified into three N classes by cluster analysis of lake water NO_3--N concentration [N] during the summers of l994--l996. The lake-N classes were best characterized as having (l ) low [N] throughout the summer, (2) high [N] in early- but low [N] in late-summer, and (3) high [N ] throughout the summer. The three lake--N classes were reconstructed perfectly by canonical discriminant analysis based mainly on lake average depth (AD), and lake water concentrations of chlorophyll α [Chla] and SO_4-S [ S ] in mid--summer. Increases in AD and [S], but decrease in [Chla] corresponded with a transition from low-- to high--N c1asses.