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Role of within‐lake processes and hydrobiogeochemical changes over 16 years in a watershed in the Adirondack Mountains of New York State, USA
Author(s) -
Mitchell Myron J.,
McHale Patrick J.,
Inamdar Shreeram,
Raynal Dudley J.
Publication year - 2001
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.249
Subject(s) - biogeochemical cycle , watershed , precipitation , hydrology (agriculture) , zoology , environmental science , chemistry , environmental chemistry , geology , meteorology , geography , biology , geotechnical engineering , machine learning , computer science
Hydrological and biogeochemical relationships were evaluated for the Arbutus Watershed in the Adirondack Mountains of New York State. Wet‐only precipitation inputs (weekly) and discharge losses were evaluated from 1983 to 1998. Precipitation from 1983–98 had significant ( p <0·05) decreases in concentrations of Ca 2+ (−0·10µmol c l −1 year −1 ), Mg 2+ (−0·07µmol c l −1 year −1 ), K + (−0·01µmol c l −1 year −1 ), Na + (−0·04µmol c l −1 year −1 ), Cl − (−0·07µmol c l −1 year −1 ), SO 4 2− (−0·82µmol c l −1 year −1 ) and H + (−0·55µmol c l −1 year −1 ), whereas NH 4 + and NO 3 − concentrations did not change. For the same period, there were decreases in solute concentrations in the Arbutus Lake outlet for Ca 2+ (−1·18µmol c l −1 year −1 ), Mg 2+ (−0·32µmol c l −1 year −1 ), K + (−0·33µmol c l −1 year −1 ), Cl − (−0·17µmol c l −1 year −1 ) and SO 4 2− (−1·90µmol c l −1 year −1 ) and a significant increase in NH 4 + concentrations (+0·07µmol c l −1 year −1 ). For the period from 1995 through 1998 the discharge measurements for the outlet and the major inlet of Arbutus Lake were combined with weekly chemical measurements supplemented with storm sampling. At the inlet there were significant relationships ( p <0·05) between discharge rates and the concentrations of all solutes except Cl − , but only for Na + , NO 3 − , H + and Al did these relationships explain more than 20% of the variation in solute concentrations. April had the greatest rates of discharge and solute flux of any month due to spring snowmelt. The dormant season (October–May) accounted for >80% of the discharge in the inlet and outlet of Arbutus Lake and >78% of the flux of all solutes. For 1995–98 the mass balances of discharge losses from the catchment draining into Arbutus Lake inlet versus precipitation inputs suggest that internal watershed processes resulted in net generation of Ca 2+ (−1342mol c ha −1 year −1 ), Mg 2+ (−313mol c ha −1 year −1 ), K + (−35mol c ha −1 year −1 ), SO 4 2− (−635mol c ha −1 year −1 ) and Cl − (−45mol c ha −1 year −1 ) and net retention of inorganic N solutes (NO 3 − +NH 4 + : 204 mol c ha −1 year −1 ) and H + (424mol c ha −1 year −1 ). Concentrations and fluxes of Ca 2+ , H + , NO 3 − , SO 4 2− and Al were lower at the lake outlet compared with the inlet. A comparison of mass balances at the Arbutus Lake inlet and outlet suggested that these decreases may have been due to within‐lake biotic processes and/or dilution from other water sources to the lake. Copyright © 2001 John Wiley & Sons, Ltd.