Winter-Time Climatic Control on Dissolved Organic Carbon Export and Surface Water Chemistry in an Adirondack Forested Watershed
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- 作者：Ji-Hyung Park ; Myron J. Mitchell ; and Charles T. Driscoll
- 刊名：Environmental Science & Technology
- 出版年：2005
- 出版时间：September 15, 2005
- 年：2005
- 卷：39
- 期：18
- 页码：6993 - 6998
- 全文大小：168K
- 年卷期：v.39,no.18(September 15, 2005)
- ISSN：1520-5851
文摘
Although most of forested watersheds in temperate andboreal regions are snow-covered for a substantial portionof the year, responses of biogeochemical processesunder the snow pack to climatic fluctuations are poorlyunderstood. We investigated responses of dissolved organiccarbon (DOC) and surface water chemistry in streamand lake discharge waters draining the Arbutus LakeWatershed in the Adirondacks of New York State to climaticfluctuations during the snow-covered months fromDecember through April. Interannual variability in streamdischarge corresponded to changes in air temperature andsnow pack depth across the winter months. Concentrationsof DOC in stream water draining a subcatchment showedimmediate positive responses to rising temperatures andsubsequent increases in runoff during most snowmelt events.Increases in DOC concentrations usually coincided withdecreases in pH and increases in total aluminum (Al)concentrations, while the correlations between concentrations of DOC and SO42- or base cations were negative.Although changes in air temperature, snow pack depth, andrunoff were all significantly correlated with streamwater concentrations of major solutes, stepwise linearregression found that runoff was the best predictor of soluteconcentrations. Results of stepwise linear regressionwith long-term monthly monitoring data collected at thelake outlet showed weaker but still consistent climatic effectson interannual variations in concentrations of DOC andother solutes. Over the 17 winter periods from December1983 through April 2000, changes in seasonal averageconcentrations of DOC, H+, and Al in lake discharge generallycorresponded to interannual variations in temperature,precipitation, and runoff, while SO42- and base cationsdisplayed an opposite trend. The results suggest thatsnowmelt-mediated DOC responses to temperaturefluctuations during the winter months might offset increasesin the surface water pH caused by decreasing acidicdeposition and pose a potential hazard of Al toxicity insurface waters.