Nitrogen mass balances and abiotic controls on N retention and yield in high‐elevation catchments of the Sierra Nevada, California, United States

Sickman, James O.; Leydecker, Al; Mélack, John M.

doi:10.1029/2000wr900371

Cited by 72 publications

(79 citation statements)

References 45 publications

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“…These authors found that the duration of winter snow cover and the subsequent heterotrophic activity in soils played a predominant role on the variability of N export. For catchments in the Sierra Nevada (California), Sickman et al (2001) found that the timing of snowmelt runoff had a large effect on nitrate pulses. Isotopic analyses suggested that the majority of the pulse was not from the snowpack, but rather from catchment soils.…”

Section: Discussionmentioning

confidence: 99%

Nutrients and organic matter in a glacial river—floodplain system (Val Roseg, Switzerland)

Tockner

Malard

Uehlinger

et al. 2002

Limnology & Oceanography

119

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Nutrient and organic matter dynamics were evaluated for a glacial river-floodplain system in the Swiss Alps (Val Roseg). Glacial melt water was the primary source of particulate organic and inorganic matter; hillslope groundwater was richest in DOC and SiO 2 ; and pulses in dissolved nitrogen were identified during spring snowmelt. Calculations of temporal coherency revealed that hydrological processes within the catchment-floodplain complex controlled nutrient and organic matter species along the main channel; however, local hydrological and/or biogeochemical processes played a major controlling role in most floodplain channels. DON and NO 3 -N were the only variables that were in average significantly correlated across all sampling sites. Comparisons of measured concentrations and concentrations based on a two end member mixing model indicated that the floodplain served as a major sink for particulate phosphorous and suspended matter but was never a source for nutrients or organic matter. Annual areaspecific export rates from the Val Roseg catchment were 7.6 kg ha Ϫ1 yr Ϫ1 for TOC (47% DOC), 4.3 kg for TP (98% particulate phosphorus), and 4.1 kg for TN (78% NO 3 -N).Quantification of nutrient and organic matter sources, transformations, and sinks at the catchment/floodplain scale is a major challenge in ecology. This is in particular true for remote arctic and high alpine streams that have received much less attention compared to more accessible areas (Milner and Petts 1994;Wissmar et al. 1997). Alpine and arctic streams appear resource limited in terms of both nutrients and organic matter. For example, Lock et al. (1990) showed that the addition of phosphorous to an arctic river resulted in a substantial stimulation of both heterotrophic and autotrophic processes. Robinson and Gessner (2000) demonstrated that nutrient addition accelerated leaf breakdown in a glacial stream. Further, there is strong evidence that zoobenthic communities in glacial streams are not solely structured by temperature and channel stability (cf. Milner and Petts 1994), but are strongly influenced by seasonal shifts in water sources and corresponding availability of nutrients and or-1 Corresponding author (tockner@eawag.ch). AcknowledgementsThis study was supported by a research grant from the Swiss National Science Foundation (SNF 21-49243). We appreciate the field support of Tina Boesch, Birgit Klein, Chris Robinson, Rainer Zah, and Peter Burgherr, and we are especially grateful to Richard Illi and Bruno Ribi for the chemical analyses. We express our sincere thanks to Plenio Testa and his crew at the 'Hotel Roseg' for their hospitality and to the communes of Pontresina and Samedan for providing access to the sampling area. We also appreciate helpful comments by Jürg Zobrist, Edith Kaiser, and Chris Robinson. Thoughtful comments by two anonymous reviewers are gratefully acknowledged.

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Section: Discussionmentioning

confidence: 99%

Nutrients and organic matter in a glacial river—floodplain system (Val Roseg, Switzerland)

Tockner

Malard

Uehlinger

et al. 2002

Limnology & Oceanography

119

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“…The changes were inverse to the deposition changes recorded in this area and attributed to increased weathering rates and increased biological activity resulting from climate warming. Sickman et al (2001) suggests that if current trends towards warmer air temperatures continue, N-retention will increase in high elevation catchments in the Sierra Nevada, USA. Rogora (2003) indicates the same for lakes in the Italian Alps.…”

Section: Discussionmentioning

confidence: 99%

What affects the nitrogen retention in Tatra Mountains lakes' catchments in Poland?

Rzychoń

Worsztynowicz

2008

Hydrol. Earth Syst. Sci.

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Abstract. The study of acidification and recovery of two lakes situated in the Polish Tatra Mountains, exposed to similar deposition of acidic substances but differing in altitude, catchment morphology, hydrology, and biodiversity is presented. Measurements were performed in 1992-1996 and 2001-2005. Simultaneously, research on the atmospheric deposition was carried out. The following physical and chemical parameters in lake water and precipitation were measured: pH, conductivity (K 25 ), Ca 2+ , Mg 2+ , Na + , K + , NH (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005). During this time the sulphate concentration decreased significantly, and the concentration of hydrogen ions in precipitation decreased at an average rate of 2.23 meq/m 3 /yr. There was no significant change in nitrate, ammonium or total nitrogen deposition. The chemical composition of water of both lakes changed significantly and showed signs of chemical recovery with decreases in sulphate concentration and increases in acid neutralising capacity. The concentration of base cations declined. Despite the lack of clear trends in nitrogen deposition, a statistically significant drop in concentration was observed in the two lakes. A significant increase of about 15% in the retention of nitrogen compounds in both catchments occurred. An improvement in nitrogen saturation status in both catchments was observed. This probably resulted mainly from decreasing acidification and global warming which prolongs the vegetative period, changes plant species composition and increases the microbiological activity of soil.

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“…The AHM model in this study has a simple biogeochemical representation of nitrogen that does not incorporate the level of complexity needed to simulate the inter-annual variability in NO 2 3 export caused by differences in precipitation. The decreased ANC simulated for wet years here would be exacerbated by the increased NO cycling under long duration snow packs (Meixner and Bales, 2003;Sickman et al, 2001). …”

Section: Climate Variabilitymentioning

confidence: 99%

Multidecadal hydrochemical response of a Sierra Nevada watershed: sensitivity to weathering rate and changes in deposition

Meixner¹,

Gutmann²,

Bales³

et al. 2004

Journal of Hydrology

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To address the responses of the very dilute waters in the Sierra Nevada, California, to acidic atmospheric deposition, the Alpine hydrochemical model (AHM) was used to simulate 47 years of runoff and solute concentrations in the Emerald Lake catchment. The AHM is a semi-distributed model of alpine watersheds that incorporates representations of the major hydrologic and biogeochemical processes that control stream chemical composition. Proxy data of discharge and snowfall were used to develop the necessary inputs for the 47-year runs. The long-term simulations were stable, but conflicts in the simulation of base cation and silica concentrations indicate that the model has a missing process or misrepresents mineral weathering. Sensitivity analysis of the weathering parameters indicates that a weathering rate of approximately 80% of the value fitted based on a oneyear calibration would match the observed base saturation and the initial one year estimate had incorrect stoichiometry. Additionally, comparison of annual modeled mass flux to observed mass flux indicates that the model overestimates cation and silica export in dry years and underestimates export in wet years. Our results indicate that the Emerald Lake watershed, as represented by AHM, is not sensitive to chronic acidification with atmospheric deposition at current levels and that there would be little episodic acidification with a doubling in atmospheric deposition. However, in the simulations climate variability had an impact on stream water pH and this sensitivity should be taken into account in assessing alpine catchment sensitivity to changes in atmospheric deposition. q

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Nitrogen mass balances and abiotic controls on N retention and yield in high‐elevation catchments of the Sierra Nevada, California, United States

Abstract: In this study we describe the interannual variability of N loading to and yield from high-elevation watersheds of the Sierra Nevada of California using a 14 year continuous record from the Emerald Lake watershed (ELW) (1985-1998) and 1445

Cited by 72 publications

References 45 publications

Nutrients and organic matter in a glacial river—floodplain system (Val Roseg, Switzerland)

Nutrients and organic matter in a glacial river—floodplain system (Val Roseg, Switzerland)

What affects the nitrogen retention in Tatra Mountains lakes' catchments in Poland?

Multidecadal hydrochemical response of a Sierra Nevada watershed: sensitivity to weathering rate and changes in deposition

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