Regulation of Nitrate‐N Release from Temperate Forests: A Test of the N Flushing Hypothesis

Creed, Irena F.; Band, Lawrence E.; Foster, N. W.; Morrison, I. K.; Nicolson, J. A.; Semkin, R. G.; Jeffries, D. S.

doi:10.1029/96wr02399

Cited by 284 publications

(313 citation statements)

References 62 publications

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“…The release of soil inorganic N to stream water can become more important than atmospheric deposition in the cold season (fall and winter) and during the onset of snowmelt, which generally occurs in April. Other studies on snowmeltdominated streams underline the importance of soil water flushing in influencing stream water chemistry (Foster et al, 1989;Arthur and Fahey, 1993;Creed et al, 1996;Stottlemeyer, 1997). NO 3 levels never below 10 µeq l −1 and occasionally over 40 µeq l −1 , suggest, on the base of Stoddard's approach (Stoddard and Traaen, 1994), that a certain level of N saturation (stage 2) can be hypothesized also for this site.…”

Section: Water Chemistry and Seasonalitymentioning

confidence: 99%

Climate control on sulphate and nitrate concentrations in alpine streams of Northern Italy along a nitrogen saturation gradient

Rogora

Arese

Balestrini

et al. 2008

Hydrol. Earth Syst. Sci.

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Abstract. The role of meteorology, hydrology and atmospheric deposition on the temporal pattern of SO 4 and NO 3 concentrations was investigated for three streams draining alpine catchments in Northern Italy.The study sites lie on a gradient of atmospheric fluxes of SO 4 and NO 3 (from about 50 to 80 meq m −2 y −1 , and from 40 to 90 meq m −2 y −1 , respectively). As a consequence of the increasing N input, the three catchments are also representative of aggrading levels of N saturation. Different methods of statistical analysis were applied to monthly data for the period 1997-2005 to identify which variables (temperature, precipitation, hydrology, SO 4 and NO 3 deposition) were the main predictors of water chemistry and its change in time. Hydrological changes and snow cover proved to be the main confounding factors in the response to atmospheric deposition in the River Masino catchment. Its particular characteristics (small catchment area, rapid flushing during runoff and thin soil cover) meant that this site responded without a significant delay to SO 4 deposition decrease. It also showed a clear seasonal pattern of NO 3 concentration, in response to hydrology and biological uptake in the growing season.The selected driving variables failed to model the water chemistry at the other study sites. Nevertheless, temperature, especially extreme values, turned out to be important in both SO 4 and NO 3 export from the catchments. This result might be largely explained by the effect of warm periods on temperature-dependent processes such as mineralization, nitrification and S desorption.Our findings suggest that surface waters in the alpine area will be extremely sensitive to a climate warming scenario: higher temperatures and increasing frequency of drought could exacerbate the effects of high chronic N deposition.Correspondence to: M. Rogora

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Section: Water Chemistry and Seasonalitymentioning

confidence: 99%

Climate control on sulphate and nitrate concentrations in alpine streams of Northern Italy along a nitrogen saturation gradient

Rogora

Arese

Balestrini

et al. 2008

Hydrol. Earth Syst. Sci.

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“…Interannual variability, sparse precipitation datasets at high latitudes, and challenges associated with quantifying winter precipitation have made it difficult to diagnose the exact causes of changes in Arctic river discharge to date (Rawlins et al 2009). However, tight linkages between hydrology and biogeochemistry in watersheds (Creed et al 1996;Creed and Band 1998;Burns 2005;Hinzman et al 1991;Steiglitz et al 2000Steiglitz et al , 2003 make changes in the export of river-borne materials inevitable as river discharge increases. Export of inorganic nutrients (N, P, Si) and DOC and DON are of particular interest because they serve as important resources for downstream ecosystems (Amon and Meon 2004;Post et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Seasonal and hydrologic drivers of dissolved organic matter and nutrients in the upper Kuparuk River, Alaskan Arctic

et al. 2010

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As the planet warms, widespread changes in Arctic hydrology and biogeochemistry have been documented and these changes are expected to accelerate in the future. Improved understanding of the behavior of water-borne constituents in Arctic rivers with varying hydrologic conditions, including seasonal variations in discharge-concentration relationships, will improve our ability to anticipate future changes in biogeochemical budgets due to changing hydrology. We studied the relationship between seasonal water discharge and dissolved organic carbon and nitrogen (DOC and DON) and nutrient concentrations in the upper Kuparuk River, Arctic Alaska. Fluxes of most constituents were highest during initial snowmelt runoff in spring, indicating that this historically under-studied period contributes significantly to total annual export. In particular, the initial snowmelt period (the stream is completely frozen during the winter) accounted for upwards of 35% of total export of DOC and DON estimated for the entire study period. DOC and DON concentrations were positively correlated with discharge whereas nitrate (NO 3 -) and silicate were negatively correlated with discharge throughout the study. However, discharge-specific DOC and DON concentrations (i.e. concentrations compared at the same discharge level) decreased over the summer whereas discharge-specific concentrations of NO 3 -and silicate increased. Soluble reactive phosphorus (SRP) and ammonium (NH 4 ? ) were negatively correlated with discharge during the spring thaw, but were less predictable with respect to discharge thereafter. These data provide valuable information on how Arctic watershed biogeochemistry will be affected by future changes in temperature, snowfall, and rainfall in the Arctic. In particular, our results add to a growing body of research showing that nutrient export per unit of stream discharge, particularly NO 3 -, is increasing in the Arctic.

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“…In most cases, nitrogen shows the characteristics of flushing, in which mobile nitrogen accumulates in specific parts of the landscape in dry periods at low flow, and is transported (flushed) as groundwater, soil water and surface water flow paths activate during storm events or seasonal wet periods [e.g., Creed et al, 1996;Band, 1998a, 1998b;Burns, 2005]. The wetness, or flow, thresholds for each flush may result in a range of responses from frequent recharge from localized sources as in the case of distributed septic systems Heisig, 2000], storm water mobilization of lawn fertilizer from suburban lawns and nutrients accumulated on impervious surfaces, or fertilizer from larger portions of the landscape during wet-up in the agricultural catchments [Poor and McDonnell, 2007;Royer et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

Streamflow distribution of non–point source nitrogen export from urban‐rural catchments in the Chesapeake Bay watershed

Shields

Band

Law

et al. 2008

Water Resources Research

144

122

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[1] Nitrogen (N) export from urban and urbanizing watersheds is a major contributor to water quality degradation and eutrophication of receiving water bodies. Methods to reduce N exports using best management practices (BMP) have targeted both source reduction and hydrologic flow path retention. Stream restoration is a BMP targeted to multiple purposes but includes increasing flow path retention to improve water quality. As restorations are typically most effective at lower discharge rates with longer residence times, distribution of N load by stream discharge is a significant influence on catchment nitrogen retention. We explore impacts of urbanization on magnitude and export flow distribution of nitrogen along an urban-rural gradient in a set of catchments studied by the Baltimore Ecosystem Study (BES). We test the hypotheses that N export magnitude increases and cumulative N export shifts to higher, less frequent discharge with catchment urbanization. We find that increasing development in watersheds is associated with shifts in nitrogen export toward higher discharge, while total magnitude of export does not show as strong a trend. Forested reference, low-density suburban, and agricultural catchments export most of the total nitrogen (TN) and nitrate (NO 3 À ) loads at relatively low flows. More urbanized sites export TN and NO 3 À at higher and less frequent flows. The greatest annual loads of nitrogen are from less developed agricultural and low-density residential (suburban/exurban) areas; the latter is the most rapidly growing land use in expanding metropolitan areas. A simple statistical model relating export distribution metrics to impervious surface area is then used to extrapolate parameters of the N export distribution across the Gwynns Falls watershed in Baltimore County. This spatial extrapolation has potential applications as a tool for predictive mapping of variations in export distribution and targeting stream channel restoration efforts at the watershed scale.

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Regulation of Nitrate‐N Release from Temperate Forests: A Test of the N Flushing Hypothesis

Cited by 284 publications

References 62 publications

Climate control on sulphate and nitrate concentrations in alpine streams of Northern Italy along a nitrogen saturation gradient

Climate control on sulphate and nitrate concentrations in alpine streams of Northern Italy along a nitrogen saturation gradient

Seasonal and hydrologic drivers of dissolved organic matter and nutrients in the upper Kuparuk River, Alaskan Arctic

Streamflow distribution of non–point source nitrogen export from urban‐rural catchments in the Chesapeake Bay watershed

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