Nitrate removal in a first-order stream: reconciling laboratory and field measurements

Kellman, Lisa

doi:10.1007/s10533-004-4318-1

Cited by 14 publications

(11 citation statements)

References 32 publications

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“…Since NO 3 − saturation of denitrification has been shown in other agriculturally influenced streams (Royer et al, 2004; Bernot and Dodds, 2005), it was important to determine the potential for increased water column NO 3 − to stimulate denitrification rates in the stream in this study. Nitrate concentrations in the unamended controls in the NO 3 − addition experiment were typical of baseflow conditions in the OGF drainage network (Thompson et al, 2000; Poe et al, 2004; Ensign et al, 2006) and were relatively low compared to other agricultural streams (Kellman, 2004; Royer et al, 2004). Streamflow in this coastal agricultural watershed was dominated by low NO 3 − during baseflow with pulses of NO 3 − observed during storm events (Ensign et al, 2006).…”

Section: Discussionmentioning

confidence: 94%

Denitrification of Nitrogen Released from Senescing Algal Biomass in Coastal Agricultural Headwater Streams

et al. 2010

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Assimilation of inorganic N by photoautotrophs has positive impacts on nutrient retention; however this retention is only temporary. As the biomass senesces, organic and inorganic forms of N are released back to the stream where they can be further transformed (i.e., nitrification, denitrification) or exported downstream. The purpose of this study was to assess the fate of the remineralized N, particularly the potential for removal by denitrification. Experiments were conducted on intact sediment cores from streams in an agricultural watershed. Cores were amended with varying ages of algal leachate and denitrification rates were measured with a membrane inlet mass spectrometer. Results of this study demonstrated that senescing algal biomass stimulated denitrification rates and provided a source of N and labile C to denitrifiers. Regardless of leachate age, addition of leachate to intact cores revealed a net loss of dissolved inorganic N from the water column. Denitrification rates were most strongly related to concentrations of dissolved and particulate C in the overlying water and secondarily to C quality (molar C to N ratio of total dissolved C and N) and NO(3)(-) flux. Using a mass balance approach, the proportion of N from senescing algal biomass that was denitrified accounted for as much as 10% of the total dissolved nitrogen (TDN) and up to 100% of the NO(3)(-) during a 3-h experiment. These results suggest an important link between instream algal uptake and eventual denitrification thereby providing a pathway for permanent removal of watershed-derived N from the stream ecosystem.

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Section: Discussionmentioning

confidence: 94%

Denitrification of Nitrogen Released from Senescing Algal Biomass in Coastal Agricultural Headwater Streams

et al. 2010

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“…Clearly the presence of debris dams in some of our suburban streams is not sufficient to consume all anthropogenic NO 3 − in these streams. However, without the heterogeneity in flow and C and N dynamics caused by the presence of these dams, NO 3 − concentrations in these streams would likely be higher (Fisher et al, 2004; Gücker and Boëchat, 2004; Kellman, 2004). Whole‐stream manipulations of debris dams are needed to truly quantify their importance as regulators of stream NO 3 − levels.…”

Section: Discussionmentioning

confidence: 99%

“…The increase in denitrification potential in debris dam samples from the forested reference stream that were amended with 2 mg NO 3 − –N L −1 confirms that this “urban effect” on denitrification is due to the high NO 3 − concentrations in urban and suburban streams. Many studies have found that denitrification in organic‐rich, anaerobic sites such as organic debris dams is NO 3 − –limited and therefore increases with increasing NO 3 − concentrations (Holmes et al, 1996; Martin et al, 2001; Kemp and Dodds, 2002; Kellman, 2004; Richardson et al, 2004; Wall et al, 2005; Tuerk and Aelion, 2005). These results suggest that high denitrification potential in debris dams rich in organic matter may play an important role in maintaining water quality by reducing NO 3 − loading to receiving waters.…”

Section: Discussionmentioning

confidence: 99%

Chloride Effects on Nitrogen Dynamics in Forested and Suburban Stream Debris Dams

Hale

Groffman

2006

J of Env Quality

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Organic debris dams (accumulations of organic material) can function as "hotspots" of nitrogen (N) processing in streams. Suburban streams are often characterized by high flows that prevent the accumulation of organic debris and by elevated concentrations of solutes, especially nitrate (NO(3)(-)) and chloride (Cl(-)). In this study we (1) studied the effects of urbanization on the extent and characteristics of debris dams in large and small streams and (2) evaluated the effects of NO(3)(-) and Cl(-) on rates of N cycle processes in these debris dams. In some suburban streams debris dams were small and rare, but in others factors that reduce the effects of high stream flows fostered the maintenance of debris dams. Ambient denitrification enzyme activity (DEA) in these suburban and forested streams was positively correlated with stream NO(3)(-) concentrations. In laboratory microcosms, DEA in debris dam material from a forested reference stream was increased by NO(3)(-) additions. Chloride additions constrained the response of DEA to NO(3)(-) additions in material from the forested stream, but had no effect on DEA in material from streams with a history of high Cl(-) levels. Chloride additions changed the sign of net N mineralization from negative (consumption of inorganic N) to positive in debris dam material from the forested reference stream, but had no effect on net mineralization in material from streams with a history of exposure to Cl(-). Understanding the factors regulating the maintenance and N cycling activity of organic debris, and incorporating them into urban stream management plans could have important effects on N dynamics in suburban watersheds.

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“…Similarly, laboratory experiments using intact stream sediment cores found denitrification rates of 100À400 mg N m À2 d À1 , whereas studies completed at the reach scale detected no denitrification once dilution of the stream by groundwater was taken into account. 29 The primary objective of this study was to link the spatial and temporal dynamics of fluid flow and denitrification. We accomplished this goal by combining pore-fluid nitrate concentration and isotopic data with point-specific infiltration rates.…”

Section: ' Introductionmentioning

confidence: 99%

Linking Denitrification and Infiltration Rates during Managed Groundwater Recharge

Schmidt

Fisher

Racz

et al. 2011

Environ. Sci. Technol.

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We quantify relations between rates of in situ denitrification and saturated infiltration through shallow, sandy soils during managed groundwater recharge. We used thermal methods to determine time series of point-specific flow rates, and chemical and isotopic methods to assess denitrification progress. Zero order denitrification rates between 3 and 300 μmol L(-1) d(-1) were measured during infiltration. Denitrification was not detected at times and locations where the infiltration rate exceeded a threshold of 0.7 ± 0.2 m d(-1). Pore water profiles of oxygen and nitrate concentration indicated a deepening of the redoxocline at high flow rates, which reduced the thickness of the zone favorable for denitrification. Denitrification rates were positively correlated with infiltration rates below the infiltration threshold, suggesting that for a given set of sediment characteristics, there is an optimal infiltration rate for achieving maximum nitrate load reduction and improvements to water supply during managed groundwater recharge. The extent to which results from this study may be extended to other managed and natural hydrologic settings remains to be determined, but the approach taken in this study should be broadly applicable, and provides a quantitative link between shallow hydrologic and biogeochemical processes.

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Nitrate removal in a first-order stream: reconciling laboratory and field measurements

Cited by 14 publications

References 32 publications

Denitrification of Nitrogen Released from Senescing Algal Biomass in Coastal Agricultural Headwater Streams

Denitrification of Nitrogen Released from Senescing Algal Biomass in Coastal Agricultural Headwater Streams

Chloride Effects on Nitrogen Dynamics in Forested and Suburban Stream Debris Dams

Linking Denitrification and Infiltration Rates during Managed Groundwater Recharge

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