Kinetic Parameters of Denitrification in a River Continuum

García‐Ruiz, Roberto; Pattinson, Sarah N.; Whitton, Brian A.

doi:10.1128/aem.64.7.2533-2538.1998

Cited by 74 publications

(35 citation statements)

References 25 publications

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“…However, nitrate supply differs greatly among lakes (Table 2) and NO 3 concentrations vary accordingly, with Burr Oak water column concentration often <10 lg N L )1 . Although little is known about the extent to which NO 3 concentration limits Stoichiometry of linked catchment-lake systems 805 denitrification in the field (Boyer et al, 2006), concentrations this low can limit denitrification rates (Garcia-Ruiz, Pattinson & Whitton, 1998). This suggests that denitrification rates are lower in Burr Oak, although it is not clear if the percentage of N removed via denitrification also would be lower.…”

Section: Stoichiometric Ratios From Inflow Streams To Reservoir Sedimmentioning

confidence: 99%

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

et al. 2011

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1. Catchments export nutrients to aquatic ecosystems at rates and ratios that are strongly influenced by land use practices, and within aquatic ecosystems nutrients can be processed, retained, lost to the atmosphere, or exported downstream. The stoichiometry of carbon and nutrients can influence ecosystem services such as water quality, nutrient limitation, biodiversity, eutrophication and the sequestration of nutrients and carbon in sediments. However, we know little about how nutrient stoichiometry varies along the pathway from terrestrial landscapes through aquatic systems. 2. We studied the stoichiometry of nitrogen and phosphorus exported by three catchments of contrasting land use (forest versus agriculture) and in the water column and sediments of downstream reservoirs. We also related stoichiometry to phytoplankton nutrient limitation and the abundance of heterocystous cyanobacteria. 3. The total N : P of stream exports varied greatly among catchments and was 18, 54 and 140 (molar) in the forested, mixed-use and agricultural catchment, respectively. Total N : P in the mixed layers of the lakes was less variable but ordered similarly: 35, 52 132 in the forested, mixed-use and agricultural lake, respectively. In contrast, there was little variation among systems in the C : N and C : P ratios of catchment exports or in reservoir seston. 4. Phytoplankton in the forested lake were consistently N limited, those in the agricultural lake were consistently P limited, and those in the mixed-use lake shifted seasonally from P-to N limitation, reflecting N : P supply ratios. Total phytoplankton and cyanobacteria biomass were highest in the agricultural lake, but heterocystous (potentially N fixing) cyanobacteria were most abundant in the forested lake, corresponding to low N : P ratios. 5. Despite large differences in catchment export and water column N : P ratios, the N : P of sediment burial (integrated over several decades) was very low and remarkably similar (4.3-7.3) across reservoirs. N and P budgets constructed for the agricultural reservoir suggested that denitrification could be a major loss of N, and may help explain the relatively low N : P of buried sediment. 6. Our results show congruence between the catchment export N : P, reservoir N : P, phytoplankton N versus P limitation and the dominance of heterocystous cyanobacteria. However, the N : P stoichiometry of sediments retained in the lakes was relatively insensitive to catchment stoichiometry, suggesting that a common set of biogeochemical processes constrains sediment N : P across lakes of contrasting catchment land use.

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Section: Stoichiometric Ratios From Inflow Streams To Reservoir Sedimmentioning

confidence: 99%

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

et al. 2011

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“…Little information has been reported on the seasonal variability in denitrification rates (Royer et al 2004) and the biogeochemical controls on aquatic rates (Seitzinger 1988), including the importance of water-column nitrate concentrations (i.e., saturation kinetics) and properties of the benthic sediment of streams and lakes such as organic C content, grain size, and the density of benthic microbial communities. Moreover, few studies of either heterotrophic or autotrophic processing of N have measured N removal rates along a stream continuum to systematically evaluate the influence of stream dynamics on metabolic processes and especially denitrification rates (Garcia-Ruiz et al 1998). These limitations have made cross-site comparisons difficult and complicated efforts to generalize denitrification rates over time and space.…”

Section: Modeling Denitrification In Aquatic Ecosystemsmentioning

confidence: 99%

“…Uncertainties also exist in the first-order assumptions that are currently used in virtually all aquatic models to quantify the rates of denitrification. The few studies of the saturation kinetics of denitrification (Garcia-Ruiz et al 1998) have reported evidence of concentration limitations, but additional research is needed to broaden understanding of these conditions in a range of aquatic ecosystems. Nevertheless, these studies raise questions about how accurately the published denitrification rates apply to streams with especially high nitrate concentrations, such as those found in agricultural watersheds where saturation kinetics may potentially limit denitrification rates.…”

Section: Key Uncertainties and Needs In Modeling Aquatic Denitrificationmentioning

confidence: 99%

Modeling Denitrification in Terrestrial and Aquatic Ecosystems at Regional Scales

Boyer

Alexander

Parton

et al. 2006

Ecological Applications

231

258

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Quantifying where, when, and how much denitrification occurs on the basis of measurements alone remains particularly vexing at virtually all spatial scales. As a result, models have become essential tools for integrating current understanding of the processes that control denitrification with measurements of rate-controlling properties so that the permanent losses of N within landscapes can be quantified at watershed and regional scales. In this paper, we describe commonly used approaches for modeling denitrification and N cycling processes in terrestrial and aquatic ecosystems based on selected examples from the literature. We highlight future needs for developing complementary measurements and models of denitrification. Most of the approaches described here do not explicitly simulate microbial dynamics, but make predictions by representing the environmental conditions where denitrification is expected to occur, based on conceptualizations of the N cycle and empirical data from field and laboratory investigations of the dominant process controls. Models of denitrification in terrestrial ecosystems include generally similar rate-controlling variables, but vary in their complexity of the descriptions of natural and human-related properties of the landscape, reflecting a range of scientific and management perspectives. Models of denitrification in aquatic ecosystems range in complexity from highly detailed mechanistic simulations of the N cycle to simpler source-transport models of aggregate N removal processes estimated with empirical functions, though all estimate aquatic N removal using first-order reaction rate or mass-transfer rate expressions. Both the terrestrial and aquatic modeling approaches considered here generally indicate that denitrification is an important and highly substantial component of the N cycle over large spatial scales. However, the uncertainties of model predictions are large. Future progress will be linked to advances in field measurements, spatial databases, and model structures.

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“…The concentration of NO 3 À in overlying water has been identified as one of the main factors controlling denitrification in sediments (King and Nedwell 1988, Seitzinger 1988, Kemp and Dodds 2002. Studies involving NO 3 À additions and utilizing a variety of measurement techniques have demonstrated that denitrification rates in freshwater and estuarine sediments respond strongly to NO 3 À addition (Andersen 1977, Oremland et al 1984, Oren and Blackburn 1979, Garcia-Ruiz et al 1998a. Garcia-Ruiz et al (1998a) measured denitrification rates along a river continuum including a highly polluted tributary.…”

Section: Importance Of Nitrate and Doc Concentrationsmentioning

confidence: 99%

“…Studies involving NO 3 À additions and utilizing a variety of measurement techniques have demonstrated that denitrification rates in freshwater and estuarine sediments respond strongly to NO 3 À addition (Andersen 1977, Oremland et al 1984, Oren and Blackburn 1979, Garcia-Ruiz et al 1998a. Garcia-Ruiz et al (1998a) measured denitrification rates along a river continuum including a highly polluted tributary. Rates increased from upland to lowland reaches and were positively correlated with NO 3 À concentration.…”

Section: Importance Of Nitrate and Doc Concentrationsmentioning

confidence: 99%

DENITRIFICATION IN NITRATE-RICH STREAMS: APPLICATION OF N₂:Ar AND¹⁵N-TRACER METHODS IN INTACT CORES

Smith

Voytek

Böhlke

et al. 2006

Ecological Applications

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Rates of benthic denitrification were measured using two techniques, membrane inlet mass spectrometry (MIMS) and isotope ratio mass spectrometry (IRMS), applied to sediment cores from two NO3(-)-rich streams draining agricultural land in the upper Mississippi River Basin. Denitrification was estimated simultaneously from measurements of N2:Ar (MIMS) and 15N[N2] (IRMS) after the addition of low-level 15NO3- tracer (15N:N = 0.03-0.08) in stream water overlying intact sediment cores. Denitrification rates ranged from about 0 to 4400 micromol N x m(-2) x h(-1) in Sugar Creek and from 0 to 1300 micromol N x m(-2) x h(-1) in Iroquois River, the latter of which possesses greater streamflow discharge and a more homogeneous streambed and water column. Within the uncertainties of the two techniques, there is good agreement between the MIMS and IRMS results, which indicates that the production of N2 by the coupled process of nitrification/denitrification was relatively unimportant and surface-water NO3- was the dominant source of NO3- for benthic denitrification in these streams. Variation in stream NO3- concentration (from about 20 micromol/L during low discharge to 1000 micromol/L during high discharge) was a significant control of benthic denitrification rates, judging from the more abundant MIMS data. The interpretation that NO3- concentration directly affects denitrification rate was corroborated by increased rates of denitrification in cores amended with NO3-. Denitrification in Sugar Creek removed < or = 11% per day of the instream NO3- in late spring and removed roughly 15-20% in late summer. The fraction of NO3- removed in Iroquois River was less than that of Sugar Creek. Although benthic denitrification rates were relatively high during periods of high stream flow, when NO3 concentrations were also high, the increase in benthic denitrification could not compensate for the much larger increase in stream NO3- fluxes during high flow. Consequently, fractional NO3- losses were relatively low during high flow.

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Kinetic Parameters of Denitrification in a River Continuum

Cited by 74 publications

References 25 publications

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

Modeling Denitrification in Terrestrial and Aquatic Ecosystems at Regional Scales

DENITRIFICATION IN NITRATE-RICH STREAMS: APPLICATION OF N₂:Ar AND¹⁵N-TRACER METHODS IN INTACT CORES

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Kinetic Parameters of Denitrification in a River Continuum

Cited by 74 publications

References 25 publications

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

Nutrient stoichiometry of linked catchment-lake systems along a gradient of land use

Modeling Denitrification in Terrestrial and Aquatic Ecosystems at Regional Scales

DENITRIFICATION IN NITRATE-RICH STREAMS: APPLICATION OF N2:Ar AND15N-TRACER METHODS IN INTACT CORES

Contact Info

Product

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DENITRIFICATION IN NITRATE-RICH STREAMS: APPLICATION OF N₂:Ar AND¹⁵N-TRACER METHODS IN INTACT CORES