The Benthic Exchange of O&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt; and Dissolved Nutrients Using Small Core Incubations

Owens, Michael S.; Cornwell, Jeffrey C.

doi:10.3791/54098

Cited by 11 publications

(11 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Water was stirred throughout the whole pre-incubation and incubation periods. Intact sediment cores were incubated in a batch mode according to standardized protocols developed for the measurement of benthic fluxes of gases and nutrients [28,29]. Incubations were performed in the laboratory at 25 • C, simulating the typical middle summer conditions in the Po River Delta.…”

Section: Measurement Of Benthic Fluxes and Denitrification Ratesmentioning

confidence: 99%

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Gervasio

Soana

Vincenzi

et al. 2022

Water

View full text Add to dashboard Cite

In transitional environments, the role of sediments biogeochemistry and denitrification is crucial for establishing their buffer potential against nitrate (NO3−) pollution. The Po River (Northern Italy) is a worldwide hotspot of eutrophication. However, benthic N dynamics and the relevance of denitrification in its delta have not yet been described. The aim of the present study was to quantify the contribution of denitrification in attenuating the NO3− loading transported to the sea during summer. Benthic fluxes of dissolved inorganic nitrogen (N) and denitrification rates were measured in laboratory incubations of intact sediment cores collected, along a salinity gradient, at three sections of the Po di Goro, the southernmost arm of the Po Delta. The correlation between NO3− consumption and N2 production rates demonstrated that denitrification was the main process responsible for reactive N removal. Denitrification was stimulated by both NO3− availability in the Po River water and organic enrichment of sediment likely determined by salinity-induced flocculation of particulate organic load, and inhibited by increasing salinity, along the river–sea gradient. Overall, denitrification represented a sink of approximately 30% of the daily N loading transported in middle summer, highlighting a previously underestimated role of the Po River Delta.

show abstract

Section: Measurement Of Benthic Fluxes and Denitrification Ratesmentioning

confidence: 99%

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Gervasio

Soana

Vincenzi

et al. 2022

Water

View full text Add to dashboard Cite

show abstract

“…Hourly rates of NO 3 − removal (mg N m −2 h −1 ) were determined from NO 3 − concentration‐time linear regression in each mesocosm, according to the equation (Owens & Cornwell, ):

N {O_{3}}^{-} removal rate = \frac{α V}{A}

where α is the slope of regression line obtained by plotting the NO 3 − concentration as a function of incubation time, V is the water volume of each mesocosm, and A is the area of the sediment surface.…”

Section: Methodsmentioning

confidence: 99%

“…Summer and winter experiments consisted of 12 incubations each: six NO 3 − levels (0.7, 1.4, 2.8, 4.2, 7.0, 11.2 mg N L −1 ) under both dark and light conditions to discriminate the effect of photosynthetic processes on N removal. Mesocosms were incubated in a batch mode according to standard protocols developed for the measurement of benthic fluxes of gases and nutrients (Dalsgaard et al., ; Owens & Cornwell, ). The gradient of NO 3 − concentrations captured the common range found in lowland drainage waters, receiving diffuse (agricultural runoff) and point‐source pollution (discharges from wastewater treatment plants) (Pierobon et al., ; Soana et al., ).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Nitrate availability affects denitrification in Phragmites australis sediments

et al. 2020

View full text Add to dashboard Cite

Understanding relationships between an increase in nitrate (NO3−) loading and the corresponding effects of wetland vegetation on denitrification is essential to designing, restoring, and managing wetlands and canals to maximize their effectiveness as buffers against eutrophication. Although Phragmites australis (Cav.) Trin. ex Steud. is frequently used to remediate nitrogen (N) pollution, no information is available on how NO3− concentration may affect plant‐mediated denitrification. In the present study, denitrification was measured in outdoor vegetated and unvegetated mesocosms incubated in both summer and winter. After spiking the mesocosms with NO3− concentrations typical of agricultural drainage water (0.7−11.2 mg N L−1), denitrification was quantified by the simultaneous measurement of NO3− consumption and dinitrogen gas (N2) production. Although denitrification rates varied with vegetation presence and season, NO3− availability exerted a significant positive effect on the process. Vegetated sediments were more efficient than bare sediments in adapting their mitigation potential to an increase in NO3−, by yielding a one‐order‐of‐magnitude increase in NO3− removal rates, under both summer (743−6007 mg N m−2 d−1) and winter (43−302 mg N m−2 d−1) conditions along the NO3− gradient. Denitrification was the dominant sink for water NO3− in winter and only for vegetated sediments in summer. Nitrification likely contributed to fuel denitrification in summer unvegetated sediments. Since denitrification rates followed Michaelis–Menten kinetics, P. australis‐mediated depuration may be considered optimal up to 5.0 mg N L−1. The present outcomes provide experimentally supported evidence that restoration with P. australis can work as a cost‐effective means of improving water quality in agricultural watersheds.

show abstract

“…Cores were sealed and stored in a cooler filled with water from respective sites and transported to Horn Point Laboratory at the University of Maryland Center for Environmental Science for analysis. Incubation methods described in Owens and Cornwell (2016) were used to perform light/dark core incubation and MIMS for N 2 and O 2 dissolved gas flux measurement.…”

Section: Denitrification and Nutrient Fluxesmentioning

confidence: 99%

The Development of Denitrification and of the Denitrifying Community in a Newly-Created Freshwater Wetland

et al. 2020

Self Cite

View full text Add to dashboard Cite

Agricultural growth and urban development have increased nutrient loading into streams to unnatural levels, negatively affecting estuaries downstream. Wetland creation along streams has the potential to mitigate watershed nutrient loading, providing the necessary conditions to encourage bacterial denitrification. We compared denitrification in two wetland systems, one recently created and one well established, along a branch of the St. Martin River, the largest and most degraded tributary flowing into the Maryland Coastal Bays. Ambient and potential denitrification rates were measured using membrane inlet mass spectrometry, and the denitrifying bacterial communities were compared using qPCR with genes nirK, nirS, nosZ-I, and nosZ-II. For all sites, denitrification rates were highly variable, but similar between the two wetlands, while potential rates increased almost 10-fold after a NO 3 − amendment, indicating that the denitrifying communities can respond to pulses of NO 3 − delivered via episodic flow events. Overall, the denitrifying community was more abundant at the created wetland, but the reference site had a higher abundance of the nosZ-I gene and, therefore, a lower genetic potential for N 2 O production. The created wetland has developed denitrification rates and a denitrifying community similar to those of the established wetland and could successfully remove excess nutrients entering the system.

show abstract

The Benthic Exchange of O<sub>2</sub>, N<sub>2</sub> and Dissolved Nutrients Using Small Core Incubations

Cited by 11 publications

References 23 publications

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

An Underestimated Contribution of Deltaic Denitrification in Reducing Nitrate Export to the Coastal Zone (Po River–Adriatic Sea, Northern Italy)

Nitrate availability affects denitrification in Phragmites australis sediments

The Development of Denitrification and of the Denitrifying Community in a Newly-Created Freshwater Wetland

Contact Info

Product

Resources

About