Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters

Jani, Jariani; Toor, Gurpal S.

doi:10.1016/j.watres.2018.02.042

Cited by 57 publications

(14 citation statements)

References 64 publications

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“…In contrast to organic N, NO x -N concentrations increased by 35-39% (mean: 30±38%) and NH 4 -N concentrations increased by 9-39% (mean: 39±16%) (Fig 3). This finding is similar to Seitzinger and Sanders [24] and Jani and Toor [21], who reported an increase in DIN concentrations and decrease in DON concentrations in the bioassay experiments. This net increase in inorganic N was likely due to the mineralization of organic N to NH 4 -N, which was further nitrified to NO x -N [25][26][27].…”

Section: Bioavailability Of Organic Nitrogensupporting

confidence: 91%

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Wet season nitrogen export from a residential stormwater pond

2020

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Stormwater runoff is recognized as a cause of water quality degradation because it may carry nitrogen (N) and other pollutants to aquatic ecosystems. Stormwater ponds are a stormwater control measure often used to manage stormwater runoff by holding a permanent pool of water, which reduces the peak flow, magnitude of runoff volume, and concentrations of nutrients and pollutants. We instrumented the outlet of a stormwater pond in an urban residential neighbourhood in Florida, United States to (1) investigate the concentration and composition of N forms during the summer rainy season (May to September 2016), and (2) determine the bioavailability of organic N in the stormwater pond with a bioassay experiment. A total of 144 outflow water samples over 13 storm events were collected at the outlet of the stormwater pond that collects runoff from the residential catchment. Samples were analysed for various inorganic N [ammonium (NH 4-N), nitrate (NO 3-N)], and organic N forms [dissolved organic nitrogen (DON), and particulate organic nitrogen (PON)]. Flowweighted mean concentration of total N (TN) in pond outflow for all collected storm events was 1.3±1.42 mg L-1 , with DON as the dominant form (78%), followed by PON and NO 3-N (each at 8%), and NH 4-N (6%). In the bioassay experiment, organic N (DON+PON) was significantly decreased by 25-28% after 5 days of incubation, suggesting that a portion of the DON carried from the pond outflow to receiving water bodies may be bioavailable. These results suggest that efforts to mitigate stormwater N outflows from urban ponds should incorporate both inorganic and organic N in management plans.

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Section: Bioavailability Of Organic Nitrogensupporting

confidence: 91%

“…The bioassay experiment was carried out following the methods described by Osborne et al [15,[19][20][21], (Fig 2). In brief, 320 mL of pond water sample was mixed with 100 mL of filtered inoculum in 1-L amber glass bottle.…”

Section: Bioassay Experimentsmentioning

confidence: 99%

Wet season nitrogen export from a residential stormwater pond

2020

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“…Hochmuth et al [53] reported that stormwater has the potential to leach nutrients from plant debris instantly, thus removal of leaf litter and plant debris must be done as soon as possible prior to storm events. Furthermore, a number of researchers, including our previous work in Tampa Bay, Florida, US, have concluded that a portion of the DON may be bioavailable and thus can be a source of water quality impairment in urban waters [3,8,39,54].…”

Section: Concentrations and Loads Of Nitrogen Forms In Stormwater Runoffmentioning

confidence: 99%

Composition of nitrogen in urban residential stormwater runoff: Concentrations, loads, and source characterization of nitrate and organic nitrogen

et al. 2020

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Stormwater runoff is a leading cause of nitrogen (N) transport to water bodies and hence one means of water quality deterioration. Stormwater runoff was monitored in an urban residential catchment (drainage area: 3.89 hectares) in Florida, United States to investigate the concentrations, forms, and sources of N. Runoff samples were collected over 22 storm events (May to September 2016) at the end of a stormwater pipe that delivers runoff from the catchment to the stormwater pond. Various N forms such as ammonium (NH 4-N), nitrate (NO x-N), dissolved organic nitrogen (DON), and particulate organic nitrogen (PON) were determined and isotopic characterization tools were used to infer sources of NO 3-N and PON in collected runoff samples. The DON was the dominant N form in runoff (47%) followed by PON (22%), NO x-N (17%), and NH 4-N (14%). Three N forms (NO x-N, NH 4-N, and PON) were positively correlated with total rainfall and antecedent dry period, suggesting longer dry periods and higher rainfall amounts are significant drivers for transport of these N forms. Whereas DON was positively correlated to only rainfall intensity indicating that higher intensity rain may flush out DON from soils and cause leaching of DON from particulates present in the residential catchment. We discovered, using stable isotopes of NO 3-, a shifting pattern of NO 3 sources from atmospheric deposition to inorganic N fertilizers in events with higher and longer duration of rainfall. The stable isotopes of PON confirmed that plant material (oak detritus, grass clippings) were the primary sources of PON in stormwater runoff. Our results demonstrate that practices targeting both inorganic and organic N are needed to control N transport from residential catchments to receiving waters.

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“…While NH 4 is considerably less mobile than NO 3 , it is more bioavailable and may enhance local stream production (Dortch, 1990). DON can also control the stock and the species composition of phytoplankton communities in downstream ecosystems, especially saline ones (Berman, 1999;Jani & Toor, 2018;Seitzinger, Sanders, et al, 2002).…”

Section: Nitrogen Mass Balancementioning

confidence: 99%

Modeling Runoff and Nitrogen Loads From a Watershed at Different Levels of Impervious Surface Coverage and Connectivity to Storm Water Control Measures

Bell

Tague

McMillan

2019

Water Resources Research

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Urban development of watersheds increases runoff and nitrogen loads by adding urban impervious surfaces and increasing the hydrologic connectivity of these surfaces to streams. Storm water control measures (SCMs) are designed to disrupt this connectivity by retaining water in biologically active depressions where nitrogen retention, transformation, and removal occur. This work applies a mechanistic, spatially distributed, hydroecological model (RHESSys) to a suburban watershed in Charlotte, NC, with 15% total imperviousness (TI) and 33% watershed area mitigated by SCMs. We developed emergent relationships between watershed‐scale predictors (TI and connectivity to SCMs) and water and nitrogen response variables (storm water runoff ratios and nitrogen load by species). Results showed that annual runoff ratios were insensitive to increases in connectivity to SCMs (varying by ~1% of rainfall) because SCMs did not substantially increase evaporation but that runoff ratios increased by an average 0.2% per 1% increase in TI due to decreases in transpiration in the watershed. Generally, nitrate loads increased with TI but decreased as more surfaces were mitigated by SCMs. However, these nitrate reductions corresponded to increased export of dissolved organic nitrogen and ammonium. Together, these results indicate that SCMs act as both removers and transformers of nitrogen at the watershed scale. SCMs showed a net assimilation of nitrogen in warm months and net release in cool months, which offset the timing of nitrogen export relative to inputs. This work highlights that using a hydroecological, process‐based model reveals both the emergent relationships between watershed condition and response and the processes controlling those relationships.

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Composition, sources, and bioavailability of nitrogen in a longitudinal gradient from freshwater to estuarine waters

Cited by 57 publications

References 64 publications

Wet season nitrogen export from a residential stormwater pond

Wet season nitrogen export from a residential stormwater pond

Composition of nitrogen in urban residential stormwater runoff: Concentrations, loads, and source characterization of nitrate and organic nitrogen

Modeling Runoff and Nitrogen Loads From a Watershed at Different Levels of Impervious Surface Coverage and Connectivity to Storm Water Control Measures

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