Fate of 15N-nitrate in unplanted, planted and harvested riparian wetland soil microcosms

Matheson, Fleur E.; Nguyen, M. L.; Cooper, Alan; Burt, Tim; Bull, David C.

doi:10.1016/s0925-8574(02)00093-9

Cited by 148 publications

(123 citation statements)

References 21 publications

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“…The low level of NO 3 À in wetland waters (Table 3) suggests that any NO 3 À that enters the wetland via seepage springs and runoff is readily removed by denitrification (Zaman et al 2008b) and other biological processes (Seitzinger 1994;Hill 1996;Fennessy and Cronk 1997;Matheson et al 2002Matheson et al , 2003. Ammonium and organic N were the predominant N fractions in both surface and subsurface waters (Table 3), likely due to inputs from farmland runoff and/or the incomplete breakdown of organic matter originating from wetland organic sediments and/or plant vegetation under anaerobic conditions (Nguyen 2000).…”

Section: Wetland Sediment Physical and Chemical Characteristics And Pmentioning

confidence: 99%

“…Given that denitrification was a minor pathway for NO 3 À transformation, the rapid NO 3 À removal observed in the first several hours following dosing may be attributed to several processes that we did not measure; specifically DNRA (Silver et al 2001;Matheson et al 2002Matheson et al , 2003, abiotic immobilisation (Davidson et al 2003), and microbial immobilisation and plant uptake (Hill 1996;Fennessy and Cronk 1997). Because the wetland soils likely included eroded materials from the adjacent Allophanic volcanic soils of the paddocks, there is potential for some portion of the dosed NO 3 À to be subject to anionic sorption (Magesan et al 1998).…”

Section: Preliminary Testing Of the Push-pull Technique Within A Confmentioning

confidence: 99%

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Nitrous oxide generation, denitrification, and nitrate removal in a seepage wetland intercepting surface and subsurface flows from a grazed dairy catchment

Zaman¹,

Nguyen

Gold

et al. 2008

Soil Res.

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Abstract.Little is known about seepage wetlands, located within agricultural landscapes, with respect to removing nitrate (NO 3 À ) from agricultural catchments, mainly through gaseous emissions of nitrous oxide (N 2 O) and dinitrogen (N 2 ) via denitrification. These variables were quantified using a push-pull technique where we introduced a subsurface water plume spiked with 15 N-enriched NO 3 À and 2 conservative tracers [bromide (Br À ) and sulfur hexafluoride (SF 6 )] into each of 4 piezometers and extracted the plume from the same piezometers throughout a 48-h period. To minimise advective and dispersive flux, we placed each of these push-pull piezometers within a confined lysimeter (0.5 m diameter) installed around undisturbed wetland soil and vegetation. Although minimal dilution of the subsurface water plumes occurred, NO 3 À -N concentration dropped sharply in the first 4 h following dosing, such that NO 3 À -limiting conditions (<2 mg/L of NO 3 -N) for denitrification prevailed over the final 44 h of the experiment. Mean subsurface water NO 3 À removal rates during non-limiting conditions were 15.7 mg/L.day. Denitrification (based on the generation of isotopically enriched N 2 O plus N 2 ) accounted for only 7% (1.1 mg/L.day) of the observed groundwater NO 3 À removal, suggesting that other transformation processes, such as plant uptake, were responsible for most of the NO 3 À removal. Although considerable increases in 15 N-enriched N 2 O levels were initially observed following NO 3 À dosing, no net emissions were generated over the 48-h study. Our results suggest that this wetland may be a source of N 2 O emissions when NO 3 À concentrations are elevated (non-limited), but can readily remove N 2 O (function as a N 2 O sink) when NO 3 À levels are low. These results argue for the use of engineered bypass flow designs to regulate NO 3 À loading to wetland denitrification buffers during high flow events and thus enhance retention time and the potential for NO 3 À -limiting conditions and N 2 O removal. Although this type of management may reduce the full potential for wetland NO 3 À removal, it provides a balance between water quality goals and greenhouse gas emissions.

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Section: Wetland Sediment Physical and Chemical Characteristics And Pmentioning

confidence: 99%

Section: Preliminary Testing Of the Push-pull Technique Within A Confmentioning

confidence: 99%

Nitrous oxide generation, denitrification, and nitrate removal in a seepage wetland intercepting surface and subsurface flows from a grazed dairy catchment

Zaman¹,

Nguyen

Gold

et al. 2008

Soil Res.

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“…Matheson et al [8], investigating the fate of 15 N-NO 3 in wetland soil microcosms, found that, in the presence of Glyceria, denitrification was elevated compared to unplanted microcosms and was the principal mechanism of NO x -N removal (61-63%). They attributed high denitrification rates and low Dissimilatory Nitrate Reduction to Ammonium (DNRA) to differences in soil redox state induced by the presence of the plant.…”

Section: Discussionmentioning

confidence: 99%

“…Wetlands have been demonstrated to be an effective means to attenuate nitrogen derived from DWP [3,4] by plant and periphyton uptake and microbial denitrification [5,6]. In some wetlands, studies have shown that denitrification is the dominant nitrate removal mechanism [4,7,8]. However, microbial activity, which controls denitrification rates, can be reduced at low temperatures [9], pH, and carbon availability [6,10].…”

Section: Introductionmentioning

confidence: 99%

Effectiveness of a Natural Headwater Wetland for Reducing Agricultural Nitrogen Loads

Uuemaa

Palliser

Hughes

et al. 2018

Water

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Natural wetlands can play a key role in controlling non-point source pollution, but quantifying their capacity to reduce contaminant loads is often challenging due to diffuse and variable inflows. The nitrogen removal performance of a small natural headwater wetland in a pastoral agricultural catchment in Waikato, New Zealand was assessed over a two-year period (2011)(2012)(2013). Flow and water quality samples were collected at the wetland upper and lower locations, and piezometers sampled inside and outside the wetland. A simple dynamic model operating on an hourly time step was used to assess wetland removal performance for key N species. Hourly measurements of inflow, outflow, rainfall and Penman-Monteith evapotranspiration estimates were used to calculate dynamic water balance for the wetland. A dynamic N mass balance was calculated for each N component by coupling influent concentrations to the dynamic water balance and applying a first order areal removal coefficient (k 20 ) adjusted to the ambient temperature. Flow and water quality monitoring showed that wetland was mainly groundwater fed. The concentrations of oxidised nitrogen (NO x -N, Total Organic Nitrogen (TON) and Total-N (TN) were lower at the outlet of the wetland regardless of flow conditions or seasonality, even during winter storms. The model estimation showed that the wetland could reduce net NO x -N, NH 4 -N, TON and TN loads by 76%, 73%, 26% and 57%, respectively.

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“…After the 15 N-labeled fertilizers (such as 15 NH 4 Cl, ( 15 NH 4 ) 2 SO 4 , K 15 NO 3 and CO ( 15 NH 2 ) 2 ) are imported into ecosystems, their traces are easily identified though determining the changes of 15 N signatures in different N pools. Matheson et al (2002) discussed the fate of 15 N-NO 3 -in three types of wetland soil microcosm (unplanted, planted (Glyceria declinata), and planted with shoot harvest) in Hamilton, and indicated that, in both types of plant-inhabited microcosm, similar proportions of added 15 N-NO 3 -were denitrified (61%-63%), soil-immobilised (24%-26%), plant-assimilated (11%-15%) and reduced to ammonium (NH 4 + ) (< 1%), while in unplanted microcosms, 49% was reduced to NH 4 + , 29% denitrified and 22% immobilised. Shoot harvest did not affect the fate of 15 N-NO 3 -, but it increased the NO 3 − assimilation capacity of shoots.…”

mentioning

confidence: 99%

Application of stable isotope techniques in studies of carbon and nitrogen biogeochemical cycles of ecosystem

Sun

Mou

et al. 2011

Chin. Geogr. Sci.

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Stable isotope techniques have been proved useful as tools for studying the carbon (C) and nitrogen (N) biogeochemical cycles of ecosystem. This paper firstly introduced the basic principles and the distribution characteristics of stable isotope, then reviewed the recent advances and applications of stable isotope in the C and N biogeochemical cycles of ecosystem. By applying the 13 C natural abundance technique, ecologists are able to understand the photosynthetic path and CO 2 fixation of plants, the CO 2 exchange and C balance status of ecosystem, the composition, distribution and turnover of soil organic C and the sources of organic matter in food webs, while by using the 13 C labeled technique, the effects of elevated CO 2 on the C processes of ecosystem and the sources and fate of organic matter in ecosystem can be revealed in detail. Differently, by applying the 15 N natural abundance technique, ecologists are able to analyze the biological N 2 -fixation, the N sources of ecosystem, the N transformation processes of ecosystem and the N trophic status in food webs, while by using the 15 N labeled technique, the sources, transformation and fate of N in ecosystem and the effects of N input on the ecosystem can be investigated in depth. The applications of both C and N isotope natural abundance and labeled techniques, combined with the elemental, other isotope ( 34 S) and molecular biomarker information, will be more propitious to the investigation of C and N cycle mechanisms. Finally, this paper concluded the problems existed in current researches, and put forward the perspective of stable isotope techniques in the studies of C and N biogeochemical cycles of ecosystem in the future.

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Fate of 15N-nitrate in unplanted, planted and harvested riparian wetland soil microcosms

Cited by 148 publications

References 21 publications

Nitrous oxide generation, denitrification, and nitrate removal in a seepage wetland intercepting surface and subsurface flows from a grazed dairy catchment

Nitrous oxide generation, denitrification, and nitrate removal in a seepage wetland intercepting surface and subsurface flows from a grazed dairy catchment

Effectiveness of a Natural Headwater Wetland for Reducing Agricultural Nitrogen Loads

Application of stable isotope techniques in studies of carbon and nitrogen biogeochemical cycles of ecosystem

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