Nitrogen removal by tropical floodplain wetlands through denitrification

Adame, Maria Fernanda; Franklin, Hannah M.; Waltham, Nathan J.; Rodríguez, Sebastián Figueroa; Turschwell, Mischa P.; Balcombe, Stephen Richard; Kaniewska, Paulina; Burford, Michele A.; Ronan, Mike

doi:10.1071/mf18490

Cited by 25 publications

(19 citation statements)

References 41 publications

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“…The hotspots were identified by multiplying the denitrification potential for wetlands within each sub-catchment (D t ; mg m −2 h −1 ), by the area of wetlands that were flooded during the day. Total denitrification was predicted from the NO − 3 concentration of the floodwater, which is a major driver of denitrification for similar wetlands in the region (Adame et al, 2019b, this study, Figure 3) and other tropical and temperate wetlands (Piña-Ochoa and Álvarez-Cobelas, 2006). The NO − 3 concentrations were obtained from the Source Catchment model and corroborated by direct measurements obtained by the Water Quality Monitoring Program of the Great Barrier Reef (Euramo station at Tully River; Orr et al, 2014).…”

Section: Nitrogen Fate and Transportmentioning

confidence: 90%

“…We measured denitrification rates at eight sites representative of coastal wetlands of these catchments. Previous studies have shown no significant differences in denitrification potential between the dry and wet seasons (Adame et al, 2019b). Thus, all measurements were conducted once at each site at the end of the wet season (May to June) in either 2017 or 2018.…”

Section: Study Sitementioning

confidence: 99%

“…and emergent grasses (Figure 2A). Denitrification rates for the two Melaleuca sites have previously been published in Adame et al (2019b). The denitrification rates were used in conjunction with a map and hydrological characteristics of a flood that occurred on March 2018 to identify hotspots of denitrification.…”

Section: Study Sitementioning

confidence: 99%

“…The potential to remove N through denitrification is closely associated with soil carbon and water NO − 3 concentration in many temperate (Piña-Ochoa and Álvarez-Cobelas, 2006;Zhou et al, 2014) and tropical wetlands (Adame et al, 2019b). Wetlands have carbon-rich soils due to high primary productivity (Mitsch and Gosselink, 2015), but NO − 3 concentrations can vary widely.…”

Section: Introductionmentioning

confidence: 99%

“…The amount of NO − 3 a wetland receives is usually dependent on anthropogenic inputs (e.g., sewage, fertilizer) from the catchment (Wells et al, 2016). Additionally, wetlands obtain NO − 3 in-situ from nitrification, the conversion of NH + 4 to NO − 3 , which, in some tropical wetlands, accounts for 30% of the NO − 3 that is denitrified (Adame et al, 2019b).…”

Section: Introductionmentioning

confidence: 99%

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Tropical Coastal Wetlands Ameliorate Nitrogen Export During Floods

et al. 2019

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Wetlands can increase resilience to extreme climatic events and have a key role in protection and water quality improvement in coastal ecosystems. Studies in tropical coastal wetlands at a catchment scale are scarce, and most work has been undertaken on small, temperate wetlands. In this study, we tested whether natural coastal wetlands in a tropical catchment (Tully-Murray, Queensland, Australia) could ameliorate nitrogen (N) exported to the Great Barrier Reef during a flood event. We measured denitrification rates in different types of coastal wetlands (mangroves, saltmarshes, waterbodies with macrophytes, and floodplain wetlands dominated by Melaleuca spp.) to assess their potential contribution to N losses during the 6-day duration of a flood in March 2018. Denitrification potential was variable across the landscape, and we identified "hotspots" in sub-catchments with high NO − 3 -N concentrations (0.4-0.6 mg L −1 ) and large areas of wetlands (>800 ha, >40% of the sub-catchment). These hotspots can denitrify up to 10 t of NO − 3 -N per day during a flood. We used our measured denitrification rates to provide input parameters for a model that includes the main biogeochemical processes affecting N transformations within wetlands (nitrification, denitrification, plant uptake, sedimentation, anammox, and mineralization), and accounts for transport via the duration, depth, and flow of water. Model simulations of a sub-catchment of the Tully-Murray indicate that flood inundation of large areas of natural wetlands (>40% of the sub-catchment area) could potentially remove 70% of the incoming NO − 3 -N load in the first 24 h of the flood. The management and restoration of coastal tropical wetlands could play a critical role in sustaining the health of coastal ecosystems through water quality improvement.

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Section: Nitrogen Fate and Transportmentioning

confidence: 90%

Section: Study Sitementioning

confidence: 99%

Section: Study Sitementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tropical Coastal Wetlands Ameliorate Nitrogen Export During Floods

et al. 2019

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Climate change mitigation and improvement of water quality from the restoration of a subtropical coastal wetland

Iram

Maher

Lovelock

et al. 2022

Ecological Applications

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Coastal wetland restoration is an important activity to achieve greenhouse gas (GHG) reduction targets, improve water quality, and reach the Sustainable Development Goals. However, many uncertainties remain in connection with achieving, measuring, and reporting success from coastal wetland restoration.We measured levels of carbon (C) abatement and nitrogen (N) removal potential of restored coastal wetlands in subtropical Queensland, Australia. The site was originally a supratidal forest composed of Melaleuca spp. that was cleared and drained in the 1990s for sugarcane production. In 2010, tidal inundation was reinstated, and a mosaic of coastal vegetation (saltmarshes, mangroves, and supratidal forests) emerged. We measured soil GHG fluxes (CH 4 , N 2 O, CO 2 ) and sequestration of organic C in the trees and soil to estimate the net C abatement associated with the reference, converted, and restored sites. To assess the influence of restoration on water quality improvement, we measured denitrification and soil N accumulation. We calculated C abatement of 18.5 Mg CO 2Àeq ha À1 year À1 when sugarcane land transitioned to supratidal forests, 11.0 Mg CO 2Àeq ha À1 year À1 when the land transitioned to mangroves, and 6.2 Mg CO 2Àeq ha À1 year À1 when the land transitioned to saltmarshes. The C abatement was due to tree growth, soil accumulation, and reduced N 2 O emissions due to the cessation of fertilization. Carbon abatement was still positive, even accounting for CH 4 emissions, which increased in the wetlands due to flooding and N 2 O production due to enhanced levels of denitrification.Coastal wetland restoration in this subtropical setting effectively reduces CO 2 emissions while providing additional cobenefits, notably water quality improvement.

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Constructed Wetlands Suitability for Sugarcane Profitability, Freshwater Biodiversity and Ecosystem Services

Canning

Smart

Dyke

et al. 2022

Environmental Management

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Freshwater ecosystems, such as wetlands, are among the most impacted by agricultural expansion and intensification through extensive drainage and pollution. There is a pressing need to identify ways of managing agricultural landscapes to ensure food and water security without jeopardising biodiversity and other environmental benefits. Here we examine the potential fish biodiversity and landholder financial benefits arising from the integration of constructed lagoons to improve drainage, flow regulation and habitat connectivity within a sugarcane dominated catchment in north Queensland, Australia. A hybrid approach was used, combining the findings of both fish ecological surveys and a financial cost-benefit analysis. We found that the constructed lagoons supported at least 36 native freshwater fishes (over half of all native freshwater fishes in the region), owing to their depth, vegetated margins, moderate water quality and high connectivity to the Tully River. In addition to biodiversity benefits, we estimated that surrounding sugarcane farms would have financially benefited from reduced flooding of cropland and the elevation of low-lying cropland with deposited spoil excavated from lagoon construction. Improved drainage and flow regulation allowed for improvement in sugarcane yield and elevated land increased gross margins from extending the length of the cane production cycle or enabling a switch from cattle grazing to cane production. Restoring or creating wetlands to reduce flooding in flood-prone catchments is a globally applicable model that could improve both agricultural productivity and aquatic biodiversity, while potentially increasing farm income by attracting payments for provision of ecosystem services.

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Nitrogen removal by tropical floodplain wetlands through denitrification

Cited by 25 publications

References 41 publications

Tropical Coastal Wetlands Ameliorate Nitrogen Export During Floods

Tropical Coastal Wetlands Ameliorate Nitrogen Export During Floods

Climate change mitigation and improvement of water quality from the restoration of a subtropical coastal wetland

Constructed Wetlands Suitability for Sugarcane Profitability, Freshwater Biodiversity and Ecosystem Services

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