Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary

Wang, Xuming; Hu, Minjie; Hong-chang, Ren; Li, Jiabing; Tong, Chuan; Musenze, Ronald S.

doi:10.1016/j.scitotenv.2017.10.175

Cited by 50 publications

(25 citation statements)

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“…The denitrification rates of both freshwater and oligohaline marsh soils varied significantly with the season ( F = 12.59, p < .01, and F = 17.23, p < .01, respectively; Figure 1; Table S2), which is consistent with the results of a previous study in which optimum temperatures triggered high denitrification rates by stimulating substrate availability and denitrification potential (Wang et al, 2017). The denitrification rates were higher during the winter than during the spring and autumn, probably owing to the increased NO 3 − ‐N availability in the winter (Table S1), which can supply more N substrates to denitrifiers.…”

Section: Resultssupporting

confidence: 90%

“…Estuarine marshes play a vital role in denitrification because they consist of a combination of anaerobic environments and include carbonaceous substrates in the soil (Marks, Chambers, & White, 2016). Previous studies confirmed that denitrification in estuaries is variable and potentially regulated by various factors, such as the soil texture, salinity and N loading (Hinshaw, Zhang, Harrison, & Dahlgren, 2020;Lee, Cherry, & Edmonds, 2017;Wang et al, 2017). Because of the influence of upstream runoff and tidal saltwater intrusion, the salinity and soil texture change significantly in estuary systems, and, at the same time, large amounts of exogenous N derived from fertilization are introduced into estuaries from runoff, tides and deposition (Hu et al, 2019;Neubauer et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Peñuelas

Sardans

et al. 2020

European J Soil Science

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The denitrification rates of freshwater and oligohaline tidal marsh soils with different textures (loam and sandy soils) in a subtropical estuary, and their responses to nitrogen (N) loading, were investigated. In both marshes, the denitrification rates varied significantly with the season only in loam soil. The denitrification rates were highest in oligohaline marsh loam soil and lowest in freshwater marsh sandy soil. NH4NO3 addition significantly increased the denitrification rates of all the marsh soils. Our findings suggest that soil texture, soil organic matter (OM) content and low‐level increases in salinity all had large effects on denitrification, indicating that the dynamics of denitrification rates in estuarine marshes with low‐level salinity were controlled by the interaction of salinity and soil texture but mainly depended on OM content. We propose that denitrification in tidal marshes plays an important role in regulating current and future N loading into estuary and inshore coastal waters, especially for tidal freshwater marshes, which introduces great uncertainty into the N dynamics of estuaries under global changes. Highlights Denitrification rates were higher in loam than sandy soil, independent of salinity. Denitrification rates were higher in oligohaline marsh loam than freshwater marsh loam. Exogenous N input enhanced denitrification in estuarine marsh soil. Loam with high N enhanced N removal, especially in freshwater environments.

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Section: Resultssupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Peñuelas

Sardans

et al. 2020

European J Soil Science

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“…Based on the gas transfer coefficient method, the mean diffusion N 2 O flux from the whole pond was estimated to be 169.1 nmol m −2 hr −1 . Notably, the mean N 2 O emission from our ponds during the aquaculture period was markedly lower than the average of 721 nmol m −2 hr −1 found in the Cyperus malaccensis marsh in an adjacent estuary during the summer and autumn periods (X. M. Wang et al, 2018). Our results suggested that the conversion of brackish marsh ecosystem to shrimp ponds could reduce N 2 O emissions during the aquaculture period.…”

Section: Discussionmentioning

confidence: 51%

Spatial Variations of N₂O Fluxes Across the Water‐Air Interface of Mariculture Ponds in a Subtropical Estuary in Southeast China

et al. 2020

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While aquaculture ponds are potentially important sources of atmospheric N 2 O, the magnitude and variability of N 2 O concentrations and fluxes both within and across the ponds remain poorly understood. In this study, we examined the small-scale spatial variations of dissolved N 2 O concentrations in water and N 2 O fluxes across the water-air interface from three mariculture ponds in a subtropical estuary in southeast China. Our results showed that the dissolved concentrations and diffusive fluxes of N 2 O in the shrimp ponds ranged between 2.3-19.2 nM and 16.4-589.7 nmol m −2 hr −1 , respectively, over the culture period. Significant variations of N 2 O concentrations and fluxes were observed within the ponds, with higher values being observed in the aeration area that could be attributed to the high rates of nitrification in the water column, as well as sediment N 2 O production and diffusive flux into the overlying water. Also, N 2 O concentrations and fluxes varied significantly among the three ponds as a result of the difference in N-NO 3 − and N-NH 4 + concentrations in the water column. The large fine-scale spatial variations of N 2 O concentrations and fluxes observed in our aquaculture ponds suggested that management practices such as aeration and bait feeding could largely affect the extent that aquaculture activities have on N 2 O emissions and climate change through their influence on the physicochemical environment (e.g., oxygen and N-NH 4 + concentrations) of the ponds.

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“…Estuaries are dynamic N 2 O hotspots due to hydrodynamic oscillations driving both nutrient cycling and the associated N 2 O production (Gonçalves et al ; Baulch et al ; Wang et al ). Here, we observed the highest nutrient concentrations in the most modified catchments and contrasting results between summer dry and winter wet seasons.…”

Section: Discussionmentioning

confidence: 99%

Land use drives nitrous oxide dynamics in estuaries on regional and global scales

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Tait

Maher

et al. 2020

Limnology & Oceanography

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Urban and agricultural development of coastal catchments is known to increase dissolved nitrogen inputs into estuaries; however, much less is known about how land use influences the production of the powerful greenhouse gas nitrous oxide (N 2 O). Here, we assess dissolved N 2 O dynamics in four nearby estuaries across a regional land use gradient and summarize the literature to put the observations into global perspective. During summer dry conditions, N 2 O saturation ranged from 131.4% AE 45.0% in the most pristine system (28% modified) to 198.6% AE 52.3% within the most modified urban system (91% modified). The N 2 O saturation in the wetter winter campaign was higher and more variable than the summer dry campaign (range 84.7-677.7%) likely due to direct transport of N 2 O into the estuaries from catchment runoff and/or produced through denitrification fueled by high nitrate inputs. During both seasons, N 2 O was lowest in areas adjacent to fringing mangroves and highest in upstream fresh/saltwater mixing areas. Coupling our results with previously published N 2 O data from 50 estuarine systems worldwide revealed that estuarine N 2 O increases concomitantly with catchment modification, dissolved inorganic nitrogen availability, and decreasing oxygen concentrations. Based on these results, a 1% increase in anthropogenic modification to global catchments (i.e., agricultural development and/or urbanization) may increase estuarine N 2 O saturation by 2.6% AE 1.2%. These findings indicate that future estuarine N 2 O emissions are likely to increase as anthropogenic modification of coastal catchments intensifies.

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Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary

Cited by 50 publications

References 59 publications

Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Spatial Variations of N₂O Fluxes Across the Water‐Air Interface of Mariculture Ponds in a Subtropical Estuary in Southeast China

Land use drives nitrous oxide dynamics in estuaries on regional and global scales

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Seasonal variations of nitrous oxide fluxes and soil denitrification rates in subtropical freshwater and brackish tidal marshes of the Min River estuary

Cited by 50 publications

References 59 publications

Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Denitrification rates in tidal marsh soils: The roles of soil texture, salinity and nitrogen enrichment

Spatial Variations of N2O Fluxes Across the Water‐Air Interface of Mariculture Ponds in a Subtropical Estuary in Southeast China

Land use drives nitrous oxide dynamics in estuaries on regional and global scales

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Spatial Variations of N₂O Fluxes Across the Water‐Air Interface of Mariculture Ponds in a Subtropical Estuary in Southeast China