Nitrogen Dynamics of Inundated Sediments in an Emerging Coastal Deltaic Floodplain in Mississippi River Delta Using Isotope Pairing Technique to Test Response to Nitrate Enrichment and Sediment Organic Matter

Li, Song; Twilley, Robert R.

doi:10.1007/s12237-021-00913-6

Cited by 11 publications

(19 citation statements)

References 89 publications

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“…S1, Li et al 2020). To support this assumption, we compared the estimated denitrification rates with recent measured denitrification rates in the same experimental sites under similar incubation conditions (Li and Twilley, 2021). We verified that the estimated denitrification rates were in the same magnitude as the measured denitrification rates using isotope pairing technique in each experimental site.…”

Section: Hydrogeomorphic Zonesmentioning

confidence: 67%

“…The int-OM sediment site is located near the fringe along a primary channel of the delta and exposed to frequent flood pulses of inorganic sedimentation, thus its OM sediment concentration is relatively lower than the higher-OM sediment site located within the interior of the island. Detailed descriptions of these experimental sites are shown in Li and Twilley (2021). The int-, higher-, and lower-OM sediment sites were sampled on 22 June, 06 July, and 20 July, respectively, in 2019.…”

Section: Methodsmentioning

confidence: 99%

“…Subtidal (>-0.75m and <-0.04m) Intertidal (>-0.04m and <0.30m) Supratidal (>0.30m and <0. site, we still collected samples and incubated cores the same way as we treated the other two sites. We compared the posthurricane sediment property and benthic fluxes in the lower-OM sediment site to the corresponding results measured in the same site in summer 2018 (Li and Twilley, 2021) to evaluate the possible hurricane effects to benthic N dynamics. Duplicate surface water (right below the air-water interface) and pore water (4 cm below the sediment-water interface using rigid aquarium tubing affixed to a 60-mL syringe) samples were collected and filtered (GF/F glass microfiber filters, 0.7 μm particle retention) in each of the three experimental sites for the analysis of inorganic nutrients.…”

Section: Hydrogeomorphic Zonesmentioning

confidence: 99%

“…through denitrification prior to export to the ocean (Li et al 2020;Li and Twilley, 2021). The patterns of benthic nutrient fluxes and pathways of N cycling vary in response to an increasing OM sediment concentrations resulting from morphological development with delta age, which makes the delta an ideal system to study the significance of N 2 fixation under different OM sediment and nutrient loading conditions (Li et al 2020;Li and Twilley, 2021).…”

mentioning

confidence: 99%

“…The patterns of benthic nutrient fluxes and pathways of N cycling vary in response to an increasing OM sediment concentrations resulting from morphological development with delta age, which makes the delta an ideal system to study the significance of N 2 fixation under different OM sediment and nutrient loading conditions (Li et al 2020;Li and Twilley, 2021). Denitrification rates have already been measured directly with 15 NO 3 − enrichment using isotope pairing technique along a gradient of OM sediment concentrations in the delta (Li and Twilley, 2021), and this research focuses on the variation of N 2 fixation during the development of coastal deltaic floodplain. This research continues to develop an understanding of how ecological feedback on geomorphology development of deltaic floodplains alters the N cycles of these newly emergent ecosystems (Twilley et al 2019).…”

mentioning

confidence: 99%

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Heterotrophic nitrogen fixation in response to nitrate loading and sediment organic matter in an emerging coastal deltaic floodplain within the Mississippi River Delta plain

Twilley

Hou

2021

Limnology & Oceanography

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Increasing nitrate (NO 3 − ) loading in rivers due to agricultural fertilization alters benthic nitrogen (N) cycling and shifts coastal wetlands from being a net source to net sink of reactive N. Heterotrophic N 2 fixation that converts N 2 to reactive N is often assumed negligible in eutrophic ecosystems and excluded in coastal N budget evaluations. We investigated N 2 fixation and denitrification in response to increasing NO 3 − loading (0, 10, and 100 μM) and sediment organic matter (OM sediment ) concentrations in the emerging Wax Lake Delta. Continuous flow-through incubations with 30 N 2 addition was applied to measure N 2 fixation. The variation of N 2 fixation rates from 0 to 437 μmol N m −2 h −1 among different NO 3 − and OM sediment concentrations were comparable to the estimated denitrification rates of 141-377 μmol N m −2 h −1 . Increasing overlying NO 3 − concentrations reduced N 2 fixation rates and facilitated denitrification rates at each OM sediment concentration. However, 100 μM of overlying NO 3 − did not thoroughly inhibit N 2 fixation rates in sites with intermediate and higher

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Section: Hydrogeomorphic Zonesmentioning

confidence: 67%

Section: Methodsmentioning

confidence: 99%

Section: Hydrogeomorphic Zonesmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Heterotrophic nitrogen fixation in response to nitrate loading and sediment organic matter in an emerging coastal deltaic floodplain within the Mississippi River Delta plain

Twilley

Hou

2021

Limnology & Oceanography

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Nitrogen removal capacity and influencing factors of inland wetland under human activities: Jiashan County, China

Li,

Zhang,

et al. 2024

River

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Inland wetlands play a vital role in mitigating non‐point source nitrogen loads through denitrification and anammox processes. However, the impact of varying human activities within the same region on these nitrogen removal processes of inland wetlands remains unclear. This study investigated the differences in nitrogen removal rates of wetland sediments under various human activities in Jiashan County, China. 15N isotope tracing was used to determine denitrification and anammox rates. Denitrification was the primary nitrogen removal pathway, with an average contribution of 82.34%. Denitrification and anammox rates varied significantly under different human influences, with the highest rates in residential and agricultural areas. NH4+, chlorophyll a, NO3−, and pH were the main environmental factors. This study highlights the need for targeted wetland management and restoration strategies based on the type and intensity of human activities. Protecting and restoring these “natural purifiers” is crucial for improving regional water quality and maintaining the ecological functions of wetlands in rapidly urbanizing landscapes.

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Hurricane Effects on Benthic Nitrogen Cycling in an Emerging Coastal Deltaic Floodplain Within the Mississippi River Delta Plain

Li,

Twilley,

Poveda

et al. 2023

Estuaries and Coasts

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Nitrogen Dynamics of Inundated Sediments in an Emerging Coastal Deltaic Floodplain in Mississippi River Delta Using Isotope Pairing Technique to Test Response to Nitrate Enrichment and Sediment Organic Matter

Cited by 11 publications

References 89 publications

Heterotrophic nitrogen fixation in response to nitrate loading and sediment organic matter in an emerging coastal deltaic floodplain within the Mississippi River Delta plain

Heterotrophic nitrogen fixation in response to nitrate loading and sediment organic matter in an emerging coastal deltaic floodplain within the Mississippi River Delta plain

Nitrogen removal capacity and influencing factors of inland wetland under human activities: Jiashan County, China

Hurricane Effects on Benthic Nitrogen Cycling in an Emerging Coastal Deltaic Floodplain Within the Mississippi River Delta Plain

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