Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone

Abstract The hyporheic zone (HZ), where surface water and groundwater interact in sediments beneath streams, presents unique conditions for nutrient dynamics, such as carbon and nitrogen (N) cycling. Organic carbon (OC) in aquatic systems has two distinct forms: dissolved organic carbon and particul...

Full description

Saved in:
Bibliographic Details
Main Authors: Xue Ping, Yang Xian, Menggui Jin
Format: Article
Language:English
Published: Wiley 2023-07-01
Series:Water Resources Research
Subjects:
Online Access:https://doi.org/10.1029/2022WR034253
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1839639709357178880
author Xue Ping
Yang Xian
Menggui Jin
author_facet Xue Ping
Yang Xian
Menggui Jin
author_sort Xue Ping
collection DOAJ
description Abstract The hyporheic zone (HZ), where surface water and groundwater interact in sediments beneath streams, presents unique conditions for nutrient dynamics, such as carbon and nitrogen (N) cycling. Organic carbon (OC) in aquatic systems has two distinct forms: dissolved organic carbon and particulate organic carbon (POC). OC affects N reduction and controls the occurrence of denitrification, a primary process by which nitrate (NO3−) is removed as gas (N2 or N2O) to the atmosphere. When POC is the predominant form of OC in streams, how POC influences NO3− reduction within a HZ remains unclear. We established a new reactive transport model incorporating POC transport and filtration processes to assess how POC deposition affects NO3− removal. Sediment permeability decreases as POC is filtrated in the streambed. Nitrate influx is reduced due to POC‐induced sediment clogging. The deposited POC in the shallow streambed serves as an OC source and supports higher biogeochemical reaction kinetics because OC is an important substrate promoting microbial activities. The filtrated POC pool enhances denitrification, thus causing a higher NO3− removal efficiency. In contrast, the POC pool is typically assumed to be distributed homogeneously in sediments, potentially causing a significant underestimation of stream‐borne NO3− removal. A lower hydraulic conductivity, a smaller POC grain size, and a larger POC filtration efficiency and in‐stream POC concentration allow for extensive POC deposition within the shallow streambed that favors nitrate removal. This study provides a better understanding of N processing and an accurate estimation of NO3− removal potential in HZs.
format Article
id doaj-art-2f02339dfd7a48c494c8ee5c213d91a1
institution Matheson Library
issn 0043-1397
1944-7973
language English
publishDate 2023-07-01
publisher Wiley
record_format Article
series Water Resources Research
spelling doaj-art-2f02339dfd7a48c494c8ee5c213d91a12025-07-04T06:40:25ZengWileyWater Resources Research0043-13971944-79732023-07-01597n/an/a10.1029/2022WR034253Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic ZoneXue Ping0Yang Xian1Menggui Jin2State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Wuhan P. R. ChinaSchool of Environmental Studies China University of Geosciences Wuhan P. R. ChinaState Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Wuhan P. R. ChinaAbstract The hyporheic zone (HZ), where surface water and groundwater interact in sediments beneath streams, presents unique conditions for nutrient dynamics, such as carbon and nitrogen (N) cycling. Organic carbon (OC) in aquatic systems has two distinct forms: dissolved organic carbon and particulate organic carbon (POC). OC affects N reduction and controls the occurrence of denitrification, a primary process by which nitrate (NO3−) is removed as gas (N2 or N2O) to the atmosphere. When POC is the predominant form of OC in streams, how POC influences NO3− reduction within a HZ remains unclear. We established a new reactive transport model incorporating POC transport and filtration processes to assess how POC deposition affects NO3− removal. Sediment permeability decreases as POC is filtrated in the streambed. Nitrate influx is reduced due to POC‐induced sediment clogging. The deposited POC in the shallow streambed serves as an OC source and supports higher biogeochemical reaction kinetics because OC is an important substrate promoting microbial activities. The filtrated POC pool enhances denitrification, thus causing a higher NO3− removal efficiency. In contrast, the POC pool is typically assumed to be distributed homogeneously in sediments, potentially causing a significant underestimation of stream‐borne NO3− removal. A lower hydraulic conductivity, a smaller POC grain size, and a larger POC filtration efficiency and in‐stream POC concentration allow for extensive POC deposition within the shallow streambed that favors nitrate removal. This study provides a better understanding of N processing and an accurate estimation of NO3− removal potential in HZs.https://doi.org/10.1029/2022WR034253particulate organic carbonsediment clogginghyporheic zonedenitrification
spellingShingle Xue Ping
Yang Xian
Menggui Jin
Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
Water Resources Research
particulate organic carbon
sediment clogging
hyporheic zone
denitrification
title Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
title_full Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
title_fullStr Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
title_full_unstemmed Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
title_short Effect of Particulate Organic Carbon Deposition on Nitrate Reduction in the Hyporheic Zone
title_sort effect of particulate organic carbon deposition on nitrate reduction in the hyporheic zone
topic particulate organic carbon
sediment clogging
hyporheic zone
denitrification
url https://doi.org/10.1029/2022WR034253
work_keys_str_mv AT xueping effectofparticulateorganiccarbondepositiononnitratereductioninthehyporheiczone
AT yangxian effectofparticulateorganiccarbondepositiononnitratereductioninthehyporheiczone
AT mengguijin effectofparticulateorganiccarbondepositiononnitratereductioninthehyporheiczone