Sediment nitrate reduction processes in response to environmental gradients along an urban river-estuary-sea continuum

Wei, He; Gao, Dengzhou; Liu, Yong; Lin, Xianbiao

doi:10.1016/j.scitotenv.2020.137185

Cited by 42 publications

(18 citation statements)

References 97 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Exchangeable ammonium (NH 4 + -N), nitrite (NO 2 – -N), and nitrate (NO 3 – -N) were extracted by adding five parts 2 M KCl to one part of fresh sediment, with the solution subsequently analyzed by spectrophotometry on a continuous-flow nutrient analyzer (SAN Plus, Skalar Analytical B.V., The Netherlands), with detection limits of 0.5 μM for NH 4 + -N and 0.1 μM for NO 2 – -N and NO 3 – -N ( Gao et al, 2017 ). Ferric oxides in sediments were extracted with a mixture of 0.5 M HCl and 0.25 M hydroxylamine hydrochloride and analyzed with the ferrozine-based colorimetric method ( Roden and Lovley, 1993 ; Wei et al, 2020 ). After treatment with 0.1 M HCl to remove sedimentary carbonate, Organic carbon (OC) was measured on a carbon-hydrogen-nitrogen elementary analyzer (VVarioELIII, Elementary, Germany) ( Lin et al, 2017 ).…”

Section: Methodsmentioning

confidence: 99%

Distribution and Diversity of Comammox Nitrospira in Coastal Wetlands of China

et al. 2020

View full text Add to dashboard Cite

Complete ammonia oxidizers (comammox), able to individually oxidize ammonia to nitrate, are considered to play a significant role in the global nitrogen cycle. However, the distribution of comammox Nitrospira in estuarine tidal flat wetland and the environmental drivers affecting their abundance and diversity remain unknown. Here, we present a large-scale investigation on the geographical distribution of comammox Nitrospira along the estuarine tidal flat wetlands of China, where comammox Nitrospira were successfully detected in 9 of the 16 sampling sites. The abundance of comammox Nitrospira ranged from 5.19 × 10 3 to 8.33 × 10 4 copies/g, 2.21 to 5.44-folds lower than canonical ammonia oxidizers: ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Phylogenetic analysis based on the alpha subunit of the ammonia monooxygenase encoding gene ( amoA ) revealed that comammox Nitrospira Clade A, mainly originating from upstream river inputs, accounts for more than 80% of the detected comammox Nitrospira , whereas comammox Nitrospira clade B were rarely detected. Comammox Nitrospira abundance and dominant comammox Nitrospira OTUs varied within the estuarine samples, showing a geographical pattern. Salinity and pH were the most important environmental drivers affecting the distribution of comammox Nitrospira in estuarine tidal flat wetlands. The abundance of comammox Nitrospira was further negatively correlated with high ammonia and nitrite concentrations. Altogether, this study revealed the existence, abundance and distribution of comammox Nitrospira and the driving environmental factors in estuarine ecosystems, thus providing insights into the ecological niches of this recently discovered nitrifying consortium and their contributions to nitrification in global estuarine environments.

show abstract

Section: Methodsmentioning

confidence: 99%

Distribution and Diversity of Comammox Nitrospira in Coastal Wetlands of China

et al. 2020

View full text Add to dashboard Cite

show abstract

“…As we all know, sediment Fe 2+ can be a controlling factor in the partitioning of denitrification and DNRA in many aquatic ecosystems [4,6]. In this study, we found that sediment Fe 2+ was positively correlated with DNRA% but negatively correlated with DEN% (Figure 3).…”

Section: Effects Of Environmental Variables On No X − Reduction Proce...supporting

confidence: 50%

“…Nitrogen (N) pollution has become increasingly aggravated in global estuarine and coastal ecosystems, in part from increased N inputs from anthropogenic activities [1][2][3][4]. Human activities, especially sewage discharge, agricultural fertilization, and industrial wastewater, have caused a series of environmental problems in estuarine and coastal regions [4][5][6], such as coastal eutrophication globally (McCrackin et al, 2017), increased harmful algal blooms [7], seasonal hypoxia [8], and nitrous oxide (N 2 O) emission [9], further tipping the balance of N biogeochemical cycles severely. The coastal wetland is a critical link between the land and the sea, which plays an important role in the removal of nutrients [10].…”

Section: Introductionmentioning

confidence: 99%

Effect of Aquaculture Reclamation on Sediment Nitrates Reduction Processes in Mangrove Wetland

Lin

Huang

2022

JMSE

View full text Add to dashboard Cite

Sediment denitrification, anaerobic ammonium oxidation (anammox), and nitrate dissimilation to ammonium (DNRA) play an important role in controlling the dynamics of nitrates (NOx−) and their fate in estuarine and coastal ecosystems. However, the effects of land-use change on NOx− reduction processes in mangrove sediments are still unclear. Here, we used a mud experiment method combined with a 15N stable isotope tracer method to study the mechanism and ecological environment of the change of land use pattern on the sediment NOx− reduction processes in mangrove wetlands. Our study showed that most physicochemical parameters, NOx− reduction rates, and their gene abundances varied considerably. The denitrification, anammox, and DNRA rates in mangrove sediment cores were in a range of 1.04–4.24 nmol g−1 h−1, 0.14–0.36 nmol g−1 h−1, and 0–2.72 nmol g−1 h−1, respectively. The denitrification, anammox, and DNRA rates in aquaculture sediment cores were in a range of 1.06–10.96 nmol g−1 h−1, 0.13–0.37 nmol g−1 h−1, and 0–1.96 nmol g−1 h−1, respectively. The highest values of denitrification, anammox, DNRA, the contribution of denitrification and DNRA to total NOx− reduction (DEN% and DNRA%), gene abundances (nirS, Amx 16S rRNA, and nrfA), total organic carbon (TOC), total nitrogen (TN), and TOC/TN in sediments were generally found in the top layer (0–5 cm) and then decreased with depth, while the contribution of anammox to total NOx− reduction (ANA%), Fe2+, and Fe2+/Fe3+ were generally increased with sediment depth in both mangrove and aquaculture ecosystems. When mangrove wetlands are transformed into pools, some properties (including TOC, TN, and Fe3+), DNRA rates, DRNA%, and nrfA gene abundances were decreased, while some properties (including NH4+, TOC/TN, Fe2+, and Fe2+/Fe3+), denitrification rates, DEN%, nirS, and ANAMMOX 16S gene abundances were increased. Sediment organic matter (TOC and TN) content and Fe2+ both affected NO3− reduction rates, with organic matter the most prominent factor. Thus, aquaculture reclamation enhances N loss while reducing N retention in sediments of mangrove wetlands, which plays an important role in regulating the source and fate of reactive N in mangrove ecosystems.

show abstract

“…In addition, other microbial processes may also influence the nutrient dynamics in the bottom waters. For example, previous studies suggested that sediment denitrification, anaerobic ammonium oxidation, and dissimilatory nitrate reduction to ammonium in sediments can all result in the NO 3 − reduction and the removal of NO 3 − in bottom waters (e.g., Wei et al., 2020). The dissolutions of SiO 3 2− and PO 4 3− in sediments may influence their concentrations in the nearby bottom waters (Wu & Liu, 2020; Z. Zhang, et al., 2021).…”

Section: Discussionmentioning

confidence: 99%

New Insights Into the Non‐Conservative Behaviors of Nutrients Triggering Phytoplankton Blooms in the Changjiang (Yangtze) River Estuary

Wang

Gao

2022

JGR Oceans

View full text Add to dashboard Cite

Four research cruises were carried out during March and July in 2015 and 2016 in the Changjiang (Yangtze) River Estuary and the adjacent shelf. Nutrient concentrations (regarded as static parameters) were measured in the surface and bottom waters collected at 86–99 stations over the course of these cruises. In addition, unfiltered seawater samples were incubated onboard for 48 hr to measure the potential change rates of nutrients (regarded as dynamic parameters). These parameters can help directly elucidate non‐conservative behaviors of nutrients in order to determine whether seawater serves as a source or a sink. Large nutrient sinks (with more negative variation rates) were consistently found at the surface during the two July cruises at the stations just along the outside edge of the turbidity maximum zone near the mouth of the river. Negative rates, although with much smaller magnitudes, were also found in most bottom water samples in July and at both the surface and bottom in March. The high net nutrient uptake rates at the surface in the summer triggered bloom events later at the seaward stations, showing that high net nutrient uptake is the cause and high chlorophyll‐a is the consequence of the bloom. Such information about biogeochemical cycling of nutrients and the mechanisms and development of bloom events occurring in large river estuarine and coastal areas could not have been obtained if these static and dynamic parameters had not been studied together.

show abstract

Sediment nitrate reduction processes in response to environmental gradients along an urban river-estuary-sea continuum

Cited by 42 publications

References 97 publications

Distribution and Diversity of Comammox Nitrospira in Coastal Wetlands of China

Distribution and Diversity of Comammox Nitrospira in Coastal Wetlands of China

Effect of Aquaculture Reclamation on Sediment Nitrates Reduction Processes in Mangrove Wetland

New Insights Into the Non‐Conservative Behaviors of Nutrients Triggering Phytoplankton Blooms in the Changjiang (Yangtze) River Estuary

Contact Info

Product

Resources

About