Denitrification in the Mississippi River network controlled by flow through river bedforms

Gomez‐Velez, Jesus D.; Harvey, J. W.; Cardenas, M. Bayani; Kiel, B.

doi:10.1038/ngeo2567

Cited by 270 publications

(345 citation statements)

References 49 publications

Supporting

Mentioning

337

Contrasting

Unclassified

Order By: Relevance

“…With the increase of ORP, the NO 3 -N of most samples changed little except five samples (one in Group D and four in Group A). The oxic environment was conducive to the stable form of NO 3 -N, and did harm to denitrification [50]. As a result, the variation of NO 3 -N may be controlled by mixing/dilution and the absorption of aquatic plants.…”

Section: Bivariate Plot and Dissolution Reactionmentioning

confidence: 99%

Spatio-Temporal Variation and Controlling Factors of Water Quality in Yongding River Replenished by Reclaimed Water in Beijing, North China

Zheng

et al. 2017

Water

View full text Add to dashboard Cite

Reclaimed water is useful for replenishing dried up rivers in North China, although changes in water quality could be an issue. Therefore, it is essential to understand the spatio-temporal variation and the controlling factors of water quality. Samples of Yongding River water were collected seasonally, and 24 water quality parameters were analyzed in 2015. All waters were alkaline, and nitrate-nitrogen was the main form of nitrogen, while phosphorus was mostly below detection level. The water quality parameters varied in time and space. Cluster analysis showed a distinct difference between winter and the other seasons and between the natural river section and the section with reclaimed water. Based on the analysis of Gibbs plots, principal component analysis, and ionic relationships, the water chemistry was controlled by dissolution of rocks in natural river section, the quality of replenished water, the effects of dilution, and the reaction of aqueous chemistry in the reclaimed water section. The positive oxidation environment in most of the river water was conducive to the formation of nitrate-nitrogen by nitrification, and not conducive to denitrification.

show abstract

Section: Bivariate Plot and Dissolution Reactionmentioning

confidence: 99%

Spatio-Temporal Variation and Controlling Factors of Water Quality in Yongding River Replenished by Reclaimed Water in Beijing, North China

Zheng

et al. 2017

Water

View full text Add to dashboard Cite

show abstract

“…The reintroduction of large woody debris (LWD) has become an integral part of many river restoration schemes world-wide and its impact on channel hydrological complexity, geomorphology and ecology have been evidenced in both field and experimental studies (Curran and Wohl 2003;Gippel 1995;Gurnell et al 1995;Miller et al 2010). LWD is known to enhance hyporheic exchange, through increased roughness (Kasahara et al 2009), and there is increasing evidence of the importance of hyporheic flow-paths for nitrogen removal (Gomez-Velez et al 2015;Krause et al 2009Krause et al , 2013. Further, LWD may also enhance nitrate removal as it encourages sediment accumulation and the decaying wood provides organic carbon (Krause et al 2014).…”

Section: Electronic Supplementary Materialsmentioning

confidence: 99%

Enhanced hyporheic exchange flow around woody debris does not increase nitrate reduction in a sandy streambed

et al. 2017

View full text Add to dashboard Cite

Anthropogenic nitrogen pollution is a critical problem in freshwaters. Although riverbeds are known to attenuate nitrate, it is not known if large woody debris (LWD) can increase this ecosystem service through enhanced hyporheic exchange and streambed residence time. Over a year, we monitored the surface water and pore water chemistry at 200 points along a * 50 m reach of a lowland sandy stream with three natural LWD structures. We directly injected 15 N-nitrate at 108 locations within the top 1.5 m of the streambed to quantify in situ denitrification, anammox and dissimilatory nitrate reduction to ammonia, which, on average, contributed 85, 10 and 5% of total nitrate reduction, respectively. Total nitrate reducing activity ranged from 0 to 16 lM h -1 and was highest in the top 30 cm of the stream bed. Depth, ambient nitrate and water residence time explained 44% of the observed variation in nitrate reduction; fastest rates were associated with slow flow and shallow depths. In autumn, when the river was in spate, nitrate reduction (in situ and laboratory measures) was enhanced around the LWD compared with non-woody areas, but this was not seen in the spring and summer. Overall, there was no significant effect of LWD on nitrate reduction rates in surrounding streambed sediments, but higher pore water nitrate concentrations and shorter residence times, close to LWD, indicated enhanced delivery of surface water into the streambed under high flow. When hyporheic exchange is too strong, overall nitrate reduction is inhibited due to short flow-paths and associated high oxygen concentrations.

show abstract

“…Os refletores nesta unidade apresentam pouca continuidade lateral com contato entre si e perda de reflexão em várias áreas, além de oscilação de amplitude, variando de alta para baixa e vice-versa. Os padrões de reflexão são típicos de ambientes de alta energia com intenso retrabalhamento de sedimentos, favorável a formação de formas de fundo do tipo ripples, em que demonstram elevado grau de modificação em um curto intervalo de tempo (Gomez-Velez et al, 2015;Kuijpers and Nielsen, 2016).…”

unclassified

Caracterização Das Principais Feições Superficiais De Fundo E Em Subsuperfície No Limite Sudoeste Da Baía De Macapá, Canal Do Norte, Rio Amazonas

2017

View full text Add to dashboard Cite

RESUMO.A Baía de Macapá, por estar inserida a zona de médio estuário do Rio Amazonas, apresenta vestígios de alterações morfológicas diferenciadas pela forte dinâmica em um curto intervalo de tempo. O reflexo de tais alterações pode ser observado nas modificações morfoestruturais presentes no leito e subsuperfície. A análise dos perfis sísmicos em alta resolução pelo intervalo de frequência de 0,7 kHz a 12,0 kHz revela que as características apresentadas nas formas de fundo desencadeiam os processos modeladores do padrão de reflexão observados nos refletores em subsuperfície. Através desta relação foi possível identificar a predominância de cinco formas de fundo, quatro unidades estruturais e cinco sismofácies com o destaque para a identificação de uma feição de paleocanal. Observou-se que as variações morfológicas do leito são influenciadas pela constante atuação dos processos hidrodinâmicos e sedimentares ocorrentes periodicamente e vice-versa, corroborando para correlação entre as feições superficiais de fundo e as feições em subsuperfície.Palavras-Chave: Morfologia, formas de fundo, sismofácies, paleocanal.ABSTRACT. The Macapá Bay, because it is inserted in the middle estuary zone of the Amazon River, presents evidences of different changes in a short time. The reflex of such changes can be observed in morphostructural modifications present in the bed and subsurfaces. The analysis of the high-resolution seismic profiles through on frequency range of 0.7 kHz to 12.0 kHz reveals that the features presented in the bedforms trigger the reflection pattern modelers processes observed in the subsurface reflectors. Through this relationship, it was possible to identify the predominance of five bedforms, four structural units and five seismic facies with highlight for the identification of a paleochannel feature. It was observed that the morphological variations of the bed are influenced by the constant actuation of the hydrodynamic processes and sedimentary that occur periodically and vice versa, corroborating to correlation between the superficial bottom features and the subsurface features.

show abstract

Denitrification in the Mississippi River network controlled by flow through river bedforms

Cited by 270 publications

References 49 publications

Spatio-Temporal Variation and Controlling Factors of Water Quality in Yongding River Replenished by Reclaimed Water in Beijing, North China

Spatio-Temporal Variation and Controlling Factors of Water Quality in Yongding River Replenished by Reclaimed Water in Beijing, North China

Enhanced hyporheic exchange flow around woody debris does not increase nitrate reduction in a sandy streambed

Caracterização Das Principais Feições Superficiais De Fundo E Em Subsuperfície No Limite Sudoeste Da Baía De Macapá, Canal Do Norte, Rio Amazonas

Contact Info

Product

Resources

About