scholarly journals Nitrogen and phosphorus concentrations and temporal variations in the waters dammed up by river mouth weir in the basin with efficient irrigation

2011 ◽  
Vol 72 (1) ◽  
pp. 57-64
Author(s):  
Yoshihiro YAMADA ◽  
Yugo MITO
Keyword(s):  
River Mouth ◽  
Temporal Variations ◽  
Nitrogen And Phosphorus

scholarly journals Spatial and Temporal Variations of Nitrogen and Phosphorus in Surface Water and Groundwater of Mudong River Watershed in Huixian Karst Wetland, Southwest China

2021 ◽  
Vol 13 (19) ◽  
pp. 10740
Author(s):  
Linyan Pan ◽  
Junfeng Dai ◽  
Zhiqiang Wu ◽  
Liangliang Huang ◽  
Zupeng Wan ◽  
...  
Keyword(s):  
Surface Water ◽  
Temporal Dynamics ◽  
Flow Direction ◽  
Influencing Factor ◽  
Shallow Groundwater ◽  
Temporal Variations ◽  
Field Investigation ◽  
Spatial And Temporal Variation ◽  
Nitrogen And Phosphorus ◽  
River Watershed

When considering the factors affecting the spatial and temporal variation of nitrogen and phosphorus in karst watersheds, the unique karst hydrogeology as an internal influencing factor cannot be ignored, as well as natural factors such as meteorological hydrology and external factors such as human activities. A watershed-scale field investigation was completed to statistically analyze spatial and temporal dynamics of nitrogen and phosphorus through the regular monitoring and collection of surface water and shallow groundwater in the agricultural-dominated Mudong River watershed in the Huixian Karst Wetland over one year (May 2020 to April 2021). Our research found that non-point source pollution of nitrogen (84.5% of 239 samples TN > 1.0 mg/L) was more serious than phosphorus (7.5% of 239 samples TP > 0.2 mg/L) in the study area, and shallow groundwater nitrogen pollution (98.3% of 118 samples TN > 1.0 mg/L) was more serious than surface water (68.6% of 121 samples TN > 1.0 mg/L). In the three regions with different hydrodynamic features, the TN concentration was higher and dominated by NO3−-N in the river in the northern recharge area, while the concentrations of TN and TP were the highest in shallow groundwater wells in the central wetland core area and increased along the surface water flow direction in the western discharge area. This research will help improve the knowledge about the influence of karst hydrodynamic features on the spatial patterns of nitrogen and phosphorus in water, paying attention to the quality protection and security of water in karst areas with a fragile water ecological environment.

scholarly journals Spatio-Temporal Dynamics of Riverine Nitrogen and Phosphorus at Different Catchment Scales in Huixian Karst Wetland, Southwest China

Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2924
Author(s):  
Linyan Pan ◽  
Junfeng Dai ◽  
Zhiqiang Wu ◽  
Zupeng Wan ◽  
Zhenyu Zhang ◽  
...  
Keyword(s):  
Human Activities ◽  
Temporal Dynamics ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Catchment Scale ◽  
Nitrogen And Phosphorus ◽  
Spatial And Temporal Scales ◽  
River Waters ◽  
Hydrological Conditions ◽  
Spatio Temporal

Spatio-temporal dynamics of riverine nitrogen (N) and phosphorus (P) in karst regions are closely linked to hydrological conditions, human activities and karst features in upstream catchments. From October 2017 to September 2019, we undertook 22 sampling campaigns in 11 nested catchments ranging from 21.00 to 373.37 km2 in Huixian karst wetland to quantify forms, concentrations, and fluxes of riverine total nitrogen (TN) and total phosphorus (TP), and to identify spatial and temporal variations of nutrients transfer from upstream to downstream, tributaries (Mudong River and Huixian River) to the main stem (Xiangsi River) in the dry and wet seasons. Considering the hydrological conditions, human activities and karst features within upstream catchments, the following three spatial and temporal variations of riverine nutrients were found over the monitoring period: (1) the dynamics of riverine nitrogen and phosphorus varied seasonally with hydrological conditions; (2) the spatial disparities of riverine nitrogen and phosphorus were induced by different human activities within catchment scales; (3) the dynamics of riverine nitrogen and phosphorus varied similarly at spatial scale restricted by karst features. The findings from this study may improve our understanding of the influence of hydrological conditions, human activities and karst features on nitrogen and phosphorus variations in river waters at different spatial and temporal scales in the Huixian karst wetland basin, and will help managers to protect and restore river water environments in karst basin from a catchment-scale perspective.

scholarly journals ANALYSIS OF TEMPORAL VARIATIONS IN TURBIDITY FOR A COASTAL AREA USING THE HILBERT-HUANG-TRANSFORM

2011 ◽  
Vol 1 (32) ◽  
pp. 25
Author(s):  
Shigeru Kato ◽  
Magnus Larson ◽  
Takumi Okabe ◽  
Shin-ichi Aoki
Keyword(s):  
Instantaneous Frequency ◽  
River Mouth ◽  
Original Data ◽  
Temporal Variations ◽  
Intrinsic Mode Functions ◽  
Hilbert Spectrum ◽  
Hilbert Huang Transform ◽  
Time Frequency ◽  
Mode Decomposition ◽  
The Hilbert Transform

Turbidity data obtained by field observations off the Tenryu River mouth were analyzed using the Hilbert-Huang Transform (HHT) in order to investigate the characteristic variations in time and in the frequency domain. The Empirical Mode Decomposition (EMD) decomposed the original data into only eight intrinsic mode functions (IMFs) and a residue in the first step of the HHT. In the second step, the Hilbert transform was applied to the IMFs to calculate the Hilbert spectrum, which is the time-frequency distribution of the instantaneous frequency and energy. The changes in instantaneous frequencies showed correspondence to high turbidity events in the Hilbert spectrum. The investigation of instantaneous frequency variations can be used to understand transitions in the state of the turbidity. The comparison between the Fourier spectrum and the Hilbert spectrum integrated in time showed that the Hilbert spectrum makes it possible to detect and quantify the cycle of locally repeated events.

scholarly journals Spatial and temporal variation of the zooplankton community in the area of influence of the Itajaí-açu River, SC (BRAZIL)

2008 ◽  
Vol 56 (3) ◽  
pp. 211-224 ◽  
Author(s):  
Charrid Resgalla Junior ◽  
Vitor Gonçalves Coutinho de Souza ◽  
Leonardo Rubi Rörig ◽  
Carlos Augusto França Schettini
Keyword(s):  
Saline Water ◽  
River Mouth ◽  
Zooplankton Community ◽  
Temporal Variations ◽  
Spatial And Temporal Variation ◽  
North Coast ◽  
Brazilian Coast ◽  
The North ◽  
Tropical Water ◽  
Area Of Influence

On the north coast of the State of Santa Catarina (Brazil), the Itajaí-Açu River mouth shows a low-saline water plume on the internal shelf with strong density gradients. This oceanographic condition has a possible influence over the pelagic community, and it has been little investigated on the Brazilian coast. The present work seeks to evaluate the spatial and temporal variations of the zooplankton community in the area of influence of the Itajaí-açu River, and its relations with the abiotic forces of temperature (seasonal variation) and salinity of the river plume. For this purpose, 14 monthly oceanographic cruises were carried out during the years 2002 and 2003, to obtain physical and chemical parameters, and zooplankton hauls in 9 sampling points. The zooplankton analyses were carried out at the lowest taxon possible to characterize the resident community of the river mouth. It was observed that the zooplankton presented the highest densities in winter and spring. The species with higher densities and frequencies of occurrence were Paracalanus quasimodo, Parvocalanus crassirostris, Acartia lilijeborgi, Temora stylifera, T. turbinata, and Penilia avirostris, indicating a prevalence in this region, of Tropical Water from the Brazil Current and greater similarity with the coastal community of the Southeast region of Brazil. However, even for the species typical of Tropical Water, there were alterations in dominance of the species, due to the seasonality and level of flow rate of the river on the salinity of the internal shelf of the study area.

scholarly journals Spatial-temporal variations of nitrogen and phosphorus forms in sediment porewater as affected by submerged plant in Lake Dianchi

2018 ◽  
Vol 30 (2) ◽  
pp. 314-325 ◽  
Author(s):  
ZHANG Yun ◽  
◽  
WANG Shengrui ◽  
DUAN Changqun ◽  
JIAO Lixin ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Submerged Plant ◽  
Nitrogen And Phosphorus ◽  
Lake Dianchi ◽  
Phosphorus Forms

scholarly journals Wetlands as pollution processors

2019 ◽  
pp. 313-319
Author(s):  
Jan Herrmann ◽  
Ann-Karin Thoren
Keyword(s):  
Urban Areas ◽  
Biological Diversity ◽  
Temporal Variations ◽  
Point Sources ◽  
Atmospheric Nitrogen ◽  
Anaerobic Conditions ◽  
Nitrogen And Phosphorus ◽  
Buffer Zones ◽  
Industrial Countries

After decades of successful measures against point sources of nutrients in industrial countries, we still have severe problems with diffuse pollution. For treatment of excessive nitrogen from agricultural and urban areas, in the form of nitrate (NO3-) and ammonium(NH4+), wetlands (including dams and buffer zones)  are constructed to favour the microbial processes that lead to denitrification of and NH4+ and NO3-, via nitrite (NO2-) and nitrous oxide (N2O), to atmospheric nitrogen (N2). hnportant factors when designing "optimal wetlands" are hydrology, temperature, sufficient carbon source, water residence time, and alternating aerobic/anaerobic conditions. Also biomass uptake and sedimentation of both nitrogen and phosphorus help with reduction of the nutrients. Conditions and possibilities for wetlands in their accumulation of storm water are also described. The importance of biological diversity in wetlands are several: more fragmentation by invertebrates, more plant surface types, more nutrient biomass uptake, more bioturbation by various animals, and more biomass that can accumulate toxicants. The efficiency and biodiversity of wetlands are due to their trait being ecotones between land and water, causing large spatial and temporal variations. Finally the recreational, esthetical and broad pedagogical values of wetlands, as well as the need of better follow-up studies, are emphasised.

Spatial and temporal variations of water quality in an artificial urban river receiving WWTP effluent in South China

2015 ◽  
Vol 73 (6) ◽  
pp. 1243-1252 ◽  
Author(s):  
Di Zhang ◽  
Yi Tao ◽  
Xiaoning Liu ◽  
Kuiyu Zhou ◽  
Zhenghao Yuan ◽  
...  
Keyword(s):  
Water Quality ◽  
Reclaimed Water ◽  
Treatment Plant ◽  
Organic Pollution ◽  
Temporal Variations ◽  
Urban River ◽  
Spatial And Temporal Variations ◽  
Pollution Load ◽  
Nitrogen And Phosphorus ◽  
Wwtp Effluent

Urban wastewater treatment plant (WWTP) effluent as reclaimed water provides an alternative water resource for urban rivers and effluent will pose a significant influence on the water quality of rivers. The objective of this study was to investigate the spatial and temporal variations of water quality in XZ River, an artificial urban river in Shenzhen city, Guangdong Province, China, after receiving reclaimed water from WWTP effluent. The water samples were collected monthly at different sites of XZ River from April 2013 to September 2014. Multivariate statistical techniques and a box-plot were used to assess the variations of water quality and to identify the main pollution factor. The results showed the input of WWTP effluent could effectively increase dissolved oxygen, decrease turbidity, phosphorus load and organic pollution load of XZ River. However, total nitrogen and nitrate pollution loads were found to remain at higher levels after receiving reclaimed water, which might aggravate eutrophication status of XZ River. Organic pollution load exhibited the lowest value on the 750 m downstream of XZ River, while turbidity and nutrient load showed the lowest values on the 2,300 m downstream. There was a higher load of nitrogen and phosphorus pollution in the dry season and at the beginning of wet season.

Time Change Rule and Source Identification of Nitrogen and Phosphorus Pollution on Huihe River in Suzhou City

2013 ◽  
Vol 712-715 ◽  
pp. 520-526
Author(s):  
Jin Mu Fu ◽  
Wei Gong ◽  
Xiao Yin Chen ◽  
Gang Fang
Keyword(s):  
Factor Analysis ◽  
Temporal Variations ◽  
Water Quantity ◽  
Climate Factors ◽  
Nitrogen And Phosphorus ◽  
Phosphorus Pollution ◽  
Natural Factors ◽  
Suzhou City ◽  
And Cluster Analysis ◽  
The Temple

For understanding the temporal variation of nitrogen and phosphorus concentrations in Huihe River, Suzhou, the observed data (including NH4+-N、 TN、TP, the temple and quantity of the water) from 2007 to 2010 were analyzed by statistical analysis including correlation, cluster and factor analysis. The results imply that the variations of concentrations of NH4+-N, TN and TP in Huihe River were significant, their concentrations are 0.05-4.22mg/L, 0.11-15.14mg/L and 0.01-1.41mg/L, respectively. Correlation and factor analysis suggest that NH4+-N、TN and TP are well correlated with water temperature, whereas there is no significant between them and water quantity. Comparative study and cluster analysis, as well as factor analysis imply that the temporal variations of nitrogen and phosphorus concentrations in Huihe River are significant, and coincide with the seasonal variation of climatic variation of the study area. The results show that either dredging project or climate factors (seasonal changes) had dramatically affected the pollution of NH4+-N, TN and TP. Moreover, the study also confirmed that NH4+-N, TN pollution is mainly anthropogenic, different with TP pollution, who is more likely to be controlled by natural factors.

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