Distribution of Nitrogen and Phosphorus in Pore Water Profiles and Estimation of Their Diffusive Fluxes and Annual Loads in Guanting Reservoir (GTR), Northern China

Increases in the concentrations of nitrogen and phosphorus occurred in the water column of Lake 227 during 15 years of fertilization with phosphoric acid and sodium nitrate. The sources of the increases were deduced by comparing the budgets of N and P to the budget for sodium, using a simple model, and from the chemistry of sediment pore water.Total inventories for sodium since fertilization began confirmed that the element was almost perfectly conservative, as expected. When model results for phosphorus and sodium were calculated, the apparent increase in phosphorus was found to be due entirely to lower water renewal rates during recent years. This agrees with the observation that phosphorus concentrations in sediment pore water did not change between 1975 and 1982. Both phosphorus and sodium in the lake have been in equilibrium with external loading for the past several years.In contrast, the observed increase in nitrogen could not be accounted for by the decreased water renewal rate, implying that the element was either becoming more efficiently recycled or that there was an increasing, unmeasured external source of the element. An increase in pore water ammonium between 1975 and 1982 was balanced by an increase in the concentration in overlying waters, so that diffusive fluxes did not change. Increasing blooms of nitrogen-fixing bluegreen algae after 1975 indicate that N2 fixation is the increasing source of nitrogen to the lake. No tendency for the nitrogen:sodium ratio to stabilize has been observed, indicating that the nitrogen budget has still not reached a new steady state.

Download Full-text

Retrieval and Evaluation of Chlorophyll-a Concentration in Reservoirs with Main Water Supply Function in Beijing, China, Based on Landsat Satellite Images

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094419 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4419

Author(s):

Yuequn Lai ◽

Jing Zhang ◽

Yongyu Song ◽

Zhaoning Gong

Keyword(s):

Remote Sensing ◽

Water Supply ◽

Chlorophyll A ◽

Phosphorus Concentration ◽

Landsat 8 ◽

Supply Function ◽

Estimation Model ◽

Nitrogen And Phosphorus ◽

Chlorophyll A Concentration ◽

Guanting Reservoir

Remote sensing retrieval is an important technology for studying water eutrophication. In this study, Guanting Reservoir with the main water supply function of Beijing was selected as the research object. Based on the measured data in 2016, 2017, and 2019, and Landsat-8 remote sensing images, the concentration and distribution of chlorophyll-a in the Guanting Reservoir were inversed. We analyzed the changes in chlorophyll-a concentration of the reservoir in Beijing and the reasons and effects. Although the concentration of chlorophyll-a in the Guanting Reservoir decreased gradually, it may still increase. The amount and stability of water storage, chlorophyll-a concentration of the supply water, and nitrogen and phosphorus concentration change are important factors affecting the chlorophyll-a concentration of the reservoir. We also found a strong correlation between the pixel values of adjacent reservoirs in the same image, so the chlorophyll-a estimation model can be applied to each other.

Download Full-text

Mechanism Analysis and Experimental Research on the Interception of Nitrogen and Phosphorus Pollutants by Gullies in Northern China

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.250-253.3392 ◽

2011 ◽

Vol 250-253 ◽

pp. 3392-3396

Author(s):

Yu Jia Song ◽

Hui Qing Liu

Keyword(s):

Total Phosphorus ◽

Nitrate Nitrogen ◽

Northern China ◽

Careful Analysis ◽

Ammonia Nitrogen ◽

Mechanism Analysis ◽

Nitrogen And Phosphorus ◽

Urban Sewage ◽

Control Section ◽

Nitrogen Pollutants

The discharge of urban sewage and agricultural non-point source pollutants is the main reason causing eutrophication in gullies in most cities of northern China. Based on a careful analysis on the ecological structure and ecological characteristics of a gully, this article preliminarily studies the interception and degradation mechanisms of nitrogen pollutants by the gully. Meanwhile, to take gullies in Changchun as the object of the study, this article carries out an experiment on the interception effect of nitrogen pollutants by gullies. This experiment respectively establishes a control section in the upper and lower reaches of a gully, and takes water samples four times in each section from May to August to determine total nitrogen, total phosphorus, nitrate nitrogen, ammonia nitrogen and salinity. The result shows: the gully plays some role in the interception of pollutants; total phosphorus accounts for the largest interception in pollutants in the experimented gully section, with the relative interception rate of 27.46%, followed by ammonia nitrogen, with the interception rate of 21.80%, which is the result of the combined effects of aquatic plants, microorganisms and sediment in the gully.

Download Full-text

Estimation of soil organic carbon, nitrogen, and phosphorus losses induced by wind erosion in Northern China

Land Degradation and Development ◽

10.1002/ldr.3288 ◽

2019 ◽

Vol 30 (8) ◽

pp. 1006-1022 ◽

Cited By ~ 7

Author(s):

Heqiang Du ◽

Tao Wang ◽

Xian Xue ◽

Sen Li

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Wind Erosion ◽

Northern China ◽

Nitrogen And Phosphorus ◽

Phosphorus Losses

Download Full-text

Geochemical evolution of clay pore water as an indicator for palaeoenvironmental variability in the Hebei Plain, northern China

Environmental Earth Sciences ◽

10.1007/s12665-015-4934-1 ◽

2016 ◽

Vol 75 (2) ◽

Cited By ~ 1

Author(s):

Hong Niu ◽

Xing Liang ◽

Menggui Jin ◽

Zhang Wen ◽

Jing Li ◽

...

Keyword(s):

Pore Water ◽

Northern China ◽

Geochemical Evolution ◽

Hebei Plain

Download Full-text

Sediment metabolism in a transitional continental - marine area: The Albufera of Majorca (Balearic Islands, Spain)

Marine and Freshwater Research ◽

10.1071/mf9950045 ◽

1995 ◽

Vol 46 (1) ◽

pp. 45 ◽

Cited By ~ 13

Author(s):

P Lopez ◽

M Vidal ◽

X Lluch ◽

JA Morgui

Keyword(s):

Oxygen Consumption ◽

Pore Water ◽

Respiratory Quotient ◽

Nutrient Dynamics ◽

Anaerobic Respiration ◽

Ammonium Phosphate ◽

Nutrient Concentrations ◽

Co2 Efflux ◽

Marine Areas ◽

Diffusive Fluxes

The concentrations of nutrients in sediment pore water and the fluxes of nutrients at the water-sediment interface were measured in a channel that joins continental and marine areas in the Albufera of Majorca in order to evaluate the role of sediments in the nutrient dynamics in this system. Upstream, surficial pore water presented lower values of Eh, which became negative in summer, whereas downstream Eh remained positive. Nutrient concentrations were especially high upstream, reaching 1000 mol L-1 of NH4 and 75 μmol L-1 of PO4 during summer. In summer, measured fluxes showed intense respiration upstream, with an oxygen consumption of 130 mg m-2 h-1 and a respiratory quotient near 4, which indicates dominance of anaerobic respiration. Total CO2 efflux and nutrient fluxes were also high, reaching 30.50 mmol m-2 h-1 for CO2, >2000 μmol m-2 h-1 for NH4 and 58 μmol m-2 h-1 for PO4. A substantial amount of the total CO2 efflux (14 mmol m-2 h-1) was due to calcium carbonate redissolution. Downstream, oxygen consumption, respiratory quotient and ammonium fluxes were lower (around 70 mg m-2 h-1, between 2 and 3, and <20 μmol m-2 h-1, respectively), which indicates a moderate rate of decomposition activity and suggests denitrification as the main respiratoy process. Differences between fluxes measured 'in situ' and those calculated from pore-water concentrations indicated non-diffusive fluxes upstream and suggest substantial denitrifying activity downstream. Extra keywords: benthic chambers, sediment fluxes, pore water, ammonium, phosphate.

Download Full-text