Novel simulation of aqueous total nitrogen and phosphorus concentrations in Taihu Lake with machine learning

2022 ◽  
Vol 204 ◽  
pp. 111940
Author(s):  
Hao Lu ◽  
Liuyan Yang ◽  
Yifan Fan ◽  
Xin Qian ◽  
Tong Liu
Keyword(s):  
Machine Learning ◽  
Total Nitrogen ◽  
Taihu Lake ◽  
Nitrogen And Phosphorus

scholarly journals Spatial–Temporal Variations of Total Nitrogen and Phosphorus in Poyang, Dongting and Taihu Lakes from Landsat-8 Data

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1704
Author(s):  
Wei Shang ◽  
Shuanggen Jin ◽  
Yang He ◽  
Yuanyuan Zhang ◽  
Jian Li
Keyword(s):  
Total Nitrogen ◽  
Taihu Lake ◽  
Poyang Lake ◽  
Social Economy ◽  
Temporal Variations ◽  
Google Earth ◽  
Dongting Lake ◽  
Landsat 8 ◽  
Monitoring Methods ◽  
Nitrogen And Phosphorus

Poyang Lake, Dongting Lake, and Taihu Lake are the largest freshwater lakes in the middle and lower reaches of the Yangtze River, China. In recent years, the eutrophication level of lakes has increased with the development of the social economy and caused many environmental and social problems. The concentrations of total nitrogen (TN) and total phosphorus (TP) are the key indicators of the degree of eutrophication, but the traditional ground monitoring methods are not capable of capturing such parameters in whole lakes with high spatial-temporal resolution. In this paper, empirical models are established and evaluated between the TN and TP and remote sensing spectral factors in the three lakes using Landsat 8 Operational Land Imager (OLI) satellite data and in-situ data. The results show that the inversion accuracy is higher than 75%. The TN and TP concentrations in the three lakes are inversed based on the Google Earth Engine (GEE) platform from 2014 to 2020 and their spatial-temporal variations are analyzed. The results show that the concentrations of TN and TP in Poyang Lake were decreased by 5.99% and 7.13% over 7 years, respectively, and the TN in Dongting Lake was decreased by 5.25% while the TP remained stable. The temporal changes in TN and TP concentrations displayed seasonal variations. A low concentration was observed in summer and high concentrations were in spring and winter. The average concentrations of TN and TP in Taihu Lake were higher than that of the other two lakes. The TP concentration was increased by 17.3% over 7 years, while the TN concentration remained almost stable. The variation in TN in Taihu Lake was the same as the growth cycle of algae, with higher value in spring and winter and lower value in summer, while the concentration of TP was lower in spring and winter and higher in summer. The spatial distribution of TN and TP concentrations in the three major lakes was significantly affected by human activities, and the concentrations of TN and TP were higher in areas near cities and agricultural activities.

scholarly journals The Effect of Bacillus licheniformis MH48 on Control of Foliar Fungal Diseases and Growth Promotion of Camellia oleifera Seedlings in the Coastal Reclaimed Land of Korea

Pathogens ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 6 ◽  
Author(s):  
Sang-Jae Won ◽  
Jun-Hyeok Kwon ◽  
Dong-Hyun Kim ◽  
Young-Sang Ahn
Keyword(s):  
Total Nitrogen ◽  
Bacillus Licheniformis ◽  
Growth Promotion ◽  
Dry Weight ◽  
Fungal Diseases ◽  
Camellia Oleifera ◽  
Bacterial Inoculation ◽  
Lytic Enzymes ◽  
Nitrogen And Phosphorus ◽  
Reclaimed Land

This study investigated the control of foliar fungal diseases and growth promotion of Camellia oleifera seedlings in coastal reclaimed land through the use of Bacillus licheniformis MH48. B. licheniformis MH48 can produce lytic enzymes chitinase and β-1,3-glucanase that can inhibit foliar pathogens by 37.4 to 50.5%. Nevertheless, foliar diseases appeared in the seedlings with bacterial inoculation, and their survival rate decreased because they were unable to withstand salt stress. However, B. licheniformis MH48 significantly increased the total nitrogen and phosphorus contents in the soils through fixing atmospheric nitrogen and solubilizing phosphorus. The growth of seedlings with bacterial inoculation increased, particularly in root dry weight, by 7.42 g plant−1, which was 1.7-fold greater than that of the control. B. licheniformis MH48 produces the phytohormone auxin, which potentially stimulates seedling root growth. C. oleifera seedlings significantly increased in total nitrogen content to 317.57 mg plant−1 and total phosphorus content to 46.86 mg plant−1. Our results revealed the effectiveness of B. licheniformis MH48 not only in the control of foliar fungal diseases but also in the growth promotion of C. oleifera seedlings in coastal lands.

scholarly journals Investigation of the decomposition and leaching dynamics of Salix, Populus and mixed leaves in the area of Lake Balaton and Kis-Balaton Wetland

2019 ◽  
pp. 119-124
Author(s):  
Brigitta Simon ◽  
Tamás Kucserka ◽  
Angéla Anda
Keyword(s):  
Total Nitrogen ◽  
Phosphorus Content ◽  
Mesh Size ◽  
Common Species ◽  
Coastal Vegetation ◽  
Lake Balaton ◽  
Decomposition Rates ◽  
Nitrogen And Phosphorus ◽  
Major Nutrient ◽  
Nitrogen Contents

In lakes and wetlands, leaf litter input from the coastal vegetation represents a major nutrient load and plays a basic structural and functional role in several ecosystems. In Hungary, at the banks of lakes and wetlands, Salix and Populus trees are the most common species. In an experiment in Lake Balaton and Kis-Balaton Wetland between 16 November 2017 to and 3 June 2018, the decomposition rates and leaching dynamics of Salix, Populus and mixed leaves (50% Salix and 50% Populus) were investigated. Total nitrogen and phosphorus content of biomass samples were measured at the beginning and end of the experiment for the leaching dynamics experiment. We found that litter mass losses (Salix, Populus and mixed leaves) were not significantly different between the two mesh size litterbags and between Lake Balaton and Kis-Balaton Wetland. Different amounts of the total nitrogen and phosphorus leaching from Salix, Populus and mixed leaves were detected. The total nitrogen contents of the plant samples were around 8-18% at the end of the investigated period. Slightly higher values were measured compared to phosphorous (27-29%).

Effects of tetracycline on simultaneous biological wastewater nitrogen and phosphorus removal

RSC Advances ◽  
2015 ◽  
Vol 5 (73) ◽  
pp. 59326-59334 ◽  
Author(s):  
A. Chen ◽  
Y. Chen ◽  
C. Ding ◽  
H. Liang ◽  
B. Yang
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Phosphorus Removal ◽  
Protective Role ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Total Nitrogen Removal

The presence of 2 and 5 mg L−1of tetracycline decreased total nitrogen removal. Tetracycline induced EPS release and decreased its protective role on cells. Denitrifiers instead of nitrifiers were negatively affected by tetracycline.

scholarly journals Reducing Nitrogen and Phosphorus Losses from Different Crop Types in the Water Source Area of the Danjiang River, China

2019 ◽  
Vol 16 (18) ◽  
pp. 3442 ◽  
Author(s):  
Mengjing Guo ◽  
Tiegang Zhang ◽  
Jing Li ◽  
Zhanbin Li ◽  
Guoce Xu ◽  
...  
Keyword(s):  
Total Nitrogen ◽  
Total Phosphorus ◽  
Unit Area ◽  
Nitrogen Concentration ◽  
Source Area ◽  
Water Source ◽  
Nutrient Loss ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
Bare Land

Nitrogen and phosphorus are essential for plant growth and are the primary limiting nutrient elements. The loss of nitrogen and phosphorus in agricultural systems can cause the eutrophication of natural water bodies. In this paper, a field simulated rainfall experiment was conducted in a typical small watershed of the Danjiang River to study the nutrient loss process of nitrogen and phosphorus in slope croplands subjected to different crops and tillage measures. The characteristics of the runoff process and nutrient migration of different slope treatments were studied, which were the bare-land (BL, as the control), peanut monoculture (PL), corn monoculture (CL), bare land (upper slope) mixed with peanut monoculture (lower slope) (BP), corn and peanut intercropping (TCP), corn and soybean intercropping (TCS), downslope ridge cultivation (BS) slope, and straw-mulched (SC), respectively. The results showed that the runoff of CL, SC, TCS, BS, BP, PL and TCP slope types were 93%, 75%, 51%, 39%, 28%, 12%, and 6% of the those of the bare land, respectively. The total nitrogen concentration in runoff on different slope types decreased in the order of BP > PL > BS > SC > TCP > BL > CL > TCS. The BL was characterized with the highest NRL-TN (the loss of total nitrogen per unit area), with the value of 1.188 kg/hm2, while those of the TCP is the smallest with the value of 0.073 kg/hm2. The total phosphorus concentration in runoff decreasd in the order of BS > BP > PL > BL > TCP > SC > CL > TCS. The PRL-TP (the loss of total phosphorus per unit area) of BL is the largest (0.016 kg/hm2), while those of TCP is the smallest (0.001 kg/hm2). These indicate that the loss of nitrogen is much higer than that of phosphorus. The loss of nitrogen in runoff is dominated by nitrate nitrogen, which accounts for 54.4%–78.9% of TN. Slope croplands in the water source area should adopt the tillage measures of TCP and PL.These measures can reduce 85% of the runoff of nitrogen and phosphorus compared to the bare land. The results may assist in agricultural non-point source pollution control and help promote improved management of the water environment in the Danjiang River’s water source area.

scholarly journals Changes in the stocks of soil organic carbon, total nitrogen and phosphorus following afforestation of post-arable soils: A chronosequence study

2019 ◽  
Vol 451 ◽  
pp. 117536 ◽  
Author(s):  
Halina Smal ◽  
Sławomir Ligęza ◽  
Jacek Pranagal ◽  
Danuta Urban ◽  
Dorota Pietruczyk-Popławska
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Total Nitrogen ◽  
Arable Soils ◽  
Nitrogen And Phosphorus
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