scholarly journals Monitoring techniques for algae blooms from space

2021 ◽  
Vol 5 (3) ◽  
pp. first
Author(s):  
Thong Nguyen Hoang ◽  
Thuyen Le Xuan ◽  
Van Tran Thi
Keyword(s):  
Near Infrared ◽  
Human Life ◽  
Water Environment ◽  
Aquatic Organisms ◽  
Water Quality Assessment ◽  
Living Environment ◽  
Lake Area ◽  
Band Ratio ◽  
Blue Green Algae ◽  
Landsat Satellite

Microalgae blooms are one of the most serious environmental problems that greatly affect the living environment of aquatic organisms. They deplete the oxygen source in the water, seriously depleting the respiratory oxygen source for organisms living in the water body. Some species of microalgae are also capable of producing toxins, typically blue-green algae, poisoning aquatic organisms and causing death, health effects on human life when ingested. This paper presents the results of research on mapping algae concentration distribution to support water quality assessment for Dau Tieng reservoir. Landsat satellite imagery was used for qualitative and quantitative assessment of algae presence in the lake area. Calculation results showed that algae concentration had a linear correlation with the band ratio of the 3-band algorithm (3BDA (2), and was a combination of spectral reflective bands in the green wavelength bands GREEN, RED and near infrared NIR. We simulated the spatial distribution of algae concentrations on the entire lake area on 3 points of time when satellite images had been collected. Result of this study showed that remote sensing technology can be used for monitoring the appearance and change of algae concentration in water, which is an essential measurement for timely providing warnings as well as assisting in monitoring and managing water environment quality to minimize damages to people and the ecosystem.

scholarly journals Monitoring Changes in the Transparency of the Largest Reservoir in Eastern China in the Past Decade, 2013–2020

2021 ◽  
Vol 13 (13) ◽  
pp. 2570
Author(s):  
Teng Li ◽  
Bozhong Zhu ◽  
Fei Cao ◽  
Hao Sun ◽  
Xianqiang He ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mean Squared Error ◽  
Eastern China ◽  
Water Environment ◽  
Relative Difference ◽  
Boreal Summer ◽  
Support Vector ◽  
Lake Area ◽  
The Past ◽  
Remote Sensing Reflectance

Based on characteristics analysis about remote sensing reflectance, the Secchi Disk Depth (SDD) in the Qiandao Lake was predicted from the Landsat8/OLI data, and its changing rates on a pixel-by-pixel scale were obtained from satellite remote sensing for the first time. Using 114 matchups data pairs during 2013–2019, the SDD satellite algorithms suitable for the Qiandao Lake were obtained through both the linear regression and machine learning (Support Vector Machine) methods, with remote sensing reflectance (Rrs) at different OLI bands and the ratio of Rrs (Band3) to Rrs (Band2) as model input parameters. Compared with field observations, the mean absolute relative difference and root mean squared error of satellite-derived SDD were within 20% and 1.3 m, respectively. Satellite-derived results revealed that SDD in the Qiandao Lake was high in boreal spring and winter, and reached the lowest in boreal summer, with the annual mean value of about 5 m. Spatially, high SDD was mainly concentrated in the southeast lake area (up to 13 m) close to the dam. The edge and runoff area of the lake were less transparent, with an SDD of less than 4 m. In the past decade (2013–2020), 5.32% of Qiandao Lake witnessed significant (p < 0.05) transparency change: 4.42% raised with a rate of about 0.11 m/year and 0.9% varied with a rate of about −0.09 m/year. Besides, the findings presented here suggested that heavy rainfall would have a continuous impact on the Qiandao Lake SDD. Our research could promote the applications of land observation satellites (such as the Landsat series) in water environment monitoring in inland reservoirs.

scholarly journals Development and evaluation of the Lake Multi-biotic Integrity Index for Dongting Lake, China

2015 ◽  
Author(s):  
Xing Wang ◽  
Binghui Zheng ◽  
Lusan Liu ◽  
Lijing Wang
Keyword(s):  
Water Quality ◽  
Water Environment ◽  
Aquatic Organisms ◽  
Dongting Lake ◽  
Assessment System ◽  
Biotic Integrity ◽  
Diatom Index ◽  
Integrity Index ◽  
Biotic Integrity Index

<p>A Lake Multi-biotic Integrity Index (LMII) for the China’s second largest interior lake (Dongting Lake) was developed to assess the water quality status using algal and macroinvertebrate metrics. Algae and benthic macroinvertebrate assemblages were sampled at 10 sections across 3 subregions of Dongting Lake. We used a stepwise process to evaluate properties of candidate metrics and selected ten for the LMII: Pampean diatom index, diatom quotient, trophic diatom index, relative abundance diatoms, Margalef index of algae, percent sensitive diatoms, % facultative individuals, % Chironomidae individuals, % predators individuals, and total number of macroinvertebrate taxa. We then tested the accuracy and feasibility of the LMII by comparing the correlation with physical-chemical parameters. Evaluation of the LMII showed that it discriminated well between reference and impaired sections and was strongly related to the major chemical and physical stressors (r = 0.766, P&lt;0.001). The re-scored results from the 10 sections showed that the water quality of western Dongting Lake was good, while that of southern Dongting Lake was relatively good and whereas that of eastern Dongting Lake was poor. The discriminatory biocriteria of the LMII are suitable for the assessment of the water quality of Dongting Lake. Additionally, more metrics belonging to habitat, hydrology, physics and chemistry should be considered into the LMII, so as to establish comprehensive assessment system which can reflect the community structure of aquatic organisms, physical and chemical characteristics of water environment, human activities, and so on.</p>

Surface Water Quality Assessment in Main Stream of Liaohe River

2013 ◽  
Vol 788 ◽  
pp. 354-358
Author(s):  
Hui Wang ◽  
Li Na Sun ◽  
Pan Du
Keyword(s):  
Water Quality ◽  
Surface Water ◽  
Quality Assessment ◽  
Membership Function ◽  
Water Environment ◽  
Surface Water Quality ◽  
Water Quality Assessment ◽  
Monitoring Station ◽  
Main Stream ◽  
Liaohe River

The objective of this research was to study the surface water quality and evolution of surface water environment in Liaohe River main stream. Results showed that the surface water quality was declining along main stream. It was better in flood reason than others. It was best in Defudian monitoring station and worst in Shuguangdaqiao monitoring station. This research would significantly improve the understanding of the evolution of surface water environment in Liaohe River main stream.Keywords: water quality assessment; Liaohe River; membership function

scholarly journals Use of multi-spectral visible and near-infrared satellite data for timely estimates of the Earth's surface reflectance in cloudy conditions: Part 2 - image restoration with HICO satellite data in overcast conditions

2021 ◽  
Author(s):  
Joanna Joiner ◽  
Zachary Fasnacht ◽  
Bo-Cai Gao ◽  
Wenhan Qin
Keyword(s):  
Spatial Resolution ◽  
Satellite Data ◽  
Precision Agriculture ◽  
Land Surface ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Space Station ◽  
Water Quality Assessment ◽  
Low Contrast

Satellite-based visible and near-infrared imaging of the Earth's surface is generally not performed in moderate to highly cloudy conditions; images that look visibly cloud covered to the human eye are typically discarded. Here, we expand upon previous work that employed machine learning (ML) to estimate underlying land surface reflectances at red, green, and blue (RGB) wavelengths in cloud contaminated spectra using a low spatial resolution satellite spectrometer. Specifically, we apply the ML methodology to a case study at much higher spatial resolution with the Hyperspectral Imager for the Coastal Ocean (HICO) that flew on the International Space Station (ISS). HICO spatial sampling is of the order of 90 m. The purpose of our case study is to test whether high spatial resolution features can be captured using multi-spectral imaging in lightly cloudy and overcast conditions. We selected one clear and one cloudy image over a portion ofthe panhandle coastline of Florida to demonstrate that land features are partially recoverable in overcast conditions. Many high contrast features are well recovered in the presence of optically thin clouds. However, some of the low contrast features, such as narrow roads, are smeared out in the heavily clouded part of the reconstructed image. This case study demonstrates that our approach may be useful for many science and applications that are being developed for current and upcoming satellite missions including precision agriculture and natural vegetation analysis, water quality assessment as well as disturbance, change, hazard, and disaster detection.

scholarly journals ADVANTAGES OF QUARTER BUILDING IN THE FORMATION OF A COMFORTABLE LIVING ENVIRONMENT

2019 ◽  
Vol 9 (4) ◽  
pp. 140-147
Author(s):  
Liudmila A. VOLKOVA ◽  
Tatyana V. LITVYAK
Keyword(s):  
Comparative Analysis ◽  
Urban Environment ◽  
Human Life ◽  
Residential Development ◽  
Living Environment ◽  
Residential Areas

The article presents a comparative analysis of the main characteristics of planning elements “quarter” and “microdistrict”, identifies their significant differences; provides an analysis of the development of approaches to the construction of residential areas in Russia in terms of creating a comfortable urban environment for human life; reveals the advantages of modern quarter as a planning element of residential development.

scholarly journals "Mineralogical & Petrographic Microfacies Study of the Zahraa formation (Pliocene– Pleistocene) in Sawa Lake Surrounding area- IRAQ "

2017 ◽  
Vol 4 (1) ◽  
pp. 11-20
Author(s):  
Saleh A. Lazam
Keyword(s):  
Organic Matter ◽  
Fresh Water ◽  
Depositional Environment ◽  
Water Environment ◽  
Lake Area ◽  
Surrounding Area ◽  
Thin Sections ◽  
Project Area ◽  
Mineralogical Study ◽  
Fresh Water Environment

"Mineralogical, Petorographic Microfacies study has been done on (16) samples of Zahraa formation (Pliocene – Pleistocene) of outcrop in Surrounded Sawa Lake area. The mineralogical study showed that Calcite is the main mineral within the rock formation, whereas the upper rocks of Zahraa Formation consist silty or sandy claystone is dominant in the middle and the upper portion, in addition to quartz, clay minerals, iron oxide and organic matter as insoluble residues. From thin sections study, Three main microfacies have been identified which are: Charophyte shelly bioclastic wackestone, Charophyte shelly bioclastic dolowackestone and Algal wackestone. Based on microfacies study and its fossils content, it has been possible to determine the depositional environment of Zahraa Formation which deposits in the area of the presence of Charaphytes, indicates fresh water environment. From the depositioal situation and the large extension in the project area, the type of fresh water environment is ephemeral freshen water lakes."

Anthropogenic and Climatic Factors Differentially Affect Waterbody Area and Connectivity in an Urbanizing Landscape: A Case Study in Zhengzhou, China

Land ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1070
Author(s):  
Chang Liu ◽  
Emily S. Minor ◽  
Megan B. Garfinkel ◽  
Bo Mu ◽  
Guohang Tian
Keyword(s):  
Yellow River ◽  
Climatic Factors ◽  
Landscape Connectivity ◽  
Aquatic Organisms ◽  
Open Water ◽  
Central China ◽  
Water Pipeline ◽  
Landsat Satellite ◽  
The City ◽  
Over Time

Urbanization alters the distribution and characteristics of waterbodies, potentially affecting both the habitat availability and connectivity for aquatic wildlife. We used Landsat satellite imagery to observe temporal and spatial changes in open-water habitats in Zhengzhou, a rapidly growing city in central China. We classified open water into six categories: perennial rivers, seasonal rivers and streams, canals, lakes, ponds, and reservoirs. From 1990 to 2020, in 5-year intervals, we identified, counted, and measured the area of each kind of waterbody, and we used a model selection approach with linear regressions to ask which climate and anthropogenic drivers were associated with these changes. We also used Conefor software to examine how these changes affected the landscape connectivity for waterfowl. Over the study period, lakes and canals were the only waterbody types to show statistically significant changes in surface area, increasing by 712% and 236%, respectively. Changes in lakes and canals were positively correlated with the length of water pipeline in the city. The connectivity of waterbodies fluctuated over the same period, mirroring fluctuations in the perennial Yellow River. Ponds contributed very little to landscape connectivity, and the importance of reservoirs decreased over time. Conversely, canals played an increasingly important role in landscape connectivity over time. Counterintuitively, the connectivity of waterbodies increased in the built-up part of the city. Our results show that urbanization can have unexpected effects—both positive and negative—on the connectivity and area of open-water habitats. These effects are likely to be important for waterfowl and other aquatic organisms.

scholarly journals Water Quality Assessment of Tributaries of Batang Baleh in Sarawak Using Cluster Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-9
Author(s):  
Teck-Yee Ling ◽  
Chen-Lin Soo ◽  
Teresa-Lee-Eng Heng ◽  
Lee Nyanti ◽  
Siong-Fong Sim ◽  
...  
Keyword(s):  
Water Quality ◽  
Cluster Analysis ◽  
Total Phosphorus ◽  
Organic Nitrogen ◽  
Suspended Solids ◽  
Oxygen Demand ◽  
Aquatic Organisms ◽  
Water Quality Assessment ◽  
Upstream Region ◽  
Nitrite Nitrate

Assessment of river water quality is essential as it provides the knowledge required to make informed decisions. Therefore, water quality was determined at 15 tributary stations located along the Batang Baleh, Sarawak. Results of the study indicate that all tributaries were well-aerated (≈ 7.7 mg/L) with pH (≈ 7.3) and conductivity (≈ 37.3 μS/cm) values falling within acceptable ranges. However, there were tributaries that showed very high turbidity (> 1000 NTU) and suspended solids (> 800 mg/L) which were contributed by the soil erosion from logging activities in the watershed. Tributary stations associated with logging activities also showed significantly higher total phosphorus and organic nitrogen. Cluster analysis demonstrated that water quality at tributary stations along the Batang Baleh exhibited a longitudinal variation from upstream to downstream regions, particularly, dissolved oxygen, five-day biochemical oxygen demand, and nitrite-nitrate nitrogen, which were found higher in upstream region and steadily decreased towards the downstream region. Two stations located at Sg. Serani and Sg. Melatai were distinct from the other stations with the highest concentrations of turbidity, total suspended solids, organic nitrogen, and total phosphorus. Thus, there is an urgent need to reduce the pollutants in the tributaries of Batang Baleh for the health of the sensitive aquatic organisms.

Volatile Compounds of the Cyanophyceae – A Review

1983 ◽  
Vol 15 (6-7) ◽  
pp. 181-190 ◽  
Author(s):  
George P Slater ◽  
Vivian C Blok
Keyword(s):  
Fatty Acids ◽  
Volatile Compounds ◽  
Organic Compounds ◽  
Green Algae ◽  
Aquatic Organisms ◽  
Blue Green Algae ◽  
Green Algal

A relationship between blue-green algae and off-flavours in water was reported as early as 1883. Continuing research has shown that two metabolites, geosmin and methylisoborneol are major contributors to unpalatable flavours in water and aquatic organisms. Many instances of the co-occurrence of these two compounds and dense blooms of blue-green algae have been recorded. Cultures of Anabaena, Lyngbya, Osciiiatoria, and Sympioca species have been shown to produce geosmin or methylisoborneol while blooms of Aphanizomenon, Anabaena, Microcystis, Oscillatoria, and Gomphosphaeria have been found in water containing geosmin or the odour of this compound. Actinomycetes have also been shown to produce these two compounds. In addition to geosmin and methylisoborneol, there is evidence that several other blue-green algal metabolites contribute to aquatic taste and odour problems. Among them is β-cyclocitral which has a distinctive tobacco flavour. Blue-green algae produce a variety of organic compounds including hydrocarbons, fatty acids, aromatics, ketones, terpenoids, amines and Sulfides which could contribute to the over-all flavour of water and aquatic organisms.

Cloud Simulation Platform for Water Environment Assessment

2013 ◽  
Vol 316-317 ◽  
pp. 670-673 ◽  
Author(s):  
Xiao Fan Ge ◽  
Di Bo Hou ◽  
Guang Xin Zhang ◽  
Ping Jie Huang
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Water Environment ◽  
Water Quality Assessment ◽  
C Language ◽  
Water Quality Simulation ◽  
Environment Assessment ◽  
Computing Framework ◽  
Water Simulation ◽  
Saas Cloud

In this paper, a platform based on SaaS cloud computing framework is developed to provide professional online cloud simulation service for water quality assessment. The DLL, WINDOWS MFC programming methods are investigated and water pollution remote simulation can be performed supported by different water simulation softwares including MATLAB, MIKE and FLUENT. The C# language is used in our programming. The major steps of establishing a water quality simulation model using FLUENT and MATLAB are introduced.

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