Characterization and causes analysis for algae blooms in large river system

Cheng, Bingfen; Xia, Rui; Zhang, Yuan; Yang, Zhongwen; Hu, Shanshan; Guo, Fen; Ma, Shuqin

doi:10.1016/j.scs.2019.101707

Cited by 53 publications

(28 citation statements)

References 46 publications

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“…On the one hand, affected by the impoundment of the Xinglong Reservoir, the Shayang River section has changed from a natural river course to a reservoir backwater area, while the Xiantao section is still a natural river course. Studies have shown that diatoms have a wide range of suitable flow rates, and the flow rate can increase rapidly within the range of 0 ~ 0.89 m s −1 (Cheng et al, 2019). The accumulation capacity of diatoms in the near‐static waters of the reservoir and the flowing waters of the river is different.…”

Section: Resultsmentioning

confidence: 99%

“…The identification of hydrodynamic conditions in the middle and lower reaches of the Han River is an important basis for providing algal bloom warnings (Cheng et al, 2019). Algal blooms began to occur in the Shayang section after the operation of the Xinglong Reservoir, so it is currently difficult to determine the early warning conditions for algal blooms based on only the hydrological and hydraulic conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Studies have shown that diatoms have a wide range of suitable flow rates, and the flow rate can increase rapidly within the range of 0~0.89 m s −1(Cheng et al, 2019). The accumulation capacity of diatoms in the near-static waters of the reservoir and the flowing waters of the river is different.…”

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confidence: 99%

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Hydrological management strategies for the control of algal blooms in regulated lowland rivers

Yin

Jia

et al. 2021

Hydrological Processes

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Reservoirs of lowland floodplain rivers with eutrophic backgrounds cause variations in the hydrological and hydraulic conditions of estuaries and low‐dam reservoir areas, which can promote planktonic algae to proliferate and algal bloom outbreaks. Understanding the ecological effects of variations in hydrological and hydraulic processes in lowland rivers is important for algal bloom control. In this study, the middle and lower reaches of the Han River, China, a typical regulated lowland river with a eutrophic background, are selected. Based on the effect of hydrological and hydraulic variability on algal blooms, a hydrological management strategy for river algal bloom control is proposed. The results showed that (a) differences in river morphology and background nutrient levels cause significant differences in the critical threshold flow velocities for algal bloom outbreaks between natural river and low‐dam reservoir sections; there is no uniform threshold flow velocity for algal bloom control. (b) There are significant differences in the river hydrological/hydraulic conditions between years with and without algal blooms. The average river flow, water level and velocity in years with algal blooms are significantly lower than those in years without algal blooms. (c) For different river sections where algal blooms occur and to meet the threshold flow velocities, the joint operation of cascade reservoirs and diversion projects is an effective method to prevent and control algal blooms in regulated lowland rivers. This study is expected to deepen our understanding of the ecological significance of special hydrological processes and guide algal bloom management in regulated lowland rivers.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Hydrological management strategies for the control of algal blooms in regulated lowland rivers

Yin

Jia

et al. 2021

Hydrological Processes

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“…here] As the largest tributary of the Yangtze River and an important water source for the Middle Route Project of the South-to-North Water Transfer, the water quality of the middle and lower reaches of the Hanjiang River has gradually deteriorated since the 1990s. The main reason is that nutrients, such as nitrogen and phosphorus in the water body, exceed the standard (Stephen et al, 2016;Cheng et al, 2019), resulting in a high degree of eutrophication in the water body, and repeated outbreaks of water blooms, during which the water body appears brown and emits a fishy and pungent odor (Fig. 2 ).…”

Section: Study Areamentioning

confidence: 99%

Spatiotemporal evolution of chlorophyll-a concentration from MODIS data inversion in the middle and lower reaches of the Hanjiang River, China

Chen

Dou

Xia

et al. 2021

Preprint

Self Cite

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The global construction of water projects has led to a clear trend of river and lake reservoir formation, spurring increasingly serious ecological environmental deterioration, especially that caused by the frequent occurrence of water blooms. Because of monitoring technology limitations, monitoring the algae content index in water has lagged behind the conventional water quality index, which makes sample monitoring too sparse in many rivers and the monitoring data incoherent, so it cannot truly reflect the evolution of water eutrophication. With moderate resolution imaging spectroradiometer (MODIS) remote sensing data monitoring, continuous chlorophyll-a observation data can be collected effectively. This method has important guiding significance for the early warning and control of water blooms. This study considers the middle and lower reaches of the Hanjiang River in China, based on the current remote sensing communication technology, MODIS remote sensing data, and statistical methods and measured chlorophyll-a concentration correlation analysis. Through the use of the trial and error method to establish the band ratio model and BP neural network model, two types of model errors were compared to determine the optimal algorithm settings for the middle and lower reaches of the Hanjiang River chlorophyll-a inversion. Subsequently, the algorithm model for 2000 to 2011 in the middle and lower reaches of the Hanjiang River chlorophyll-a concentration inversion and the results of the inversion analysis of spatiotemporal evolution characteristics we used to determine the influence of various environmental factors on the chlorophyll-a concentration change.

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“…Algae blooms refer to a massive range of algae which are basically plant-like planktons that photosynthesize in underwater conditions. The rage of algae in dams and reservoirs around the country, especially during the summer season, is repeatedly threatening the habitat environment of these water resources by significantly lowering the dissolved oxygen concentration level [1]. In order to remedy this problem, it is necessary to seek a countermeasure to recover the already lowered dissolved oxygen level in an effective way.…”

Section: Introductionmentioning

confidence: 99%

Oxygen Transfer Efficiency Evaluation of Underwater Bubbles

Jun¹,

Lee²

2020

IJBSBT

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This paper presents the study results on the dissolved oxygen concentration behavior in water body with underwater bubbling. The rage of algae in dams and reservoirs around the country, especially during the summer season, is threatening the habitat environment of these water resources by significantly lowering the dissolved oxygen concentration level. Different aeration devices based on underwater bubbling are widely applied in order to remedy this problem, however, fundamental study results on the performance of these devices in terms of dissolved oxygen level improvement are rarely reported in literature. In the present study, we focus on the quantitative evaluation of oxygen transfer performance of bubble diffusion process, which is the underlying physical model of aeration devices. For this purpose, related physical laws such as Henry's law of solubility, Fick's law of diffusion along with water quality standards are reviewed and a new test apparatus is established for this study, with which both the degassing and aeration can be systematically simulated. The test apparatus is composed of a closed water tank (stainless steel; 0.65m×0.65m×1.0m) with depressurization and degassing feature, underwater bubbler and measurement system for temperature, pressure and oxygen level. This system is capable of maintaining minimum pressure level of 0.1 atm and the dissolved oxygen concentration level down to 2 mg/L. According to the test results for a commercially available bubbler at three different air flow rates (10, 20, and 30 slpm) and at two bubbling depths of 0.4m and 0.8m, the oxygen transfer efficiency of 1.3-2.5% are confirmed and the best performing conditions could be successfully identified.

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Characterization and causes analysis for algae blooms in large river system

Cited by 53 publications

References 46 publications

Hydrological management strategies for the control of algal blooms in regulated lowland rivers

Hydrological management strategies for the control of algal blooms in regulated lowland rivers

Spatiotemporal evolution of chlorophyll-a concentration from MODIS data inversion in the middle and lower reaches of the Hanjiang River, China

Oxygen Transfer Efficiency Evaluation of Underwater Bubbles

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