DOM stratification and characteristics versus thermal stratification – A case study in the Panjiakou Reservoir, China

Wei, Mengjiao; Huang, Suiliang; Zhang, Tianqi; Li, Ming; Li, Ling; Akram, Waseem; Gao, Rui; Ge, Zhengkui; Sun, Yixuan

doi:10.1016/j.ejrh.2022.101160

Cited by 6 publications

(4 citation statements)

References 55 publications

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“…During the rainy season, temperatures are consistently higher than during the dry season, confirming a pattern also observed in other Brazilian semiarid reservoirs as reported by Carneiro et al (2023). The increase in water temperatures is a well-known contributor to intensified thermal stratification (Miao et al, 2023;Wei et al, 2022).…”

Section: Temperaturesupporting

confidence: 83%

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Diel and seasonal mixing patterns and water quality dynamics in a multipurpose tropical semiarid reservoir

Rocha,

Barros,

Filho

et al. 2023

Preprint

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Eutrophication has become a recurrent concern in reservoirs worldwide. This problem is intensified in tropical semiarid regions, where the reservoirs have high seasonal and annual variability of water level and volume. Therefore, an extensive understanding of the diel variation of water quality key-parameters can help improve management of such reservoirs. This study focuses on Castanhão reservoir, the largest multipurpose dam in the Brazilian semiarid. Its main water uses are irrigation, fish farming, and human supply. The reservoir faced a decline in water quality due to a prolonged drought period. While previous research has predominantly emphasized the seasonal dynamics of thermal and chemical stratification, our investigation provides diel assessments of multiple water quality parameters, including nutrient concentrations and phytoplankton abundance. Our primary objective is to compare seasonal and diel variations in stratification and nutrient distribution within the reservoir. Key findings reveal a diel cycle of thermal stratification, primarily during dry season, driven by higher wind speeds. This is corroborated by a significant negative correlation between wind speed and the relative water column stability index. In contrast, during the rainy season, the reservoir experiences continuous thermal stratification due to inflowing water being warmer than the reservoir’s water temperature. Notably, a significant negative correlation between total phosphorus and chlorophyll-a, along with a two-fold increase of this nutrient throughout the day during the rainy season, underscores the influence of the phytoplankton community dynamics on the diel nutrient variation. Chemical stratification of dissolved oxygen occurred during dry and rainy seasons, indicating that even during the dry season, where there is no significant inflow, the internal nutrient loading can also significantly impact the water quality of a reservoir. This study advances the understanding of diel water quality dynamics in tropical semiarid reservoirs, shedding light on both climatic and anthropogenic influences on water resources.

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Section: Temperaturesupporting

confidence: 83%

“…Since this process absorbs CO2 and releases O2 which increases the pH in the epilimnion. With an increase of depth, photosynthesis process decreases and consequently pH decreases (Wei et al, 2022).…”

Section: Phytoplankton Communitymentioning

confidence: 99%

Diel and seasonal mixing patterns and water quality dynamics in a multipurpose tropical semiarid reservoir

Rocha,

Barros,

Filho

et al. 2023

Preprint

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“…Since higher temperature contributes to increase phytoplankton biomass, higher DO concentration would be expected (He et al, 2019;Li et al, 2021;Pećić et al, 2023). As for P5 and P6, the ones with the lowest DO concentration (Figure S22A) and more persistent chemical strati cation (Figure S3), the negative correlation between DO and temperature indicates that in those sampling points, temperature is one of the factors that is contributing to the low DO concentrations; since higher temperature decreases oxygen solubility at the water (Nong et al, 2023;Wei et al, 2022). In contrast, P3 and P4 did not show any signi cant correlation between DO and temperature both at the bottom and the top of the reservoir.…”

Section: Pearson's Correlation Analysesmentioning

confidence: 93%

Understanding the Water Quality Dynamics in a Large Tropical Reservoir Under Hydrological Drought Conditions

Rocha,

Barros,

Costa

et al. 2024

Water Air Soil Pollut

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Castanhão is a multipurpose reservoir located in the semiarid region of Brazil. From 2012 to 2019, a severe drought occurred in the area, leading to a signi cant degradation of the water quality in the reservoir, spanning from oligotrophic to eutrophic/hypereutrophic state. In addition, this deterioration resulted in massive sh mortality events and highly-increased water treatment costs. Those negative impacts motivated an in-depth water quality monitoring program of this reservoir, which started in 2016. Although numerous studies have addressed the water quality issue in tropical reservoirs, limited availability of water quality data during drought periods has created a knowledge gap regarding the understanding of water quality dynamics under these conditions. Therefore, this study aimed to comprehensively understand the spatio-temporal dynamics of water quality in the Castanhão reservoir during a hydrological drought, with the objective of providing scienti cally sound references for water management. The ndings of this study indicate that total phosphorus and nitrogen concentrations in the reservoir follow approximately a complete-mixing pattern on a monthly basis, with temporal variations in nutrient levels being much more signi cant than spatial variations. This indicates that it is possible to apply a complete-mixing model at a monthly time-step to evaluate the nutrient dynamics of the reservoir. Additionally, the reservoir exhibits stronger chemical strati cation of dissolved oxygen compared to thermal strati cation, with dissolved oxygen levels decreasing from upstream to downstream. Furthermore, hypoxic conditions are predominant during the rainy season. In summary, this study offers an advance in the knowledge of water quality dynamics in a large tropical reservoir during a hydrological drought period. The ndings highlight the vulnerability of tropical reservoirs to water quality deterioration during droughts and provide valuable insights into the spatio-temporal dynamics of water quality in such water bodies. These ndings are crucial for improving water quality management in similar tropical reservoirs.

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“…Organic matter and its biological utilization will respond to the presence of thermal stratification to a certain extent [120]. There are evident interface effects on bacterial community composition [119], but the stratification of organic matter does not necessarily align perfectly with thermal stratification [121].…”

Section: The Impact Of Thermal Stratification On Aquatic Organismsmentioning

confidence: 99%

Challenge to Lake Ecosystems: Changes in Thermal Structure Triggered by Climate Change

Zhang,

Shen,

et al. 2024

Water

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Human activities, global warming, frequent extreme weather events, and changes in atmospheric composition affect the solar radiation reaching the Earth’s surface, affect mass and heat transfer at the air–water interface, and induce oscillations in wind-driven internal waves. This leads to changes in the spatiotemporal characteristics of thermal stratification in lakes, altering lake circulation patterns and vertical mass transfer. However, thermal stratification structures are often overlooked. The intensification of lake thermal stratification due to warming may lead to increased release of bottom pollutants, spreading through the dynamic behavior of the thermocline to the epilimnion. Moreover, the increased heat storage is beneficial for the growth and development of certain phytoplankton, resulting in rapid transitions of the original steady state of lakes. Consequently, water quality deterioration, ecological degradation, and declining biodiversity may occur. Conventional surface water monitoring may not provide comprehensive, accurate, and timely assessments. Model simulations can better predict future thermal stratification behaviors, reducing financial burdens, providing more refined assessments, and thus preventing subsequent environmental issues.

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DOM stratification and characteristics versus thermal stratification – A case study in the Panjiakou Reservoir, China

Cited by 6 publications

References 55 publications

Diel and seasonal mixing patterns and water quality dynamics in a multipurpose tropical semiarid reservoir

Diel and seasonal mixing patterns and water quality dynamics in a multipurpose tropical semiarid reservoir

Understanding the Water Quality Dynamics in a Large Tropical Reservoir Under Hydrological Drought Conditions

Challenge to Lake Ecosystems: Changes in Thermal Structure Triggered by Climate Change

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