A single semi-analytical algorithm to retrieve chlorophyll-a concentration in oligo-to-hypereutrophic waters of a tropical reservoir cascade

Though biological and ecological characteristics of Scopimera globosa have been intensively investigated, little has been understood on bioturbation, especially sediment reworking. This study was designed to evaluate variation on sediment reworking of S. globosa based on feeding pellet production (FP) and burrowing pellet production (BP) with influencing factors and estimating the chlorophyll content reduction within the surface sediment by its feeding. The FP and BP largely fluctuated according to chlorophyll a concentration and crab density, but both were not influenced by temperature. The FP was enhanced by chlorophyll a concentration, whereas both FP and BP were restricted by crab density. The daily individual production was highest in spring, followed by fall and summer, with values of 25.61, 20.70 and 3.90 g ind.−1 d−1, respectively, while the total daily production was highest in fall, followed by summer and spring 2150, 1660 and 660 g m−2 d−1, respectively. The daily sediment reworking based on the FP and BP of Scopimera was highest in fall, followed by summer and spring, with values of 1.91, 1.70 and 0.77 mm d-1 and the annual sediment reworking rate of this species was calculated 40 cm year−1 based on its density in this study area. The chlorophyll a reduction ratio was estimated from 11 to 24% in one day by its feeding. These results imply that the sediment reworking of S. globosa is regulated by food abundance and its density, and Scopimera is an important bioturbator, greatly influencing biogeochemical changes in the intertidal sediments.

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

A novel multi-source data fusion method based on Bayesian inference for accurate estimation of chlorophyll-a concentration over eutrophic lakes

Environmental Modelling & Software ◽

10.1016/j.envsoft.2021.105057 ◽

2021 ◽

pp. 105057

Author(s):

Cheng Chen ◽

Qiuwen Chen ◽

Gang Li ◽

Mengnan He ◽

Jianwei Dong ◽

...

Keyword(s):

Bayesian Inference ◽

Data Fusion ◽

Chlorophyll A ◽

Accurate Estimation ◽

Fusion Method ◽

Eutrophic Lakes ◽

Chlorophyll A Concentration ◽

Source Data

Download Full-text