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Pesticide residues from watersheds are increasingly exported into seawater, negatively impacting marine ecosystem health. However, existing watershed and flux models for pesticides are limited and insufficient. This study developed a Pesticides Export from Watersheds to Sea (PEWS) model to assess the transport processes of four common pesticides-atrazine, nicosulfuron, chlorpyrifos, and imidacloprid-in Laizhou Bay, China. The model was calibrated and analyzed using field surveys and geographic information system (GIS) data to evaluate the spatiotemporal distribution of pesticide fluxes within the watershed. The results indicated a decreasing trend in pesticide flux into Laizhou Bay from 2001 to 2023, with annual fluxes in 2023 recorded as 11.5 × 10, 0.1 × 10, 0.01 × 10, and 0.6 × 10 kg/yr for atrazine, nicosulfuron, chlorpyrifos, and imidacloprid in 2023, respectively. The seasonal pattern followed an inverted U-shape, with fluxes peaking in summer and declining in winter. Spatially, pesticide fluxes were highest in agricultural areas, with atrazine and nicosulfuron fluxes peaking in the downstream regions of the Xiaoqing River watershed, imidacloprid fluxes highest in the Mi and Bailang Rivers, and chlorpyrifos fluxes more prominent in the upstream regions of the Weihe River. The study further revealed that less than 3 % of the total pesticide load was exported into the sea, while 1 %-4 % was absorbed by crops, and over 90 % remained trapped in soil and river systems. The PEWS model couples Global NEWS and SWAT frameworks to simulate watershed-scale pesticide export. By quantifying pesticide export fluxes from watersheds to the sea, this study contributes to the development of effective strategies for controlling pesticide pollution.
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http://dx.doi.org/10.1016/j.marpolbul.2025.118576 | DOI Listing |
Mar Environ Res
September 2025
CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.
Zooplankton are sensitive indicators of environmental changes and crucial components of marine food webs, facilitating energy transfer between primary producers and higher trophic levels. This study used ZooScan image analysis to investigate variations in zooplankton abundance and biovolume in Shandong coastal waters during spring (May 2022), summer (August 2022), and winter (December 2022 and February 2023). Functional indices such as taxonomic diversity, the normalized biomass size spectrum (NBSS), size diversity, and mean body size were calculated to describe the seasonal dynamics of energy transfer efficiency in zooplankton.
View Article and Find Full Text PDFWater Res
August 2025
School of Marine Science and Technology, Tianjin University, Tianjin 300072, China. Electronic address:
Microplastic pollution has become a global environmental problem, posing a potential threat to ecosystems and human health. Traditionally, microplastic monitoring has relied on spectral methods, which have significant limitations in terms of cost and time efficiency. To achieve low cost, rapid and large-scale detection, remote sensing technology has been applied to microplastic monitoring, but its accuracy needs to be improved.
View Article and Find Full Text PDFFront Microbiol
August 2025
School of Ocean, Yantai University, Yantai, China.
is a key picocyanobacterium in coastal ecosystems, yet its seasonal bloom dynamics and environmental responses remain unclear in temperate coastal seas. Here, we integrated flow cytometry and gene analysis to investigate its bloom development and community succession in Laizhou Bay, based on 3 years of 10 seasonal surveys and a year-long monthly observation at a fixed station. blooms reached their peak in summer (up to 10 cells mL), particularly in the southern part of the bay, with high abundances in autumn as well.
View Article and Find Full Text PDFInt J Syst Evol Microbiol
August 2025
School of Ocean, Yantai University, Yantai, 264005, PR China.
Coral reefs are experiencing significant degradation, largely driven by rising seawater temperatures. The bacterial communities within coral holobionts play crucial roles that support coral reef conservation and restoration, offering potential solutions to mitigate the impacts of environmental stressors. A Gram-negative bacterium, designated strain D0M16, was isolated from seawater surrounding coral in Daya Bay, Shenzhen, Guangdong Province, China.
View Article and Find Full Text PDFMar Pollut Bull
August 2025
Key Laboratory of Marine Chemistry Theory and Technology, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ministry of Education, Ocean University of China, Qingdao 266100, China; College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China; L
Pesticide residues from watersheds are increasingly exported into seawater, negatively impacting marine ecosystem health. However, existing watershed and flux models for pesticides are limited and insufficient. This study developed a Pesticides Export from Watersheds to Sea (PEWS) model to assess the transport processes of four common pesticides-atrazine, nicosulfuron, chlorpyrifos, and imidacloprid-in Laizhou Bay, China.
View Article and Find Full Text PDF