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The equivalent propagation method adopts a variable propagation velocity in lightning location, minimizing the location error caused by various factors in the long-range lightning location network. To verify the feasibility of this method, we establish a long-range lightning location network in China. A new method is used to extract the ground wave peak points of the lightning sferics and is combined with the equivalent propagation velocity method for lightning location. By comparing with the lightning data detected by the lightning locating system called advanced direction and time-of-arrival detecting (ADTD) that has been widely used for tens of years in China, the feasibility of this method is initially verified. Additionally, it is found that the relative detection efficiency of our long-range lightning location network can reach 53%, the average location error is 9.17 km, and the detection range can reach more than 3000 km. The equivalent propagation method can improve the average location accuracy by ~1.16 km, compared with the assumed light speed of lightning-radiated sferic from the lightning stroke point to the observation station. The 50th percentile of the equal propagation velocity is 0.998c, which may be used in the long-range lightning location networks. [ABSTRACT FROM AUTHOR]

It is generally considered that the main carbon sequestration capacity of seagrass beds depends on the burial of organic matter in anaerobic sediments, and plants in aerobic conditions contribute little to carbon sequestration due to decomposition. However, the role of phytolith-occluded carbon (PhytOC) in eelgrass to protect against aerobic degradation shows a long term mechanisms of carbon stabilization that is poorly understood. Eelgrass is a silicon-rich plant, and plants with a high silicon content generally contain phytoliths that occlude carbon. Thus, it is speculated that eelgrass contains phytoliths and sequesters carbon through PhytOC. To confirm this inference, eelgrass in Swan Lake, Yangjia Bay and Shuangdao Bay, China, was investigated. The solids extracted from eelgrass did not discolor when they were exposed to iodine, and their morphology was similar to the phytoliths of land plants. Thus, these solids were phytoliths rather than starch grains. The phytolith morphology varied with eelgrass habitat and plant part, but it was mainly irregular. The sequestrated carbon stock of eelgrass plants through PhytOC in Shuangdao Bay in March, June and November were 87.30, 252.70 and 36.09 mg/m2, respectively. Thus, PhytOC is a potentially important and unrealized form of carbon sequestration in eelgrass beds. • Contrary to previous thinking, eelgrass contains phytoliths. • The main type of phytolith in eelgrass is irregular. • Carbon sequestration of eelgrass plants through PhytOC is important. [ABSTRACT FROM AUTHOR]

Nutrient pollution intensifies the strain on coastal ecosystems globally. Despite wetlands' significant nutrient removal potential, process-based assessments of nutrient removal in large-scale coastal wetlands face limitations that hinder accurate quantification of water quality improvements. This study proposes a novel quantitative approach by developing a coupled hydrodynamic-water quality-wetland biogeochemical model. The spatio-temporal distributions of water-sediment-vegetation nutrients in a coastal wetland and bay were simulated over an annual cycle, with model parameters and results calibrated and validated through field investigations and laboratory experiments. The findings show distinct spatio-temporal characteristics of nutrient pollutant reduction in coastal wetlands. In the Liaohe estuarine tidal wetland, a large-scale coastal wetland in China, nitrogen and phosphorus reduction fluxes reached 1184 t·yr -1 and 53 t·yr -1 , accounting for 19 % and 12 % of the river's fluxes to the sea, respectively. These results underscore the critical function of coastal wetlands in mitigating coastal nutrient pollution. This study presents a novel framework for quantifying coastal water quality improvements by wetlands on a larger scale., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Human activities have intensified the global challenge of coastal eutrophication. Recently, water resource managers have encountered difficulties in formulating precise pollutant reduction strategies to mitigate coastal eutrophication. Despite the recognized importance of coastal wetlands and pollution sources in influencing coastal nutrient levels, accurately quantifying their impact remains difficult. To address this challenge, this study introduces a novel approach for optimizing water environmental capacity. A coupled model integrating hydrodynamics, water quality, and wetland nutrient mechanisms was developed to simulate the spatio-seasonal distribution of water, sediment, and vegetation nutrients in a semi-enclosed bay (Liaodong Bay, China) and a large-scale coastal wetland (Liaohe estuary wetland, China). Model parameters and simulation results were calibrated and validated using extensive long-term field investigations and laboratory experiments. The average root mean square errors between simulated and observed values for all validation points were as follows: 0.80 mg L -1 , 0.53 mg L -1 , 0.08 mg L -1 , 6.70 μg L -1 , and 0.50 μg L -1 for dissolved oxygen, chemical oxygen demand, dissolved inorganic nitrogen, dissolved inorganic phosphorus, and chlorophyll-a, respectively. The total nitrogen (TN) and total phosphorus (TP) in the sediment were 0.10 g kg -1 and 0.05 g kg -1 , respectively. For Suaeda salsa, the TN and TP were 2.91 g kg -1 and 0.08 g kg -1 , respectively. For Phragmites australis, the TN and TP were 114.22 g kg -1 and 6.21 g kg -1 , respectively. The results suggest that excessive river discharge and a stable residual circulation structure contribute to the persistent eutrophication in Liaodong Bay. The Liaohe estuary wetland enhances the environmental capacity of dissolved inorganic nitrogen and dissolved inorganic phosphorus in Liaodong Bay to 271 ± 31 t yr -1 and 8 ± 1 t yr -1 , respectively, accounting for 1.8 ± 0.2% and 1.3 ± 0.2% of their respective environmental capacities. The reduction in dissolved inorganic nitrogen concentration is significant, with a maximum decrease of 0.17 mg L -1 . The maximum contributions of atmospheric deposition and aquaculture wastewater to dissolved inorganic nitrogen concentration are 0.08 mg L -1 and 0.03 mg L -1 , respectively, with higher contributions in spring and summer than in fall and winter. These findings highlight the critical role of coastal wetlands in mitigating eutrophication and underscore the need for spatio-seasonal water management programs. This work serves as a model for effectively reducing global coastal pollution emissions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)