Shellfish and algae mariculture make up an important part of the marine fishery carbon sink. Carbon sink research is necessary to ensure China achieves its goal of carbon neutrality. This study used the material quality assessment method to estimate the carbon sink capacity of shellfish and algae. Product value, carbon storage value, and oxygen release value were used to calculate the economic value of shellfish and algae carbon sequestration. The results showed that the annual average shellfish and algae carbon sink in China was 1.10 million tons from 2003 to 2019, of which shellfish accounted for 91.63%, wherein Crassostreagigas, Ruditapesphilippinarum, and Chlamysfarreri were the main contributors. The annual average economic value of China’s shellfish and algae carbon sequestration was USD 71,303.56 million, and the product value was the main contributor, accounting for 99.11%. The carbon sink conversion ratios of shellfish and algae were 8.37% and 5.20%, respectively, thus making shellfish the aquaculture species with the strongest carbon sink capacity and the greatest carbon sink potential. The estimated growth rate in the shellfish and algae removable carbon sink was 33,900 tons/year in China, but this trend was uncertain. The capacity for carbon sequestration and exchange by aquaculture can be improved by expanding breeding space, promoting multi-level comprehensive breeding modes, and marine artificial upwelling projects.

The blue carbon ecosystem has a strong capacity for carbon sequestration, but its research progress and development are still unclear. This study used CiteSpace to conduct a visual analysis, based on the analysis of 908 articles retrieved from the Web of Science Core Collection. The results showed that blue carbon research has gone through an early exploratory stage based on the scientific concept research, a research stage on the carbon sequestration process of the diverse blue carbon ecosystems, and a blue carbon protection and restoration stage based on climate change and human activities. The blue carbon theoretical framework has been continuously improved and the subject is currently more focused. The hot research topics are different at different stages. In the early stage, they focused on the types of blue carbon ecosystems and the process of carbon sequestration. Blue carbon research has developed from a single ecosystem type to multiple ecosystem types, and from concept recognition to system assessment research. Recently, research on the response, restoration and protection of blue carbon ecosystems has become a hotspot under the combined effect of human activities and climate change. In the future, it is necessary to strengthen the scientific research on blue carbon, to protect the integrity of the ecosystem structure and service functions, and to make a greater contribution to the global carbon neutrality strategy.

With the development of cities, urban area source pollution has become more severe and a significant source of water pollution. To study the relationship between urban area source pollution and water environmental quality in a river network, this study uses a city in the Yangtze River Delta, China, as an example. The Storm Water Management Model (SWMM) model and the MIKE11 model were combined into a unified modeling framework and used to simulate dynamic changes in the water quality of a river network under light rain, moderate rain, and heavy rain. In the study period, the annual urban area source input loads of potassium permanganate (COD_Mn), total phosphorus (TP), and ammonia nitrogen were 29.8, 0.9, and 4.8 t, respectively. The influence of light rain on the water quality of the river network was lagging and temporary, and rainfall area pollution was the primary contributor. Under the scenario of moderate rain, overflow from a pipeline network compounded rainfall runoff, resulting in a longer duration of impact on the water quality in the river. Additionally, the water quality in the river course was worse under moderate rain than under light or heavy rain. Under the scenario of heavy rain, rain mainly served a dilutive function. This research can provide support for urban area source pollution control and management.

In recent years, there have been frequent water pollution emergencies, which seriously threaten the environment of water supply sources and affect the safety and quality of the water supply. These emergencies have aroused concern from the public and the government and highlight the necessity of plans for the emergency treatment of the affected water sources. In this paper, a sudden pollution of a river drinking water source is used as the research object. A mathematical simulation method was used to investigate the water quality near and downstream of a wharf in the state of a sudden oil spill. The wharf is located 1.34 km upstream of the water intake position of this river water source. Based on our investigation, we have established a risk assessment method for an oil spill emergency pollution event. Our aim was to provide a basis for the assessment of the water intake quality and water safety status of a river-based water plant and to provide technical support for developing an effective treatment plan in the event of a sudden environmental pollution accident.

This study aimed to examine the pollution characteristics of rainfall runoff as well as the runoff scouring effect and pollution traceability in adjacent new and old urban areas. The sampling and monitoring of rainfall runoff for different rainfall underlying surfaces were conducted for roads, green spaces, roofs, and a food market. The concentration of chemical oxygen demand (COD) and nutrients in the rainfall runoff of the market area was higher than that measured for roads, green spaces, and roofs. The initial scouring effect of each underlying surface was obvious during rainstorms, and 30% of the runoff transported nearly 50% of the pollutants. Further, 30% of the runoff transported about 30% of the pollutants under moderate and heavy rain conditions, and the overall initial scouring effect was not obvious. The results of this study showed that, as a considered underlying surface area, the market and possibly other similar service facilities had a significant impact on the calculation of runoff pollution load, and these should be included in the research scope of rainfall runoff and the impact of underlying surfaces. The purpose of this study was to provide reliable and practical information for water pollution prevention and control, especially for pollution prevention and control of rainfall runoff in areas where new and old urban parts of cities exist side by side.

Dissolved organic matter (DOM) is a central component in the biogeochemical cycles of marine and terrestrial carbon pools, and its structural features greatly impact the function and behavior of ecosystems. In this study, the Wanggang River, which is a seagoing river that passes through Yancheng City, was selected as the research object. Three-dimensional (3D) fluorescence spectral data and UV–visible spectral data were used for component identification and source analysis of DOM based on the PARAFAC model. The results showed that the DOM content of the Wanggang River during the dry season was significantly higher than during the wet season; the DOM content increased gradually from the upper to lower reaches; the proportion of terrigenous components was higher during the wet season than during the dry. UV–Vis spectral data a₂₈₀ and a₃₅₅ indicated that the relative concentrations of protein-like components in the DOM of the Wanggang River were higher than those of humic-like components, and the ratio of aromatic substances in the DOM of the Wanggang River water was higher during the wet season. The DOM in the Wanggang River was dominated by protein-like components (>60%), and the protein-like components were dominated by tryptophan proteins (>40%). This study showed that the temporal and spatial distributions of DOM in rivers can be accurately determined using 3D fluorescence spectroscopy combined with the PARAFAC model. This provides useful insight into the biogeochemical process of DOM in rivers of coastal areas.