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Approximately 80% of marine plastic waste originates from land-based sources and enters oceans through rivers. Hence, to create effective regulations, it is crucial to thoroughly examine the processes by which land-based plastic waste flows into marine environments. To this end, this review covers the complete journey of macro- and microplastics from their initial input into rivers to their ultimate release into oceans. Here, we also discuss the primary influencing factors and current popular research topics. Additionally, the principles, applicability, accuracy, uncertainty, and potential improvement of the standard methods used for flux estimation at each stage are outlined. Emission estimates of land-based macro- and microplastics are typically assessed using the emission factor approach, coefficient accounting approach, or material flow analysis. Accurately estimating mismanaged plastic waste is crucial for reducing uncertainty in the macroplastic emission inventory. In our review of the processes by which land-originating plastics enter rivers, we categorized them into two major types: point-source and diffuse-source pollution. Land surface hydrological models simulate transport from diffuse sources to rivers, necessitating further research. Riverine (micro)plastic flux to the ocean is often estimated using monitoring statistics and watershed hydrological models at the watershed scale; however, standardized monitoring methods have not yet been established. At the global scale, algorithms based on river datasets are often used, which require further improvements in river data selection and microplastic number-mass conversion factors. Furthermore, the article summarizes the accuracy and sources of uncertainty of various methods. Future research efforts should focus on quantifying and mitigating uncertainties in resultant projections. Overall, this review deepens our understanding of the processes by which land-based plastic waste enters the ocean and helps scholars efficiently select or improve relevant methods when studying land-ocean transport fluxes. [Display omitted] • The complete journey of plastics from their emission into rivers to their release into the ocean is summarized in this review. • Reasonably estimating mismanaged waste is critical when quantifying macroplastic emissions. • Hydrological models can simulate diffuse source-to-river transport and require further research. • Riverine flux measurements into oceans urgently require standardization. [ABSTRACT FROM AUTHOR]

The Yangtze River is an important global channel for plastics and microplastics (MPs) to enter the sea. However, the existing research on MPs in the Yangtze River has primarily focused on the mainstream region, without regarding the occurrence, spatial distribution, and ecological risks associated with tributaries, as well as their relationship with the mainstream. To address this knowledge gap, we conducted a large-scale catchment-wide investigation of the surface water in the Yangtze River, encompassing MPs (48 µm–5 mm) of the mainstream and 15 important tributaries. Tributaries and upstream regions exhibited relatively higher levels of MPs compared with the mainstream and different sections of the river. The distribution of MPs is primarily influenced by the emission of arable land and the pH of water. Notably, the upstream tributary areas demonstrated the highest ecological risks associated with MPs. Further analysis highlighted that the tributaries accounted for a contribution ranging from 16% to 67% in quantity and from 14% to 90% in mass of the microplastics observed in the mainstream. Our results suggest that the pollution of tributaries and their associated ecological risk migration must be effectively regulated. [Display omitted] • MPs abundance in tributaries was relatively higher than that in the mainstream. • The emission of arable land and the pH of water affected MP distribution. • The ecological risk of upstream tributaries was the highest. • Tributaries contributed approximately 35% of MPs of the mainstream on average. • The flux of MPs at different nodes should be monitored based on risk. [ABSTRACT FROM AUTHOR]

Accelerated Arctic warming has raised concerns about future environmental conditions in the Bering Sea, one of the world's most productive marine ecosystems. Marine Isotope Stage (MIS) 11 (424–374 ka), a period with orbital parameters similar to those of the current interglacial (Holocene), is thought to be a suitable analog to predict future marine environments. Here, we reconstruct paleoredox changes in the Bering Sea over the last 800 kyr using high-resolution U/Th ratios from four sites, which were sampled by the Integrated Ocean Drilling Program (IODP) Expedition 323. During the early stages of MIS 11 (MIS11c), four IODP Expedition 323 sites (U1339, U1340, U1343, and U1345) with different water depths (1100–1900 m) had highly elevated U/Th ratios, indicating a substantial loss of dissolved oxygen (O 2) in the intermediate waters of the Bering Sea. High U/Th ratios were closely associated with extremely high %biogenic opal in the Bering Sea and an exceptionally warm Arctic climate. We speculate that during this period, the highest amplitude deglacial warming led to the onset of a super interglacial (MIS 11c) in the Arctic regions, via Arctic amplification. The exceptionally warm Arctic climate resulted in particularly high export productivity in the Bering Sea via physiological effects, a reduction in sea ice, and increased river discharge. Due to high productivity, increased organic matter degradation caused severe hypoxia in the intermediate waters of the Bering Sea. Our study shows that severe hypoxia may also appear in the Bering Sea if Arctic warming accelerates in the future. • Higher U/Th ratios suggest severe hypoxia in the Bering Sea in MIS 11c. • A very warm Arctic resulted in high productivity, which led to severe hypoxia. • Future warming of the Arctic may stimulate higher productivity and severe hypoxia. [ABSTRACT FROM AUTHOR]

Understanding past changes in oceanic circulation and the corresponding heat, salt delivery variations are essential for assessing the climatic roles of ocean dynamic processes since the last glacial period. Unravelling salinity budget variation in the North Pacific and its controls is important to better understand the North Pacific Intermediate/Deep Water formation and associated climate impacts. The Tsushima Warm Current (TWC), the northernmost Kuroshio branch entering the semi-closed Japan Sea through the shallow strait, is regarded as a fundamental component for oceanographic changes in the Japan Sea. To obtain a comprehensive history of the Japan Sea salinity budget, this study reconstructed the evolution history of the TWC inflow by compiling paleo-hydrographic records in the Japan Sea. Following a persistent but weakened TWC inflow during Marine Isotope Stage 3, radiolarian assemblage data revealed that the TWC taxa disappeared since ∼30 thousand years ago (ka). The synchronous onset of the low salinity anomaly event was in response to the cutoff of saline TWC inflow due to the rapid fall in global sea level at 30 ka. Extreme restriction of seawater exchange caused a persistent freshening of the glacial Japan Sea and formed a low-salinity water mass in the upper ocean. The compiled paleodata confirmed that the Japan Sea accumulated excess freshwater during the glacial sea-level lowstands and the low-salinity pool extended downward to ∼900 m depths. Coinciding with the peak of the low salinity anomaly event, re-emerging TWC inflow after 19 ka reflected the reconnection of the open ocean to the Japan Sea. The persistent TWC inflow mainly drove the reduction in magnitude of the deep low-salinity pool during the last deglaciation. As a large and isolated freshwater sink for the glacial North Pacific, the deep low-salinity pool evolution could potentially have strong impacts on the North Pacific salinity budget and subsequent large-scale circulation. • Radiolarian reconstruction indicates a persistent but weakened influence of the TWC inflow in the Japan Sea during MIS 3. • The low-salinity pool extended downward to ∼900 m depths in the Japan Sea during the LGM. • The link between global sea-level change and deep low-salinity pool evolution is sought. [ABSTRACT FROM AUTHOR]

The Okhotsk Sea, located between the Asian continent and the western Pacific, is a natural laboratory for investigating sediments source-to-sink influenced by atmosphere–ocean–land–sea ice interactions. However, despite their paleoenvironmental significance, changes in sediment provenance within the Okhotsk Sea are still debated due to the diversity of sediment sources and transport processes. Here, we investigate Sr and Nd isotope compositions in surface sediment samples from regions across the Okhotsk Sea, as well as Sr and Nd isotope compositions and elemental abundances in the sediments of core LV55‐40-1, collected from the southwestern Okhotsk Sea. Our results reveal an increasing trend of εNd values over the past ∼110 kyr, with an abrupt increase during the transition into the last deglacial/early Holocene (MIS 1). We also observed minor variations characterized by less radiogenic εNd during the glacial/stadial (G/S) periods (MIS 5d, MIS 5b, MIS 4, MIS 2), and more radiogenic εNd during the interglacial/interstadial (I/I) periods (MIS 5c, MIS 5a, MIS 3). The major terrigenous sediment sources in the northwestern Okhotsk Sea are via the Amur River and from Sakhalin Island (∼60–80%), with a minor volcanic contribution (∼20–40%) from the Okhotsk-Chukotka volcanic belt and the southern Kuril Islands/Hokkaido. Provenance variations are primarily controlled by the interplay of sea-ice drifting and ocean circulation, reflecting a dominant transport mode shift from sea ice to surface current dominance since the early Holocene. During the G/S periods with severe sea-ice condition, terrigenous materials from the Amur River and Sakhalin Island were transported to the study site, due to the southeastward drift of sea ice driven by the prevailing northwesterly winds and enhanced Okhotsk Sea Intermediate Water circulation. In contrast, during the I/I periods with moderate sea-ice conditions, an increased contribution from the Okhotsk-Chukotka volcanic belt was caused by sea-ice drifting southwestwards under the prevailing northerly and northeasterly winds, supplemented by surface currents. This study provides the first Sr-Nd isotopes record spanning the last glacial cycle in the Okhotsk Sea and it offers new insights into the relationship between sediment provenance and the interplay of sea ice and ocean currents in this region. • First record of Sr-Nd isotopes in the Okhotsk Sea over the last glacial cycle. • The Amur River and Sakhalin Island were primary sediments sources in this region. • Volcanic materials increased during the interglacial/interstadial periods. • Shift of sediments provenance was driven by sea-ice drifting and ocean currents. [ABSTRACT FROM AUTHOR]

Long-term organic matter (OM) burial in the ocean is essential to the global carbon cycle. Mud deposits, such as South Yellow Sea mud deposit (SYSMD) located in the central South Yellow Sea (SYS), are ideal for the study of long-term OM burial. A sediment core YS-A from the SYSMD was analyzed for lignin phenols and bulk OM properties to reveal the driving forces of sedimentary OM (SOM) fate during the Holocene. SOM burial was found to be dominantly influenced by sea level rise and increased East Asian summer monsoon during 11.0–7.0 ka BP. During 7.0–1.0 ka BP, the fate of SOM was controlled by El Niño Southern Oscillation on the millennial time scale, and correlated with East Asian winter monsoon variability on the centennial time scale. Remarkably, anthropogenic perturbation has gradually overwhelmed long-term climate control on the fate of SOM since 1.0 ka BP, and this phenomenon became more evident after 0.4 ka BP. • Sea level and East Asian summer monsoon controlled sedimentary organic matter (SOM) burial during 11.0–7.0 ka BP. • Climatic controlled on the fate of SOM during 7.0–1.0 ka BP. • Anthropogenic perturbation has gradually overwhelmed long-term climate control on the fate of SOM since 1.0 ka BP. [ABSTRACT FROM AUTHOR]

Regional-scale Holocene sea-level reconstruction is the key to understanding natural climatic variability. The tidal flat, salt marsh, and tidal floodplain in the Yangtze River Delta were very sensitive to morphological changes and sea-level variation during the early Holocene. In this study, the lithology, radiocarbon ages, sediment grain size, benthic foraminifera, and ostracods of three new cores were analyzed. Twenty-four sea-level index points were extracted from incised-valley fills beneath the westernmost part of the Yangtze River Delta and used to construct a detailed relative sea-level curve for 11.03–7.25 ka. The relative sea level were − 38.90 ± 3.48 and 1.59 ± 3.28 m at 11.03 and 7.25 ka, respectively, and the average rate of sea-level rise was 10.71 mm/yr. The relative sea level gradually increased at 11.03–10.10 and 9.29–8.33 ka from 4.80 to 13.30 and 3.19 to 19.59 mm/yr, respectively. The rate of relative sea-level rise gradually decreased from 19.59 mm/yr at 8.33 ka to 13.40 mm/yr at 7.82 ka and further decreased to 5.53 mm/yr at 7.25 ka. The Yangtze River Delta recorded accelerations in the rate of sea-level rise from 8.72 to 8.18 ka of 14.2–19.59 mm/yr, corresponding to the pre-8.2 ka event. A comparison of the sea-level histories of the Yangtze River Delta and other regions indicates tectonics, glacial isostatic adjustment, and coastal levering effects caused by the marine inundation of the continental shelves. These new sea-level data contribute to the understanding of the difference in the sea-level rise rate during the early–mid Holocene. • New and high-quality sea-level index points of the early and middle Holocene are produced for the Yangtze delta • The sea-level was -38.90 ± 3.45 m at 11.03 ka and 1.59 ± 3.28 m at 7.25 ka, the average rate of sea-level rise was 10.71 mm/yr. • The Yangtze Delta recorded accelerations in rate of sea-level rise in 8.72–8.18 ka, correspond to the pre-8.2 ka-event. [ABSTRACT FROM AUTHOR]

Autotrophic carbon-fixing bacteria affect carbon sequestration in coastal wetland systems. However, it remains uncertain how carbon-fixing bacterial communities and their carbon-fixing genes play crucial roles in soil carbon fixation and respond to plant community change. Here, we explored changes in soil properties, carbon-fixing genes, and bacterial community structure associated with 5-year-old Spartina alterniflora (SA5), 15-year-old SA (SA15), 21-year-old SA (SA21), and native plants Suaeda salsa (SS) and Phragmites australis (PA) compared to in bare flat (BF) at three soil layers (0–10, 10–30, and 30–60 cm) in coastal salt marsh wetlands. The soil organic carbon (SOC) content, absolute abundance of carbon-fixing genes (cbbM and cbbL), and relative abundance of dominant carbon-fixing genera in all soil layers significantly differed among plant communities (P < 0.05). The effect of plant community on these factors was more pronounced than that of soil depth. The SOC content peaked in SA15 soil. The absolute abundance of cbbM and cbbL was significantly higher in plant soil than in BF soil (P < 0.05). The dominant bacterial genus with carbon-fixing genes in BF, SA5, and SA15 soils was Sulfurovum , in SA21 soil was Bacillus , and in SS and PA soils was Thioalkalispira. Salinity was the key driver affecting the community structure of carbon-fixing bacteria. The soil physicochemical properties of coastal salt marsh wetlands changed with the plant community and soil depth, resulting in shifts in the carbon-fixing bacterial communities. Our findings suggest that plant community change can strongly influence carbon-fixing bacterial communities and highlight the importance of microbial carbon fixation in soil carbon accumulation in coastal salt marsh wetlands. • Soil organic carbon content peaked in the 15-year-old Spartina alterniflora soil. • Plant community change strongly affects carbon-fixing bacteria. • Salinity was the key driver of the carbon-fixing bacterial community structure. [ABSTRACT FROM AUTHOR]

• Microplastics (MPs) with co-existing pollutant solutions increase toxicity to fish. • MPs elevate negative effects on immune system, metabolism, and oxidative damage. • Toxicity changes are related to fish life stage and MP size. • Toxicity changes are not related to logKow, exposure time, pollutant or MP type. • Current laboratory studies have certain limitations. Aquatic ecosystems are among the main destination for microplastics (MPs) in the environment. MPs that enter aquatic ecosystems can contribute to pollution together with other co-existing pollutants. However, whether such pollution results in higher or lower toxicity to fish than that caused by co-existing pollutants alone remains controversial. This study aimed at closing this research gap based on 1380 biological endpoints under the background of environmental MP concentrations collected from 55 laboratory studies. Overall, MPs in co-existing pollutant solutions significantly increased the toxicity to fish. Specifically, MPs elevated negative effects on the immune system, metabolism, and oxidative damage. Subgroup analysis indicated that changes in toxicity were related to fish life stage and MP size, but not to co-existing pollutant or MP type. Meta-regression analysis indicated that changes in toxicity were not related to the logarithm of the octanol–water partition coefficient (logKow) or exposure time. Finally, the differences between laboratory research and the actual aquatic environment were discussed from four aspects: MPs, co-existing pollutants, environmental factors, and experimental objects. Our study provides a basis for further understanding the potential impact of MPs on aquatic organisms from a combined pollution perspective. Moreover, our results can provide a reference for the conservation and management of aquatic ecosystems. [Display omitted] [ABSTRACT FROM AUTHOR]

Reconstructing Holocene changes in regional sea level is useful for understanding future sea-level scenarios. In this paper we examined the sedimentology, pollen, foraminifera, and organic matter properties of a well-dated profile from the Subei Basin that spans the last 6.7 ka. By integrating our findings with the archaeological record, we investigated mid- to late Holocene vegetation responses to relative sea-level fluctuations and considered the impact of climatic variations on cultural development. In the middle Holocene, the rapid and abrupt expansion of salt marsh vegetation (Chenopodiaceae, Cyperaceae, and Poaceae) suggests a relative rise in sea level. From 5.7 to 4.2 cal ka BP, lowland swamps were settled by Neolithic communities, as indicated by peak levels of microscopic charcoal and a significant rise in herbaceous pollen species, such as Cyperaceae, Typha , Myriophyllum , and Poaceae. From 4.2 to 3.7 cal ka BP, a major increase in Chenopodiaceae abundance and a δ13C excursion were observed along with a decrease in Cyperaceae and Poaceae levels, which revealed that human activity significantly decreased following the 4.2 ka climate event. Evidence suggests that the area under investigation experienced a relatively high sea level between 6.7 and 6.0 ka, a relative decrease in sea level between 6.0 and 5.7 ka, a steady sea-level condition between 5.7 and 4.2 ka, and gradual replacement by a freshwater marsh between 5.7 and 4.2 ka. The pollen and δ13 C records demonstrate that the relative sea level rose quickly from 4.2 to 3.7 ka, which could correspond to the 4.2 ka event. Enhanced El Niño-Southern Oscillation (ENSO) variance and intense climatic events in eastern China were the driving forces behind the mid-late Holocene relative sea-level shift. The rise in relative sea level eventually led to the collapse of the Qingdun and Jiangzhuang sites in the Subei Basin. Our results provide independent vegetation evidence of the simultaneous changes in relative sea level and variations in climate. • Vegatation and environment changes are investigated from ∼6700 cal a BP. • The significant relative sea-level rise in the Subei Plain during 4.2–3.7 cal ka BP. • The rise in relative sea level led to the collapse of the Qingdun site and Jiangzhuang site in the Subei Basin. [ABSTRACT FROM AUTHOR]

Asian dust deposition in the northwestern Pacific is generally linked to high-latitude paleoclimate evolution during the Quaternary. However, whether low-latitude tropical Pacific processes, such as El Niño-Southern Oscillation (ENSO), influence Asian dust input into the northwestern Pacific remains uncertain. Here, we present clear periodic variations in potassium content (K (wt%)) and gamma-ray attenuation (GRA) bulk density, which are closely linked to the variations in Asian dust, in a sediment core recovered at Site U1438 in the Amami Sankaku Basin (ASB), northwestern Philippine Sea. Based on the shipboard age-depth model, we tuned the GRA to the mass accumulation rate curve on the Chinese Loess Plateau and the 8-kyr-lagged obliquity curve, and established the astronomical timescale. The K (wt%) content and GRA were higher during glacials and lower during interglacials, as driven by the variability in the Northern Hemisphere ice sheet (NHIS) during the Quaternary. In addition, strong long eccentricity 405-kyr cycles were observed in the dust records (K (wt%) content and GRA) during the early Pleistocene. The 405-kyr filter results showed that increased (decreased) Asian dust corresponded to the La Niña-like (El Niño-like) state, suggesting that Asian dust input into the northwestern Pacific was modulated by ENSO on 405-kyr cycles in the early Pleistocene. Our study illustrated the possible link between long eccentricity 405-kyr cycles in the Asian interior and low-latitude forcing, including potential modulation by ENSO. • K (wt%) and GRA from Site U1438 are related to input of Asian dust. • Dust signals were used to reconstruct the orbital chronological model. • Dust signals have clear 405-kyr cycles during the early Pleistocene. • Long eccentricity forcing Asian dust input into the northwestern Pacific. [ABSTRACT FROM AUTHOR]

The Japan Sea is ideal for investigating deep water formation due to its unique topography and hydrography. However, because of the scarcity of reliable indicator and high-resolution ventilation records, the driving mechanisms behind ventilation changes in the entire Japan Sea since the Last Glacial Maximum (LGM) remain elusive. In this study, we analyze the radiolarian assemblage in three sediment cores from the southwestern, central, and northwestern Japan Sea to reveal ventilation variations over the last 25 ka. Our results suggest that weak ventilation was a widespread phenomenon in the Japan Sea during the LGM. This is inferred by the low relative abundances of species belonging into the Japan Sea Proper Water (JSPW) Assemblage, which are indicative of deep water ventilation in the Japan Sea. The JSPW Assemblage have gradually become the predominant species in studied cores from the last deglaciation to the early Holocene, suggesting an abrupt transition from oxygen poorer to oxygen richer conditions. All investigated regions show re-ventilation during the deglaciation, albeit at different times. The JSPW ventilation in the central Japan Sea started during the 19 ka Melt-water Pulse (MWP) and remained in an interglacial mode after MWP-1A (~14.7 ka), presumably due to the opening of the Tsushima Strait and intrusion of the Tsushima Warm Current (TWC). An abrupt increase in productive shallow water export during the Bølling-Allerød (B/A) was likely the key factor causing poorly oxygenated deep-water conditions in the southwestern Japan Sea. In contrast, the weakening ventilation in the northwestern Japan Sea during the B/A and Younger Dryas was probably caused by the blocking effect of the sea ice. • New 25 ka-long radiolarian assemblage records along a meridional transect offer a comprehensive history of deep-water ventilation in the Japan Sea. • The JSPW ventilation underwent drastic changes from suboxic to oxic conditions during the last deglaciation. • The drastic changes in the deep ventilation in the Japan Sea were sensitive to eustatic sea-level. [ABSTRACT FROM AUTHOR]

High emissions of synthetic compounds are damaging the marine environment and threatening human health. This study represents the first extensive and comprehensive analysis of three typical persistent organic pollutants (POPs), i.e., organochlorine pesticides (n = 228), perfluoroalkyl substances (n = 202), and short-chain chlorinated paraffins (n = 162), using a highly resolved spatial dataset. The results revealed the complex distribution of POPs in the Eastern China Marginal Seas (ECMSs). POPs in the surface sediments of the ECMSs showed spatial heterogeneity, with high levels observed mainly in areas with fine-grained sediments (e.g., the Yellow River and Changjiang River estuaries and the central south Yellow Sea). Strong positive correlations were identified between POP concentration and sediment grain size/components/longitude/latitude in the ECMSs, suggesting that POP distribution was significantly influenced by river input and regional hydrodynamics. The annual deposition fluxes of POPs in the ECMSs were also calculated and high values were recorded in the Yellow River Estuary and East China Sea. Human-induced changes in the catchments could affect the fate of POPs in the ECMSs and other river-dominated marginal seas worldwide. Our findings highlight concerns regarding local aquaculture and provide a basis for government decision-making. We also suggest the need for increased attention to be paid to the effects of marine organic pollution on aquaculture on a global scale. ga1 • The distribution of POPs in the ECMSs have obvious spatial heterogeneity. • Terrestrial input and stable sedimentary environment determined high POPs level. • The influence of pollution center on aquaculture needs to be paid enough attention. • Costal oceans in the worldwide will undergo similar drastic threat. [ABSTRACT FROM AUTHOR]

Assessing modern radiolarian distribution in the marginal seas is essential for understanding its relationship to hydrographic and environmental variables, upon which subsequent interpretation of past radiolarian records can be made reliably. Here, we combine published radiolarian assemblages in 69 surface sediments from the Japan Sea with those obtained from 15 new surface sediments in this study to determine the modern distribution of radiolarians. The Tsushima Warm Current (TWC) taxa are only found in the south of the Subpolar Front. The results of redundancy analysis confirm that the temperature at 10 m depth (temperature 10m) is the main factor controlling the spatial variability of TWC taxa. The water depth plays a key role in affecting the abundances of Japan Sea Proper Water (JSPW) Assemblage including Larcopyle buetschlii Dreyer (adult), Cycladophora davisiana Ehrenberg, and Actinomma group. The JSPW Assemblage can be used as a reliable indicator of ventilation changes in the Japan Sea. Based on the newly developed TWC taxa and JSPW Assemblage, we further reconstructed the water column structure in the central Japan Sea over the past 25 ka. There was weak ventilation in the central Japan Sea even during the Last Glacial Maximum (LGM), although a distinct decrease in the TWC inflow resulted in surface-water freshening and water column stratification. After the LGM, the TWC taxa together with JSPW Assemblage resumed in the central Japan Sea at the 19 ka meltwater pulse (MWP). The MWP-1A was clearly marked by an enhanced intrusion of the TWC. Synchronously, JSPW was ventilated deeply down after ~14.6 ka attaining to the similar level of the Holocene as a result of changing sea surface conditions. Along with the continuing sea-level rise, the matured TWC entered the Japan Sea at 7 ka and since then the modern hydrographic condition has been established. We suggest that the changes in the sea level and TWC strength predominantly determined the surface hydrography and deep ventilation in the central Japan Sea since 25 ka, and the TWC might have notably affected the Japan Sea since the Bølling-Allerød. • Radiolarian distribution patterns in the surface sediments are correlated well with water column environmental variables. • The water structure of the Japan Sea since the last deglaciation is reconstructed based on radiolarian assemblages. • Inflow of the TWC into the central Japan Sea resumed at around 19 ka, earlier than previously thought. • The modern-like deep water ventilation in the central Japan Sea has been established during the B/A. [ABSTRACT FROM AUTHOR]

The microbial community colonized on microplastics (MPs), known as the 'plastisphere', has attracted extensive concern owing to its environmental implications. Coastal salt marshes, which are crucial ecological assets, are considered sinks for MPs. Despite their strong spatial heterogeneity, there is limited information on plastisphere across diverse environments in coastal salt marshes. Herein, a 1-year field experiment was conducted at three sites in the Yancheng salt marsh in China. This included two sites in the intertidal zone, bare flat (BF) and Spartina alterniflora vegetation area (SA), and one site in the supratidal zone, Phragmites australis vegetation area (PA). Petroleum-based MPs (polyethylene and expanded polystyrene) and bio-based MPs (polylactic acid and polybutylene succinate) were employed. The results revealed significant differences in bacterial community composition between the plastisphere and sediment at all three sites examined, and the species enriched in the plastisphere exhibited location-specific characteristics. Overall, the largest difference was observed at the SA site, whereas the smallest difference was observed at the BF site. Furthermore, the MP polymer types influenced the composition of the bacterial communities in the plastisphere, also exhibiting location-specific characteristics, with the most pronounced impact observed at the PA site and the least at the BF site. The polybutylene succinate plastisphere bacterial communities at the SA and PA sites were quite different from the plastispheres from the other three MP polymer types. Co-occurrence network analyses suggested that the bacterial community network in the BF plastisphere exhibited the highest complexity, whereas the network in the SA plastisphere showed relatively sparse interactions. Null model analyses underscored the predominant role of deterministic processes in shaping the assembly of plastisphere bacterial communities across all three sites, with a more pronounced influence observed in the intertidal zone than in the supratidal zone. This study enriches our understanding of the plastisphere in coastal salt marshes., 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.)

Pollution status and ecological risks associated with sediment heavy metals (Cu, Pb, Zn, Cd, and Cr) were investigated around Xincun Bay, assessing their spatial variations and relationship with sediment physiochemical factors. Higher concentrations and associated risks were observed in the central region, where mariculture activities were concentrated, compared to non-maricultured areas. Despite with overall low concentrations, Cd had a higher ecological risk. Correlation and principal component analyses revealed similar sources for all metals in Xincun Bay. Heavy metal concentrations varied with expansion of mariculture operations in terms of quantity and scale, confirming the influence of mariculture activities. Sediments around mariculture had higher contents of clay, silt, and total organic carbon (TOC), and finer particle sizes. Quantitative analyses through correlation and linear regression indicated that TOC significantly regulated heavy metal concentration and distribution (p < 0.05). Considering its significant association with TOC, the influence of mean grain size should not be overlooked., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2023. Published by Elsevier Ltd.)

Microplastic pollution on bathing beaches threatens the health of human beings and coastal organisms. There is a lack of assessment on the level of microplastic pollution and the health risk associated with plastics. As one of the earliest open bathing beaches in China, Liandao is well known as the two high-quality beaches. However, little is known about the extent of microplastic pollution on these bathing beaches. Based on the analysis of microplastic pollution abundance, distribution, shape, size, color, and composition at the Liandao bathing beaches, this study puts forward a novel approach to comprehensively evaluate the microplastic pollution level and risk level by using the Nemerow pollution index (NPI) and polymer hazard index (PHI). The results show that the average abundance of microplastics on the Liandao bathing beaches is 135.42 ± 49.58 items/kg; the main shapes are fibers, fragments, and granules. Most of the microplastics are transparent, brown, and black, accounting for 71.54%, and they have an average particle size of 0.63 ± 0.43 mm. The main components are PE, PP, PS, PET, and nylon, of which nylon appears in the highest proportion (54.77%). The microplastic NPI and PHI values are 0.38 and 74.81, respectively, indicating that the pollution level and health risk index of microplastics on the Liandao bathing beaches are both low. With the increase in population and per capita consumption, plastic waste generated on land will continue to increase. Finally, this study puts forward some suggestions regarding microplastic monitoring, plastic waste management, and environmental attitudes and behavior., (© 2023. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Organic pollutant fractions should be closely investigated because of their different ecological risks. In this study, we examined the distribution of organophosphate ester (OPE) fractions (labile, stable-adsorbed, and tight-adsorbed fractions) in sediments from Eastern China Marginal Seas (ECMSs) and assessed the influencing factor of the fractions. The mean values of total OPEs in ECMSs are 13.70 ± 6.16 μg L -1 in seawater and 32.04 ± 14.31 μg kg -1 in sediment. The results showed that OPE concentration decreased from the northern to the southern ECMSs, and tris(1-chloro-2-propyl) phosphate and tris(1,3-dichloro-2-propyl) phosphate were the primary OPEs. The mean contents of labile, stable-adsorbed, and tight-adsorbed fractions in the ECMSs were 9.50, 11.29, and 11.71 μg kg -1 , respectively. Labile OPEs were predominant in offshore waters; the percentage of stable- and tight-adsorbed fractions increased progressively with offshore distance in ECMSs. The specific surface area and surface functional groups of sediment were not consistent with the fraction concentrations from the correlation coefficient, but the gross domestic product per coastline agreed well with the fraction distribution. Based on this, we conclude that human activity, rather than physicochemical characteristics of sediments, may be the primary influencing factor of the relative distribution of different OPE concentration fractions in ECMSs., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The effect of carbon dioxide (CO 2 ) on the desulfurization of sintering flue gas with hydrate (Ca(OH) 2 ) as an absorbent was investigated, and the formation of calcium carbonate (CaCO 3 ) and its effect on the desulfurization was discussed. The competitive relationship between carbon dioxide (CO 2 ) and sulfur dioxide (SO 2 ) with the deacidification agent in sintering flue gas is discussed thermodynamically, showing that sulfates are more likely to be generated under high oxygen potential conditions and that SO 2 reacts more preferentially than CO 2 under a thermodynamic standard state. The amount of produced CaCO 3 increases under the condition that the CO 2 concentration is absolutely dominant to SO 2 in the sintering flue gas atmosphere. The effect of temperature, humidity and CO 2 concentration on the desulfurization of Ca(OH) 2 are discussed experimentally. The increasing temperature is not conducive to desulfurization, and the humidity can promote desulfurization, while excessive humidity could inhibit desulfurization. The suitable relative humidity is 20%. In situ generated calcium carbonate has a certain desulfurization effect, but the desulfurization effect is not as good as Ca(OH) 2 . However, a large proportion of CaCO 3 was produced in the desulfurization ash under the condition that CO 2 concentration was absolutely dominant to SO 2 in the sintering flue gas atmosphere.

Marine microplastic pollution is a major environmental challenge that threatens marine ecosystems and human health. Several models have been used to calculate and predict the theoretical amount of plastic waste discharged into the sea by coastal countries. Unlike earlier theoretical models of source discharge, we used the method of data normalisation to focus on the actual distribution of microplastics and their potential ecological risk in offshore surface waters. Our findings indicate that the average normalised abundance of microplastics in near-shore region of Bohai Sea was greater than the average normalised abundance of microplastics in the seas near the Yangtze River Delta urban agglomeration and the Pearl River Delta urban agglomeration. Moreover, the average amount of plastic waste discharged from terrestrial sources to the ocean per kilometre exhibited the following order: Bohai Rim urban agglomeration (150.90) (tonnes km -1 ) < the Pearl River Delta urban agglomeration (274.30) (tonnes km -1 ) < Yangtze River Delta urban agglomeration (577.44) (tonnes km -1 ). Further, the average microplastics abundance in offshore areas of different countries and the amount of plastic discharged per kilometre of the coastline were significantly negatively correlated, implying that microplastics were not necessarily abundant in coastal areas where large amounts of plastic are discharged into the sea. Hydrodynamic conditions had the greatest influence on the distribution of microplastics in offshore surface waters. The transport of nutrient salts from terrestrial areas to offshore waters was also influenced by hydrodynamics, with enrichment patterns in offshore areas exhibiting similar to those of microplastics. Therefore, when the offshore microplastic accumulation area overlapped with the nutrient salt enrichment zone, the health risk associated with the consumption of edible fish from offshore communities increased. In view of these findings, coastal countries must implement policies to reduce marine plastic waste emissions and develop management strategies based on their local pollution levels., 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 © 2022 Elsevier Ltd. All rights reserved.)

We investigated microplastics (MPs) pollution in 349 Larimichthys polyactis specimens from the coastal area of Jiangsu Province, China. The MP abundance in L. polyactis was 1.03 ± 1.04 items/individual and 0.95 ± 0.92 items/10 g (wet weight). The MP abundance in specimens from the Haizhou Bay fishing ground was slightly higher than that in specimens from the Lvsi fishing ground. Spearman's correlation showed that MP abundance was positively correlated with body length when expressed as items/individual, but not items/10 g. The abundance in the gastrointestinal tract was slightly higher than that in the gills, but the differences were not significant for either measurement index. The MPs predominantly ingested by L. polyactis were <1 mm, fibrous, blue and had a cellophane composition. The MP pollution in L. polyactis in the coast of Jiangsu Province is at a medium to low level, as compared with other regions of China., (Copyright © 2021. Published by Elsevier Ltd.)

Marine fishes are consumed in large quantities by humans as nutritious food. However, the intake of fish polluted by chemicals may pose a severe threat to human health. This study measured the concentrations of 16 priority polycyclic aromatic hydrocarbons (PAHs) in the muscles of 22 species of marine fish from two coastal regions, i.e., Tanmen and Zhuhai, identified the source of PAHs, and assessed the human health risk by dietary exposure. Total PAH (Σ 16 PAHs) levels in Tanmen and Zhuhai fish were in the range of 24.29-684.83 ng g -1 dry weight (dw) and 13.74-42.59 ng g -1 dw, averaging 161.46 ng g -1 dw and 31.21 ng g -1 dw, respectively. Compared with other regions in the world, PAH concentrations in Tanmen fish were at median levels, and Zhuhai fish were at low levels. Low molecular weight PAHs (with 2- and 3-rings) were the predominant compounds detected. Molecular diagnostic ratios suggested that PAHs in Tanmen mainly originated from petrogenic sources such as vessel operations or tanker accidents, while Zhuhai fish were mainly polluted by pyrolytic sources such as combustion of coal and wood. The human health risk assessment results indicated that the risk of PAH intake via fish consumption from Zhuhai was negligible, while five species from Tanmen may pose potential health risks to local residents., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

We investigated the pollution characteristics, the spatial distributions of microplastics, and the source compositions in the Jiangsu Coastal Area, China. The average abundance of microplastics in the surface water and sediment were 0.0998 ± 0.0720 items/m 3 (using a trawl with 333-μm mesh)and 0.1858 ± 0.0927items/g, respectively. The concentration of microplastics showed a distribution trend of high near shore and low far shore in the east-west direction, and were the highest in the southernmost part. According to microplastics found in the surface water, the results of a quantitative source apportionment indicate that the most common source in the northernmost and southernmost regions were clothing fibers, accounting for 38.40% and 40.44% of the total source, respectively. While the major source type in the middle region was the decomposition of hard, large plastic waste. Finally, we suggested some control measures for the main types of microplastics observed in the different regions., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The operation of coastal nuclear power plants and thermal power plants (CNATPPs) can cause regional sea surface temperature (SST) increases. To assess their effects on coastal ecosystems, the scope and extent of their impacts must be understood. We aimed to quantitatively assess the SST increases caused by thermal discharge under climate warming by comparing SSTs between control and test groups and among different offshore buffer zones based on daily MODIS SST data from 2002 to 2017. The results showed that (1) a good correlation occurred between the CNATPP installed capacity and SST increase in the 0-2 km offshore waters; (2) the SST increase caused by thermal discharge was the largest in summer and the smallest in winter; and (3) the effect of thermal discharge occurred within 2 km offshore when the installed capacity exceeded 2000 MW and extended to 5 km when it reaches more than 4000 MW., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

As prime coastal recreational areas, beaches attract an increasing number of users worldwide. However, current studies have shown that beaches are subject to plastic pollution, one of the most significant global environmental threats. Considering the health of tourists and ecological environmental management of beaches, microplastics on recreational beaches are urgently being studied. This paper first focused on microplastics on the recreational beaches of Haichow Bay, which is located on the central coast of China and faces the Yellow Sea. The microplastic pollution level, occurrence, and distribution were investigated. Our study demonstrated that microplastics were consistently found on all studied beaches, which emphasized their extensive distribution throughout recreational beaches. The average microplastic abundance was 106.50 ± 34.41 items/kg, demonstrating that the microplastic pollution level on the studied beaches tended to be in the middle-to-low position compared with previous studies. In total, eight colors were found, more than 90% of microplastics were less than 1 mm in size, and fiber and fragments were the dominant shapes. Resort beaches contained the highest number of microplastics, indicating that the microplastic pollution level on recreational beaches was directly related to the tourism intensity. Five types of plastic were found in the samples, i.e., polyethylene (PE), polypropylene (PP), PS (polystyrene (PS), polyethylene terephthalate (PET) and nylon. Land inputs were the main source of pollution. This study provided baseline information on microplastic pollution that can be used for effective and comprehensive management of recreational beaches and suggests that the management of plastic use and recycling on beaches should be integrated into China's'coastal zone management practices.

In recent years, to meet the needs of economic development, an increasing number of coastal nuclear power plants and thermal power plants (CNATPPs) have used seawater as the source and sink of cooling water. Considering six CNATPPs along the coast of China, based on the model of conservation of mass and energy for an environmental fluid medium, this study quantitatively evaluates the thermal diffusion capacity (TDC) and contribution rate of factors influencing the thermal plume. The results showed that (1) the current velocity, shoreline topography and horizontal diffusion coefficient are linearly correlated with the TDC. The former two variables were the same and the largest and are highly sensitive parameters; (2) the average contribution rates of the current velocity and shoreline topography were the largest at 0.32, and that of the water depth ranged from 0 to 0.28; (3) the shoreline topography close to the outfall affects the TDC of the emitting source of CNATPPs, rather than the geographical location; and (4) this study can provide a comprehensive measurement tool for the planning, site selection and layout of CNATPPs to reduce the impact of their thermal pollution on aquatic organisms in the receiving water. Considering the TDC and thermal sensitivity of marine organisms, it might be assumed that the same heat and the same volume of thermal pollution may have smaller impacts on marine organisms in the East China Sea than in the South China Sea., 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 © 2020 Elsevier Ltd. All rights reserved.)

Human-induced catchment changes have affected the sedimentary processes in marginal seas, which will impact the transport and burial processes of materials and inevitably impact marine biogeochemical cycles. Organochlorine pesticides (OCPs) and sediment characteristics in surface sediments from the East China Sea (ECS) at two time points (2006 and 2018) were compared to understand the response of OCPs to human-induced catchment changes. A significant coarsening trend occurred after the impoundment of the Three Gorges Dam (TGD), with the mean grain size increasing from 6.4 ± 1.2 Φ to 4.4 ± 2.1 Φ, suggesting that the sedimentary environment in the ECS changed drastically. OCP concentrations in the ECS evidently decreased after the impoundment of the TGD, with mean values decreasing from 2.55 ± 1.51 ng g -1 to 1.08 ± 0.84 ng g -1 . The deposition flux of OCP also decreased from 2.65 ± 1.67 ng cm -2 yr -1 to 0.89 ± 0.60 ng cm -2 yr -1 . The reduction in the riverine input might be the reason that caused variations in the OCP concentration and deposition flux. In addition, sediment coarsening is likely to be the another primary factor influencing the differences in the distribution and deposition flux of the OCPs in the ECS. Therefore, the distribution and burial of OCPs in the ECS have been changed drastically, which may broadly impact the marine environment and biogeochemical cycles., (Copyright © 2019 Elsevier Ltd. All rights reserved.)