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Intertidal wetlands are important carbon reservoirs that play a significant role in climate change mitigation. However, the lack of large‐scale quantification and source identification of sediment organic carbon (SOC) in different discharge estuaries hampers the assessment of the carbon storage potential in these systems. In this study, based on the elemental ratios and stable carbon isotopes of the core sediment from the intertidal wetlands along the east coast of China, we quantified the contribution of organic carbon (OC) derived from terrestrial/estuarine particulate organic matter (POM), marine phytoplankton, and local plants, such as mangrove and salt marsh plants in the study area. We explored the hydrological and plant drivers controlling the variation in the contribution of OC sources among different coastal environmental settings. We found that SOC in high discharge estuaries (river runoff more than 50 billion m3/a) originated predominantly from terrestrial/estuarine POM (45 ± 6%), whereas the primary source for low discharge estuaries was marine phytoplankton OC (51 ± 14%). Moreover, our estimates revealed a sharp increase in the contribution of OC from mangroves to deep sediments compared with surface sediments, owing to the infiltration of mangrove roots at greater depths and the slow degradation of roots contributing to the substantial refractory OC buried in the deep sediments. These findings indicate that carbon storage in the intertidal wetlands varies among contrasting coastal environmental conditions, which provides implications for intertidal wetlands as a critical carbon sink in the global carbon budget. Plain Language Summary: Better constraints on the sources of sediment organic carbon (SOC) in intertidal wetlands are very important for calculating the global carbon budget. Many researchers have studied the distribution, source, burial of SOC, but still, there is an obvious lack of quantification of the contributions of multiple SOC sources in different discharge estuaries across a large geographical area. Terrestrial/estuarine particulate organic matter (POM), marine phytoplankton, and local plants contribute organic carbon (OC) to sediments, varying in different places. In this study, by comparing the total organic carbon and total nitrogen content, δ13C values, and C/N ratios of the sediment cores, we quantified the relative contributions of three OC sources to sediments from 12 intertidal wetlands along the east coast of China. We found a higher percentage of terrestrial/estuarine POM input in high discharge estuaries (river runoff more than 50 billion m3/a). Results suggest that the contribution of terrestrial/estuarine POM increases with river runoff, whereas the contribution of marine phytoplankton OC decreases with runoff. Moreover, there was a sharp increase in the relative contribution of long‐term OC supplied by mangrove OC with depth. The large‐scale quantification of the contributions of SOC sources has important implications for better estimation of the potential of OC sequestration. Key Points: Organic carbon (OC) contribution was assessed in coastal wetlands of China by using MixSIARThe contribution of terrestrial/estuarine particulate organic matter rose with river runoff, while the contribution of marine OC decreasedThe infiltration of mangrove roots resulted in mangrove OC dominated in deeper sediments and preserved [ABSTRACT FROM AUTHOR]

Tidal flats form around the estuarine and coastal zone by continuous terrigenous sediment transport and deposition processes. Now a large body of published carbon research work frame within the vegetated area (mangrove forests, sea grass bed, and salt marshes). Nonvegetated tidal flats, which are characterized by predominantly silts and clays sediment, were generally impressed with low carbon stock due to their meager primary productivity. However, these regions may be a potentially important carbon sink, given their high burial rate, expanding areal coverage, and detrial organic carbon derived from watershed and adjacent vegetated area. Low carbon densities (<0.01 g cm−3) were found in Chinese tidal flat sediments by the study, but the carbon sequestration rates ranged from 35 to 361 g C m−2 yr−1, which were comparable to rates of worldwide vegetated coastal areas. The high rates can be ascribed to rapid sedimentation rates (1–2 cm yr−1) during the past several decades. The highest areal carbon stocks were located at tidal flat sites proximal to mangrove forests. The majority of carbon stocks (100 cm) was found in the unvegetated tidal flats instead of in the vegetated tidal flats. The former occupied 87% of the entire tidal area, 6.7 times larger than the latter. Tidal flats in coastal China store 78.07 Tg C (100 cm), accounting for nearly 80% of the C deposited in entire coastal tidal area. The future carbon sequestration rates of Chinese tidal flats are facing uncertainties under the pressures of reduced fluvial sediment loads from major rivers. Key Points: Soil organic carbon density is lower in the Chinese unvegetated tidal flats than vegetated coastal area in the worldThe overall carbon sequestration rate of Chinese tidal flats is comparable to rates of global coastal marshesTidal flats account for nearly 80% of the C stored in the Chinese tidal area [ABSTRACT FROM AUTHOR]

Global nitrogen (N) enrichment has resulted in increased nitrous oxide ( N2O) emission that greatly contributes to climate change and stratospheric ozone destruction, but little is known about the N2O emissions from urban river networks receiving anthropogenic N inputs. We examined N2O saturation and emission in the Shanghai city river network, covering 6300 km2, over 27 months. The overall mean saturation and emission from 87 locations was 770% and 1.91 mg N2O-N m−2 d−1, respectively. Nitrous oxide ( N2O) saturation did not exhibit a clear seasonality, but the temporal pattern was co-regulated by both water temperature and N loadings. Rivers draining through urban and suburban areas receiving more sewage N inputs had higher N2O saturation and emission than those in rural areas. Regression analysis indicated that water ammonium ( NH4+) and dissolved oxygen ( DO) level had great control on N2O production and were better predictors of N2O emission in urban watershed. About 0.29 Gg N2O-N yr−1 N2O was emitted from the Shanghai river network annually, which was about 131% of IPCC's prediction using default emission values. Given the rapid progress of global urbanization, more study efforts, particularly on nitrification and its N2O yielding, are needed to better quantify the role of urban rivers in global riverine N2O emission. [ABSTRACT FROM AUTHOR]

• The growth of tumor was inhibited by Ag85B-ENO1 46-82. • Ag85B-ENO1 46-82 was beneficial for anti-tumor immune responses in the TME. • The CD8 + T cell immune responses were indispensable for the therapeutic effect of Ag85B-ENO1 46-82. Lung cancer is the leading cause of cancer-related morbidity and mortality in China. However, the effect of traditional cancer treatment is limited. Herein, we designed a therapeutic cancer vaccine based on the tumor-associated antigen mENO1, which can prevent lung cancer growth in vivo, and explored the underlying mechanism of Ag85B-ENO1 46-82 therapy. Lewis lung carcinoma (LLC) tumor-bearing immunocompetent C57BL/6 mice that received Ag85B-ENO1 46-82 treatment showed antitumor effect. Further, we detected CD8+ T, CD4+ T in LLC-bearing C57BL/6 mice to understand the impact of Ag85B-ENO1 46-82 therapy on antitumor capacity. The Ag85B-ENO1 46-82 therapy induced intensive infiltration of CD4+ and CD8+ T cells in tumors, increased tumor-specific IFN-γ and TNF-α secretion by CD8+ T cells and promoted macrophage polarization toward M1 phenotype. Flow cytometric analysis revealed that CD8+ T effector memory (TEM) cells and central memory (TCM) cells were upregulated. qPCR and ELISA analysis showed that the expression of IFN-γ and TNF-α were upregulated, whereas of IL1β, IL6 and IL10 were downregulated. This study demonstrated that Ag85B-ENO1 46-82 vaccine augmented antitumor efficacy, which was CD8+ T cells dependent. Our findings paved the way for therapeutic tumor-associated antigen peptide vaccines to enhance anti-tumor immunotherapy for treatment of cancer. [ABSTRACT FROM AUTHOR]

The focus of urban water environment renovation has shifted to high nitrate (NO 3 - ) load. Nitrate input and nitrogen conversion are responsible for the continuous increase in nitrate levels in urban rivers. This study utilized nitrate stable isotopes (δ 15 N-NO 3 - and δ 18 O-NO 3 - ) to investigate NO 3 - sources and transformation processes in Suzhou Creek, located in Shanghai. The results demonstrated that NO 3 - was the most common form of dissolved inorganic nitrogen (DIN), accounting for 66 ± 14% of total DIN with a mean value of 1.86 ± 0.85 mg L -1 . The δ 15 N-NO 3 - and δ 18 O-NO 3 - values ranged from 5.72 to 12.42‰ (mean value: 8.38 ± 1.54‰) and -5.01 to 10.39‰ (mean value: 0.58 ± 1.76‰), respectively. Based on isotopic evidence, the river received a significant amount of nitrate through direct exogenous input and sewage ammonium nitrification, while nitrate removal (denitrification) was insignificant, resulting in nitrate accumulation. Analysis using the MixSIAR model revealed that treated wastewater (68.3 ± 9.7%), soil nitrogen (15.7 ± 4.8%) and nitrogen fertilizer (15.5 ± 4.9%) were the main sources of NO 3 - in rivers. Despite the fact that Shanghai's urban domestic sewage recovery rate has reached 92%, reducing nitrate concentrations in treated wastewater is crucial for addressing nitrogen pollution in urban rivers. Additional efforts are needed to upgrade urban sewage treatment during low flow periods and/or in the main stream, and to control non-point sources of nitrate, such as soil nitrogen and nitrogen fertilizer, during high flow periods and/or tributaries. This research provides insights into NO 3 - sources and transformations, and serves as a scientific basis for controlling NO 3 - in urban rivers., 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 © 2023 Elsevier Inc. All rights reserved.)

Nitrification is a crucial step in ecosystem nitrogen (N) cycling, but scaling up from plot-based measurements of gross nitrification to catchments is difficult. Here, we employed a newly developed method in which the oxygen isotope anomaly (Δ 17 O) of nitrate (NO 3 ) is used as a natural tracer to quantify in situ catchment-scale gross nitrification rate (GNR) for a temperate forest from 2014 to 2017 in northeastern China. The annual GNR ranged from 71 to 120 kg N ha - ) is used as a natural tracer to quantify in situ catchment-scale gross nitrification rate (GNR) for a temperate forest from 2014 to 2017 in northeastern China. The annual GNR ranged from 71 to 120 kg N ha -1 yr -1 (average 94 ± 10 kg N ha -1 yr -1 ) over the 4 years in this forest. This result and high stream NO 3 - loss (4.2-8.9 kg N ha -1 yr -1 ) suggest that the forested catchment may have been N-saturated. At the catchment scale, the total N output of 10.7 kg N ha -1 yr -1 , via leaching and gaseous losses, accounts for 56% of the N input from bulk precipitation (19.2 kg N ha -1 yr -1 ). This result indicates that the forested catchment is still retaining a large fraction of N from atmospheric deposition. Our study suggests that estimating in situ catchment-scale GNR over several years when combined with other conventional flux estimates can facilitate the understanding of N biogeochemical cycling and changes in the ecosystem N status.

While nitrogen (N 2 ) fixation is an important process in nitrogen (N) biogeochemical cycling, supplying a significant portion of the N in natural ecosystems, few quantitative constraints exist concerning its contribution to the N enrichment and export from river ecosystems. This study estimates the N 2 fixation rates of urban rivers in the Yangtze Estuary area using acetylene reduction. The results demonstrate that the prominent spatiotemporal variability of river N 2 fixation rates is driven by various environmental factors. River N 2 fixation rates are significantly higher in the summer (90.57 ± 14.60 ngN·L -1 ·h -1 ) than in the winter (57.98 ± 15.73 ngN·L -1 ·h -1 ). Spatially, rivers draining urban and suburban areas have higher N 2 fixation rates than those draining rural areas. The N 2 fixation rates are positively correlated with the N 2 fixing cyanobacteria density, water temperature, light, and the water phosphorus (P) concentration, but they are negatively correlated with the dissolved N concentration (NH 4 + -N and NO 3 - -N). The N 2 fixation rates annually range from 53.20 to 89.24 ngN·L -1 ·h -1 for all of the sampling rivers, which is equivalent to a depth integrated (0-0.6 m) N input of 0.163-0.274 gN·m -2 ·a -1 . The determined annual N input via N 2 fixation is generally higher than that of marine systems, but it is lower than that of eutrophic lakes. This study provides robust evidence that N 2 fixation can supply a substantial portion of the N input to human-impacted river ecosystems, which has not been sufficiently accounted for when determining the N mass balance of riverine ecosystems. A high N 2 fixation rate may increase the ratio of N to P input to river systems, and therefore render P the limiting factor in aquatic eutrophication.