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Study on evolution characteristics of tidal wetlands in the Bohai Rim based on remote sensing data cube
No full text近年来，人类活动以及自然因素使得环渤海潮滩湿地面临退化的威胁，需要精确掌握环渤海潮滩湿地历史动态变化信息以及人类活动和自然因素对其产生的影响信息。当前，卫星遥感技术已被广泛用于地表变化监测，但使用卫星遥感对潮滩湿地的监测易受到遥感影像时间分辨率和云的影响，导致潮滩湿地监测不准确。因此，本研究提出基于时空数据融合算法的潮滩湿地监测方法，并将其应用于环渤海潮滩湿地的监测。首先对比了三种时空数据融合算法应用于潮滩湿地提取的有效性，以选取适用于潮滩湿地提取的最佳时空数据融合算法。然后基于所选取的最佳时空数据融合算法，融合环渤海沿岸Landsat数据和MODIS数据，以对稀疏原始观测数据进行补充，达到构建环渤海沿岸遥感数据立方体的目的；并通过像元淹没频率算法从所构建的遥感数据立方体中提取环渤海潮滩湿地的空间分布。最后对环渤海及其典型区潮滩湿地的时空演变特征、人类活动和自然因素对环渤海及典型区潮滩湿地的影响进行分析。对环渤海潮滩湿地的研究，对于维护环渤海海岸带生态平衡、保护生物多样性和实现可持续发展至关重要。
主要研究内容：（1）环渤海沿岸遥感数据立方体构建研究：通过对比与分析不同类型时空数据融合算法的融合结果应用于潮滩湿地提取的有效性，选取适用于潮滩湿地提取的最佳时空数据融合算法，并将其结果用于增补稀疏原始观测数据，构建遥感数据立方体，以用于环渤海潮滩湿地提取。（2）环渤海潮滩湿地时空演变特征研究：分析环渤海及其典型区潮滩湿地的时空演变特征。（3）人类活动对环渤海潮滩湿地的影响研究：分析人类活动对环渤海及其典型区的潮滩湿地陆地一侧的影响。（4）自然因素对环渤海潮滩湿地的影响研究：分析自然因素中的侵蚀作用和淤积作用对环渤海及其典型区的潮滩湿地向海一侧的影响。
主要结论：（1）选取FSDAF算法作为用于潮滩湿地提取的最佳时空数据融合算法，其所生成的Landsat-like影像能够呈现出潮滩湿地向海一侧的边界，可应用于环渤海潮滩湿地的提取。（2）1986-2022年，环渤海潮滩湿地总体面积减少。其89.37%的陆地一侧边界受到人类活动的影响而向海推进。人类活动与自然因素中的侵蚀作用分别使得潮滩湿地陆地一侧和向海一侧减少，自然因素中的淤积作用使得潮滩湿地向海一侧增加。（3）辽宁、河北、天津和山东的潮滩湿地面积在1986-2022年均减少。各省市的潮滩湿地在空间上逐年收缩，由连片分布变为零散分布。人类活动和自然因素使得山东省潮滩湿地变化最大，而使得天津市潮滩湿地变化最小。（4）辽河口、曹妃甸、天津港、现代黄河口以及莱州湾五处典型区的潮滩湿地面积在1986-2022年均减少，天津港和现代黄河口处潮滩湿地的损失面积分别最多和最少。人类活动对曹妃甸处和天津港处潮滩湿地陆地一侧影响较大，而自然因素中的侵蚀作用和淤积作用对现代黄河口处潮滩湿地向海一侧的影响较大。
本研究提出了基于时空数据融合算法的潮滩湿地监测方法。采用时空数据融合算法构建遥感数据立方体，以用于环渤海潮滩湿地的提取。传统潮滩湿地监测方法易受到遥感影像时间分辨率和云的影响，使得潮滩湿地的提取精度较低；而本研究中的方法克服了这一局限，提高了潮滩湿地提取的精度。基于所提出的监测方法，本研究进一步揭示了环渤海潮滩湿地演变特征以及人类活动和自然因素对其影响的规律。环渤海潮滩湿地面积1986-2022年减少，人类活动与自然因素中的侵蚀作用分别使得潮滩湿地陆地一侧和向海一侧减少，自然因素中的淤积作用使得潮滩湿地向海一侧增加
Flame-retardant waterborne polyurethane based on the synergistic effect of HGB and DOPO derivatives
No full textThe inherent combustibility of waterborne polyurethane (WPU) with a limiting oxygen index (LOI) of only 18.0% has impeded its versatile applications in the automotive industry, furniture coatings, leather, and other domains. Therefore, enhancing the fire safety of WPU is imperative. This work reports the synthesis of novel reactive flame retardants and their subsequent chemical grafting onto WPU to ameliorate its flammability weakness. Using the novel flame-retardant intermediate 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and para-hydroxybenzaldehyde as precursors, phosphorus-based flame retardants (DOPOs) were prepared. Hollow glass microspheres (HGB) were modified with a silane coupling agent (KH550) and incorporated into the WPU prepolymerization. Finally, chemical grafting occurred between the hydroxyl groups of DOPOs and the modified HGB to produce dual-component flame retardants involved in the prepolymerization. The addition of 2 wt% synergistic flame retardants to WPU increased its LOI to 26% and eliminated dripping during combustion
Analysis of multiple salinization processes and quality of shallow and deep groundwater in coastal delta using hydrochemical approaches: A case study in Luanhe River Delta
No full textCoastal groundwater salinization, contaminants and water resource shortage have become the main coastal groundwater environmental issues globally, drastically affecting human living and ecological environments. This study provides a new insight into the salinization process and influencing factors of groundwater in different aquifers of coastal deltas. Luanhe River Delta, a typical estuarine delta, is used to analyze multiple salinization processes and the quality of shallow and deep groundwater using hydrochemical and monitoring approaches. The analysis has verified the obvious difference of groundwater quality and, the location and influencing factors of saline-fresh water interface in shallow groundwater and deep groundwater. For shallow groundwater, water-rock interactions, seawater intrusion, evaporation and reclamation are the main salinization processes. For deep groundwater, water-rock interactions, saline water intrusion, evaporation and marine transgression are the main salinization processes. The salinization and quality of groundwater are divided into four units in shallow groundwater and three units in deep groundwater. Coastal groundwater salinization causes complex groundwater quality unsuitable for human consumption in some areas. Groundwater resources in different aquifers of coastal deltas should be managed and used in different zones. Local governments should formulate groundwater exploitation plans and rationally plan for groundwater utilization
Effects of different soil water matric potentials on growth traits and yield characteristics of sunflower (<i>Helianthus annuus</i> Linn.) under drip irrigation in a salinized farmland in northern China
No full textCrop irrigation based on controlling the matric potential of soil water at the depth of soil fixation in the root zone is more suitable than deficit irrigation for promoting cultivation in arid agricultural areas. However, it remains challenging to determine how controlled irrigation (CI) quantifies crop the response to water limitation and to establish the appropriate CI thresholds based on soil water matric potential. This study was conducted on sunflower fields in Hetao Irrigation District, a typical arid agricultural area in China where this crop is widely grown. Five CI treatments were applied for different soil water matric potentials (-8, -16, -24, -32, and - 40 kPa) to study the effects of CI on the soil environment and the relationship with crop yield. The following conclusions were drawn: (1) after 2 years of CI treatments, secondary salinization was significantly reduced below the defined criteria for saline soils (4 dS/m), achieving desalination of the entire soil profile; (2) the application of CI as an irrigation strategy in the management of sunflower fields significantly improved physiological traits during the crucial period of sunflower yield formation by increasing plant height while reducing stem thickness; (3) two treatments with the greatest difference in the lower limit of control of soil water matric potential under this irrigation strategy exhibited a yield variance ratio that increased from 0.14% in the first year to 15.37% in the second year; and (4) the treatment that controlled soil water matric potential at -24 kPa obtained the highest yield of all treatments in the test cycle, leading to an increase in seed yield of up to 1266.66 kg/ha in 2022 compared to the previous year
Does invasive submerged macrophyte diversity affect dissimilatory nitrate reduction processes in sediments with varying microplastics?
No full textNitrogen removal is essential for restoring eutrophic lakes. Microorganisms and aquatic plants in lakes are both crucial for removing excess nitrogen. However, microplastic (MP) pollution and the invasion of exotic aquatic plants have become increasingly serious in lake ecosystems due to human activity and plant -dominant traits. This field mesocosm study explored how the diversity of invasive submerged macrophytes affects denitrification (DNF), anammox (ANA), and dissimilatory nitrate reduction to ammonium (DNRA) in lake sediments with varying MPs. Results showed that invasive macrophytes suppressed DNF rates, but DNRA and ANA were less sensitive than DNF to the diversity of invasive species. Sediment MPs increased the biomass of invasive species more than native species, but did not affect microbial processes. The effects of MPs on nitrate dissimilatory reduction were process -specific. MPs increased DNF rates and the competitive advantage of DNF over DNRA by changing the sediment environment. The decoupling of DNF and ANA was also observed, with increased DNF rates and decreased ANA rates. The study findings suggested new insights into how the invasion of exotic submerged macrophytes affects the sediment nitrogen cycle complex environments
Facile fluorescence detection of malachite green in fish using molecularly imprinted polymers doped CdTe quantum dots based system
No full textMalachite green (MG) possesses high toxicity, therefore, the detection of MG in fish tissues is of vital importance. A novel core-shell MIPs doped CdTe quantum dots coated silica nanoparticles (CdTe-MIP/SiO2 NPs) were synthesized via a simple one -pot strategy. The materials were characterized carefully. The resulting CdTe-MIP/ SiO2 NPs were coated on the thin layer chromatography plate, and coupled with miniaturized fluorimeter for fluorescence detection of MG in fish samples. The resulting CdTe-MIP/SiO2 NPs based system possessed good linearity (0.01 - 20 mu mol/L), high recoveries (98.36 %-101.45 %) and low detection limit (3.7 nmol/L) for MG. Furthermore, CdTe-MIP/SiO2 NPs based system were employed to measure fish samples spiked with MG, meanwhile, HPLC was utilized to evaluate the accuracy and reliability. And the paired t -test was conducted to evaluate differences between fluorescence method and HPLC, P > 0.05 means no significant difference was observed, the results demonstrated that both fluorescence method and HPLC are suitable for MG analysis
Moderate increase of precipitation stimulates CO<sub>2</sub> production by regulating soil organic carbon in a saltmarsh
No full textSaltmarsh is widely recognized as a blue carbon ecosystem with great carbon storage potential. Yet soil respiration with a major contributor of atmospheric CO2 can offset its carbon sink function. Up to date, mechanisms ruling CO2 emissions from saltmarsh soil remain unclear. In particular, the effect of precipitation on soil CO2 emissions is unclear in coastal wetlands, due the lack of outdoor data in real situations. We conducted a 7-year field manipulation experiment in a saltmarsh in the Yellow River Delta, China. Soil respiration in five treatments (-60%, -40%, +0%, +40%, and + 60% of precipitation) was measured in the field. Topsoils from the last 3 years (2019-2021) were analyzed for CO2 production potential by microcosm experiments. Furthermore, quality and quantity of soil organic carbon and microbial function were tested. Results show that only the moderate precipitation rise of +40% induced a 66.2% increase of CO2 production potential for the microcosm experiments, whereas other data showed a weak impact. Consistently, soil respiration was also found to be strongest at +40%. The CO2 production potential is positively correlated with soil organic carbon, including carbon quantity and quality. But microbial diversity did not show any positive response to precipitation sizes. r-/K-strategy seemed to be a plausible explanation for biological factors. Overall, our finding reveal that a moderate precipitation increase, not decrease or a robust increase, in a saltmarsh is likely to improve soil organic carbon quality and quantity, and bacterial oligotroph:copiotroph ratio, ultimately leading to an enhanced CO2 production
Effects of seawater acidification and warming on morphometrics and biomineralization-related gene expression during embryo-larval development of a lightly-calcified echinoderm
No full textCO2-induced ocean acidification and warming pose ecological threats to marine life, especially calcifying species such as echinoderms, who rely on biomineralization for skeleton formation. However, previous studies on echinoderm calcification amid climate change had a strong bias towards heavily calcified echinoderms, with little research on lightly calcified ones, such as sea cucumbers. Here, we analyzed the embryo-larval development and their biomineralization-related gene expression of a lightly calcified echinoderm, the sea cucumber (Apostichopus japonicus), under experimental seawater acidification (OA) and/or warming (OW). Results showed that OA (- 0.37 units) delayed development and decreased body size (8.58-56.25 % and 0.36-19.66 % decreases in stage duration and body length, respectively), whereas OW (+3.1 degrees C) accelerated development and increased body size (33.99-55.28 % increase in stage duration and 2.44-14.41 % enlargement in body length). OW buffered the negative effects of OA on the development timing and body size of A. japonicus. Additionally, no target genes were expressed in the blastula stage, and only two biomineralization genes (colp3 alpha, cyp2) and five TFs (erg, tgif, foxN2/3, gata1/2/3, and tbr) were expressed throughout the embryo-larval development. Our findings suggest that the low calcification in A. japonicus larvae may be caused by biomineralization genes contraction, and low expression of those genes. Furthermore, this study indicated that seawater acidification and warming affect expression of biomineralization-related genes, and had an effect on body size and development rate during the embryo-larval stage in sea cucumbers. Our study is a first step toward a better understanding of the complexity of high pCO(2) on calcification and helpful for revealing the adaptive strategy of less-calcified echinoderms amid climate change
Fatty acid esters of hydroxy fatty acids: A potential treatment for obesity-related diseases
No full textObesity, a burgeoning worldwide health system challenge, is associated with multiple chronic diseases, including diabetes and chronic inflammation. Fatty acid esters of hydroxy fatty acids (FAHFAs) are newly identified lipids with mitigating and anti-inflammatory effects in diabetes. Increasing work has shown that FAHFAs exert antioxidant activity and enhance autophagy in neuronal cells and cardiomyocytes. We systematically summarized the biological activities of FAHFAs, including their regulatory effects on diabetes and inflammation, antioxidant activity, and autophagy augmentation. Notably, the structure-activity relationships and potential biosynthesis of FAHFAs are thoroughly discussed. FAHFAs also showed potential roles as diagnostic biomarkers. FAHFAs are a class of resources with promising applications in the biomedical field that require in-depth research and hotspot development, as their structure has not been fully resolved and their biological activity has not been fully revealed
Monitoring Off-Shore Fishing in the Northern Indian Ocean Based on Satellite Automatic Identification System and Remote Sensing Data
No full textSatellite-derived Sea Surface Temperature (SST) and sea-surface Chlorophyll a concentration (Chl-a), along with Automatic Identification System (AIS) data of fishing vessels, were used in the examination of the correlation between fishing operations and oceanographic factors within the northern Indian Ocean from March 2020 to February 2023. Frequency analysis and the empirical cumulative distribution function (ECDF) were used to calculate the optimum ranges of two oceanographic factors for fishing operations. The results revealed a substantial influence of the northeast and southwest monsoons significantly impacting fishing operations in the northern Indian Ocean, with extensive and active operations during the period from October to March and a notable reduction from April to September. Spatially, fishing vessels were mainly concentrated between 20 degrees N and 6 degrees S, extending from west of 90 degrees E to the eastern coast of Africa. Observable seasonal variations in the distribution of fishing vessels were observed in the central and southeastern Arabian Sea, along with its adjacent high sea of the Indian Ocean. Concerning the marine environment, it was observed that during the northeast monsoon, the suitable SST contributed to high CPUEs in fishing operation areas. Fishing vessels were widely distributed in the areas with both mid-range and low-range Chl-a concentrations, with a small part distributed in high-concentration areas. Moreover, the monthly numbers of fishing vessels showed seasonal fluctuations between March 2020 and February 2023, displaying a periodic pattern with an overall increasing trend. The total number of fishing vessels decreased due to the impact of the COVID-19 pandemic in 2020, but this was followed by a gradual recovery in the subsequent two years. For fishing operations in the northern Indian Ocean, the optimum ranges for SST and Chl-a concentration were 27.96 to 29.47 degrees C and 0.03 to 1.81 mg/m3, respectively. The preliminary findings of this study revealed the spatial-temporal distribution characteristics of fishing vessels in the northern Indian Ocean and the suitable ranges of SST and Chl-a concentration for fishing operations. These results can serve as theoretical references for the production and resource management of off-shore fishing operations in the northern Indian Ocean