Institutional Repository of Yantai Institute of Coastal Zone Research, CAS
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Moderate nitrogen enrichment increases CO<sub>2</sub> sink strength in a coastal wetland
No full textCoastal wetlands remarkably influence terrestrial carbon (C) stock by serving as natural reservoirs for 'blue carbon'. Anthropogenic nitrogen (N) enrichment shapes the dynamics of soil and plant communities, consequently affecting the C balance and ecosystem functions. The impacts of various levels of N enrichment on CO2 sequestration in coastal wetlands, however, remain elusive. Here we conducted a long-term field study of N fertilization in a coastal wetland in the Yellow River Delta, China, to investigate N effects on soil properties, indicators of plant dynamics, and fluxes of ecosystem CO2. The results indicated that moderate N enrichment (5 g N m(-2) y(-1)) stimulated C fluxes with increases in gross primary productivity (+26.4%), ecosystem respiration (+23.3%), and net ecosystem exchange (NEE, +31.5%) relative to the control. High (10 g N m(-2) y(-1)) and extreme (20 g N m(-2) y(-1)) amounts of N enrichment, however, had relatively minor impacts on these CO2 fluxes. Overall, we observed a decrease in soil electrical conductivity (-24.6%) and increases in soil organic C (+25.2%) and microbial biomass C (+369.3%) for N enrichment. N enrichment also altered the composition of plant species, with a higher proportion of a local dominant species (Phragmites australis), and affected root biomass distribution, with more biomass near the soil surface. Structural equation modeling explained 65.2% of the variance of NEE and supported the assumption that N enrichment could alter the dynamics of soil properties and plant conditions and accelerate ecosystem CO2 sequestration. These findings have important implications for forecasting the C cycle with increasing N deposition in coastal wetlands, contributing to the projections of the global C budget
Effects of Vegetation Restoration Age on Soil C: N: P Stoichiometry in Yellow River Delta Coastal Wetland of China
No full textVegetation restoration can alter carbon (C), nitrogen (N), and phosphorus (P) cycles in coastal wetlands affecting C: N: P stoichiometry. However, the effects of restoration age on soil C: N: P stoichiometry are unclear. In this study, we examined the responses of soil C, N, and P contents and their stoichiometric ratios to vegetation restoration age, focusing on below-ground processes and their relationships to aboveground vegetation community characteristics. We conducted an analysis of temporal gradients based on the 'space for time' method to synthesize the effects of restoration age on soil C: N: P stoichiometry in the Yellow River Delta wetland of China. The findings suggest that the combined effects of restoration age and soil depth create complex patterns of shifting soil C: N: P stoichiometry. Specifically, restoration age significantly increased all topsoil C: N: P stoichiometries, except for soil total phosphorus (TP) and the C: N ratio, and slightly affected subsoil C: N: P stoichiometry. The effects of restoration age on the soil C: N ratio was well constrained owing to the coupled relationship between soil organic carbon (SOC) and total nitrogen (TN) contents, while soil TP content was closely related to changes in plant species diversity. Importantly, we found that the topsoil C: N: P stoichiometry was significantly affected by plant species diversity, whereas the subsoil C: N: P stoichiometry was more easily regulated by pH and electric conductivity (EC). Overall, this study shows that vegetation restoration age elevated SOC and N contents and alleviated N limitation, which is useful for further assessing soil C: N: P stoichiometry in coastal restoration wetlands
Progress in culture technology and active substance research on <i>Nostoc sphaeroides</i> Kützing
No full textNostoc sphaeroides K & uuml;tzing is a freshwater edible cyanobacterium that is rich in active substances such as polysaccharides, proteins and lipids; it has a variety of pharmacological effects such as antioxidant, anti-inflammatory, antitumor and cholesterol-lowering effects; and is often used as a traditional Chinese medicine with many potential applications in food, cosmetics, medical diagnostics and disease treatment. However, to meet the needs of different fields, such as medicine, there is an urgent need for basic research and technological innovation in culture technology, extraction and preparation of active substances, and the pharmacological mechanism of N. sphaeroides. This paper reviews the pharmacological effects of N. sphaeroides active substances, discusses current culture techniques and methods for extracting active components, and outlines the challenges encountered in cultivating and industrializing N. sphaeroides while discussing future development trends. (c) 2024 Society of Chemical Industry
Biochar, phosphate, and magnesium oxide in seaweed and cornstarch dregs co-composting: Enhancing organic matter degradation, humification, and nitrogen retention
No full textSeaweed waste, abundant and rich in plant-stimulating properties, has the potential to be transformed into valuable soil amendments through proper composting and utilization management. Given its low carbon-to- nitrogen ratio, co-composting seaweed with carbon-rich cornstarch dregs is an effective strategy. However, the potential application of co-composting largely depends on the efficiency of the composting and the quality of the product. This study explores the effects of adding 10 % corn stalk biochar to a co-composting system of seaweed and cornstarch dregs, alongside varying buffering capacities of phosphates (KH2PO4 2 PO 4 and K2HPO4 & sdot;3H2O- 2 HPO 4 & sdot;3H 2 O- KH2PO4) 2 PO 4 ) and MgO, on the degradation efficiency of organic matter, nitrogen transformation, and humification. The results indicate that the addition of biochar and salts enhances the oxygen utilization rate (OUR) and cellulase activity during the thermophilic phase. Additionally, X-ray diffraction (XRD) and parallel factor analysis (PARAFAC) demonstrate more intense solubilization and transformation of proteinaceous substances, along with cellulose degradation. These processes are crucial for enhancing organic matter degradation and humification, significantly boosting degradation (with an increase of 28.6% to 33.8 %) and humification levels (HA/FA increased by 37.1 % to 49.6 %). Specifically, groups with high buffering capacity significantly promote the formation of NO3--N 3 --N and NH4+-N, 4 +-N, and a higher degree of humification, creating an optimal environment for significantly improving nitrogen retention (increased by 4.80 %). Additionally, this treatment retains and slightly enhances the plant-stimulating properties of seaweed. These findings underscore the potential of integrating biochar with specific ratios of phosphates and MgO to enhance composting efficiency and product quality while preserving the plant-stimulating effects of seaweed
Variations of the atmospheric polycyclic aromatic hydrocarbon concentrations, sources, and health risk and the direct medical costs of lung cancer around the Bohai Sea against a background of pollution prevention and control in China
No full textThe Bohai Sea (BS) region, an area of China that is severely polluted with atmospheric polycyclic aromatic hydrocarbons (PAHs), has received wide attention in recent decades. To characterize the variations of the concentrations and sources of PAHs from June 2014 to May 2019, 15 PAH congeners (Sigma(15)PAHs) were measured in atmospheric samples (N=228) collected at 12 sites around the BS, and the health risk and direct medical costs associated with lung cancer caused by exposure to PAHs were also estimated. The annual daily average concentration of Sigma(15)PAHs was 56.78 +/- 4.75ng m(-3), which was dominated by low molecular weight PAHs (LMW-PAHs) containing three rings (58.7 +/- 7.8%). During the 5-year sampling period, the atmospheric Sigma(15)PAHs concentration reduced by 17.5% for the whole BS region, with an especially large drop of 51.7% observed in the tightly controlled area of Tianjin (TJ), which was mainly due to a decrease in the concentration of high molecular weight PAHs (HMW-PAHs) containing five or six rings. Generally, the concentration of Sigma(15)PAHs was highest in winter and lowest in summer, which can mainly be attributed to the change in LMW-PAH concentration. Based on the positive matrix factorization (PMF) model, PAHs in the BS region were mainly ascribed to coal combustion and biomass burning. The PAH contributions of coal combustion and motor vehicles showed different trends for the BS region (PAHs from coal combustion rose by 7.2% and PAHs from motor vehicles fell by 22.4%) and for TJ (PAHs from coal combustion fell by 12.6% and PAHs from motor vehicles rose by 6.9%). The incidence of lung cancer (ILCR) caused by exposure to atmospheric PAHs decreased by 74.1% and 91.6% from 2014 to 2018 in the BS region and in TJ, respectively. This was mainly due to the decrease in the concentration of highly toxic HMW-PAHs and was reflected in USD10.7 million of savings in direct medical costs of lung cancer caused by exposure to PAHs, which represent a decrease of 46.1% compared to the corresponding costs before air pollution prevention and control was implemented around the BS. There was an even higher reduction in medical costs of 54.5% in TJ. Hence, this study proves that implementing pollution prevention and control not only effectively reduced the concentration of pollutants and the risks caused by them, but it also significantly reduced the medical costs of diseases caused by the corresponding exposure
Investigation of the causes and mechanisms of hypoxia in the central Bohai Sea in the summer of 2022
No full textThe deep-water area in the central Bohai Sea (BS) serves as a spawning ground and nursery for fish, shrimp, and crabs. Frequent hypoxia will affect the ecological environment in the central BS. Data from an on-site investigation of the central BS in the spring and summer of 2022 were used to analyze the relevant factors generating the occurrence of hypoxia in the central BS through the eutrophication index E, apparent oxygen consumption (AOU), and Spearman correlation. The hypoxia area was largely distributed in the study area's deep water section, and stratification was the main cause of hypoxia at the bottom. Organic matter mineralization, degradation, and biological respiration further exacerbated the hypoxia. In the summer of 2022, temperature stratification was the dominant factor influencing hypoxia
Multi-scenario Simulation and Spatial-temporal Analysis of LUCC in China's Coastal Zone Based on Coupled SD-FLUS Model
No full textIncreased human activities in China's coastal zone have resulted in the depletion of ecological land resources. Thus, conducting current and future multi-scenario simulation research on land use and land cover change (LUCC) is crucial for guiding the healthy and sustainable development of coastal zones. System dynamic (SD)-future land use simulation (FLUS) model, a coupled simulation model, was developed to analyze land use dynamics in China's coastal zone. This model encompasses five scenarios, namely, SSP1-RCP2.6 (A), SSP2-RCP4.5 (B), SSP3-RCP4.5 (C), SSP4-RCP4.5 (D), and SSP5-RCP8.5 (E). The SD model simulates land use demand on an annual basis up to the year 2100. Subsequently, the FLUS model determines the spatial distribution of land use for the near term (2035), medium term (2050), and long term (2100). Results reveal a slowing trend in land use changes in China's coastal zone from 2000-2020. Among these changes, the expansion rate of construction land was the highest and exhibited an annual decrease. By 2100, land use predictions exhibit high accuracy, and notable differences are observed in trends across scenarios. In summary, the expansion of production, living, and ecological spaces toward the sea remains prominent. Scenario A emphasizes reduced land resource dependence, benefiting ecological land protection. Scenario B witnesses an intensified expansion of artificial wetlands. Scenario C sees substantial land needs for living and production, while Scenario D shows coastal forest and grassland shrinkage. Lastly, in Scenario E, the conflict between humans and land intensifies. This study presents pertinent recommendations for the future development, utilization, and management of coastal areas in China. The research contributes valuable scientific support for informed, long-term strategic decision making within coastal regions
Vertical distribution of microplastics in sediment columns along the coastline of China
No full textAt present, there has been relatively less coverage of microplastics (MPs) pollution in sediment columns, especially across a large geographical span. This study collected sediment columns across 11 provinces along the coastline of China for MPs pollution investigation. The study found higher MPs diversity (Simpson diversity index) in sediment columns than in surface sediments, mostly comprising fiber MPs with dominant transparent and blue colors. Lower MPs pollution was noted in mangrove reserves, while estuarine and coastal areas showed higher pollution levels. Spearman correlation analysis shows that vertical of MPs abundance significantly decreased with depth at 6 of 11 sites. Large-sized MPs with diverse colors in deeper sediments ( >40 cm) suggests that burial processes may render MPs more resistant to degradation. Our research highlights varied MPs distribution in coastal sediment, aiding future marine MPs pollution prediction and assessment
Activity Pattern and Habitat Use of Shorebirds in an Artificial Wetland Complex: A Case Study of Breeding Pied Avocet in the Yellow River Delta, China
No full textWith the loss of substantial natural wetlands in coastal zones, artificial wetlands provide alternative habitats for many shorebirds. Scientific management of artificial wetlands used by shorebirds plays an important role in maintaining the stability of shorebird population. Satellite tracking technique can obtain high-precision location information of individuals day and night, providing a good technical support for the study of quantitative relationship between waterfowls and their habitats. In this study, satellite tracking method, Remote Sensing (RS) and Geographic Information System (GIS) technology were used to analyze the activity pattern and habitat utilization characteristics of Pied Avocet during breeding period in an artificial wetland complex in the Yellow River Delta (YRD), China. The results showed that the breeding Pied Avocets had a small range of activity, with a total core and main home range of 33.10 km2 and 216.30 km2, respectively. This species tended to forage in the pond and salt pan during the day and night, respectively, with an unfixed staying time in the breeding ground. The distance between breeding ground and feeding ground was less than 6 km. It is emphasized that in addition to improving the conditions of the remaining natural habitats, effective managing artificial habitats is a priority for shorebird conservation. This research could provide reference for the management of artificial wetlands in coastal zones and supply technique support for the protection of shorebirds and their habitats, and alleviate human-bird conflicts and sustainable development of coastal zones
Peptide-Driven Assembly of Magnetic Beads for Potentiometric Sensing of Bacterial Enzyme at a Subcellular Level
No full textBacterial enzymes with different subcellular localizations play a critical ecological role in biogeochemical processing. However, precisely quantifying enzymes localized at certain subcellular levels, such as extracellular enzymes, has not yet been fully realized due to the complexity and dynamism of the bacterial outer membrane. Here we present a magneto-controlled potentiometric sensing platform for the specific detection of extracellular enzymatic activity. Alkaline phosphatase (ALP), which is one of the crucial hydrolytic enzymes in the ocean, was selected as the target enzyme. Magnetic beads functionalized with an ALP-responsive self-assembled peptide (GGGGGFFFpYpYEEE, MBs-peptides) prevent negatively charged peptides from entering the bacterial outer membrane, thereby enabling direct potentiometric sensing of extracellular ALP both attached to the bacterial cell surface and released into the surrounding environment. The dephosphorylation-triggered assembly of peptide-coupled magnetic beads can be directly and sensitively measured by using a magneto-controlled sensor. In this study, extracellular ALP activity of Pseudomonas aeruginosa at concentrations ranging from 10 to 1.0 x 10(5) CFU mL(-1) was specifically and sensitively monitored. Moreover, this magneto-controlled potentiometric method enabled a simple and accurate assay of ALP activity across different subcellular localizations