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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
Heterogeneous degradation of chloramphenicol antibiotic by peroxymonosulfate activated by FeS and FeS<sub>2</sub>: Mechanism and effects of catalysts dosage and pH
No full textAntibiotics in the environmental waters pose long-term threat to ecological safety because of their persistent and potential toxic nature. FeS and FeS2 were proved to be efficient catalysts for the activation of peroxymonosulfate (PMS) and the generation of sulfate radical generation for refractory pollutant degradation. However, their performance for antibiotic degradation has not yet been comparatively and comprehensively investigated. Herein, the FeS/PMS and FeS2/PMS systems were developed to explore chloramphenicol (CAP) degradation under equal conditions. The results show that CAP was efficiently degraded in both two systems, with a removal efficiency exceeding 90 % within 120 min using 6 mM PMS and 0.6 g/L catalysts. Acceleration in degradation rate was observed in the FeS2/PMS system when the catalyst dosage ranged from 0.1 g/L to 1.0 g/L (constant PMS concentration) with a reaction rate constant (k(obs)) of 2.1-fold higher than that in the FeS/PMS system. However, the k(obs) were comparable with the PMS concentration range (constant catalyst dosage) in the two systems, suggesting that the catalysts were the rate-limiting step in CAP degradation process. The initial pH strongly affected CAP degradation in the FeS/PMS system but had little effect on that in the FeS2/PMS system. Surface Fe2+ played a dominant role in PMS activation, and S-2(2-)/S2- facilitated Fe2+ regeneration. Further, both FeS and FeS2 had stable activity for PMS activation during long-term use. This study proves the effectiveness of FeS and FeS2 for PMS activation for antibiotic degradation and differentiates their catalytic qualities, which will provide alternative heterogeneous catalysts for practical application
Erosion of cultivated kelp facilitates dissolved organic carbon release
No full textGrowing trend of interests for contributions of cultivation of kelp to carbon sequestration have been driven globally. Saccharina japonica is an important cultivated seaweed, with erosion phenomenon usually occurs at the distal part of the frond in S. japonica throughout the growth cycle. However, the dynamics of dissolved organic carbon (DOC) release induced by erosion of S. japonica are not well understood. This study revealed that erosion induced a substantial increase in DOC release, with a 14% increase under low light (LL) conditions and a 54% increase under high light (HL) conditions. A 10 cm of long slit cut into the distal part of S. japonica increased the rate of DOC release by 56% under LL conditions, and by 13% under HL conditions. Additionally, the epibiotic microorganisms facilitate the release of DOC, and the effects were even more pronounced in erosive S. japonica. Conversely, the proximal part of S. japonica exhibited a higher photosynthetic carbon fixation capacity, with a carbon-to-nitrogen (C/N) ratio approximately 1.76 times higher than that in distal part. During the growth of S. japonica, excess photosynthetic products were often transported from the proximal part into distal part, further facilitating DOC release. In summary, DOC released induced by erosion of S. japonica could make contributions to oceanic carbon sequestration
Zebrafish gender-specific anxiety-like behavioral and physiological reactions elicited by caffeine
No full textCaffeine exerts a biphasic effect on zebrafish behavior. High doses of caffeine have been associated with increased stress and anxiety, whereas low doses have been found to enhance performance on tasks requiring focus and attention. However, the sex-specific nature of these biphasic effects on behavior and physiology remains unclear. This study assessed the behavioral responses and hormone levels in male and female zebrafish after acute exposure to caffeine ranging from 0.3 to 600 mg/L. The results showed no significant difference in caffeine intake between males and females after acute exposure at each concentration. Caffeine-induced behavioral and physiological responses indicated a threshold dosage existed between 30 and 300 mg/L. Female fish displayed increased anxiety-like behavioral phenotypes, i.e., latency to upper and freezing, whereas males exhibited more erratic movement following acute exposure to a high-dose treatment. In addition, females exhibited a significant increase in whole-body cortisol levels, while males experienced a testosterone elevation at 300 mg/L of caffeine acute exposure. There was a significant decrease in the duration of erratic movements in males treated with the androgen receptor antagonist flutamide compared to the control group. The transcriptome analysis uncovered 511 and 592 up-regulated and 761 and 922 down-regulated differential expression genes in males and females, respectively, compared to the control. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) pathway analysis revealed that caffeine has the potential to impact various pathways in zebrafish, including phototransduction and steroid hormone biosynthesis. Our findings demonstrate that testosterone and cortisol play a combined role in regulating stress responses in both behavior and physiology. Furthermore, our study highlights the significance of encompassing both male and female zebrafish as a model system
Advancements and greenification potential of magnetic molecularly imprinted polymers for chromatographic analysis of veterinary drug residues in milk
No full textMilk, as a widely consumed nutrient-rich food, is crucial for bone health, growth, and overall nutrition. The persistent application of veterinary drugs for controlling diseases and heightening milk yield has imparted substantial repercussions on human health and environmental ecosystems. Due to the high demand, fresh consumption, complex composition of milk, and the potential adverse impacts of drug residues, advanced greener analytical methods are necessitated. Among them, functional materials-based analytical methods attract wide concerns. The magnetic molecularly imprinted polymers (MMIPs), as a kind of typical functional material, possess excellent greenification characteristics and potencies, and they are easily integrated into various detection technologies, which have offered green approaches toward analytes such as veterinary drugs in milk. Despite their increasing applications and great potential, MMIPs' use in dairy matrices remains underexplored, especially regarding ecological sustainability. This work reviews recent advances in MMIPs' synthesis and application as efficient sorbents for veterinary drug extraction in milk followed by chromatographic analysis. The uniqueness and effectiveness of MMIPs in real milk samples are evaluated, current limitations are addressed, and greenification opportunities are proposed. MMIPs show promise in revolutionizing green analytical procedures for veterinary drug detection, aligning with the environmental goals of modern food production systems
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
Artificial wetlands providing space gain for the suitable habitat of coastal Pied Avocet
No full textA large number of artificial wetlands have replaced natural wetlands along waterbird migration routes to supply breeding, resting and feeding grounds for waterbirds. Effective identification of potential artificial wetlands that could serve as suitable habitats for waterbirds can provide important reference for field investigation and waterbird conservation. In this study, the habitat suitability of the Pied Avocet in the Yellow River Delta (YRD), China was simulated with the optimized MaxEnt model based on its occurrence records and environmental variables. The results showed that the MaxEnt model could well predict the habitat suitability of the Pied Avocet (Recurvirostra avosetta) in the YRD. The suitable habitats were distributed in the specific areas of the coastal zone, and artificial wetlands such as salt pans and mariculture ponds were the main components in the high-suitability area. The top three environmental factors affecting habitat selection were the land use and land cover (LULC), distance to the coastline and normalized difference vegetation index (NDVI). This paper emphasizes the role of artificial wetlands in providing suitable habitat for waterbirds. In order to better protect the habitat of waterbirds and alleviate human-bird conflict in the YRD, some targeted suggestions were put forward for the management gap of artificial wetlands. This study has strong practical significance for the protection and habitat management of waterbirds in the YRD. The methodology we employed is transferable to other wetlands, where efficient management is inhibited due to a lack of comprehensive field investigations
Albifimbrins A and B, a pair of epimeric tetrahydrofuran-containing linear polyketide derivatives from the marine-derived fungus<i> Albifimbria</i> verrucaria CD1-4
No full textA pair of new epimeric polyketides, named albifimbrins A and B (1 and 2), were isolated from the cultures of the shellfish-derived fungus Albifimbria verrucaria CD1-4. Their structures were determined by extensive spectroscopic analysis including HR-MS, 1D and 2D NMR data, together with the CD exciton chirality method. Compounds 1 and 2 possess unusual tetrahydrofuran moiety in their linear molecule structures. The antimicroalgal assay indicated that compounds 1 and 2 shown moderate inhibitory activities against marine harmful micro-algae, Prorocentrum donghaiense, Amphidinium carterae and Heterocapsa circulariaquama
Zooplankton community variations in response to summer hypoxia in Sishili Bay, North Yellow Sea, China
No full textHypoxia may cause severe disturbances to coastal ecosystems. The potential effects of summer hypoxia on zooplankton communities in Sishili Bay, China, was investigated in three cruises conducted during the summer from 2015 to 2017. Comparative analysis was performed on zooplankton communities at hypoxic and normoxic sites. Results show that the number and abundance of zooplankton species at hypoxic sites were lower than those at normoxic sites. Copepods exhibited greater dominance at the hypoxic sites compared to the normoxic sites, suggesting a higher tolerance to low oxygen concentrations than other taxonomic groups. Specifically, Oithona spp. was particularly prevalent at hypoxic sites and displayed a negative correlation with dissolved oxygen concentration at sea bottom. Additionally, the zooplankton community at hypoxic sites also exhibited lower Shannon-Wiener diversity and Margalef richness indices. The normalized biovolume size spectrum of the hypoxic sites showed steep slopes, suggesting a shift towards smaller species and lower transfer efficiency in pelagic food webs for the zooplankton community
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