SCIENCE OF THE TOTAL ENVIRONMENT
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2019
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IF 5.589
Yuxi Lu,Xuelu Gao,Jinming Song,Chen-Tung Arthur Chen,Jinling Chu
The environmental characteristics of colloidal toxic trace metals Cd, Cu and Pb in riverine and estuarine waters collected from two urban rivers of Yantai City in eastern China, the Guangdang and Xin'an Rivers, were investigated using a modified centrifugal ultrafiltration (CUF) method in conjunction with acid extraction and inductively coupled plasma mass spectrometry. The target metals in dissolved pool were divided into four CUF fractions, i.e. <1 kDa, 1–3 kDa, 3–10 kDa and 10 kDa–0.2 μm, and the results showed that colloidal Cd, Cu and Pb were dominated by 1–10 kDa (1–3 and 3–10 kDa), 1–3 kDa and 10 kDa–0.2 μm fractions, respectively. The coagulation/flocculation of low-molecular-weight (1–10 kDa) colloidal Cd and Cu in the estuaries was obvious and strong, while the enrichment of dissolved Pb in the 10 kDa–0.2 μm fraction may be mainly related to its biogeochemical interactions with Fe-oxides, which is easy to occur in macromolecular colloids. In addition, the actual molecular weight cutoffs (MWCOs) of the three used CUF units with nominal MWCOs of 1, 3 and 10 kDa were determined to be 4.9, 8.5 and 33.9 kDa, respectively, indicating that membrane calibration is essential for explaining the actual fraction of dissolved trace metals and verifying the integrity of ultrafiltration membrane. Overall, the results in this study provide a further understanding of the heterogeneity in biogeochemical features, migration and fate of toxic trace metals in aquatic ecosystems, especially that of the river-sea mixing zone.
研究领域:
环境科学
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海洋学
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DOI
PubMed
高影响因子
Journal of Environmental Sciences
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2023
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IF 6.9
Ruixue Liu,Yinshun Dai,Yucheng Feng,Shiwen Sun,Xiaodong Zhang,Chunjiang An,Shan Zhao
Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent, however, the mechanism on the hydroxyl radical (HO · ) production by pyrite under estuarine environmental conditions is still poorly understood. The batch experiments were performed to investigate the effects of estuarine conditions including aging (in air, in water), seawater anions (Cl − , Br − and HCO 3 − ) and light on the HO · production by pyrite oxidation. The one-electron transfer dominated the process from O 2 to HO · induced by oxidation of pyrite. The Fe (oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer, and the combined effect of the two resulted in a suppression of HO · production in the early stage of aging and a promotion of HO · production in the later stage of aging. Corrosion of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO · production by Cl − and Br − , and the generation of Cl · and Br · may also play a role in the scavenging of HO · . HCO 3 − increased the average rate of HO · production through surface-CO 2 complexes formed by adsorption on the surface of pyrite. The significant enhancement of HO · production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide layers. These findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.
研究领域:
环境科学
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地球化学
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DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
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2024
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IF 8.2
Tong Wang,Dan Li,Xin Tian,Guolin Huang,Meilin He,Changhai Wang,Ali Nawaz Kumbhar,Abeselom Ghirmai Woldemicael
Salinity stress in estuarine environments poses a significant challenge for microalgal survival and proliferation. The interaction between microalgae and bacteria shows promise in alleviating the detrimental impacts of salinity stress on microalgae. Our study investigates this interaction by co-cultivating Chlorella sorokiniana , a freshwater microalga, with a marine growth-promoting bacterium Pseudomonas gessardii , both of which were isolated from estuary. In this study, bacteria were encapsulated using sodium alginate microspheres to establish an isolated co-culture system, preventing direct exposure between microalgae and bacteria. We evaluated microalgal responses to different salinities (5 PSU, 15 PSU) and interaction modes (free-living, gel-encapsulated), focusing on growth, photosynthesis, cellular metabolism, and extracellular polymeric substances (EPS) properties. High salinity inhibited microalgal proliferation, while gel-fixed interaction boosted Chlorella growth rate by 50.7 %. Both attached and free-living bacteria restored Chlorella 's NPQ to normal levels under salt stress. Microalgae in the free-living interaction group exhibited a significantly lower respiratory rate compared to the pure algae group (−17.2 %). Increased salinity led to enhanced EPS polysaccharide secretion by microalgae, particularly in interaction groups (19.7 %). Both salt stress and interaction increased the proportion of aromatic proteins in microalgae's EPS, enhancing its stability by modulating EPS glycosidic bond C-O-C and protein vibrations. This alteration caused microalgal cells to aggregate, free-living bacteria co-culture group, and fixed co-culture group increasing by 427.5 %, 567.1 %, and 704.1 %, respectively. In gel-fixed bacteria groups, reduced neutral lipids don't accumulate starch instead, carbon redirects to cellular growth, aiding salt stress mitigation. These synergistic activities between salinity and bacterial interactions are vital in mitigating salinity stress, improving the resilience and growth of microalgae in saline conditions. Our research sheds light on the mechanisms of microalgal-bacterial interactions in coping with salt stress, offering insights into the response of estuarine microorganisms to global environmental changes and their ecological stability.
研究领域:
微生物学
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环境科学
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海洋生物学
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植物生理学
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生物技术
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DOI
PubMed
高影响因子
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