In an attempt to assess the paleoenvironments of terrestrial sediments,some twenty-two representa-tive Chinese non-marine sediment samples were studied using the molecular organic geochemistry method.The sediment samp...In an attempt to assess the paleoenvironments of terrestrial sediments,some twenty-two representa-tive Chinese non-marine sediment samples were studied using the molecular organic geochemistry method.The sediment samples stuied include oilshale,shale,mudstone and glauber salt from Tertiary to Cretaceous in age.Judging from geological/geochemical data and paleosalinity data,the samples studied are of lacustrine sedimentary origin and can be divided into three different types:fresh water,brackish and saline/hypersaline lake sediments.The aliphatic fractions were separated from the extracts of the samples and analysed by means of GC and GC/MS instruments,giving a number of parameters such as relative abundances of alkanes and cycloalkanes as shown in the mass chromatograms.展开更多
Dissolved oxygen(DO)and apparent oxygen utilization(AOU)are essential parameters for evaluating the impact of climate change on marine ecosystems.In this study,we utilized data on DO and AOU collected from the Amundse...Dissolved oxygen(DO)and apparent oxygen utilization(AOU)are essential parameters for evaluating the impact of climate change on marine ecosystems.In this study,we utilized data on DO and AOU collected from the Amundsen Sea(western Antarctic)and the Cosmonaut Sea(eastern Antarctic)during the 38th Chinese National Antarctic Research Expedition,along with chlorophyll a(Chl a)data,to analyze the impact of primary production and the spatial distribution and structural features of water masses in these regions.The findings show that the standard deviation range of parallel DO samples is between 0.1 and 3.9μmol·L^(-1),meeting the precision criteria of the survey method.AOU values lower than 0.0μmol·L^(-1) were commonly observed in the surface waters of both regions,with the highest incidence in the polynya of Amundsen Sea,indicating a strong influence of high primary production.The Cosmonaut Sea exhibited the highest AOU values(higher than 160.0μmol·L^(-1))in the 75-500 m layer,while AOU value in the Amundsen Sea did not exceed 160.0μmol·L^(-1),suggesting potential upwelling of Circumpolar Deep Water to 100 m in the Cosmonaut Sea with minimal changes in its properties,whereas significant changes were noted in the properties of upwelling modified Circumpolar Deep Water in the Amundsen Sea.AOU values lower than 125.0μmol·L^(-1)were detected in the near-bottom waters of the Cosmonaut Sea,indicating the presence of Antarctic Bottom Water.展开更多
Agricultural plastic mulch film represents a significant source of microplastic contamination in soils, raising concerns about soil health and food security. Oxo-degradable plastics (ODPs) have emerged as a potentiall...Agricultural plastic mulch film represents a significant source of microplastic contamination in soils, raising concerns about soil health and food security. Oxo-degradable plastics (ODPs) have emerged as a potentially more sustainable alternative to current plastic mulch films, however, uncertainty remains around the degradation rate of ODPs in soil and their impacts on soil quality and crop health. The study evaluated the dynamics and impact of different concentrations of micro- and macroplastics derived from a commercial d2w ODP (0.01%, 0.1%, 1% and 10% w/w) on the growth of Zea mays in an agricultural soil over a 6-week period. Chemical analysis revealed the ODP contained about 0.29% additives by weight, primarily comprising antioxidants (tris(2,4-di-tert-butylphenyl) phosphite and its oxidized form) and lubricants, with minimal heavy metal content. ODP degradation was mainly limited to chain scission and had only partial formation of oxygenated groups, without an increase in carbonyl groups. The rate of ODP degradation was found to be inversely related to the ODP concentration in soil. Overall, typical field levels of plastic contamination (0.01% w/w) had negligible effect on soil quality or plant performance. However, higher levels of ODP contamination resulted in significant changes in soil pH, EC, NO_(3)^(−) and bulk density. At extreme plastic loading rates (10% w/w), both micro- and macro-sized ODPs caused significant reductions in plant growth, with microplastic treatments having consistently greater effects than the macroplastic treatments. Changes in bacterial 16S rRNA community composition were driven by Acidobacteriota and Gemmatimonadota. Macroplastics significantly altered these bacterial communities, while microplastics had minimal effect. These findings indicate that at realistic field concentrations, ODPs are likely to have little effect on agroecosystem functioning in the short-term but might persist in soil for long periods of time, leading to their progressive accumulation in agricultural soils if used over repeated cropping cycles.展开更多
Plastic film mulching(PFM)enhances plant growth and productivity by modifying soil properties.In Sri Lanka,the adoption of PFM is gradually rising,especially for high-value crops.However,its influence on soil remains ...Plastic film mulching(PFM)enhances plant growth and productivity by modifying soil properties.In Sri Lanka,the adoption of PFM is gradually rising,especially for high-value crops.However,its influence on soil remains a topic of significant scrutiny,especially in environmentally delicate locations such as the wet zone(WZ)of Sri Lanka.This research examines how different PFMs affect soil physicochemical properties and plant performance in chili production within the WZ.Chili(Capsicum annuum cv.MICH HY-1)was cultivated under a non-biodegradable low-density polyethylene(LDPE)mulch(PEUK),a reflective LDPE mulch,a PLA-PBAT biodegradable mulch(BD)and no mulch film application for one growing season.Soil physicochemical properties(pH,EC,moisture,nutrients and temperature),plant height and leaf chlorophyll content(SPAD)were measured monthly.The fresh biomass of roots,leaves,stems and remaining fruits was measured at the end of the season.This study demonstrated that mulching effectively conserved soil NO_(3)^(–)and available P while having no significant impact on NH_(4)^(+)levels.Mulching increased gravimetric moisture content(GMC)and soil temperature compared to the control,with PEUK achieving the highest soil temperature(36.3±0.71°C).Mulching did not influence soil pH,but the control consistently had the lowest EC(17.6±1.54µS·cm^(−1)).Mulching significantly improved plant height(PEUK of 70.2±1.7 cm),SPAD(PEUK of 65.6±1.4),yield(BD of 1230±84 g)and fresh biomass relative to the control(height of 58.8±2.3 cm,SPAD of 49.7±1.5 and yield of 736±59 g).Overall,the findings demonstrate that biodegradable mulch performed similarly to non-biodegradable plastic mulches in improving both soil properties and crop yield,indicating it could be a sustainable alternative for chili production in wet tropical regions.展开更多
基金This project was financially supported by the National Natural Science Foundation of China.
文摘In an attempt to assess the paleoenvironments of terrestrial sediments,some twenty-two representa-tive Chinese non-marine sediment samples were studied using the molecular organic geochemistry method.The sediment samples stuied include oilshale,shale,mudstone and glauber salt from Tertiary to Cretaceous in age.Judging from geological/geochemical data and paleosalinity data,the samples studied are of lacustrine sedimentary origin and can be divided into three different types:fresh water,brackish and saline/hypersaline lake sediments.The aliphatic fractions were separated from the extracts of the samples and analysed by means of GC and GC/MS instruments,giving a number of parameters such as relative abundances of alkanes and cycloalkanes as shown in the mass chromatograms.
基金supported by the Scientific Research Fund of the Second Institute of Oceanography,MNR(Grant nos.JG2211 and JG2212)the National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(Grant nos.IRASCC 01-01-02A and IRASCC 02-02)+1 种基金the National Key Research and Development Program of China(Grant no.2022YFE0136500)the National Natural Science Foundation of China(Grant no.41976228)。
文摘Dissolved oxygen(DO)and apparent oxygen utilization(AOU)are essential parameters for evaluating the impact of climate change on marine ecosystems.In this study,we utilized data on DO and AOU collected from the Amundsen Sea(western Antarctic)and the Cosmonaut Sea(eastern Antarctic)during the 38th Chinese National Antarctic Research Expedition,along with chlorophyll a(Chl a)data,to analyze the impact of primary production and the spatial distribution and structural features of water masses in these regions.The findings show that the standard deviation range of parallel DO samples is between 0.1 and 3.9μmol·L^(-1),meeting the precision criteria of the survey method.AOU values lower than 0.0μmol·L^(-1) were commonly observed in the surface waters of both regions,with the highest incidence in the polynya of Amundsen Sea,indicating a strong influence of high primary production.The Cosmonaut Sea exhibited the highest AOU values(higher than 160.0μmol·L^(-1))in the 75-500 m layer,while AOU value in the Amundsen Sea did not exceed 160.0μmol·L^(-1),suggesting potential upwelling of Circumpolar Deep Water to 100 m in the Cosmonaut Sea with minimal changes in its properties,whereas significant changes were noted in the properties of upwelling modified Circumpolar Deep Water in the Amundsen Sea.AOU values lower than 125.0μmol·L^(-1)were detected in the near-bottom waters of the Cosmonaut Sea,indicating the presence of Antarctic Bottom Water.
基金his study was part of a project funded by the UK Natural Environment Research Council Global Challenges Research Fund program on Reducing the Impacts of Plastic Waste in Developing Countries (NE/V005871/1).
文摘Agricultural plastic mulch film represents a significant source of microplastic contamination in soils, raising concerns about soil health and food security. Oxo-degradable plastics (ODPs) have emerged as a potentially more sustainable alternative to current plastic mulch films, however, uncertainty remains around the degradation rate of ODPs in soil and their impacts on soil quality and crop health. The study evaluated the dynamics and impact of different concentrations of micro- and macroplastics derived from a commercial d2w ODP (0.01%, 0.1%, 1% and 10% w/w) on the growth of Zea mays in an agricultural soil over a 6-week period. Chemical analysis revealed the ODP contained about 0.29% additives by weight, primarily comprising antioxidants (tris(2,4-di-tert-butylphenyl) phosphite and its oxidized form) and lubricants, with minimal heavy metal content. ODP degradation was mainly limited to chain scission and had only partial formation of oxygenated groups, without an increase in carbonyl groups. The rate of ODP degradation was found to be inversely related to the ODP concentration in soil. Overall, typical field levels of plastic contamination (0.01% w/w) had negligible effect on soil quality or plant performance. However, higher levels of ODP contamination resulted in significant changes in soil pH, EC, NO_(3)^(−) and bulk density. At extreme plastic loading rates (10% w/w), both micro- and macro-sized ODPs caused significant reductions in plant growth, with microplastic treatments having consistently greater effects than the macroplastic treatments. Changes in bacterial 16S rRNA community composition were driven by Acidobacteriota and Gemmatimonadota. Macroplastics significantly altered these bacterial communities, while microplastics had minimal effect. These findings indicate that at realistic field concentrations, ODPs are likely to have little effect on agroecosystem functioning in the short-term but might persist in soil for long periods of time, leading to their progressive accumulation in agricultural soils if used over repeated cropping cycles.
基金supported by UKRI Global Challenges Research Fund (NE/V005871/1).
文摘Plastic film mulching(PFM)enhances plant growth and productivity by modifying soil properties.In Sri Lanka,the adoption of PFM is gradually rising,especially for high-value crops.However,its influence on soil remains a topic of significant scrutiny,especially in environmentally delicate locations such as the wet zone(WZ)of Sri Lanka.This research examines how different PFMs affect soil physicochemical properties and plant performance in chili production within the WZ.Chili(Capsicum annuum cv.MICH HY-1)was cultivated under a non-biodegradable low-density polyethylene(LDPE)mulch(PEUK),a reflective LDPE mulch,a PLA-PBAT biodegradable mulch(BD)and no mulch film application for one growing season.Soil physicochemical properties(pH,EC,moisture,nutrients and temperature),plant height and leaf chlorophyll content(SPAD)were measured monthly.The fresh biomass of roots,leaves,stems and remaining fruits was measured at the end of the season.This study demonstrated that mulching effectively conserved soil NO_(3)^(–)and available P while having no significant impact on NH_(4)^(+)levels.Mulching increased gravimetric moisture content(GMC)and soil temperature compared to the control,with PEUK achieving the highest soil temperature(36.3±0.71°C).Mulching did not influence soil pH,but the control consistently had the lowest EC(17.6±1.54µS·cm^(−1)).Mulching significantly improved plant height(PEUK of 70.2±1.7 cm),SPAD(PEUK of 65.6±1.4),yield(BD of 1230±84 g)and fresh biomass relative to the control(height of 58.8±2.3 cm,SPAD of 49.7±1.5 and yield of 736±59 g).Overall,the findings demonstrate that biodegradable mulch performed similarly to non-biodegradable plastic mulches in improving both soil properties and crop yield,indicating it could be a sustainable alternative for chili production in wet tropical regions.
