Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives ...Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.展开更多
Historical and novel data on the geographic and bathymetric distribution of ascidians from Antarctic, Magellan and Chilean waters are compiled, and an inventory of taxa comprising 162 species reported over a 150 year ...Historical and novel data on the geographic and bathymetric distribution of ascidians from Antarctic, Magellan and Chilean waters are compiled, and an inventory of taxa comprising 162 species reported over a 150 year period from the Antarctic region South Polar Province （SPP） compiled. The ascidian fauna from the South Shetland Islands （SSI） is compared with that of the Magellan region, Patagonia and the Chilean coast. We collected 46 ascidian species along the Chilean coast, and during four expeditions to King George Island （SSI） by SCUBA between 2003-2012. About 15% of King George Island （SSI） species are observed to occur also in shallow waters of southern Chile （SCL）. Few species known from warm temperate southeastern Pacific （Northern Chile, NCL） waters are absent from the Chilean part of the Magellan Province （SCL）. With most data contributed from the Chilean coast coming from the SCL, and with limited sampling having been undertaken at depths exceeding 100 m in the NCL, apparent differences in species richness along the Chilean coast could be attributabed to differential sampling effort. We detail 12 species from our Antarctic and Chilean collections in detail, including one, Diplosoma listerianum, not previously reported from Chilean waters, and the genus Botryllus, previously known from them on the basis of a single record.展开更多
<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of...<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of Japan, geochemical factors were calculated. The algae geochemical anomaly index (I<sub>GA</sub>) characterizes the degree of excess of the background concentrations of metals. The heavy metal pollution factor (F<sub>p</sub>) is used to estimate the degree of pollution of the marine environment with heavy metals. The Peter the Great Bay has a low level of heavy metal pollution, but some parts of second-order bays, such as Amurskii Bay, Ussuriiskii Bay and Vostok Bay, have a moderate degree of pollution. The high pollution level was registed on the western coast of the Ussuriiskii Bay near the Vladivostok city landfill. Thirty percent of sampling stations were noted to have higher threshold levels of metals in the algae. These areas need to be monitored to assess their environmental status and measures should be applied to reduce the impact on the environment. </div>展开更多
The main objective of the study was to prepare a highly active antimicrobial remedy by combining active agents such as tannic acid and silver nanoparticles,which are usually used separately.This was achieved by applyi...The main objective of the study was to prepare a highly active antimicrobial remedy by combining active agents such as tannic acid and silver nanoparticles,which are usually used separately.This was achieved by applying a coating of 11 alternating layers of an insoluble complex of tannic acid with polyvinyl alcohol on paper by the layerby-layer approach,on the surface of which uniformly distributed spherical silver nanoparticles of uniform size,mainly 20–30 nm,were synthesized by in situ reduction using tannic acid,which also acts as a stabilizer,or an external reducing agent,which prevented polyphenol oxidation.This gave an insight into which form-oxidized or reduced-ismore active against microorganisms.It was shown that sterilization was not required after the coating of the paper with tannic acid and silver nanoparticles.When combined,their activity against the studied bacteria-gram-negative Escherichia coli and gram-positive Staphylococcus aureus,as well as yeast Candida albicans was higher and lasting up to 7 days than when tannic acid and silver nanoparticles were used separately,indicating possible synergism in their action.展开更多
This study was used oceanographic database in the Sea of Okhotsk between the period from 1929 to 2020(131286 stations).The paper used gas hydrate dissociation parameters for the“pure methane-seawater”system obtained...This study was used oceanographic database in the Sea of Okhotsk between the period from 1929 to 2020(131286 stations).The paper used gas hydrate dissociation parameters for the“pure methane-seawater”system obtained in the study by Dickens GR and Quinby-Hunt MS.The results have elucidated the spatiotemporal variability of distribution of such parameters at the upper boundary of the gas hydrate stability zone(GHSZ)as water temperature,salinity,and top depth of the stability zone.As the study has shown(based on average long-term spatial distributions),the minimum temperature and depth values of the GHSZ upper boundary in the Sea of Okhotsk occur off the western and southwestern parts of the water area.The maximum temperature and depth values of the GHSZ upper boundary are typical of the southeastern sea area and over the Kamchatka Peninsula slope.This study has also identified an area,where there are no thermobaric conditions for the emergence and stable existence of methane hydrates in the water column.The results presented agree well with the materials of observations conducted during expeditions and the previous data of predictive simulations for the Sea of Okhotsk.展开更多
The paper deals with the urgent problem of gas-geochemical parameters in the seas and shelf transit zones based on a comparison of field studies and remote sensing data.The results of complex gas-geochemical studies o...The paper deals with the urgent problem of gas-geochemical parameters in the seas and shelf transit zones based on a comparison of field studies and remote sensing data.The results of complex gas-geochemical studies of the Daginsky gas-hydrothermal system are presented,as well as an assessment of methane emissions from the studied area.The Daginsky gas-hydrothermal system is located on the northeastern coast of Sakhalin Island,and is a unique object due to a combination of a number of factors:from zonality due to the proximity of the Okhotsk Sea and the geological structure,to the interaction of deep and surface processes manifested in the presence of biogenic and thermogenic methane,as well as mantle helium.Tectonic faults and oil and gas bearing structures of the northeastern shelf of Sakhalin,which determine the direction of natural gas flows and facilitate its migration to the surface,make a significant contribution to the gas appearance of thermal springs.The main gas is methane up to 90%,homologues of methane up to and including pentane have been established,and isolated high concentrations of helium and hydrogen,both dissolved and in the free gas of bubbles,have also been noted.The conducted isotope studies allow to speak about the complex genesis of the gas.δ^(13)C isotopic composition,ranging from−49.4‰to−60.2‰shows the dominance of biogenic methane with an admixture of thermogenic component.This is also confirmed by the presence of a fraction of mantle helium.The flow of methane into the atmosphere from the Daginsky area is 963757.5 mol/(km^(2)·day),or about 15.4 t/(km^(2)·year),which indicates the importance of this region for the regional and global carbon cycle.The dynamics of methane emissions can vary depending on various factors,such as seasonal fluctuations and geological activity,which further complicates the understanding of processes in the region.展开更多
The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed ...The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed throughout the World Ocean.This event was notable for its unprecedented global impact and the early appearance of tsunami waves at distant coastal stations.So,the first waves at tide gauge stations in Chile and Peru were recorded 4 hours earlier than the arrival time of tsunami waves to the tide gauge after the eruption of Tonga volcano.Two mechanisms are possible for the generation of early tsunami waves:acoustic Lamb waves generated by a volcanic explosion and submarine landslides that occurred on the slopes of the volcano during the preparatory phase of the eruption.In this study,numerical simulation of various pre-eruption landslide scenarios on the slope of Hunga Tonga volcano is carried out in an attempt to explain these early tsunami waves.Under computation the elastoplastic model of landslide was taken into account.Wave characteristics of a tsunami on the coast of Chile and Peru generated by a landslide process on a volcanic slope are obtained.A detailed comparison of virtual tide gauge data with observational ones is used to validate this model.The results obtained can be used to improve early warning systems.展开更多
Ulmus furcinervis (Borsuk) Ablaev is first recognized and described in the Paleocene Wuyun flora from Heilongjiang Province, China. The combination of key characteristics for identification of these leaf specimens is ...Ulmus furcinervis (Borsuk) Ablaev is first recognized and described in the Paleocene Wuyun flora from Heilongjiang Province, China. The combination of key characteristics for identification of these leaf specimens is that they have craspedodromous secondary veins forked near the leaf marginal, tertiary veins percurrent and marginal teeth convex. Specimens formerly described as leaves of Planera cf. microphylla auct. non Newberry and Sorbaria wuyunensis Tao et Xiong in Wuyun flora are reexamined and assigned to U. furcinervis.展开更多
Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated...Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated in Trochodendron sp. were reviewed and assigned to Amersinia obtrullata. Leaves described as Populus carneosa, Celastrophyllum subprotophyllum, Viburnum antiquum, V. asperum, Viburniphyllum finale, Protophyllum wuyunense, P. cf. haydenii, P. ovatifolium, Credneria inordinata were also restudied and assigned to Beringiaphyllum pseudoantiquum.展开更多
Pure fraction (92%-95%) of phagocytes (FP) and a mixture of amoebocytes(62%) and morula cells (38 %) FPMC of the holothurian Eupentacta fraudatrix (Holothuroidea, Dendrochirota) were obtained by using ficoll verograph...Pure fraction (92%-95%) of phagocytes (FP) and a mixture of amoebocytes(62%) and morula cells (38 %) FPMC of the holothurian Eupentacta fraudatrix (Holothuroidea, Dendrochirota) were obtained by using ficoll verographine step gradient. Basal production of reactive oxygen species (ROS) in FP quantified by using reduction of nitroblue tetrazolium (NBT) was more than twice that in FPMC. Thermostable toxin of Yersinia pseudotuberculosis (TST) at different concentrations ( 0.2; 0.5; 2.5 μg/ml, but not 0.1 μg/ml) stimulated NBT reduction in FPMC after 24 h incubation. In FP, TST at concentrations of 0.1 and 0.2 μg/ml inhibited and at concentrations of 0.5 and 2.5 μg/ml stimulated NBT reduction after 24 h incubation. Maximal effect was observed in FP and FPMC at TST concentrations of 0.5 and 0.2 μg/ml, respectively. Addition of catalase (0.7 μg/ml) to the cells treated with TST (2.5 μg/ml) was followed by a decrease in NBT reduction compared to that under toxin treatment alone. TST stimulated superoxide dismutase activity in concentration dependent manner (maximum at 0.5 μg/ml concentration in FP) after 24 h treatment, and this stimulation was prevented by a commercial catalase. Plant lectin concanavalin A stimulated NBT reduction more than 5 fold in FPMC compared to the control. With addition of TST, lectin stimulated ROS to lesser extent than that with lectin alone. When catalase, TST, and lectin were added into the FPMC simultaneously, ROS increase was similar to that under lectin treatment alone. On the whole, data obtained indicated that ROS generation in holothurian coelomocytes especially occurs in both stimulated and not stimulated phagocytes, and that changes in ROS production by these cells may be one of the mechanisms of antibacterial protection of holothurians.展开更多
The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial...The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.展开更多
Cardiovascular diseases and diabetes mellitus are leading causes of mortality in modern society. The search for a novel effective remedy represents an important task for modern medicine. A total mixture of phospho- an...Cardiovascular diseases and diabetes mellitus are leading causes of mortality in modern society. The search for a novel effective remedy represents an important task for modern medicine. A total mixture of phospho- and glycolipids from sea macrophytes Sargassum pallidum, Ulva fenestrata, Zostera marina was separated and the fatty acid composition was determined. The biological activity of the mixtures of polar lipids and natural redox-active compounds (echinochrome A from the flat sea urchin Scaphechinus mirabilis and a polyphenolic complex from the sea grass Zostera marina) was studied under conditions of impairments of carbohydrate and lipid metabolism. Doses and compositions of mixtures of pola lipids and redox-active compounds possessing high corrective activity were optimized in mice with the experimental model of hyperlipidemia and diabetes. Based on these results possible mechanisms of the effects of polar lipids containing various polyunsaturated fatty acids and the investigated redox-active compounds (echinochrome A, rosmarinic acid, luteolin and its sulphate conjugates) have been proposed. The developed compositions may be used for creation of new biologically active additives and remedies.展开更多
The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein conten...The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein content in leaves inoculated with a mixture of TMV(2 μg/mL) and chitosan(1 mg/mL) were lower in the early period of infection(3 days after inoculation), by 63% and 66% respectively, than in leaves inoculated with TMV only. Treatment of leaves with chitosan 24 h before inoculation with TMV also caused the antiviral effects, but these were less apparent than when the virus and polysaccharide were applied simultaneously. The inhibitory effects of the agent decreased as the infection progressed. Inoculation of leaves with TMV together with chitosan considerably enhanced the activity of hydrolases(proteases, RNases) in the leaves, in comparison with leaves inoculated with TMV alone. Electron microscope assays of phosphotungstic acid(PTA)-stained suspensions from infected tobacco leaves showed that, in addition to the normal TMV particles(18 nm in diameter, 300 nm long), these suspensions contained abnormal(swollen, "thin" and "short") virions. The highest number of abnormal virions was found in suspensions from leaves inoculated with a mixture of TMV and chitosan. Immuno-electron microscopy showed that "thin" virus particles, in contrast to the particles of normal diameter, lost the ability to bind to specific antiserum. It seems that the chitosan-induced activation of hydrolases stimulates the intracellular degradation of TMV particles and hence hydrolase activation may be considered to be one of the polysaccharide-mediated cellular defense mechanisms that limit virus accumulation in cells.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U2342208)support from NSF/Climate Dynamics Award#2025057。
文摘Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.
基金supported by the International Bureau, Bonn, FRG (Grant no. CHL07/007)the Direction of Investigation and Development of the University Austral de Chile, Valdivia, UACh, Chile (Grant no. S-2008-14)the Chilean Antarctic Institute, INACh (Grant no. T_21-09)
文摘Historical and novel data on the geographic and bathymetric distribution of ascidians from Antarctic, Magellan and Chilean waters are compiled, and an inventory of taxa comprising 162 species reported over a 150 year period from the Antarctic region South Polar Province （SPP） compiled. The ascidian fauna from the South Shetland Islands （SSI） is compared with that of the Magellan region, Patagonia and the Chilean coast. We collected 46 ascidian species along the Chilean coast, and during four expeditions to King George Island （SSI） by SCUBA between 2003-2012. About 15% of King George Island （SSI） species are observed to occur also in shallow waters of southern Chile （SCL）. Few species known from warm temperate southeastern Pacific （Northern Chile, NCL） waters are absent from the Chilean part of the Magellan Province （SCL）. With most data contributed from the Chilean coast coming from the SCL, and with limited sampling having been undertaken at depths exceeding 100 m in the NCL, apparent differences in species richness along the Chilean coast could be attributabed to differential sampling effort. We detail 12 species from our Antarctic and Chilean collections in detail, including one, Diplosoma listerianum, not previously reported from Chilean waters, and the genus Botryllus, previously known from them on the basis of a single record.
文摘<div style="text-align:justify;"> According to the content of heavy metals Fe, Mn, Cu, Zn, Pb, Cd and Ni in brown algae <em>Sargassum miyabei</em> from the Peter the Great Bay of the Sea of Japan, geochemical factors were calculated. The algae geochemical anomaly index (I<sub>GA</sub>) characterizes the degree of excess of the background concentrations of metals. The heavy metal pollution factor (F<sub>p</sub>) is used to estimate the degree of pollution of the marine environment with heavy metals. The Peter the Great Bay has a low level of heavy metal pollution, but some parts of second-order bays, such as Amurskii Bay, Ussuriiskii Bay and Vostok Bay, have a moderate degree of pollution. The high pollution level was registed on the western coast of the Ussuriiskii Bay near the Vladivostok city landfill. Thirty percent of sampling stations were noted to have higher threshold levels of metals in the algae. These areas need to be monitored to assess their environmental status and measures should be applied to reduce the impact on the environment. </div>
基金funded by the Russian Science Foundation,grant 22-13-00337.
文摘The main objective of the study was to prepare a highly active antimicrobial remedy by combining active agents such as tannic acid and silver nanoparticles,which are usually used separately.This was achieved by applying a coating of 11 alternating layers of an insoluble complex of tannic acid with polyvinyl alcohol on paper by the layerby-layer approach,on the surface of which uniformly distributed spherical silver nanoparticles of uniform size,mainly 20–30 nm,were synthesized by in situ reduction using tannic acid,which also acts as a stabilizer,or an external reducing agent,which prevented polyphenol oxidation.This gave an insight into which form-oxidized or reduced-ismore active against microorganisms.It was shown that sterilization was not required after the coating of the paper with tannic acid and silver nanoparticles.When combined,their activity against the studied bacteria-gram-negative Escherichia coli and gram-positive Staphylococcus aureus,as well as yeast Candida albicans was higher and lasting up to 7 days than when tannic acid and silver nanoparticles were used separately,indicating possible synergism in their action.
基金the POI FEB RAS,entitled“Study of the Structure and Dynamics of World’s Oceans Waters in Conditions of Current Climate Change”(reg.no.124022100079-4).
文摘This study was used oceanographic database in the Sea of Okhotsk between the period from 1929 to 2020(131286 stations).The paper used gas hydrate dissociation parameters for the“pure methane-seawater”system obtained in the study by Dickens GR and Quinby-Hunt MS.The results have elucidated the spatiotemporal variability of distribution of such parameters at the upper boundary of the gas hydrate stability zone(GHSZ)as water temperature,salinity,and top depth of the stability zone.As the study has shown(based on average long-term spatial distributions),the minimum temperature and depth values of the GHSZ upper boundary in the Sea of Okhotsk occur off the western and southwestern parts of the water area.The maximum temperature and depth values of the GHSZ upper boundary are typical of the southeastern sea area and over the Kamchatka Peninsula slope.This study has also identified an area,where there are no thermobaric conditions for the emergence and stable existence of methane hydrates in the water column.The results presented agree well with the materials of observations conducted during expeditions and the previous data of predictive simulations for the Sea of Okhotsk.
基金funded by a grant Russian Science Foundation(No.23-77-10038,https://rscf.ru/project/23-77-10038/)partly within the framework of the state task of the POI FEB RAS(No.124022100078-7).
文摘The paper deals with the urgent problem of gas-geochemical parameters in the seas and shelf transit zones based on a comparison of field studies and remote sensing data.The results of complex gas-geochemical studies of the Daginsky gas-hydrothermal system are presented,as well as an assessment of methane emissions from the studied area.The Daginsky gas-hydrothermal system is located on the northeastern coast of Sakhalin Island,and is a unique object due to a combination of a number of factors:from zonality due to the proximity of the Okhotsk Sea and the geological structure,to the interaction of deep and surface processes manifested in the presence of biogenic and thermogenic methane,as well as mantle helium.Tectonic faults and oil and gas bearing structures of the northeastern shelf of Sakhalin,which determine the direction of natural gas flows and facilitate its migration to the surface,make a significant contribution to the gas appearance of thermal springs.The main gas is methane up to 90%,homologues of methane up to and including pentane have been established,and isolated high concentrations of helium and hydrogen,both dissolved and in the free gas of bubbles,have also been noted.The conducted isotope studies allow to speak about the complex genesis of the gas.δ^(13)C isotopic composition,ranging from−49.4‰to−60.2‰shows the dominance of biogenic methane with an admixture of thermogenic component.This is also confirmed by the presence of a fraction of mantle helium.The flow of methane into the atmosphere from the Daginsky area is 963757.5 mol/(km^(2)·day),or about 15.4 t/(km^(2)·year),which indicates the importance of this region for the regional and global carbon cycle.The dynamics of methane emissions can vary depending on various factors,such as seasonal fluctuations and geological activity,which further complicates the understanding of processes in the region.
基金funded by the Ministry of Science and Higher Education of the Russian Federation(agreement No.075-15-2022-1127 dated July 1,2022).
文摘The paper considers a catastrophic event-the eruption of Hunga Tonga-Hunga Ha’apai volcano on January 15,2022.The process of preparation and eruption of Hunga Tonga volcano generated tsunami waves that were observed throughout the World Ocean.This event was notable for its unprecedented global impact and the early appearance of tsunami waves at distant coastal stations.So,the first waves at tide gauge stations in Chile and Peru were recorded 4 hours earlier than the arrival time of tsunami waves to the tide gauge after the eruption of Tonga volcano.Two mechanisms are possible for the generation of early tsunami waves:acoustic Lamb waves generated by a volcanic explosion and submarine landslides that occurred on the slopes of the volcano during the preparatory phase of the eruption.In this study,numerical simulation of various pre-eruption landslide scenarios on the slope of Hunga Tonga volcano is carried out in an attempt to explain these early tsunami waves.Under computation the elastoplastic model of landslide was taken into account.Wave characteristics of a tsunami on the coast of Chile and Peru generated by a landslide process on a volcanic slope are obtained.A detailed comparison of virtual tide gauge data with observational ones is used to validate this model.The results obtained can be used to improve early warning systems.
文摘Ulmus furcinervis (Borsuk) Ablaev is first recognized and described in the Paleocene Wuyun flora from Heilongjiang Province, China. The combination of key characteristics for identification of these leaf specimens is that they have craspedodromous secondary veins forked near the leaf marginal, tertiary veins percurrent and marginal teeth convex. Specimens formerly described as leaves of Planera cf. microphylla auct. non Newberry and Sorbaria wuyunensis Tao et Xiong in Wuyun flora are reexamined and assigned to U. furcinervis.
文摘Specimens of Amersinia obtrullata and Beringiaphyllum pseudoantiquum in Paleocene Wuyun flora, Heilongjiang Province, Northeast China, were described and assigned to Cornaceae sensu. Infructescences formally allocated in Trochodendron sp. were reviewed and assigned to Amersinia obtrullata. Leaves described as Populus carneosa, Celastrophyllum subprotophyllum, Viburnum antiquum, V. asperum, Viburniphyllum finale, Protophyllum wuyunense, P. cf. haydenii, P. ovatifolium, Credneria inordinata were also restudied and assigned to Beringiaphyllum pseudoantiquum.
文摘Pure fraction (92%-95%) of phagocytes (FP) and a mixture of amoebocytes(62%) and morula cells (38 %) FPMC of the holothurian Eupentacta fraudatrix (Holothuroidea, Dendrochirota) were obtained by using ficoll verographine step gradient. Basal production of reactive oxygen species (ROS) in FP quantified by using reduction of nitroblue tetrazolium (NBT) was more than twice that in FPMC. Thermostable toxin of Yersinia pseudotuberculosis (TST) at different concentrations ( 0.2; 0.5; 2.5 μg/ml, but not 0.1 μg/ml) stimulated NBT reduction in FPMC after 24 h incubation. In FP, TST at concentrations of 0.1 and 0.2 μg/ml inhibited and at concentrations of 0.5 and 2.5 μg/ml stimulated NBT reduction after 24 h incubation. Maximal effect was observed in FP and FPMC at TST concentrations of 0.5 and 0.2 μg/ml, respectively. Addition of catalase (0.7 μg/ml) to the cells treated with TST (2.5 μg/ml) was followed by a decrease in NBT reduction compared to that under toxin treatment alone. TST stimulated superoxide dismutase activity in concentration dependent manner (maximum at 0.5 μg/ml concentration in FP) after 24 h treatment, and this stimulation was prevented by a commercial catalase. Plant lectin concanavalin A stimulated NBT reduction more than 5 fold in FPMC compared to the control. With addition of TST, lectin stimulated ROS to lesser extent than that with lectin alone. When catalase, TST, and lectin were added into the FPMC simultaneously, ROS increase was similar to that under lectin treatment alone. On the whole, data obtained indicated that ROS generation in holothurian coelomocytes especially occurs in both stimulated and not stimulated phagocytes, and that changes in ROS production by these cells may be one of the mechanisms of antibacterial protection of holothurians.
基金The National Natural Science Foundation of China under contract No.41721005the China Ocean Mineral Resources R&D Association(COMRA)Program under contract No.DY135-E2-2-03+1 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology under contract No.2018SDKJ0104-3the Ministry of Science and Education of Russia Project under contract No.АААА-А17-117030110033-0.
文摘The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.
文摘Cardiovascular diseases and diabetes mellitus are leading causes of mortality in modern society. The search for a novel effective remedy represents an important task for modern medicine. A total mixture of phospho- and glycolipids from sea macrophytes Sargassum pallidum, Ulva fenestrata, Zostera marina was separated and the fatty acid composition was determined. The biological activity of the mixtures of polar lipids and natural redox-active compounds (echinochrome A from the flat sea urchin Scaphechinus mirabilis and a polyphenolic complex from the sea grass Zostera marina) was studied under conditions of impairments of carbohydrate and lipid metabolism. Doses and compositions of mixtures of pola lipids and redox-active compounds possessing high corrective activity were optimized in mice with the experimental model of hyperlipidemia and diabetes. Based on these results possible mechanisms of the effects of polar lipids containing various polyunsaturated fatty acids and the investigated redox-active compounds (echinochrome A, rosmarinic acid, luteolin and its sulphate conjugates) have been proposed. The developed compositions may be used for creation of new biologically active additives and remedies.
基金supported by the Programs for Fundamental Research of the Presidium of the Russian Academy of Sciences"Molecular-cell biology"
文摘The effect of chitosan on the development of infection caused by Tobacco mosaic virus(TMV) in leaves of Nicotiana tabacum L. cv. Samsun has been studied. It was shown that the infectivity and viral coat protein content in leaves inoculated with a mixture of TMV(2 μg/mL) and chitosan(1 mg/mL) were lower in the early period of infection(3 days after inoculation), by 63% and 66% respectively, than in leaves inoculated with TMV only. Treatment of leaves with chitosan 24 h before inoculation with TMV also caused the antiviral effects, but these were less apparent than when the virus and polysaccharide were applied simultaneously. The inhibitory effects of the agent decreased as the infection progressed. Inoculation of leaves with TMV together with chitosan considerably enhanced the activity of hydrolases(proteases, RNases) in the leaves, in comparison with leaves inoculated with TMV alone. Electron microscope assays of phosphotungstic acid(PTA)-stained suspensions from infected tobacco leaves showed that, in addition to the normal TMV particles(18 nm in diameter, 300 nm long), these suspensions contained abnormal(swollen, "thin" and "short") virions. The highest number of abnormal virions was found in suspensions from leaves inoculated with a mixture of TMV and chitosan. Immuno-electron microscopy showed that "thin" virus particles, in contrast to the particles of normal diameter, lost the ability to bind to specific antiserum. It seems that the chitosan-induced activation of hydrolases stimulates the intracellular degradation of TMV particles and hence hydrolase activation may be considered to be one of the polysaccharide-mediated cellular defense mechanisms that limit virus accumulation in cells.
