This study aims, first, to examine the limit for tolerance to lower salinity by an oceanic sea skater, Halobates micans, and , second, to make it clear whether exclusively fresh water Halobatinae species, Metrocoris h...This study aims, first, to examine the limit for tolerance to lower salinity by an oceanic sea skater, Halobates micans, and , second, to make it clear whether exclusively fresh water Halobatinae species, Metrocoris histrio has salinity tolerance. Adults of H. micans were collected using Neuston Net from the starboard side of R/V MIRAI on a fixed station at 8°S, 80°E, whereas those of M. histrio were collected from a small pond filled with a spring fresh water in Kochi (33°N, 133°E), Japan. Time in survival was measured in starved condition under several salinity conditions: 0‰, 2‰, 4‰, 6‰, 8‰, 9‰ and 10‰ for H. micans;0‰, 5‰, 10‰, 12.5‰, 15‰ for M. histrio. Half of adults were in coma due to lower salinity under 10‰ and time in survival was less than 10 hours under less than 4‰ for H. micans. Time in survival was half at 5‰ of 80 hours on average at 0‰ as a control and less than 10 hours at 10‰ or higher salinity for M. histrio. Relatively flexible osmo-regulation ability by H. micans would be related to wide variety of salinity condition of surface oceanic water, whereas very limited tolerance even to lower salinity of 5‰ may be permitted by the no chances to be exposed to brackish water in natural habitats of M. histrio. This study showed that salinity tolerance of Halobatinae species would reflect, directly, the salinity condition of their habitats.展开更多
Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation,i.e.,the moisture recycling ratio,but various isotope-based models usually lead to different results,...Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation,i.e.,the moisture recycling ratio,but various isotope-based models usually lead to different results,which affects the accuracy of local moisture recycling.In this study,a total of 18 stations from four typical areas in China were selected to compare the performance of isotope-based linear and Bayesian mixing models and to determine local moisture recycling ratio.Among the three vapor sources including advection,transpiration,and surface evaporation,the advection vapor usually played a dominant role,and the contribution of surface evaporation was less than that of transpiration.When the abnormal values were ignored,the arithmetic averages of differences between isotope-based linear and the Bayesian mixing models were 0.9%for transpiration,0.2%for surface evaporation,and–1.1%for advection,respectively,and the medians were 0.5%,0.2%,and–0.8%,respectively.The importance of transpiration was slightly less for most cases when the Bayesian mixing model was applied,and the contribution of advection was relatively larger.The Bayesian mixing model was found to perform better in determining an efficient solution since linear model sometimes resulted in negative contribution ratios.Sensitivity test with two isotope scenarios indicated that the Bayesian model had a relatively low sensitivity to the changes in isotope input,and it was important to accurately estimate the isotopes in precipitation vapor.Generally,the Bayesian mixing model should be recommended instead of a linear model.The findings are useful for understanding the performance of isotope-based linear and Bayesian mixing models under various climate backgrounds.展开更多
The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined th...The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined the relationship between population density and surface water and air temperatures in the sampling sites during three science cruises in the tropical to temperate zone of the Pacific Ocean. A higher density of H. micans was observed in sites with higher water and air temperatures at 28℃?- 30℃?than that at site with lower temperatures of 23℃?- 28℃. A higher density of H. germanus was observed in sites with extremely high temperatures of 29.6℃?and 30℃?than that in sites with moderately high temperatures of 28℃?- 29℃?in the Pacific Ocean, while a relatively high density was observed in sites with a wide range of temperatures from 24℃?- 30℃?in the southern hemisphere Pacific Ocean. The relatively low temperature preference of 23℃?- 28℃?exhibited by H. sericeus may be related to its size as the smallest among the three species and its relatively wide latitudinal distribution ranging up to 40?N.展开更多
Aerosol optical properties are simulated using the Spectral Radiation Transport Model I~）r Aerosol Species （SPRINTARS） coupled with the Non-hydrostatic ICosahedral Atmospheric Model （NICAM）. The 3-year global mea...Aerosol optical properties are simulated using the Spectral Radiation Transport Model I~）r Aerosol Species （SPRINTARS） coupled with the Non-hydrostatic ICosahedral Atmospheric Model （NICAM）. The 3-year global mean all-sky aerosol optical thickness （AOT） at 550 nm, theAngstr/Sm Exponent （AE） based on AOTs at 440 and 870 nm, and the single scattering albedo （SSA） at 550 nm are estimated at 0.123, 0.657 and 0.944, respectively. For each aerosol species, the mean AOT is within the range of the AeroCom models. Both the modeled all-sky and clear-sky results are compared with observations from the Moderate Resolution Imaging Spectroradiometer （MODIS） and the Aerosol Robotic Network （AERONET）. The simulated spatiotemporal distributions of all-sky AOTs can generally reproduce the MODIS retrievals, and the correlation and model skill can be slightly improved using the clear-sky results over most land regions. The differences between clear-sky and all-sky AOTs are larger over polluted regions. Compared with observations from AERONET, the modeled and observed all-sky AOTs and AEs are generally in reasonable agreement, whereas the SSA variation is not well captured. Although the spatiotemporal distributions of all-sky and clear-sky results are similar, the clear-sky results are generally better correlated with the observations. The clear-sky AOT and SSA are generally lower than the all-sky results, especially in those regions where the aerosol chemical composition is contributed to mostly by sulfate aerosol. The modeled clear-sky AE is larger than the all-sky AE over those regions dominated by hydrophilic aerosol, while the＇opposite is found over regions dominated by hydrophobic aerosol.展开更多
With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-w...With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-weight relationship,age composition,growth pattern,mortality,and exploitation rates of the yellow goosefish in the Yellow Sea.Total length(TL)of females and males ranged from 173 to 582 mm and 178 to 500 mm,respectively.The length-weight relationships were also estimated for females and males.Age classes from 2 to 4 years predominated in the samples.The von Bertalanffy growth function(VBGF),estimated based on non-linear least-squares methodology,showed significant differences between sexes.Females attained a greater estimated asymptotic total length(765 mm TL)compared to males(579 mm TL).The VBGF did not differ significantly between stocks of the northern Yellow Sea and the southern Yellow Sea.Estimated natural instantaneous mortality rate(M)ranged from 0.25/a to 0.33/a based on four age-and length-based methods.Total instantaneous mortality rate(Z)of total samples calculated by the age-based catch curve method was 0.591/a and the average fishing mortality(F)was 0.30/a.Estimated exploitation rate(E)was approximately 0.5,indicating that the population of L.litulon in the Yellow Sea may be sustainable.These results provide a reference for the present status of L.litulon and information for the management.展开更多
To address various fisheries science problems around Japan, the Japan Fisheries Research and Education Agency (FRA) has developed an ocean forecast system by combining an ocean circulation model based on the Regional ...To address various fisheries science problems around Japan, the Japan Fisheries Research and Education Agency (FRA) has developed an ocean forecast system by combining an ocean circulation model based on the Regional Ocean Modeling System (ROMS) with three-dimensional variational analysis schemes. This system, which is called FRA-ROMS, is a basic and essential tool for the systematic conduct of fisheries science. The main aim of FRA-ROMS is to realistically simulate mesoscale variations over the Kuroshio-Oyashio region. Here, in situ oceanographic and satellite data were assimilated into FRA-ROMS using a weekly time window. We first examined the reproducibility through comparison with several oceanographic datasets with an Eulerian reference frame. FRA-ROMS was able to reproduce representative features of mesoscale variations such as the position of the Kuroshio path, variability of the Kuroshio Extension, and southward intrusions of the Oyashio. Second, using a Lagrangian reference frame, we estimated position errors between ocean drifters and particles passively transported by simulated currents, because particle tracking is an essential technique used in applications of reanalysis products to fisheries science. Finally, we summarize recent and ongoing fisheries studies that use FRA-ROMS and mention several new developments and enhancements that will be implemented in the near future.展开更多
Measurement, data collection, and analyzing statistically the spectral response of different bottom types are all important steps in mapping shallow water bottom types with remote sensing. Five small islands in the Sp...Measurement, data collection, and analyzing statistically the spectral response of different bottom types are all important steps in mapping shallow water bottom types with remote sensing. Five small islands in the Spermonde archipelago, South Sulawesi, in Indonesia, were selected to measure the reflectance spectral of benthic communities. The objective of this study was to determine optical properties of the live corals, dead corals covered with algae, coral rubber covered with algae, broken shell, sand, seagrass and macro algae. Pearson correlation coefficient and cluster analysis were used to determine spectral similarity in and among coral species based on spectral responses at observed wavelengths and to examine the similarities between the categories. Several benthic communities appear to be highly correlated with one another when the entire spectrum is considered, which may lead to classification errors. Porites meyeri, dead corals and coral rubber （〉 3 months ago） share a high degree of similarity in reflectance. The other coastal benthic communities are readily discriminated.展开更多
Bacterial community structure and diversity of two closely located stations are usually considered similar which can be verified by more intensive investigations using relatively large amount of datasets from the next...Bacterial community structure and diversity of two closely located stations are usually considered similar which can be verified by more intensive investigations using relatively large amount of datasets from the next generation sequencer. This study was conducted to assess the bacterial community structure and diversity between two closely located coastal stations, the port side and the sea side of the Oarai, Ibaraki, Japan from March 2013 to July 2014 using 454 GS Junior sequencer. Two stations underwent similar changes in physicochemical properties but the community structure and diversity was different. The Proteobacteria (the class Alphaproteobacteria, followed by the Gammaproteobacteria) and the Bacteroidetes (the class Flavobacteriia) were two abundant phyla in both the stations. But, the Flavobacteriia was more abundant in the port side, contributed about 26% to 48%, compared to the sea side (about 12% to 39%). Conversely, the relative abundance of the Gammaproteobacteria was higher on the sea side, about 10% to 17%, compared to the port side (about 4% to 12%). Among others, the phyla Cyanobacteria, Deferribacteres, Verrucomicrobia and the class Betaproteobacteria were also relatively abundant at the sea side. Because of their dominancy, the class Flavobacteriia and Alphaproteobacteria were further analysed at a lower phylogenetic level and marked differences were observed between the stations. Bacterial biodiversity in terms of the species richness (Chao index) and evenness (inverse Simpson) indicated higher patterns of diversity in the sea side area compared to the port side. Non-metric Multidimensional Scaling fitting with the environmental features (metaMDS), redundancy analysis (RDA) and Bray-Curtis clustering analysis also showed marked differences in bacterial community structure and diversity between the stations. However, some OTUs were commonly found in both the stations in all the sampling periods. So, the bacterial community structure and diversity of the coastal areas are distinguishable even between two closely located sampling points.展开更多
Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity ...Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity and the migration speed of the monsoon rain band over the East Asian region are altered in the recent decade,resulting in the drier conditions in late spring and the earlier onset of Changma.In early August when a climatological monsoon break was clear in the earlier decade,the precipitation has increased dramatically with a meridional coherency.The response to the enhanced convection over the South China Sea and southeastern China provides a favorable condition for more precipitation in early August through the changes in moisture transport and tropical cyclone passage.展开更多
Sediment samples were collected in the intertidal zone of the Dagu River Estuary, Jiaozhou Bay, China in April,July and October 2010 and February 2011 for examining seasonal dynamics of meiofaunal distribution and the...Sediment samples were collected in the intertidal zone of the Dagu River Estuary, Jiaozhou Bay, China in April,July and October 2010 and February 2011 for examining seasonal dynamics of meiofaunal distribution and their relationship with environmental variables. A total of ten meiofaunal taxa were identified, including free-living marine nematodes, benthic copepods, polychaetes, oligochaetes, bivalves, ostracods, cnidarians, turbellarians,tardigrades and other animals. Free-living marine nematodes were the most dominant group in both abundance and biomass. The abundances of marine nematodes were higher in winter and spring than those in summer and autumn. Most of the meiofauna distributed in the 0–2 cm sediment layer. The abundance of meiofauna in hightidal zone was lower than those in low-tidal and mid-tidal zones. Results of correlation analysis showed that Chlorophyll a was the most important factor to influence the seasonal dynamics of the abundance, biomass of meiofauna and abundances of nematodes and copepods. CLUSTER analysis divided the meiofaunal assemblages into three groups and BIOENV results indicated that salinity, concentration of organic matter, sediment sorting coefficient and sediment median diameter were the main environmental factors influencing the meiofaunal assemblages.展开更多
The Japanese Spanish mackerel Scomberomorus niphonius(Cuvier,1832)is widely distributed in the subtropical and temperate waters of the northwestern Pacific Ocean,supporting one of the most important commercial fisheri...The Japanese Spanish mackerel Scomberomorus niphonius(Cuvier,1832)is widely distributed in the subtropical and temperate waters of the northwestern Pacific Ocean,supporting one of the most important commercial fisheries in China.However,ignoring the potential population structure changes induced by fishing pressure and climate change may undermine the population stability under the current management strategy.In this study,the population structure of the Japanese Spanish mackerel was investigated based on a morphometric truss network system.A total of 534 individuals were randomly collected from commercial gill nets spanning eight major spawning grounds in the Bohai,Yellow,and East China Seas during the peak spawning seasons respectively.A total of 17 measurements(including eye diameter)were conducted in each specimen and subjected to principal component analysis(PCA)and discriminant function analysis(DFA).The results of PCA indicated that the first two factors cumulatively caused 78.38%of the total morphometric variation and observable differences,primarily fin the caudal and trunk areas.The results of DFA revealed that the eight spawning groups can be divided into three stocks,i.e.,southern,middle,and northern stocks,with 68.7%of total accuracy.In contrast to previous studies,the spawning groups of the Japanese Spanish mackerel demonstrated a tendency to disperse to northern regions.In conclusion,this study found that to maintain the stability of the population structure and the total production of Japanese Spanish mackerel S.niphonius(Cuvier,1832),a newly revised management method should be developed and implemented.展开更多
After decades of low year classes,the stock of Japanese sardine(Sardinops melanostictus)has begun to recover since the mid-2000s.The hatch dates and otolith growth rates of age-0 juvenile sardine,which were collected ...After decades of low year classes,the stock of Japanese sardine(Sardinops melanostictus)has begun to recover since the mid-2000s.The hatch dates and otolith growth rates of age-0 juvenile sardine,which were collected in the subarctic Oyashio waters in autumn 2018,were determined from an otolith microstructure analysis.The sardines were hatched from late January to late April,while mostly in February and March.The otolith growth rate increased continuously up to 60 d after hatching and thereafter de-creased.The revealed growth rate in a crucial growth period is faster than that reported for juvenile sardines collected in the 1990s,which is coincided with the recent recovery trend of the sardine stock.Two groups with different hatch dates,growth histories,and migration routes were identified using unsupervised random forest clustering analysis.They were considered inshore and offshore migration individuals in accordance with recent researches.In the offshore group,a high proportion of sardine juveniles hatched late and grew faster in the Kuroshio-Oyashio transitional waters,a finding consistent with the hypothesis of growth-rate-dependent re-cruitment.This finding on the population composition and growth rate of juvenile sardine in the Oyashio waters can be a basis for an improved prediction of their survival and provides us with valuable information on the recruitment processes of this stock during the period of stock recovery.展开更多
The study of δ13CCpDB （Pee Dee Belemnite） and nitrogen contents in 1 to 5-pm-diameter microdinmonds included in garnets from the qnartz-feldspathic gneisses （Erzgehirge, Germany） was performed in situ with the Na...The study of δ13CCpDB （Pee Dee Belemnite） and nitrogen contents in 1 to 5-pm-diameter microdinmonds included in garnets from the qnartz-feldspathic gneisses （Erzgehirge, Germany） was performed in situ with the Nano-scale Secondary Ion Mass Spectrometer. The results revealed that there were two stages of diamond crystallization from a C-O-H supeeritical fluid rich in biogenic carbon and diverse minor elements of crustal origin. The δ13CCpDB Of the Erzgebirge diamond of the first stage falls in the range -17‰ to 19‰, with an average value of -17.8‰; the average content of nitrogen is 820 ppm. Diamonds of the second stage are characterized by δ13CPDB=-21.5‰ to -25.5‰, with an average value of -23.24‰; the average nitrogen content is non-homogeneously scattered from 740 ppm to 3 370 ppm among 6 diamonds situated in garnets within the same polished rock slide. Both diamond of the first stage and diamond of the second stage carbon reservoirs belong to biogenic matter, therefore confirming deep subduction of the continental crust sediments and their subsequent exhumation during the Variscan orogeny.展开更多
Geochronology is essential for understanding Earth's history. The availability of precise and accurate isotopic data is increasing; hence it is crucial to develop transparent and accessible data reduction techniqu...Geochronology is essential for understanding Earth's history. The availability of precise and accurate isotopic data is increasing; hence it is crucial to develop transparent and accessible data reduction techniques and tools to transform raw mass spectrometry data into robust chronological data. Here we present a Monte Carlo sampling approach to fully propagate uncertainties from linear regressions for isochron dating. Our new approach makes no prior assumption about the causes of variability in the derived chronological results and propagates uncertainties from both experimental measurements(analytical uncertainties) and underlying assumptions(model uncertainties) into the final age determination.Using synthetic examples, we find that although the estimates of the slope and y-intercept(hence age and initial isotopic ratios) are comparable between the Monte Carlo method and the benchmark‘‘Isoplot" algorithm, uncertainties from the later could be underestimated by up to 60%, which are likely due to an incomplete propagation of model uncertainties. An additional advantage of the new method is its ability to integrate with geological information to yield refined chronological constraints. The new method presented here is specifically designed to fully propagate errors in geochronological applications involves linear regressions such as Rb-Sr, Sm-Nd, Re-Os, Pt-Os, Lu-Hf, U-Pb(with discordant points),Pb-Pb and Ar-Ar.展开更多
The Mariana Trench is the deepest location on earth and harbors unique microbial communities as evidenced by 16S rRNA gene amplicon and metagenomic sequencing.Obtaining culturable microorganisms from the Mariana Trenc...The Mariana Trench is the deepest location on earth and harbors unique microbial communities as evidenced by 16S rRNA gene amplicon and metagenomic sequencing.Obtaining culturable microorganisms from the Mariana Trench will contribute to a further understanding of hadal biogeochemical processes and act as a unique microbial reservoir with potential applications.Here,825 bacterial strains,identified by 16S rRNA gene sequencing,were isolated from 12 water depths(0-10,400 m)of the Mariana Trench with 2216E and R2A media at 4℃ or 28℃ on four cruises during 2015-2017.These bacteria belong to four phyla,nine classes,27 orders,45 families and 108 genera.Alphaproteobacteria,Gammaproteobacteria,Actinobacteria_c,Bacilli and Flavobacteriia were the most abundant classes,accounting for 37.9%,33.0%,11.8%,8.6%and 8.0%of the total bacterial isolates,respectively.2216E and R2A media were found to have a better selectivity to Bacilli and Flavobacteriia,respectively.Fifty strains were potential novel bacterial species with a 16S rRNA gene similarity<98.65%,and a higher percentage of novel strains were obtained from R2A than 2216E medium.Additionally,301(150 species)out of 354 strains(178 species)selected from each depth could degrade at least one of the ten kinds of macromolecules tested.These results indicate that there is a high diversity of culturable bacteria in the Mariana Trench and they can produce a variety of extracellular enzymes.Our study provides a valuable resource of microorganisms for investigating their biogeochemical roles in the Mariana Trench and for industrial applications.展开更多
Objective:To examine the effects of fasting and refeeding on intestinal cell proliferation and apoptosis in an opportunistic predator,hammerhead shark(Sphyrna lewini)of elasmobranch fishes which are among the earliest...Objective:To examine the effects of fasting and refeeding on intestinal cell proliferation and apoptosis in an opportunistic predator,hammerhead shark(Sphyrna lewini)of elasmobranch fishes which are among the earliest known extant groups of vertebrates to have the valvular intestine ty pical for the primitive species.Methods:Animals were euthanized after 5-10 d of fasting or feeding,or after 10-day fasting and 5-day refeeding.Intestinal apoptosis and cell proliferation were assessed by using oligonucleotide detection assay,terminal deoxynucleotidyl transferase dUTP nick end labeling staining,and immunohistochemistry of proliferating cells nuclear antigen.Results:Plasma levels of cholesterol and glucose were reduced by fasting.Intestinal apoptosis generally decreased during fasting.Numerous apoptotic cells were observed around the tips of the villi,primarily in the epithelium in the fed sharks,whereas fewer labeled nuclei were detected in the epithelium of fasted sharks.Reeding returned intestinal apoptosis to the level in the fed sharks.Proliferating cells were observed in the epithelium around the troughs of the villi and greater in number in fed sharks,whereas fewer labeled nuclei were detected in fasted sharks.Conclusions:The cell turnover is modified in both intestinal epithelia of the shark and the murines by fasting/feeding,but in opposite directions.The difference may reflct the feeding ecology of the elasmobranchs,primitive intermittent feeders.展开更多
A large number of gases are releasing from the medium-high temperature geothermal fields distributed along the large-scale strike-slip fault zones in the southeastern margin of the Tibetan Plateau.In this study,11 hot...A large number of gases are releasing from the medium-high temperature geothermal fields distributed along the large-scale strike-slip fault zones in the southeastern margin of the Tibetan Plateau.In this study,11 hot spring water and the associated bubbling gas samples were collected along the Xianshuihe-Anninghe fault zones(XSH-ANHFZ)and analyzed for chemical and isotopic compositions.The δ^(18)_(H_(2)O) and δD_(H_(2)O) values indicate that hot spring waters are predominantly meteoric origin recharged from different altitudes.Most water samples are significantly enriched in Na^(+) and HCO_(3) due to the dissolution of regional evaporites,carbonates and Na-silicates.^(3)He/^(4)He ratios of the gas samples are 0.025-2.73 times the atmospheric value.The ^(3)He/^(4)He ratios are high in the Kangding region where the dense faults are distributed,and gradually decrease with increasing distance from Kangding towards both sides along the Xianshuihe fault zones(XSHFZ).Hydrothermal fluids have dissolved inorganic carbon(DIC)concentrations from 2 to 42 mmol L^(-1),δ^(13)C_(DIC) from -6.9‰ to 1.3‰,δ^(13)C_(CO_(2)) from -7.2‰ to -3.6‰ and Δ^(14)C from -997‰ to -909‰.Combining regional geochemical and geological information,the CO_(2)sources can be attributed to deep-sourced CO_(2)from mantle and metamorphism of marine carbonate,and shallow-sourced CO_(2)from the dissolution of marine carbonate and biogenic CO_(2).The mass balance model shows that 11±6% of the DIC is sourced from the dissolution of shallow carbonate minerals,9±8% formed by pyrolysis of sedimentary organic matter,80±9% derived from deep metamorphic origin and mantle-derived CO_(2).Among them,the deep-sourced CO_(2)in Anninghe fault zones(ANHFZ)is merely metamorphic carbon,whereas ca.12% and ca.88% of the deep-sourced CO_(2)in the XSHFZ are derived from the mantle and metamorphic carbon,respectively.The average deep-sourced CO_(2)flux in the Kangding geothermal field is estimated to be 160 ta^(-1).If all the hot springs in various fault zones in the southeastern margin of the Tibetan Plateau are taken into account,the regional deep-sourced CO_(2)flux would reach ca.10^(5) ta^(-1).These results show that the deep-sourced CO_(2)released from nonvolcanic areas might account for a considerable proportion of the total amount of global deep-sourced carbon degassing,which should be paid more attention to.展开更多
This study investigates water vapor isotopic patterns and controls over China using high-quality water vapor δD data retrieved from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography （SCIAMACH...This study investigates water vapor isotopic patterns and controls over China using high-quality water vapor δD data retrieved from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography （SCIAMACHY） observations. The results show that water vapor δD values on both annual and seasonal time-scales broadly exhibit a continental effect, with values largely decreasing northwestward from coastal lowlands to high-elevation mountainous regions. However, region-specific analysis reveals spatially distinct patterns of water vapor dD between seasons. In the monsoon domain （e.g., China south of 35~N）, depletion in D in the summer and fall seasons is closely tied to monsoon moisture sources （the Indian and Pacific oceans） and subsequent amount effect, but higher 8D values in winter and spring are a result of isotopically-enriched conti- nental-sourced moisture proceeded by less rainout. In contrast, farther inland in China （non-monsoon domain）, moisture is de- rived overwhelmingly from the dry continental air masses and local evaporation, and 8D values are largely controlled by the temperature effect, exhibiting a seasonality with isotopically enriched summer and depleted winter/spring. The observation that the spatial pattern of water vapor δD is the opposite to that of precipitation δD in the summer season also suggests that partial evaporation of falling raindrops is a key driver of water vapor isotope in the non-monsoon domain. This study highlights the importance of non-Rayleigh factors in governing water vapor isotope, and provides constraints on precipitation isotope inter- pretation and modern isotope hydrological processes over China.展开更多
文摘This study aims, first, to examine the limit for tolerance to lower salinity by an oceanic sea skater, Halobates micans, and , second, to make it clear whether exclusively fresh water Halobatinae species, Metrocoris histrio has salinity tolerance. Adults of H. micans were collected using Neuston Net from the starboard side of R/V MIRAI on a fixed station at 8°S, 80°E, whereas those of M. histrio were collected from a small pond filled with a spring fresh water in Kochi (33°N, 133°E), Japan. Time in survival was measured in starved condition under several salinity conditions: 0‰, 2‰, 4‰, 6‰, 8‰, 9‰ and 10‰ for H. micans;0‰, 5‰, 10‰, 12.5‰, 15‰ for M. histrio. Half of adults were in coma due to lower salinity under 10‰ and time in survival was less than 10 hours under less than 4‰ for H. micans. Time in survival was half at 5‰ of 80 hours on average at 0‰ as a control and less than 10 hours at 10‰ or higher salinity for M. histrio. Relatively flexible osmo-regulation ability by H. micans would be related to wide variety of salinity condition of surface oceanic water, whereas very limited tolerance even to lower salinity of 5‰ may be permitted by the no chances to be exposed to brackish water in natural habitats of M. histrio. This study showed that salinity tolerance of Halobatinae species would reflect, directly, the salinity condition of their habitats.
基金This study was supported by the National Natural Science Foundation of China(42261008,41971034)the Natural Science Foundation of Gansu Province,China(22JR5RA074).
文摘Stable water isotopes are natural tracers quantifying the contribution of moisture recycling to local precipitation,i.e.,the moisture recycling ratio,but various isotope-based models usually lead to different results,which affects the accuracy of local moisture recycling.In this study,a total of 18 stations from four typical areas in China were selected to compare the performance of isotope-based linear and Bayesian mixing models and to determine local moisture recycling ratio.Among the three vapor sources including advection,transpiration,and surface evaporation,the advection vapor usually played a dominant role,and the contribution of surface evaporation was less than that of transpiration.When the abnormal values were ignored,the arithmetic averages of differences between isotope-based linear and the Bayesian mixing models were 0.9%for transpiration,0.2%for surface evaporation,and–1.1%for advection,respectively,and the medians were 0.5%,0.2%,and–0.8%,respectively.The importance of transpiration was slightly less for most cases when the Bayesian mixing model was applied,and the contribution of advection was relatively larger.The Bayesian mixing model was found to perform better in determining an efficient solution since linear model sometimes resulted in negative contribution ratios.Sensitivity test with two isotope scenarios indicated that the Bayesian model had a relatively low sensitivity to the changes in isotope input,and it was important to accurately estimate the isotopes in precipitation vapor.Generally,the Bayesian mixing model should be recommended instead of a linear model.The findings are useful for understanding the performance of isotope-based linear and Bayesian mixing models under various climate backgrounds.
文摘The main purpose of this study is to investigate temperature preference for habitat of three species of oceanic sea skaters, Halobates micans, H. germanus and H. sericeus. For each of the three species, we examined the relationship between population density and surface water and air temperatures in the sampling sites during three science cruises in the tropical to temperate zone of the Pacific Ocean. A higher density of H. micans was observed in sites with higher water and air temperatures at 28℃?- 30℃?than that at site with lower temperatures of 23℃?- 28℃. A higher density of H. germanus was observed in sites with extremely high temperatures of 29.6℃?and 30℃?than that in sites with moderately high temperatures of 28℃?- 29℃?in the Pacific Ocean, while a relatively high density was observed in sites with a wide range of temperatures from 24℃?- 30℃?in the southern hemisphere Pacific Ocean. The relatively low temperature preference of 23℃?- 28℃?exhibited by H. sericeus may be related to its size as the smallest among the three species and its relatively wide latitudinal distribution ranging up to 40?N.
基金National Natural Science Funds of China (Grant Nos. 41130104, and 41475031)Open Research Program of Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration from Nanjing University of Information Science and Technology (Grant No. KDW1302)+4 种基金the Public Meteorology Special Foundation of MOST (Grant No. GYHY201406023)the National Key Basic Research and Development Program (973 Program, 2011CB403401)Teruyuki NAKAJIMA is supported by projects from JAXA/EarthC ARE, MEXT/VL for Climate System Diagnosticsthe MOE/Global Environment Research Fund A-1101, NIES/GOSAT, NIES/CGER, MEXT/RECCA/SALSAthe S-12 of the MOE
文摘Aerosol optical properties are simulated using the Spectral Radiation Transport Model I~）r Aerosol Species （SPRINTARS） coupled with the Non-hydrostatic ICosahedral Atmospheric Model （NICAM）. The 3-year global mean all-sky aerosol optical thickness （AOT） at 550 nm, theAngstr/Sm Exponent （AE） based on AOTs at 440 and 870 nm, and the single scattering albedo （SSA） at 550 nm are estimated at 0.123, 0.657 and 0.944, respectively. For each aerosol species, the mean AOT is within the range of the AeroCom models. Both the modeled all-sky and clear-sky results are compared with observations from the Moderate Resolution Imaging Spectroradiometer （MODIS） and the Aerosol Robotic Network （AERONET）. The simulated spatiotemporal distributions of all-sky AOTs can generally reproduce the MODIS retrievals, and the correlation and model skill can be slightly improved using the clear-sky results over most land regions. The differences between clear-sky and all-sky AOTs are larger over polluted regions. Compared with observations from AERONET, the modeled and observed all-sky AOTs and AEs are generally in reasonable agreement, whereas the SSA variation is not well captured. Although the spatiotemporal distributions of all-sky and clear-sky results are similar, the clear-sky results are generally better correlated with the observations. The clear-sky AOT and SSA are generally lower than the all-sky results, especially in those regions where the aerosol chemical composition is contributed to mostly by sulfate aerosol. The modeled clear-sky AE is larger than the all-sky AE over those regions dominated by hydrophilic aerosol, while the＇opposite is found over regions dominated by hydrophobic aerosol.
基金Supported by the National Key R&D Program of China(No.2018YFD0900902)。
文摘With the decline in the most fisheries resources in the Yellow Sea,the yellow goosefish Lophius litulon has increased in commercial and ecological importance in recent years.We studied the length distribution,length-weight relationship,age composition,growth pattern,mortality,and exploitation rates of the yellow goosefish in the Yellow Sea.Total length(TL)of females and males ranged from 173 to 582 mm and 178 to 500 mm,respectively.The length-weight relationships were also estimated for females and males.Age classes from 2 to 4 years predominated in the samples.The von Bertalanffy growth function(VBGF),estimated based on non-linear least-squares methodology,showed significant differences between sexes.Females attained a greater estimated asymptotic total length(765 mm TL)compared to males(579 mm TL).The VBGF did not differ significantly between stocks of the northern Yellow Sea and the southern Yellow Sea.Estimated natural instantaneous mortality rate(M)ranged from 0.25/a to 0.33/a based on four age-and length-based methods.Total instantaneous mortality rate(Z)of total samples calculated by the age-based catch curve method was 0.591/a and the average fishing mortality(F)was 0.30/a.Estimated exploitation rate(E)was approximately 0.5,indicating that the population of L.litulon in the Yellow Sea may be sustainable.These results provide a reference for the present status of L.litulon and information for the management.
文摘To address various fisheries science problems around Japan, the Japan Fisheries Research and Education Agency (FRA) has developed an ocean forecast system by combining an ocean circulation model based on the Regional Ocean Modeling System (ROMS) with three-dimensional variational analysis schemes. This system, which is called FRA-ROMS, is a basic and essential tool for the systematic conduct of fisheries science. The main aim of FRA-ROMS is to realistically simulate mesoscale variations over the Kuroshio-Oyashio region. Here, in situ oceanographic and satellite data were assimilated into FRA-ROMS using a weekly time window. We first examined the reproducibility through comparison with several oceanographic datasets with an Eulerian reference frame. FRA-ROMS was able to reproduce representative features of mesoscale variations such as the position of the Kuroshio path, variability of the Kuroshio Extension, and southward intrusions of the Oyashio. Second, using a Lagrangian reference frame, we estimated position errors between ocean drifters and particles passively transported by simulated currents, because particle tracking is an essential technique used in applications of reanalysis products to fisheries science. Finally, we summarize recent and ongoing fisheries studies that use FRA-ROMS and mention several new developments and enhancements that will be implemented in the near future.
文摘Measurement, data collection, and analyzing statistically the spectral response of different bottom types are all important steps in mapping shallow water bottom types with remote sensing. Five small islands in the Spermonde archipelago, South Sulawesi, in Indonesia, were selected to measure the reflectance spectral of benthic communities. The objective of this study was to determine optical properties of the live corals, dead corals covered with algae, coral rubber covered with algae, broken shell, sand, seagrass and macro algae. Pearson correlation coefficient and cluster analysis were used to determine spectral similarity in and among coral species based on spectral responses at observed wavelengths and to examine the similarities between the categories. Several benthic communities appear to be highly correlated with one another when the entire spectrum is considered, which may lead to classification errors. Porites meyeri, dead corals and coral rubber （〉 3 months ago） share a high degree of similarity in reflectance. The other coastal benthic communities are readily discriminated.
文摘Bacterial community structure and diversity of two closely located stations are usually considered similar which can be verified by more intensive investigations using relatively large amount of datasets from the next generation sequencer. This study was conducted to assess the bacterial community structure and diversity between two closely located coastal stations, the port side and the sea side of the Oarai, Ibaraki, Japan from March 2013 to July 2014 using 454 GS Junior sequencer. Two stations underwent similar changes in physicochemical properties but the community structure and diversity was different. The Proteobacteria (the class Alphaproteobacteria, followed by the Gammaproteobacteria) and the Bacteroidetes (the class Flavobacteriia) were two abundant phyla in both the stations. But, the Flavobacteriia was more abundant in the port side, contributed about 26% to 48%, compared to the sea side (about 12% to 39%). Conversely, the relative abundance of the Gammaproteobacteria was higher on the sea side, about 10% to 17%, compared to the port side (about 4% to 12%). Among others, the phyla Cyanobacteria, Deferribacteres, Verrucomicrobia and the class Betaproteobacteria were also relatively abundant at the sea side. Because of their dominancy, the class Flavobacteriia and Alphaproteobacteria were further analysed at a lower phylogenetic level and marked differences were observed between the stations. Bacterial biodiversity in terms of the species richness (Chao index) and evenness (inverse Simpson) indicated higher patterns of diversity in the sea side area compared to the port side. Non-metric Multidimensional Scaling fitting with the environmental features (metaMDS), redundancy analysis (RDA) and Bray-Curtis clustering analysis also showed marked differences in bacterial community structure and diversity between the stations. However, some OTUs were commonly found in both the stations in all the sampling periods. So, the bacterial community structure and diversity of the coastal areas are distinguishable even between two closely located sampling points.
基金the Korea Meteorological Administration(KMA) Research and Development Program under Grant CATER 2006- 4205 and by BK21 program.Partial support for M.Kimoto was given by the Innovative Program of Climate Change for the 21st Century of the Japanese Ministry of Education, Culture,Sports,Science and Technology.
文摘Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity and the migration speed of the monsoon rain band over the East Asian region are altered in the recent decade,resulting in the drier conditions in late spring and the earlier onset of Changma.In early August when a climatological monsoon break was clear in the earlier decade,the precipitation has increased dramatically with a meridional coherency.The response to the enhanced convection over the South China Sea and southeastern China provides a favorable condition for more precipitation in early August through the changes in moisture transport and tropical cyclone passage.
基金The National Natural Science Foundation of China under contract No.41576135the Student Research Development Program of Ocean University of China(OUC-SRDP)under contract No.101201051
文摘Sediment samples were collected in the intertidal zone of the Dagu River Estuary, Jiaozhou Bay, China in April,July and October 2010 and February 2011 for examining seasonal dynamics of meiofaunal distribution and their relationship with environmental variables. A total of ten meiofaunal taxa were identified, including free-living marine nematodes, benthic copepods, polychaetes, oligochaetes, bivalves, ostracods, cnidarians, turbellarians,tardigrades and other animals. Free-living marine nematodes were the most dominant group in both abundance and biomass. The abundances of marine nematodes were higher in winter and spring than those in summer and autumn. Most of the meiofauna distributed in the 0–2 cm sediment layer. The abundance of meiofauna in hightidal zone was lower than those in low-tidal and mid-tidal zones. Results of correlation analysis showed that Chlorophyll a was the most important factor to influence the seasonal dynamics of the abundance, biomass of meiofauna and abundances of nematodes and copepods. CLUSTER analysis divided the meiofaunal assemblages into three groups and BIOENV results indicated that salinity, concentration of organic matter, sediment sorting coefficient and sediment median diameter were the main environmental factors influencing the meiofaunal assemblages.
基金supported by the Fundamental Research Funds for the Central Universities of Ocean University of China(Nos.201762015 and 201822027)
文摘The Japanese Spanish mackerel Scomberomorus niphonius(Cuvier,1832)is widely distributed in the subtropical and temperate waters of the northwestern Pacific Ocean,supporting one of the most important commercial fisheries in China.However,ignoring the potential population structure changes induced by fishing pressure and climate change may undermine the population stability under the current management strategy.In this study,the population structure of the Japanese Spanish mackerel was investigated based on a morphometric truss network system.A total of 534 individuals were randomly collected from commercial gill nets spanning eight major spawning grounds in the Bohai,Yellow,and East China Seas during the peak spawning seasons respectively.A total of 17 measurements(including eye diameter)were conducted in each specimen and subjected to principal component analysis(PCA)and discriminant function analysis(DFA).The results of PCA indicated that the first two factors cumulatively caused 78.38%of the total morphometric variation and observable differences,primarily fin the caudal and trunk areas.The results of DFA revealed that the eight spawning groups can be divided into three stocks,i.e.,southern,middle,and northern stocks,with 68.7%of total accuracy.In contrast to previous studies,the spawning groups of the Japanese Spanish mackerel demonstrated a tendency to disperse to northern regions.In conclusion,this study found that to maintain the stability of the population structure and the total production of Japanese Spanish mackerel S.niphonius(Cuvier,1832),a newly revised management method should be developed and implemented.
基金supported by the National Natural Science Foundation of China(Nos.41930534,41861134-037,and 41876177)funding to the Third Institute of Oceanography through the National Program on Global Change and Air-Sea Interaction(No.GASI-02-PAC-YDaut).
文摘After decades of low year classes,the stock of Japanese sardine(Sardinops melanostictus)has begun to recover since the mid-2000s.The hatch dates and otolith growth rates of age-0 juvenile sardine,which were collected in the subarctic Oyashio waters in autumn 2018,were determined from an otolith microstructure analysis.The sardines were hatched from late January to late April,while mostly in February and March.The otolith growth rate increased continuously up to 60 d after hatching and thereafter de-creased.The revealed growth rate in a crucial growth period is faster than that reported for juvenile sardines collected in the 1990s,which is coincided with the recent recovery trend of the sardine stock.Two groups with different hatch dates,growth histories,and migration routes were identified using unsupervised random forest clustering analysis.They were considered inshore and offshore migration individuals in accordance with recent researches.In the offshore group,a high proportion of sardine juveniles hatched late and grew faster in the Kuroshio-Oyashio transitional waters,a finding consistent with the hypothesis of growth-rate-dependent re-cruitment.This finding on the population composition and growth rate of juvenile sardine in the Oyashio waters can be a basis for an improved prediction of their survival and provides us with valuable information on the recruitment processes of this stock during the period of stock recovery.
基金supported by Japanese Society for Promotion of Science
文摘The study of δ13CCpDB （Pee Dee Belemnite） and nitrogen contents in 1 to 5-pm-diameter microdinmonds included in garnets from the qnartz-feldspathic gneisses （Erzgehirge, Germany） was performed in situ with the Nano-scale Secondary Ion Mass Spectrometer. The results revealed that there were two stages of diamond crystallization from a C-O-H supeeritical fluid rich in biogenic carbon and diverse minor elements of crustal origin. The δ13CCpDB Of the Erzgebirge diamond of the first stage falls in the range -17‰ to 19‰, with an average value of -17.8‰; the average content of nitrogen is 820 ppm. Diamonds of the second stage are characterized by δ13CPDB=-21.5‰ to -25.5‰, with an average value of -23.24‰; the average nitrogen content is non-homogeneously scattered from 740 ppm to 3 370 ppm among 6 diamonds situated in garnets within the same polished rock slide. Both diamond of the first stage and diamond of the second stage carbon reservoirs belong to biogenic matter, therefore confirming deep subduction of the continental crust sediments and their subsequent exhumation during the Variscan orogeny.
基金funded by the State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences (SKL-K201706)the total endowment fundYale University for support
文摘Geochronology is essential for understanding Earth's history. The availability of precise and accurate isotopic data is increasing; hence it is crucial to develop transparent and accessible data reduction techniques and tools to transform raw mass spectrometry data into robust chronological data. Here we present a Monte Carlo sampling approach to fully propagate uncertainties from linear regressions for isochron dating. Our new approach makes no prior assumption about the causes of variability in the derived chronological results and propagates uncertainties from both experimental measurements(analytical uncertainties) and underlying assumptions(model uncertainties) into the final age determination.Using synthetic examples, we find that although the estimates of the slope and y-intercept(hence age and initial isotopic ratios) are comparable between the Monte Carlo method and the benchmark‘‘Isoplot" algorithm, uncertainties from the later could be underestimated by up to 60%, which are likely due to an incomplete propagation of model uncertainties. An additional advantage of the new method is its ability to integrate with geological information to yield refined chronological constraints. The new method presented here is specifically designed to fully propagate errors in geochronological applications involves linear regressions such as Rb-Sr, Sm-Nd, Re-Os, Pt-Os, Lu-Hf, U-Pb(with discordant points),Pb-Pb and Ar-Ar.
基金funded by the National Natural Science Foundation of China(Nos.91751202,41976101 and 41730530)Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.2018SDKJ0406-4).
文摘The Mariana Trench is the deepest location on earth and harbors unique microbial communities as evidenced by 16S rRNA gene amplicon and metagenomic sequencing.Obtaining culturable microorganisms from the Mariana Trench will contribute to a further understanding of hadal biogeochemical processes and act as a unique microbial reservoir with potential applications.Here,825 bacterial strains,identified by 16S rRNA gene sequencing,were isolated from 12 water depths(0-10,400 m)of the Mariana Trench with 2216E and R2A media at 4℃ or 28℃ on four cruises during 2015-2017.These bacteria belong to four phyla,nine classes,27 orders,45 families and 108 genera.Alphaproteobacteria,Gammaproteobacteria,Actinobacteria_c,Bacilli and Flavobacteriia were the most abundant classes,accounting for 37.9%,33.0%,11.8%,8.6%and 8.0%of the total bacterial isolates,respectively.2216E and R2A media were found to have a better selectivity to Bacilli and Flavobacteriia,respectively.Fifty strains were potential novel bacterial species with a 16S rRNA gene similarity<98.65%,and a higher percentage of novel strains were obtained from R2A than 2216E medium.Additionally,301(150 species)out of 354 strains(178 species)selected from each depth could degrade at least one of the ten kinds of macromolecules tested.These results indicate that there is a high diversity of culturable bacteria in the Mariana Trench and they can produce a variety of extracellular enzymes.Our study provides a valuable resource of microorganisms for investigating their biogeochemical roles in the Mariana Trench and for industrial applications.
基金Supported in part by Grants-in-Aid for Scientific Research(Grant.17570049 and 19570057 from JSPS)Research Fel owships for Young Scientists(Grant.192156 and 214892 from JSPS)the Japan-USA Research Cooperative Program(Grant 07033011-000122 from JSPS)
文摘Objective:To examine the effects of fasting and refeeding on intestinal cell proliferation and apoptosis in an opportunistic predator,hammerhead shark(Sphyrna lewini)of elasmobranch fishes which are among the earliest known extant groups of vertebrates to have the valvular intestine ty pical for the primitive species.Methods:Animals were euthanized after 5-10 d of fasting or feeding,or after 10-day fasting and 5-day refeeding.Intestinal apoptosis and cell proliferation were assessed by using oligonucleotide detection assay,terminal deoxynucleotidyl transferase dUTP nick end labeling staining,and immunohistochemistry of proliferating cells nuclear antigen.Results:Plasma levels of cholesterol and glucose were reduced by fasting.Intestinal apoptosis generally decreased during fasting.Numerous apoptotic cells were observed around the tips of the villi,primarily in the epithelium in the fed sharks,whereas fewer labeled nuclei were detected in the epithelium of fasted sharks.Reeding returned intestinal apoptosis to the level in the fed sharks.Proliferating cells were observed in the epithelium around the troughs of the villi and greater in number in fed sharks,whereas fewer labeled nuclei were detected in fasted sharks.Conclusions:The cell turnover is modified in both intestinal epithelia of the shark and the murines by fasting/feeding,but in opposite directions.The difference may reflct the feeding ecology of the elasmobranchs,primitive intermittent feeders.
基金supported by China Seismic Experimental Site(CSES)(Grant No.2019CSES0104)the National Natural Science Foundation of China(Grant No.41930642)。
文摘A large number of gases are releasing from the medium-high temperature geothermal fields distributed along the large-scale strike-slip fault zones in the southeastern margin of the Tibetan Plateau.In this study,11 hot spring water and the associated bubbling gas samples were collected along the Xianshuihe-Anninghe fault zones(XSH-ANHFZ)and analyzed for chemical and isotopic compositions.The δ^(18)_(H_(2)O) and δD_(H_(2)O) values indicate that hot spring waters are predominantly meteoric origin recharged from different altitudes.Most water samples are significantly enriched in Na^(+) and HCO_(3) due to the dissolution of regional evaporites,carbonates and Na-silicates.^(3)He/^(4)He ratios of the gas samples are 0.025-2.73 times the atmospheric value.The ^(3)He/^(4)He ratios are high in the Kangding region where the dense faults are distributed,and gradually decrease with increasing distance from Kangding towards both sides along the Xianshuihe fault zones(XSHFZ).Hydrothermal fluids have dissolved inorganic carbon(DIC)concentrations from 2 to 42 mmol L^(-1),δ^(13)C_(DIC) from -6.9‰ to 1.3‰,δ^(13)C_(CO_(2)) from -7.2‰ to -3.6‰ and Δ^(14)C from -997‰ to -909‰.Combining regional geochemical and geological information,the CO_(2)sources can be attributed to deep-sourced CO_(2)from mantle and metamorphism of marine carbonate,and shallow-sourced CO_(2)from the dissolution of marine carbonate and biogenic CO_(2).The mass balance model shows that 11±6% of the DIC is sourced from the dissolution of shallow carbonate minerals,9±8% formed by pyrolysis of sedimentary organic matter,80±9% derived from deep metamorphic origin and mantle-derived CO_(2).Among them,the deep-sourced CO_(2)in Anninghe fault zones(ANHFZ)is merely metamorphic carbon,whereas ca.12% and ca.88% of the deep-sourced CO_(2)in the XSHFZ are derived from the mantle and metamorphic carbon,respectively.The average deep-sourced CO_(2)flux in the Kangding geothermal field is estimated to be 160 ta^(-1).If all the hot springs in various fault zones in the southeastern margin of the Tibetan Plateau are taken into account,the regional deep-sourced CO_(2)flux would reach ca.10^(5) ta^(-1).These results show that the deep-sourced CO_(2)released from nonvolcanic areas might account for a considerable proportion of the total amount of global deep-sourced carbon degassing,which should be paid more attention to.
基金supported by the JSPS FellowshipNational Natural Science Foundation of China(Grant No.41171022)Tianjin Municipal Education Commission(Grant No.20080520)
文摘This study investigates water vapor isotopic patterns and controls over China using high-quality water vapor δD data retrieved from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography （SCIAMACHY） observations. The results show that water vapor δD values on both annual and seasonal time-scales broadly exhibit a continental effect, with values largely decreasing northwestward from coastal lowlands to high-elevation mountainous regions. However, region-specific analysis reveals spatially distinct patterns of water vapor dD between seasons. In the monsoon domain （e.g., China south of 35~N）, depletion in D in the summer and fall seasons is closely tied to monsoon moisture sources （the Indian and Pacific oceans） and subsequent amount effect, but higher 8D values in winter and spring are a result of isotopically-enriched conti- nental-sourced moisture proceeded by less rainout. In contrast, farther inland in China （non-monsoon domain）, moisture is de- rived overwhelmingly from the dry continental air masses and local evaporation, and 8D values are largely controlled by the temperature effect, exhibiting a seasonality with isotopically enriched summer and depleted winter/spring. The observation that the spatial pattern of water vapor δD is the opposite to that of precipitation δD in the summer season also suggests that partial evaporation of falling raindrops is a key driver of water vapor isotope in the non-monsoon domain. This study highlights the importance of non-Rayleigh factors in governing water vapor isotope, and provides constraints on precipitation isotope inter- pretation and modern isotope hydrological processes over China.
