期刊文献+
共找到249篇文章
< 1 2 13 >
每页显示 20 50 100
Evolution of free amino acids, biogenic amines and volatile compounds in fermented sausages inoculated with Lactiplantibacillus plantarum and Staphylococcus simulans
1
作者 Xuefei Shao Huhu Wang +3 位作者 Xiangyu Song Mingyuan Huang Jian Sun Xinglian Xu 《Food Science and Human Wellness》 SCIE CAS CSCD 2024年第6期3642-3651,共10页
Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects ... Lactic acid bacteria and coagulase-negative staphylococci play an important role in the production of fermented sausages,such as inhibiting the growth of undesirable bacteria and antioxidant.In this study,the effects of inoculation with different starter cultures(Lactiplantibacillus plantarum HN108 and Staphylococcus simulans NJ209)on the free amino acids(FAAs),biogenic amines(BAs)and volatile compounds of fermented sausages were investigated using an amino acid analyzer,ultra performance liquid chromatography and gas chromatography-ion mobility spectrometry,respectively.The pH and carbonyl content of the inoculated group was significantly lower than those in the control group(P<0.05).L.plantarum HN108 significantly reduced the content of FAAs and BAs in fermented sausage production(P<0.05),while S.simulans NJ209 promoted the formation of FAAs(especially bitter amino acids)and exhibited slight BAs-reducing activity.In addition,L.plantarum HN108 promoted the formation of volatile compounds such as ketones,alcohols and alkenes in sausages.In conclusion,L.plantarum HN108 could contribute to reducing the content of putrescine and tyramine and forming the desirable flavor compounds in fermented sausages.Thus,L.plantarum HN108 is expected to be a starter culture that can improve the safety and flavor of fermented sausages. 展开更多
关键词 Fermented sausages Starter cultures Free amino acids biogenic amines Volatile compounds
下载PDF
Effects of potassium lactate on sensory attributes,bacterial community succession and biogenic amines formation in Rugao ham
2
作者 Renyong Liao Ying Wang +4 位作者 Qiang Xia Changyu Zhou Fang Geng Daodong Pan Jinxuan Cao 《Food Science and Human Wellness》 SCIE CSCD 2024年第1期198-210,共13页
To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community a... To deepen the understanding in the effect of potassium lactate on the sensory quality and safety of Rugao ham,sensory attributes,physicochemical parameters,total volatile basic nitrogen(TVBN),microorganism community and biogenic amines of Rugao ham manufactured with different potassium lactate levels(0%,0.5%,1%,2%)were investigated;the relationship between microbial community and the formation of TVBN and biogenic amines was further evaluated.With the increase of potassium lactate from 0%to 2%,the increased sensory scores and the decreased total aerobic bacterial count and TVBN were observed;the abundance of Staphylococcus increased,while the content of Halomonas decreased.LDA effect size(LEf Se)and correlations analysis showed that Staphylococcus equorum and Lactobacillus fermentum could be the key species to improve sensory scores and decrease biogenic amines and TVBN.Metabolic pathway analysis further showed that amino acids metabolism and nitrogen metabolism were mainly involved in decreasing TVBN and biogenic amines in the treatment of 2%potassium lactate. 展开更多
关键词 Rugao ham Potassium lactate biogenic amines Microbial community Metabolic pathways
下载PDF
Spatiotemporal changes of biogenic elements in the Changjiang River Estuary and adjacent waters in summer over the last decade 被引量:2
3
作者 Lu Yang Yujia Zhang +3 位作者 Xiaoli Wang Qiulu Wang Long He Xiao Li 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第1期83-90,共8页
The long-term spatiotemporal changes of surface biogenic elements in the Changjiang River Estuary and adjacent waters during the summer of 2008–2016 were analyzed in this study.The concentrations of dissolved inorgan... The long-term spatiotemporal changes of surface biogenic elements in the Changjiang River Estuary and adjacent waters during the summer of 2008–2016 were analyzed in this study.The concentrations of dissolved inorganic nitrogen(DIN),soluble reactive phosphate(PO_(4)^(3−))and silicate(SiO_(3)^(2−))were generally stable,with a slight decrease of DIN and PO_(4)^(3−),and a slight increase of SiO_(3)^(2−),which mainly occurred in the estuarine waters.The grey correlation analysis was carried out between biogenic elements and chlorophyll a(Chl-a).Results showed that compared with the absolute values of biogenic elements,the correlations between the concentration ratio of nitrogen to phosphorus(N/P),ratio of silicon to nitrogen(Si/N)and Chl-a were closer,indicating the important influence on phytoplankton by the structure of biogenic elements.The study area was generally in a state of potential P limitation,and could have potential impact on the phytoplankton community,triggering the shift of red tide dominant species from diatoms to dinoflagellates. 展开更多
关键词 Changjiang River Estuary biogenic elements spatiotemporal changes
下载PDF
Distribution of Biogenic Silica Content in Surface Sediments from the Southern South China Sea and Its Environmental Dignificance 被引量:5
4
作者 张兰兰 陈木宏 +2 位作者 向荣 陆钧 张丽丽 《Marine Science Bulletin》 CAS 2009年第1期43-52,共10页
Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific... Biogenic silica content was determined in 25 surface sediment samples from the southern South China Sea to study its distribution and its modern oceanic environmental significance, which may provide further scientific evidence for paleoceanography explaination. This study showed that biogenic silica content in surface sediments and its water depth have evidently positive correlation, and the correlation coefficient was up to 0.782. Biogenic silica content was very low in continental shelf shallows and could not reflect the productivity of siliceous micropaleontology in surface waters, which may be affected by sedimentary types and terrigenous matter dilution. Distribution of biogenic silica content in surface sediments from deep water areas showed that it could not only reflect the paleoproductivity of siliceous micropaleontology in surface waters, but also indicate the strong or feeble upwelling. Thus, it was further confirmed that using biogenic silica content in sediments to trace upwelling and its change was effective and reliable. The analyzed result showed that radiolariia and poriferous specula have more contribution for biogenic opal, comparing with diatom in surface sediments from the northern studied area, probably owing to the diatom dissolved easily away and eaten by other organisms with little effort. In the upwelling areas, radiolarian, diatom and poriferous specula all approximately showed high abundance, which was consistent with high biogenic silica content. 展开更多
关键词 southern SCS surface sediments biogenic silica UPWELLING
下载PDF
Status of research on biogenic coalbed gas generation mechanisms 被引量:7
5
作者 WANG, Aikuan QIN, Yong +1 位作者 WU, Yanyan WANG, Baowen 《Mining Science and Technology》 EI CAS 2010年第2期271-275,共5页
Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods... Biogenic coalbed gas,how it is generated and the geochemical characteristics of the gas are gaining global attention.The ways coalbed gas is generated,the status of research on the generation mechanism and the methods of differentiating between biogenic gasses are discussed.The generation of biogenic coalbed methane is consistent with anaerobic fermentation theory.Commercial biogenic coalbed gas reservoirs are mainly generated by the process of CO2 reduction.The substrates used by the microbes living in the coal include organic compounds,CO2,H2 and acetate.The production ratio and quantity of biogenic coalbed methane depend on the exposed surface area,the solubility and permeability of the coal and the microbial concentration in the coal seam.It is generally believed that biogenic coalbed gas has a value for δ13C1<-5.5%,C1/C1+>0.95.The H isotope ratio is controlled by both the environment and the generation mechanism:typically δD1<-20%.Biogenic methane formed by CO2 reduction has more δD1 than that formed by acetate fermentation. 展开更多
关键词 coalbed gas biogenic coalbed gas secondary biogenic coalbed gas generation mechanism DISCRIMINATION
下载PDF
Anthropogenic Effects on Biogenic Secondary Organic Aerosol Formation 被引量:3
6
作者 Li XU Lin DU +1 位作者 Narcisse T.TSONA Maofa GE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2021年第7期1053-1084,共32页
Anthropogenic emissions alter biogenic secondary organic aerosol(SOA)formation from naturally emitted volatileorganic compounds(BVOCs).We review the major laboratory and field findings with regard to effects of anthro... Anthropogenic emissions alter biogenic secondary organic aerosol(SOA)formation from naturally emitted volatileorganic compounds(BVOCs).We review the major laboratory and field findings with regard to effects of anthropogenicpollutants(NO_(x),anthropogenic aerosols,SO_(2),NH_(3))on biogenic SOA formation.NO_(x) participate in BVOC oxidationthrough changing the radical chemistry and oxidation capacity,leading to a complex SOA composition and yield sensitivitytowards NO_(x) level for different or even specific hydrocarbon precursors.Anthropogenic aerosols act as an importantintermedium for gas-particle partitioning and particle-phase reactions,processes of which are influenced by the particlephase state,acidity,water content and thus associated with biogenic SOA mass accumulation.SO_(2)modifies biogenic SOAformation mainly through sulfuric acid formation and accompanies new particle formation and acid-catalyzedheterogeneous reactions.Some new SO_(2)-involved mechanisms for organosulfate formation have also been proposed.NH_(3)/amines,as the most prevalent base species in the atmosphere,influence biogenic SOA composition and modify theoptical properties of SOA.The response of SOA formation behavior to these anthropogenic pollutants varies amongdifferent BVOCs precursors.Investigations on anthropogenic-biogenic interactions in some areas of China that aresimultaneously influenced by anthropogenic and biogenic emissions are summarized.Based on this review,somerecommendations are made for a more accurate assessment of controllable biogenic SOA formation and its contribution tothe total SOA budget.This study also highlights the importance of controlling anthropogenic pollutant emissions witheffective pollutant mitigation policies to reduce regional and global biogenic SOA formation. 展开更多
关键词 biogenic volatile organic compounds anthropogenic pollutants secondary organic aerosol anthropogenic-biogenic interactions China
下载PDF
Biogenic silica in intertidal marsh plants and associated sediments of the Yangtze Estuary 被引量:11
7
作者 Lijun Hou Min Liu +3 位作者 Yi Yang Dongni Ou Xiao Lin Hui Chen 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第3期374-380,共7页
Biogenic silica (BSi) contents in the marsh plants (Phragmites australis, Scirpus mariqueter and Spartina alterniflora) and associated sediments in Chongming Island eastern intertidal flat of the Yangtze Estuary w... Biogenic silica (BSi) contents in the marsh plants (Phragmites australis, Scirpus mariqueter and Spartina alterniflora) and associated sediments in Chongming Island eastern intertidal flat of the Yangtze Estuary were determined. The BSi contents in P. australis, S. mariqueter and S. alterniflora varied from 25.78–42.74 mg/g, 5.71–19.53 mg/g and 6.71–8.92 mg/g, respectively. Over the entire growth season, P. australis and S. mariqueter were characterized by linear accumulation patterns of BSi. The aboveground biomass (leaves and culms) of the marsh plants generally contained more BSi than underground biomass (roots). BSi contents were relatively higher in dead plant tissues than in live tissues which was probably due to the decomposition and the leaching of labile components of plant tissues such as organic carbon and nitrogen. Comparing with the habitats of S. mariqueter and S. alterniflora, the highest BSi content was recorded in sediments inhabited by P. australis, with an annual average of 15.69 mg/g. Overall, the intertidal marshes in the Yangtze Estuary may act as a net sink of BSi via plant uptake and sedimentary burial. 展开更多
关键词 biogenic silica marsh plants intertidal flat the Yangtze Estuary
下载PDF
Biogenic VOCs emission inventory development of temperate grassland vegetation in Xilin River Basin, Inner Mongolia, China 被引量:6
8
作者 HENian-peng HANXing-guo SUNWei PanQing-min 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第6期1024-1032,共9页
Given the key role of biogenic volatile organic compounds(VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurate VOCs emission inventories. However, only a less fraction of plan... Given the key role of biogenic volatile organic compounds(VOCs) to tropospheric chemistry and regional air quality, it is important to generate accurate VOCs emission inventories. However, only a less fraction of plant species, in temperate grassland of Inner Mongolia, has been characterized by quantitative measurements. A taxonomic methodology, which assigns VOCs measurements to unmeasured species, is an applicable and inexpensive alternation for extensive VOCs emission survey, although data are needed for additional plant families and genera to further validate the taxonomic approach in grassland vegetation. In this experiment, VOCs emission rates of 178 plant species were measured with a portable photoionization detector(PID). The results showed the most of genera and some families have consistent feature of their VOCs emission, especially for isoprene, and provide the basic premise of taxonomic methodology to develop VOCs emission inventories for temperate grassland. Then, the taxonomic methodology was introduced into assigning emission rate to other 96 species, which no measured emission rates available here. A systematical emission inventory of temperate grassland vegetation in Inner Mongolia was provided and further evidence that taxonomy relationship can serve as a useful guide for generalizing the emissions behavior of many, but not all, plant families and genera to grassland vegetation. 展开更多
关键词 VOCs PID biogenic emission ISOPRENE MONOTERPENE grassland vegetation taxonomic methodology
下载PDF
Distribution and accumulation of biogenic silica in the intertidal sediments of the Yangtze Estuary 被引量:7
9
作者 HOU Lijun LIU Min +4 位作者 XU Shiyuana YAN Huimin OU Dongni CHENG Shubo LIN Xiao 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2008年第5期543-550,共8页
Sedimentary biogenic silica is known to be an important parameter to understand biogeochemical processes and paleoenviromental records in estuarine and coastal ecosystems. Consequently, it is of great significance to ... Sedimentary biogenic silica is known to be an important parameter to understand biogeochemical processes and paleoenviromental records in estuarine and coastal ecosystems. Consequently, it is of great significance to investigate accumulation and distribution of biogenic silica in sediments. The two-step mild acid-mild alkaline extraction procedure was used to leach biogenic silica and its early diagenetic products in intertidal sediments of the Yangtze Estuary. The results showed that total biogenic silica (t-BSi) in the intertidal sediments varied from 237.7-419.4 μmol Si/g, while the mild acid leachable silica (Si-HCl) and the mild alkaline leachable silica (Si- Alk) were in the range of 25.1-72.9 μmol Si/g and 208.1-350.4 μmol Si/g, respectively. Significant correlations were observed for the grain size distributions of sediments and different biogenic silica pools in intertidal sediments. This confirms that grain size distribution can significantly affect biogenic silica contents in sediments. Close relationships of biogenic silica with organic carbon and nitrogen were also found, reflecting that there is a strong coupling between biogenic silica and organic matter biogeochemical cycles in the intertidal system of the Yangtze Estuary. Additionally, the early diagenetic changes of biogenic silica in sediments are discussed in the present study. 展开更多
关键词 biogenic silica early diagenesis intertidal flats the Yangtze Estuary
下载PDF
Characteristics and accumulation model of the late Quaternary shallow biogenic gas in the modern Changjiang delta area, eastern China 被引量:6
10
作者 Xia Zhang Chun-Ming Lin 《Petroleum Science》 SCIE CAS CSCD 2017年第2期261-275,共15页
The Changjiang(Yangtze)is one of the largest rivers in the world.It formed a huge incised valley at its mouth during the Last Glacial Maximum;the incised-valley fill,approximately 80–110 m thick,supplies an importa... The Changjiang(Yangtze)is one of the largest rivers in the world.It formed a huge incised valley at its mouth during the Last Glacial Maximum;the incised-valley fill,approximately 80–110 m thick,supplies an important foundation for the generation of shallow biogenic-gas reservoirs.Two cores and 13 cone penetration tests were used to elaborate the characteristics,formation mechanism,and distribution of the shallow biogenic-gas reservoirs in the study area.The natural gas is mainly composed of CH4(generally[95%)with a δ^13CCH4 and δ^13CCO2 of-75.8 to-67.7% and -34.5 to-6.6%,respectively,and a δDCH4 of-215 to-185%,indicating a biogenic origin by the carbon dioxide reduction pathway.Commercial biogenic gas occurs primarily in the sand bodies of fluvial-channel,floodplain,and paleo-estuary facies with a burial depth of 50–80 m.Gas sources as well as cap beds are gray to yellowish-gray mud of floodplain,paleoestuary,and offshore shallow marine facies.The organic matter in gas sources is dominated by immature type Ⅲ kerogen(gas prone).The difference in permeability(about4–6 orders of magnitude)between cap beds and reservoirs makes the cap beds effectively prevent the upward escape of gas in the reservoirs.This formation mechanism is consistent with that for the shallow biogenic gas in the late Quaternary Qiantang River incised valley to the south.Therefore,this study should provide further insight into understanding the formation and distribution of shallow biogenic gas in other similar postglacial incised-valley systems. 展开更多
关键词 biogenic gas - Formation mechanism Late Quaternary Modern Changjiang delta Eastern China
下载PDF
Biogenic carbonate formation and sedimentation in the Xisha Islands: evidences from living Halimeda 被引量:4
11
作者 XU Hong ZHAO Xinwei +8 位作者 EBERLI G.P. LIU Xinyu ZHU Yurui CAI Ying LUO Wei YAN Guijing ZHANG Bolin WEI Kai SHI Jian 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2015年第4期62-73,共12页
A recent island survey reveals that the Xuande Atoll and the Yongle Atoll in the Xisha Islands can be classified into one of two systems:the depleted atoll system and growth atoll system;the survey also indicates tha... A recent island survey reveals that the Xuande Atoll and the Yongle Atoll in the Xisha Islands can be classified into one of two systems:the depleted atoll system and growth atoll system;the survey also indicates that the decreased area of several shoals is an unbearable burden for the Xisha Islands, of which the largest island area is 2.13 km2 and the minimum elevation is 1.4 m. According to a survey on the ecological characteristics of Halimeda in the Laolongtou breaker zone of Shidao Island in the Xisha Islands, the green and white living Halimeda are collected, the isotopic ages of 14C contained in the Halimeda are shown to be 27 years and 55 years, respectively, and carbonate mainly occurs in five types, i.e., luster, segment, sand, sand grain, and marl in the formation. The Halimeda segments mainly provide the carbonate sediments of long-term biogenic deposits in the reef environment and the annual productivity per area is 60–100 g/m2;the characteristics of the microstructure of the Halimeda are analyzed, the aragonite raphide carbonate is deposited and enriched in the cortexes, medullas and cysts, and the Halimeda generally contain major elements such as C, O, Ca, Cl, Mg, K, Na, S and Al, and are rich in trace elements such as tellurium (Te), rhodium (Rh) and strontium. It is believed that the Halimeda grow slowly, including the biotic community of reef corals in the reef areas, thus they possess an environmental remediation capacity, but it takes much time to remedy the environment, and it is necessary to make the law to protect the diversity and vulnerability of the Xisha marine ecology, the ecology of the reef community and the island environment in a scientific way. As indicated in the survey, under the background of global warming and sea-level rise, the discovery of large amounts of Halimeda in the Laolongtou sea area is significant for the natural increase of the depleted atoll system of the Xuande Atoll, while the Halimeda segments represent the primary form of the fossil Halimeda, of which the species can be identified and preserved in great numbers under geological conditions. The Miocene was discovered in large amounts in the Xichen-1 well, therefore the study on the characteristics and mechanism of Halimeda carbonate sediments plays a pivotal role in the formation and construction of organic reefs in the South China Sea as well as oil and gas exploration. 展开更多
关键词 Xisha Islands HALIMEDA composition of biogenic carbonate 14^C accelerator mass spectrometrydating segment aragonite raphide trace elements
下载PDF
New Approaches and Markers for Identifying Secondary Biogenic Coalbed Gas 被引量:4
12
作者 TAO Mingxin LI Jing +6 位作者 LI Xiaobin MA Yuzhen LI Zhongping WANG Zuodong GAO Zhongliang ZHANG Xiaojun WANG Yanlong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第1期199-208,共10页
According to the adsorption-desorption characteristics of coalbed gas and analysis of various experimental data, this paper proposes that the generation of secondary biogenic gas (SBG) and its mixing of with the res... According to the adsorption-desorption characteristics of coalbed gas and analysis of various experimental data, this paper proposes that the generation of secondary biogenic gas (SBG) and its mixing of with the residual thermogenic gas at an early stage inevitably lead to secondary changes of the thermogenic gas and various geochemical additive effects. Experimental results also show that the fractionation of the carbon isotope of methane of coal core desorption gas changes very little; the δ13C1 value of the mixed gas of biogenic and thermogenic gases is between the δ13C1 values of the two "original" gases, and the value is determined by the carbon isotopic compositions and mixing proportions of the two "original" methanes. Therefore this paper proposes that the study on the secondary changes of the thermogenic gas and various additive effects is a new effective way to study and identify SBG. Herein, a systematic example of research on the coalbed gas (Huainan coalbed gas) is further conducted, revealing a series of secondary changes and additive effects, the main characteristics and markers of which are: (1) the contents of CO2 and heavy-hydrocarbons decrease significantly; (2) the content of CH4 increases and the gas becomes drier; (3) the δ13C and δD values of methane decrease significantly and tend to have biogenetic characteristics; and (4) the values of 513C2 and δ13Cc02 grow higher. These isotopic values also change with the degradation degrees by microbes and mixing proportions of the two kinds of gases in different locations. There exists a negative correlation between the △13C1 It'S δ13Cco2 values. The δ13Cc2-c1 values obviously become higher. The distributions of the △δ^13Cco2-C1 values are within certain limits and show regularity. There exist a positive correlation between the N2 versus Ar contents, and a negative correlation between the N2 versus CH4 contents, indicating the down forward infiltration of the surface water containing air. These are important markers of the generation and existence of SBG . 展开更多
关键词 secondary biogenic gas thermogenic coalbed gas components and isotopes secondary change mixing effect differentiating markers
下载PDF
Effects of river damming on biogenic silica turnover:implications for biogeochemical carbon and nutrient cycles 被引量:3
13
作者 Nan Ma Zhaoliang Song +5 位作者 Baoli Wang Fushun Wang Xiaomin Yang Xiaodong Zhang Qian Hao Yuntao Wu 《Acta Geochimica》 EI CAS CSCD 2017年第4期626-637,共12页
Rivers link terrestrial ecosystems and marine ecosystems, and they transport large amounts of substances into oceans each year, including several forms of silicon(Si), carbon(C), and other nutrients. However, river da... Rivers link terrestrial ecosystems and marine ecosystems, and they transport large amounts of substances into oceans each year, including several forms of silicon(Si), carbon(C), and other nutrients. However, river damming affects the water flow and biogeochemical cycles of Si, C, and other nutrients through biogeochemical interacting processes. In this review, we first summarize the current understanding of the effects of river damming on the processes of biogeochemical Si cycle, especially the source, composition, and recycling process of biogenic silica(BSi). Then, we introduce dam impacts on the cycles of C and some other nutrients. Dissolved silicon in rivers is mainly released from phytolith dissolution and silicate weathering. BSi in suspended matter or sediments in most rivers mainly consists of phytoliths and mainly originates from soil erosion. However, diatom growth and deposition in many reservoirs formed by river interception may significantly increase the contribution of diatom Si to total BSi, and thus significantly influence the biogeochemical Si,C, and nutrient cycles. Yet the turnover of phytoliths and diatoms in different rivers formed by river damming is still poorly quantified. Thus, they should be further investigated to enhance our understanding about the effects of river damming on global biogeochemical Si, C and nutrient cycles. 展开更多
关键词 River damming biogenic silica Biogeochemical cycles River ecosystem
下载PDF
Biogenic Sedimentary Structures of the Yellow River Delta in China and Their Composition and Distribution Characters 被引量:3
14
作者 WANG Yuanyuan HU Bin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2014年第5期1488-1498,共11页
The biogenic sedimentary structures (i.e., the morphology and trace makers of burrows, tracks, trails and traces made by extant organisms) and their composition and distribution characters in different micro environ... The biogenic sedimentary structures (i.e., the morphology and trace makers of burrows, tracks, trails and traces made by extant organisms) and their composition and distribution characters in different micro environments and sub environments of the Yellow River delta in China are described. Three ichnocoenosis can be recognized: (1) Steinichnus-like ichnocoenosis, includes F, Y-shaped traces, birds' footprints on bedding plane, and Y, U-shaped burrows in intrastratal bedding, produced by Coleoptera (Heteroceridae), Orthoptera (Gryllotalpidae) and birds. It is majorly found at the delta plain point bar deposits, denoting the fresh water-related terrestrial environments. (2) Steinichnus-Psilonichnus-like ichnocoenosis, consitsis of Steinichnus-like traces on the bedding plane and Psilonichnus-like burrow which a vertical, irregularly J-, Y-, or U-shaped burrows, some of them with bulbous basal cells burrows in the intrastratal bedding, created by Coleoptera (Heteroceridae), Orthoptera (Gryllotalpidae) and crabs. It is observed in the delta plain abandoned distributary channels, and the delta front tidal creek and subaquous distributary channels, indicating the brackish water environment. (3) Palaeophycus-like ichnocoenosis, includes the round entrance burrows or with craters-shaped loop-protrusionsand and the parallel forked trails on the bedding plane, and the U, J or vertical shaped feeding burrows are in the intrastratal bedding, majorly produced by the clam (bivalve molluscs), gastropods and Nereis. It is present in the subaqueous interdistributary bay, reflecting the intertidal related environment. 展开更多
关键词 biogenic sedimentary structures modern ichnocoenosis Yellow River delta China
下载PDF
Relationship between biogeochemical features of biogenic elements and flocculation in the Changjiang Estuary 被引量:3
15
作者 Lin Yi’an Tang Renyou +2 位作者 Li Yan Dong Henglin Guan Xuwei and Chen Yinzu (Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China Shanghai Survey and Designing Institute of Ministry of Energy and Ministry of Water Resources, 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1995年第2期225-234,共10页
This paper reports the relationship between the biogeochemical characteristics of C. N. P and flocculation and settling of suspended materials in the Changjiang Estuary. Regional activities of bacteria and the plankto... This paper reports the relationship between the biogeochemical characteristics of C. N. P and flocculation and settling of suspended materials in the Changjiang Estuary. Regional activities of bacteria and the plankton and biogeochemical processes at the water-particle interface under some environmental conditions are quite variable. This leads to the transition of material phase with speciation variation of elements C. N. P. in the transfer processes. Therefore, the composition and reactivity of particle surface and dissolved constituent are modified, affecting the stability of the particulate dispersion system. In summer, the concentration of NO3 and PO4 are positively correlated with turbidity, while the weight percentage of PON, POC and PP are negatively correlated with turbidity. When particles in the river move seaward, two zones can be distinguished: i) zone with maximum flocculation speed, in salinity 0. 1~2. 0 ;ii) zone with huge coagulating particles netting and high turbidity at the bottom, in salinity 2~11.The highest values of C/N in particles (or the low valley of C. E. C.of particle surface) appear in the two zones. These results demonstrate that the biogeochemical action is one of the major factors and mechanisms to dominate the flocculation of particles in the Changjiang Estuary. 展开更多
关键词 FLOCCULATION biogeochemical features suspended particle matter biogenic elements the Changjiang Estuary
下载PDF
A biogenic volatile organic compounds emission inventory for Yunnan Province 被引量:2
16
作者 WANGZhi-hui BAIYu-hua ZHANGShu-yu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2005年第3期353-359,共7页
The first detailed inventory for volatile organic compounds(VOC) emissions from vegetation over Yunnan Province, China was presented. The spatially and temporally resolved inventory was developed based on a geographic... The first detailed inventory for volatile organic compounds(VOC) emissions from vegetation over Yunnan Province, China was presented. The spatially and temporally resolved inventory was developed based on a geographic information system(GIS), remote sensing(RS) data and field measurement data, such as digitized land-use data, normalized difference vegetation index(NDVI) and temperature data from direct real-time measurement. The inventory has a spatial resolution of 5 km×5 km and a time resolution of 1 h. Urban, agriculture, and natural land-use distributions in Yunnan Province were combined with biomass factors for each land-use category to produce a spatially resolved biomass inventory. A biogenic emission inventory was developed by combining the biomass inventory with hourly emission rates for tree, shrub and ground cover species of the study area. Correcting for environmental factors, including light intensity and temperature, a value of 1.1×10 12 gC for total annual biogenic VOC emissions from Yunnan Province, including 6.1×10 11 gC for isoprene, 2.1×10 11 gC for monoterpenes, and 2.6×10 11 gC for OVOC was obtained. The highest VOC emissions occurred in the northwestern, southwestern and north region of Yunnan Province. Some uncertainties were also discussed in this study. 展开更多
关键词 biogenic VOC ISOPRENE MONOTERPENE emissions inventory Yunnan Province
下载PDF
Contribution of phytoliths to total biogenic silica volumes in the tropical rivers of Malaysia and associated implications for the marine biogeochemical cycle 被引量:2
17
作者 臧家业 刘森 +2 位作者 刘焱光 马永星 冉祥滨 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2016年第5期1076-1084,共9页
The contribution of phytoliths to total biogenic silica(BSi) volumes in rivers worldwide,and the associated implications for the biogeochemical cycle,require in-depth study.Based on samples from rivers in Peninsular M... The contribution of phytoliths to total biogenic silica(BSi) volumes in rivers worldwide,and the associated implications for the biogeochemical cycle,require in-depth study.Based on samples from rivers in Peninsular Malaysia,this project investigated the source and characteristics of B Si found in Asian tropical rivers,as well as the process of reverse weathering taking place in these fluvial systems.Results indicated that BSi samples collected in sediments consisted of phytolith,diatom and sponge spicules.Phytoliths,predominantly of the elongate form,comprised 92.8%-98.3% of BSi in the Pahang River.Diatom BSi in this river consisted mainly of pennatae diatoms,but represented a relatively small proportion of the total BSi volume.However,diatom BSi(predominantly of the Centricae form) was more prevalent in the Pontian and Endau Rivers with shares of 68.8% and 79.3% of the total BSi volumes,respectively,than Pahang River.Carbon contents of the BSi particulates ranged from 1.85% to 10.8% with an average of 4.79%.These values are higher than those recorded in other studies to date,and indicate that BSi plays a major role in controlling permanent carbon burial.This study suggests that phytoliths from terrestrial plants are the primary constituents of BSi in the rivers of Peninsular Malaysia,and therefore represent a significant proportion of the coastal silica budget. 展开更多
关键词 biogenic silica PHYTOLITH DIATOM MALAYSIA biogeochemical cycle
下载PDF
Effects of biogenic amines on the testicular development in mud crabs Scylla serrata 被引量:2
18
作者 YE Haihui HUANG Huiyang +2 位作者 LI Shaojing WANG Guizhong LI Qifu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2006年第2期119-124,共6页
The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the ma... The regulation of three biogenic amines over the reproductive neuroendoerine activity of the male Scylla serrata was investigated by in vivo injection and in vitro incubation. The testicular index, the ratio of the mature sections in testes, and the ratio of Type B cells in androgenic gland were taken as the quantitative indexes. The in vivo injections indicated that: 5-HT can significantly promote the testicular development and the secretion of the androgenic gland in S. serrata; DA can inhibit the testicular development, but no influence on the secretion of the androgenic gland was found; no significant difference was observed between the OA-injected group and the concurrent control group. In vitro incubations showed that: 5-HT can stimulate the secretion of the brain and the thoracic ganglia, thus accelerating that of the androgenic gland; however, neither OA nor DA showed any significant influence on the secretion of the brain and the thoracic ganglionic mass. As to the optic ganglia, the three biogenic amines hardly have any effect on its secretion. It is the first time to report the regulation of biogenic amines over the reproductive neuroendocrine of male crustaceans through vitro experiments. Results corroborate that 5-HT activates the brain and the thoracic ganglia to secret GSH first, then promote the testicular development through the activity of the androgenic gland. 展开更多
关键词 biogenic amines Scylla serrata neuroendocrine organs androgenic gland REPRODUCTION
下载PDF
The Burial of Biogenic Silica, Organic Carbon and Organic Nitrogen in the Sediments of the East China Sea 被引量:2
19
作者 WANG Lisha ZHANG Chuansong SHI Xiaoyong 《Journal of Ocean University of China》 SCIE CAS 2015年第3期464-470,共7页
We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the... We sampled the sediments of the East China Sea during 2005 and 2006, and analysed the contents of the biogenic matters: biogenic silica, organic carbon, and organic nitrogen. From the surface distribution we found the contents of these substances to be in the ranges of 0.72%-1.64%, 0.043%-0.82%, and 0.006%-0.11%, respectively. Their distributions were similar to each other, being high inside the Hangzhou Bay and low outside the bay. The vertical variations of the contents were also similar. In order to discuss the relation between them we analysed the variations of content with depth. They increased in the first 7 cm and then decreased with depth. The peaks were found at depths between 20 to 25 cm. The distribution of carbonate showed an opposite trend to that of biogenic matters. The content of total carbon was relatively stable with respect to depth, and the ratio of high organic carbon to carbonate showed a low burial efficiency of carbonate, which means that the main burial of carbon is organic carbon. In order to discuss the source of organic matters, the ratio of organic carbon to organic nitrogen was calculated, which was 8.01 to 9.65, indicating that the organic matter in the sediments was derived mainly from phytoplankton in the seawater. 展开更多
关键词 BURIAL sediment biogenic matters carbon and nitrogen ratio East China Sea
下载PDF
Emissions of Biogenic Sulfur Gases(H2S,COS)from Phragmites australis Coastal Marsh in the Yellow River Estuary of China 被引量:2
20
作者 LI Xinhua ZHU Zhenlin +1 位作者 YANG Liping SUN Zhigao 《Chinese Geographical Science》 SCIE CSCD 2016年第6期770-778,共9页
Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using ... Emissions of biogenic sulfur gases(hydrogen sulfide(H_2S) and carbonyl sulfide(COS)) from Phragmites australis coastal marsh in the Yellow River estuary of China were determined during April to December in 2014 using static chamber-gas chromatography technique with monthly sampling. The results showed that the fluxes of H_2S and COS both had distinct seasonal and diurnal variations. The H_2S fluxes ranged from 0.09 μg/(m^2·h) to 7.65 μg/(m^2·h), and the COS fluxes ranged from –1.10 μg/(m^2·h) to 3.32 μg/(m^2·h). The mean fluxes of H_2S and COS from the P. australis coastal marsh were 2.28 μg/(m^2·h), and 1.05 μg/(m^2·h), respectively. The P. australis coastal marsh was the emission source of both H_2S and COS over the whole year. Fluxes of H_2S and COS were both higher in plant growing season than in the non-growing season. Temperature had a dramatic effect on the H_2S emission flux, while the correlations between COS flux and the environmental factors were not found during sampling periods. More in-depth and comprehensive research on other related factors, such as vegetation, sediment substrates, and tidal action is needed to discover and further understand the key factors and the release mechanism of sulfur gases. 展开更多
关键词 biogenic sulfur gases hydrogen sulfide carbonyl sulfide emission flux Phragmites australis coastal marsh the Yellow River estuary
下载PDF
上一页 1 2 13 下一页 到第
使用帮助 返回顶部