The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trend...The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m3/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05 –0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55(mgC/m2·d)/(m3/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m2·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs.1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth.展开更多
Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the orig...Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the origin of the CO_2 involved in chemical weathering reactions.Spatial variations of major elements ratios measured in water samples can be explained by a change of the chemical composition of the volcanic rocks between the volcanic cone(trachytes)and the basaltic shield as evidenced by the variations in the composition of these rocks.Hence,DIC results from the neutralization of CO_2 by silicate rocks.DIC concentrations vary from 0.3 to 2.5 mmol/L and carbon isotopic compositions of DIC measured in rivers vary from-14.2‰to 3.5‰.At a first order,the DIC transported by rivers is derived from the chemical weathering’s consumption of CO_2 with a magmatic origin,enriched in^(13)C(-5%)and biogenic soil CO_2 with lower isotopic compositions.The highest δ^(13)C values likely result from C isotopes fractionation during CO_2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO_2 varied from less than 20%to more than 70%.Uncertainties in this calculation associated with CO_2 degassing in rivers are difficult to quantify,and the consequence of CO_2 degassing would be an overestimation of the contribution of DIC derived from the neutralization of magmatic CO_2 by silicate rocks.展开更多
The morphology and toxicity of Pseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang (Yangtze) River in Year 2002 and tentatively identified as Pseudo-nitzschia pungens, were studied. The strain w...The morphology and toxicity of Pseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang (Yangtze) River in Year 2002 and tentatively identified as Pseudo-nitzschia pungens, were studied. The strain was identified morphologically as P. pungens using scanning electronic microscope (SEM). The ana- lytical results of LC-PDA (liquid chromatography with photodiode array detector), LC-MS (liquid chromatogra- phy with mass detector), and the toxicity data from mouse bioassay, showed that no domoic acid was produced by the strain. However, the mechanism of domoic acid production by Pseudo-nitzschia species is complicated. More works are needed to assess the toxic species and to evaluate the potential risk of amnesic shellfish poison- ing (ASP) in China.展开更多
We describe two new species of Sellaphora from Lake Fuxian, Ytmnan Plateau, China. Based on both light and scanning electron microscopy, these species are described as S. yunnanensis sp. nov. and S. sinensis sp. nov. ...We describe two new species of Sellaphora from Lake Fuxian, Ytmnan Plateau, China. Based on both light and scanning electron microscopy, these species are described as S. yunnanensis sp. nov. and S. sinensis sp. nov. The primary features of S. yunnanens& are: elliptical to linear-elliptical valves with broadly rounded ends, straight filiform raphe, almost straight central endings and small, slightly expanding central pores, small central area, symmetrical or slightly asymmetrical central nodule. The primary features of S. sinensis are: elliptical valves, obtusely rounded ends, similar raphe and axial area, transapically less expanded central area, larger, elliptical central nodule. We compare these species to those of a similar shape and morphology.展开更多
The research and development history of silicon Neutron Transmutation Doping (NTD) technology and its applications at home and abroad are introduced in this paper.The advantages of NTD,compared with conventional techn...The research and development history of silicon Neutron Transmutation Doping (NTD) technology and its applications at home and abroad are introduced in this paper.The advantages of NTD,compared with conventional technology of doping,are narrated.The principle of NTD as well as the implementation of the main procedures related to Si NTD is explained.The market demand tendency is prospected,and the advanced measures on NTD quality control are described.展开更多
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
Diatom taxa in samples collected from the uppermost 1-cm sediment of the South China Sea (SCS) during cruises in 2000, 2001, and 2007 were investigated. Among them, two genera, Rutilaria and Trigoniurn, and 11 marin...Diatom taxa in samples collected from the uppermost 1-cm sediment of the South China Sea (SCS) during cruises in 2000, 2001, and 2007 were investigated. Among them, two genera, Rutilaria and Trigoniurn, and 11 marine taxa (species and varieties) were described for the first time in China. The 11 taxa, Rutilaria radiata, Asterolampra grevillei, Biddulphia turrigera, Cocconeis cyclophora var. decora, Cocconeis ocellata, Dictyoneis rnarginata, Entogonia davyana, Tryblionella campechiana, Plagiogramma kinkeri, Plagiogramma nankoorense and Trigonium cf. contumax, were mainly extant species, although Rutilaria radiata and Entogonia davyana are fossils. Available data show that these species are mainly present in the eastern and western Pacific Ocean and the Indian Ocean. A large number of taxa newly recorded in this study were previously reported in the Philippines. The presence of these taxa in both locations is likely a result of seawater exchange in the SCS through the Bashi Channel Taxonomic descriptions, habitats, and distributions of each diatom taxon are provided herein.展开更多
Fossil woods were collected from the Upper Cretaceous to Paleocene beds distributed around Heilong- jang (Amur) River area of China and Russia. A total of 43 specimens were collected from Baishantou, Long- gushan, a...Fossil woods were collected from the Upper Cretaceous to Paleocene beds distributed around Heilong- jang (Amur) River area of China and Russia. A total of 43 specimens were collected from Baishantou, Long- gushan, and Yong'ancun in Jiayin, China, and 85 specimens from Zeya-Bureya Basin lying southeast of Blagoveshchensk in Russia. Selected specimens were sectioned and studied anatomically. The source deposits of almost all identifiable specimens belong to the Upper Cretaceous (Campanian) Taipinglinchang Formation and the Paleocene Wuyun Formation in China, and the Paleocene Upper Tsagayan Formation in Russia. Al- though the results obtained are still far from complete, the taxonomic composition of the fossil woods show marked stratigraphic differences between the two horizons beyond the K/T boundary in China. There is also a strong similarity in wood flora between the Wuyun Formation of China and the Upper Tsagayan Formation of Russia. All identified specimens from the Taipinglinchang Formation are Xenoxylon latiporosum, This is one of the stratigraphically younger records of Xenoxylon, which is a conifer morphogenus of uncertain affinity most common in the Triassic to Early Cretaceous. Only one specimen with possible derivation from either the Wuyun or the Maastriehtian Furao Formation in China was identified as Taxodioxylon sp. The Wuyun Formation yielded both conifers and dicotyledonous woods. The conifers include Taxodioxylon sequoianum of the Taxodiaceae, and Protopiceoxylon amurense, which is attributable to the extant genera Keteleeria or Nothotsuga of the Pinaeeac, both are at present endemic to China. At least two morphotypes of dicotyledonous woods were recognized, with one identified as el. Hamamelidoxylon , and the other diffuse porous wood is characterized by numerous heterogeneous rays. From the Zeya-Buleya Basin of Russia, Taxodioxylon sequoianum and cf. Hamamelidoxylon sp. were identified from the Upper Tsagayan Formation. The similarity of wood composition in both Wuyun and Upper Tsagayan Formations support lithological as well as biostratigraphic correlations proposed for the two formations.展开更多
The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Chang^iang (Yangtze) River, China...The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Chang^iang (Yangtze) River, China. In total, 267 diatom taxa and two silicoflagellate species were identified from the sediments. The spatial variations in abundance and diversity were classified into three distinct geographic patterns using Q mode clustering: a south-north geographic pattern, a coastal-offshore pattern and a unique pattern in the Changjiang River mouth. The south-north geographic pattern was related to the spatial variations in sea temperature. Coscinodiscus oculatus, a warm-water species, indicated these variations by a gradual decrease in abundance from the south to the north. The coastal-offshore pattern was in response to the spatiaJ variations in salinity. Cyclotella stylorum, Actinocyclus ehrenbergii and Dictyocha messanensis, the dominant brackish species in coastal waters, significantly decreased at the isobaths of approximately 30 m, where the salinity was higher than 31. Paralia sulcata and Podosira stelliger indicated the impact of the Yellow Sea Warm Current in the central Yellow Sea. The unique pattern in the Changjiang River mouth showed the highest species diversity but lower abundance, apparently because: freshwater input can significantly increase the proportion of brackish species; nutrients can supply the growth ofphytoplankton; and high sedimentation rates can dilute the mierofossil abundance in the sediments. Our results show that an integration of environmental factors (e.g., nutrient levels, sedimentation rate, sea temperature, salinity and water depth) determined the spatial characteristics of the siliceous micro fossils in the surface sediments.展开更多
The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from differen...The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.展开更多
There are a series of special mountain soils on the Tibetan Plateau of China in an alpine environment for the high altitude. However, very few studies have focused on major soil elements in relation to soil formation ...There are a series of special mountain soils on the Tibetan Plateau of China in an alpine environment for the high altitude. However, very few studies have focused on major soil elements in relation to soil formation in this area. Aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K) and magnesium (Mg) contents of 237 topsoil samples covering a 2.8-km altitudinal gradient in uncultivated areas along the Qinghai-Tibet Railway of China were measured using inductively coupled plasma atomic emission spectroscopy. The spatial distribution of the elements and its relationship to the parent rocks and climatic parameters were analyzed. Soils along the gradient are derived from a range of parent materials, but most are less than 30 cm deep with little development (Cambisols). Soil Al, Fe and Mg contents showed a decreasing trend from the start station (Xining Station) to end station (Lhasa Station) of the Qinghai-Tibet Railway, whereas soil K and Na contents were relative stable from Xining Station to the Kunlun Mountains and then increased gradually. Soil Ca content was lower in the southern part of the Tanggula Mountains. The major soil element contents clearly reflected the parent rock and climatic influences. Soils with higher Ca content appeared in areas with Ca-Mg carbonate rocks, soils with higher Al were found in areas with silicate-rich and high-Al silicate clastic rocks and silicate-rich aluminosilicate loose sediments. Soils with higher K and Na contents appeared in areas with high-K, high-Na and silicate-rich aluminosilicate rocks. Soil Na and K contents were affected by temperature, whereas the contents of Mg, Fe, Ca and Al were more affected by precipitation. Soil Na and K contents increased with increasing temperatures, whereas the contents of Mg, Fe, Ca and Al decreased with increasing precipitation. This analysis provides a relationship between soil properties and rapidly changing environmental conditions. The data can be used to investigate the effect of the climate or land use change on soil properties.展开更多
基金This study was funded by NSFC (No. 40036010), and the Director’s Fund of the Beihai Sea Monitoring Center, the State Oceanic Administration.
文摘The authors analyzed the data collected in the Ecological Station Jiaozhou Bay from May 1991 to November 1994, including 12 seasonal investigations, to determine the characteristics, dynamic cycles and variation trends of the silicate in the bay. The results indicated that the rivers around Jiaozhou Bay provided abundant supply of silicate to the bay. The silicate concentration there depended on river flow variation. The horizontal variation of silicate concentration on the transect showed that the silicate concentration decreased with distance from shorelines. The vertical variation of it showed that silicate sank and deposited on the sea bottom by phytoplankton uptake and death, and zooplankton excretion. In this way, silicon would endlessly be transferred from terrestrial sources to the sea bottom. The silicon took up by phytoplankton and by other biogeochemical processes led to insufficient silicon supply for phytoplankton growth. In this paper, a 2D dynamic model of river flow versus silicate concentration was established by which silicate concentrations of 0.028–0.062 μmol/L in seawater was yielded by inputting certain seasonal unit river flows (m3/s), or in other words, the silicate supply rate; and when the unit river flow was set to zero, meaning no river input, the silicate concentrations were between 0.05 –0.69 μmol/L in the bay. In terms of the silicate supply rate, Jiaozhou Bay was divided into three parts. The division shows a given river flow could generate several different silicon levels in corresponding regions, so as to the silicon-limitation levels to the phytoplankton in these regions. Another dynamic model of river flow versus primary production was set up by which the phytoplankton primary production of 5.21–15.55(mgC/m2·d)/(m3/s) were obtained in our case at unit river flow values via silicate concentration or primary production conversion rate. Similarly, the values of primary production of 121.98–195.33 (mgC/m2·d) were achieved at zero unit river flow condition. A primary production conversion rate reflects the sensitivity to silicon depletion so as to different phytoplankton primary production and silicon requirements by different phytoplankton assemblages in different marine areas. In addition, the authors differentiated two equations (Eqs.1 and 2) in the models to obtain the river flow variation that determines the silicate concentration variation, and in turn, the variation of primary production. These results proved further that nutrient silicon is a limiting factor for phytoplankton growth.
基金supported by the National Natural Science Foundation of China through Grant No.41473023
文摘Major elements and carbon isotopes of dissolved inorganic carbon(DIC)have been measured in the waters of Changbaishan mountain,a volcanic area in northeastern China,between June and September 2016 to decipher the origin of the CO_2 involved in chemical weathering reactions.Spatial variations of major elements ratios measured in water samples can be explained by a change of the chemical composition of the volcanic rocks between the volcanic cone(trachytes)and the basaltic shield as evidenced by the variations in the composition of these rocks.Hence,DIC results from the neutralization of CO_2 by silicate rocks.DIC concentrations vary from 0.3 to 2.5 mmol/L and carbon isotopic compositions of DIC measured in rivers vary from-14.2‰to 3.5‰.At a first order,the DIC transported by rivers is derived from the chemical weathering’s consumption of CO_2 with a magmatic origin,enriched in^(13)C(-5%)and biogenic soil CO_2 with lower isotopic compositions.The highest δ^(13)C values likely result from C isotopes fractionation during CO_2 degassing in rivers.A mass balance based on carbon isotopes suggest that the contribution of magmatic CO_2 varied from less than 20%to more than 70%.Uncertainties in this calculation associated with CO_2 degassing in rivers are difficult to quantify,and the consequence of CO_2 degassing would be an overestimation of the contribution of DIC derived from the neutralization of magmatic CO_2 by silicate rocks.
基金Supported by the projects of Ministry of Science and Technology (No.2001CB409704 and No. 2001BA804A20), and the innovation project ofthe Institute of Oceanology, CAS (No. 200223107)
文摘The morphology and toxicity of Pseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang (Yangtze) River in Year 2002 and tentatively identified as Pseudo-nitzschia pungens, were studied. The strain was identified morphologically as P. pungens using scanning electronic microscope (SEM). The ana- lytical results of LC-PDA (liquid chromatography with photodiode array detector), LC-MS (liquid chromatogra- phy with mass detector), and the toxicity data from mouse bioassay, showed that no domoic acid was produced by the strain. However, the mechanism of domoic acid production by Pseudo-nitzschia species is complicated. More works are needed to assess the toxic species and to evaluate the potential risk of amnesic shellfish poison- ing (ASP) in China.
基金Supported by the National Basic Research Program (973 Program) (No.2010CB833404)the Knowledge Innovation Program of the Chinese Academy of Sciences (Nos. KZCX2-YW-319 and KZCX1-YW-14)the National Natural Science Foundation of China (No. 40972114)
文摘We describe two new species of Sellaphora from Lake Fuxian, Ytmnan Plateau, China. Based on both light and scanning electron microscopy, these species are described as S. yunnanensis sp. nov. and S. sinensis sp. nov. The primary features of S. yunnanens& are: elliptical to linear-elliptical valves with broadly rounded ends, straight filiform raphe, almost straight central endings and small, slightly expanding central pores, small central area, symmetrical or slightly asymmetrical central nodule. The primary features of S. sinensis are: elliptical valves, obtusely rounded ends, similar raphe and axial area, transapically less expanded central area, larger, elliptical central nodule. We compare these species to those of a similar shape and morphology.
文摘The research and development history of silicon Neutron Transmutation Doping (NTD) technology and its applications at home and abroad are introduced in this paper.The advantages of NTD,compared with conventional technology of doping,are narrated.The principle of NTD as well as the implementation of the main procedures related to Si NTD is explained.The market demand tendency is prospected,and the advanced measures on NTD quality control are described.
基金supported by the National Key Basic Research Program (973) (Grant No. 2010CB428701)
文摘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.
基金Supported by the National Natural Science Foundation of China (Nos.40676026,41076079,40876079,40831160519,40906058)the National Basic Research Program of China(973 Program)(No. 2010CB428704)
文摘Diatom taxa in samples collected from the uppermost 1-cm sediment of the South China Sea (SCS) during cruises in 2000, 2001, and 2007 were investigated. Among them, two genera, Rutilaria and Trigoniurn, and 11 marine taxa (species and varieties) were described for the first time in China. The 11 taxa, Rutilaria radiata, Asterolampra grevillei, Biddulphia turrigera, Cocconeis cyclophora var. decora, Cocconeis ocellata, Dictyoneis rnarginata, Entogonia davyana, Tryblionella campechiana, Plagiogramma kinkeri, Plagiogramma nankoorense and Trigonium cf. contumax, were mainly extant species, although Rutilaria radiata and Entogonia davyana are fossils. Available data show that these species are mainly present in the eastern and western Pacific Ocean and the Indian Ocean. A large number of taxa newly recorded in this study were previously reported in the Philippines. The presence of these taxa in both locations is likely a result of seawater exchange in the SCS through the Bashi Channel Taxonomic descriptions, habitats, and distributions of each diatom taxon are provided herein.
基金NSFC Project 30220130698 to G. S.the Grant-in-Aid for Scientific Research no.1425507 from the Ministry of Education,Culture,Sports,Science and Technology of Japan to H.N.
文摘Fossil woods were collected from the Upper Cretaceous to Paleocene beds distributed around Heilong- jang (Amur) River area of China and Russia. A total of 43 specimens were collected from Baishantou, Long- gushan, and Yong'ancun in Jiayin, China, and 85 specimens from Zeya-Bureya Basin lying southeast of Blagoveshchensk in Russia. Selected specimens were sectioned and studied anatomically. The source deposits of almost all identifiable specimens belong to the Upper Cretaceous (Campanian) Taipinglinchang Formation and the Paleocene Wuyun Formation in China, and the Paleocene Upper Tsagayan Formation in Russia. Al- though the results obtained are still far from complete, the taxonomic composition of the fossil woods show marked stratigraphic differences between the two horizons beyond the K/T boundary in China. There is also a strong similarity in wood flora between the Wuyun Formation of China and the Upper Tsagayan Formation of Russia. All identified specimens from the Taipinglinchang Formation are Xenoxylon latiporosum, This is one of the stratigraphically younger records of Xenoxylon, which is a conifer morphogenus of uncertain affinity most common in the Triassic to Early Cretaceous. Only one specimen with possible derivation from either the Wuyun or the Maastriehtian Furao Formation in China was identified as Taxodioxylon sp. The Wuyun Formation yielded both conifers and dicotyledonous woods. The conifers include Taxodioxylon sequoianum of the Taxodiaceae, and Protopiceoxylon amurense, which is attributable to the extant genera Keteleeria or Nothotsuga of the Pinaeeac, both are at present endemic to China. At least two morphotypes of dicotyledonous woods were recognized, with one identified as el. Hamamelidoxylon , and the other diffuse porous wood is characterized by numerous heterogeneous rays. From the Zeya-Buleya Basin of Russia, Taxodioxylon sequoianum and cf. Hamamelidoxylon sp. were identified from the Upper Tsagayan Formation. The similarity of wood composition in both Wuyun and Upper Tsagayan Formations support lithological as well as biostratigraphic correlations proposed for the two formations.
基金Supported by the National Natural Science Foundation of China(No.41376121)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA11020405)+1 种基金the Natural Science Foundation of Shandong Province(No.JQ201414)the Cooperation Project of Chinese Academy of Sciences and Hebei Academy of Sciences(No.13001001)
文摘The spatial distribution of siliceous microfossils (diatoms and silicoflagellates) in the surface sediments was mapped at 113 sites in the Yellow Sea and sea areas adjacent to the Chang^iang (Yangtze) River, China. In total, 267 diatom taxa and two silicoflagellate species were identified from the sediments. The spatial variations in abundance and diversity were classified into three distinct geographic patterns using Q mode clustering: a south-north geographic pattern, a coastal-offshore pattern and a unique pattern in the Changjiang River mouth. The south-north geographic pattern was related to the spatial variations in sea temperature. Coscinodiscus oculatus, a warm-water species, indicated these variations by a gradual decrease in abundance from the south to the north. The coastal-offshore pattern was in response to the spatiaJ variations in salinity. Cyclotella stylorum, Actinocyclus ehrenbergii and Dictyocha messanensis, the dominant brackish species in coastal waters, significantly decreased at the isobaths of approximately 30 m, where the salinity was higher than 31. Paralia sulcata and Podosira stelliger indicated the impact of the Yellow Sea Warm Current in the central Yellow Sea. The unique pattern in the Changjiang River mouth showed the highest species diversity but lower abundance, apparently because: freshwater input can significantly increase the proportion of brackish species; nutrients can supply the growth ofphytoplankton; and high sedimentation rates can dilute the mierofossil abundance in the sediments. Our results show that an integration of environmental factors (e.g., nutrient levels, sedimentation rate, sea temperature, salinity and water depth) determined the spatial characteristics of the siliceous micro fossils in the surface sediments.
基金Under the auspices of National Natural Science Foundation of China (No 40971116)Major State Basic Research Development Program of China (No 2009CB426305)Technology Innovation Project of Northeast Normal University in Eleventh Five-Year Plan Period (No NENU-Stb07002)
文摘The Changbai Mountains,located in the temperate monsoon climate zone of East Asia,is an ideal loca-tion for the research on timberline response to global changes.In this study,the topsoils were collected from different vertical vegetation zones on the northern slope of the Changbai Mountains,Northeast China in August 2009,and phytoliths in the soil samples were extracted by using wet oxidation method and identified with Motic 2.0 microscope in laboratory.The results show that phytoliths are abundant in the topsoils of the study area.The herbal phytoliths are primarily composed of elongated,tooth-shaped,point-shaped and hat-shaped phytoliths,as well as a small amount of fan-shaped and square-shaped ones.The elongated,tooth-shaped,point-shaped and hat-shaped phytoliths are representative of cold climate,while fan-shaped and square-shaped ones are representative of warm and humid climate.In the conifer broadleaved mixed forest zone,coniferous forest zone and broadleaf forest zone,there are close correlations between vegetation and woody phytoliths in the topsoils,indicating that the woody plants of a region can be reconstructed from the woody phytolith assemblages in the topsoils.Meanwhile,the topsoil phytolith assemblages can also be used to reconstruct the understory herbs effectively.The phytolith assemblages in the topsoils of the forest community and herbal community differ significantly,which can help indicate the historical location of the timberline.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (No.XDB03030500)the National Key Technology Research and Development Program of China (No.2013BAC04B02)the National Natural Science Foundation of China (Nos.40801042 and 90202012)
文摘There are a series of special mountain soils on the Tibetan Plateau of China in an alpine environment for the high altitude. However, very few studies have focused on major soil elements in relation to soil formation in this area. Aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K) and magnesium (Mg) contents of 237 topsoil samples covering a 2.8-km altitudinal gradient in uncultivated areas along the Qinghai-Tibet Railway of China were measured using inductively coupled plasma atomic emission spectroscopy. The spatial distribution of the elements and its relationship to the parent rocks and climatic parameters were analyzed. Soils along the gradient are derived from a range of parent materials, but most are less than 30 cm deep with little development (Cambisols). Soil Al, Fe and Mg contents showed a decreasing trend from the start station (Xining Station) to end station (Lhasa Station) of the Qinghai-Tibet Railway, whereas soil K and Na contents were relative stable from Xining Station to the Kunlun Mountains and then increased gradually. Soil Ca content was lower in the southern part of the Tanggula Mountains. The major soil element contents clearly reflected the parent rock and climatic influences. Soils with higher Ca content appeared in areas with Ca-Mg carbonate rocks, soils with higher Al were found in areas with silicate-rich and high-Al silicate clastic rocks and silicate-rich aluminosilicate loose sediments. Soils with higher K and Na contents appeared in areas with high-K, high-Na and silicate-rich aluminosilicate rocks. Soil Na and K contents were affected by temperature, whereas the contents of Mg, Fe, Ca and Al were more affected by precipitation. Soil Na and K contents increased with increasing temperatures, whereas the contents of Mg, Fe, Ca and Al decreased with increasing precipitation. This analysis provides a relationship between soil properties and rapidly changing environmental conditions. The data can be used to investigate the effect of the climate or land use change on soil properties.