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1.
The compounds of sterols such as C27 ,C2s ,C29 and C30 are recorded from C-8 core of the Chukchi Sea. The double bond position is located at 5-, 5,22 as well as 22-,24-. The compound of sterols such as C27 ,C28 ,C29 are recorded from B2-9 core of the Bering Sea. The double bond position is located at 5-, 5, 22 as well as 22. The composition characteristics of sterols indicate that the substance is mainly contributed by the terrigenous origin and marine silicate organisms. The results are also suggest that the record of abnormal sterols from the surface sediments （2 -0 era）in the Chukchi Sea and the Bering Sea represent the period from 1980s to the late 1990s. The strong signal of the Arctic warming is preserved in the sediments, which indicates the eco - environmental change responding to climatic effect of circumjacent. 相似文献
2.
Clara Deal 《极地研究(英文版)》2008,19(2):218-229
Primary production in the Bering and Chukchi Seas is strongly influenced by the annual cycle of sea ice. Here pelagic and sea ice algal ecosystems coexist and interact with each other. Ecosystem modeling of sea ice associated phytoplankton blooms has been understudied compared to open water ecosystem model applications. This study introduces a general coupled ice-ocean ecosystem model with equations and parameters for 1-D and 3-D applications that is based on 1-D coupled ice-ocean ecosystem model development in the landfast ice in the Chukchi Sea and marginal ice zone of Bering Sea. The biological model includes both pelagic and sea ice algal habitats with 10 compartments： three phytoplankton （pelagic diatom, flagellates and ice algae： D, F, and Ai） , three zooplankton （copepods, large zooplankton, and microzooplankton ： ZS, ZL, ZP） , three nutrients （ nitrate ＋ nitrite, ammonium, silicon ： NO3 , NH4, Si） and detritus （Det）. The coupling of the biological models with physical ocean models is straightforward with just the addition of the advection and diffusion terms to the ecosystem model. The coupling with a multi-category sea ice model requires the same calculation of the sea ice ecosystem model in each ice thickness category and the redistribution between categories caused by both dynamic and thermodynamic forcing as in the physical model. Phytoplankton and ice algal self-shading effect is the sole feedback from the ecosystem model to the physical model. 相似文献
3.
The East Asian monsoon system influences the sedimentation and transport of organic matter in East Asian marginal seas that is derived from both terrestrial and marine sources. In this study, we determined organic carbon (OC) isotope values, concentrations of marine biomarkers, and levels of OC and total nitrogen (TN) in core YSC-1 from the central South Yellow Sea (SYS). Our objectives were to trace the sources of OC and variations in palaeoproductivity since the middle Holocene, and their relationships with the East Asian monsoon system. The relative contributions of terrestrial versus marine organic matter in core sediments were estimated using a two-end-member mixing model of OC isotopes. Results show that marine organic matter has been the main sediment constituent since the middle Holocene. The variation of terrestrial organic carbon concentration (OCter) is similar to the EASM history. However, the variation of marine organic carbon concentration (OCmar) is opposite to that of the EASM curve, suggesting OCmar is distinctly influenced by terrestrial material input. Inputs of terrestrial nutrients into the SYS occur in the form of fluvial and aeolian dust, while concentrations of nutrients in surface water are derived mainly from bottom water via the Yellow Sea circulation system, which is controlled by the East Asian winter monsoon (EAWM). Variations in palaeoproductivity represented by marine organic matter and biomarker records are, in general, consistent with the recent EAWM intensity studies, thus, compared with EASM, EAWM may play the main role to control the marine productivity variations in the SYS. 相似文献
4.
Abundance of general aerobic heterotrophic bacteria in the Bering Sea and Chukchi Sea and their adaptation to temperature 总被引：3，自引：0，他引：3
1 IntroductionInthedeepseawithawatertemperaturelowerthan5℃andtheseabottom ,theor ganicmattersareoxidizedmainlybytheaerobicbacteria (BenderandHeggie 1 984;Her bert 1 986) ,whichmeansthattheaerobicbacteriainthisenvironmentareratherabun dant.Thearcticseaareaisanareawhereenvironmentispermanentlycold ,butsomere searchresults (Sahmetal.1 998)indicatethattherearedominantbacteria eubacteriainthearcticseawaterandsediment,andtheiradaptationtotemperaturehasnosubstantialdifferenceincomparisonwiththatof… 相似文献
5.
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6.
Terrestrial organic matter(TOM) is an important component of marine sedimentary OM, and revealing the origins and transport mechanisms of TOM to the East China Sea(ECS) is important for understanding regional carbon cycle. A novel approach combining molecular proxies and compound-specific carbon isotopes is used to quantitatively constrain the origins and transport mechanisms of TOM in surface sediments from the ECS shelf. The content of terrestrial biomarkers of(C_(27)+C_(29)+C_(31)) n-alkanes(52 to 580 ng g~(-1)) revealed a seaward decreasing trend, the δ~(13)CTOC values(-20.6‰ to-22.7‰) were more negative near the coast, and the TMBR(terrestrial and marine biomarker ratio) values(0.06 to 0.40) also revealed a seaward decreasing trend. These proxies all indicated more TOM(up to 48%) deposition in the coastal areas. The Alkane Index, the ratio of C_(29)/(C_(29)+C_(31)) n-alkanes indicated a higher proportion of grass vegetation in the coastal area; While the δ13C values of C_(29) n-alkane(-_(29).3‰ to-33.8‰) indicated that terrestrial plant in the sediments of the ECS shelf were mainly derived from C_3 plants. Cluster analysis afforded detailed estimates of different-sourced TOM contributions and transport mechanisms. TOM in the Zhejiang-Fujian coastal area was mostly delivered by the Changjiang River, and characterized by higher %TOM(up to 48%), higher %C_3 plant OM(68%-85%) and higher grass plant OM(56%-61%); TOM in the mid-shelf area was mostly transported by aerosols, and characterized by low %TOM(less than 17%), slightly lower C_3 plant OM(56%-72%) and lower grass plant OM(49%-55%). 相似文献
7.
A model study is conducted to examine the role of Pacific water in the dramatic retreat of arctic sea ice during summer 2007. The model generally agrees with the observations in showing considerable seasonal and interannual variability of the Pacific water inflow at Bering Strait in response to changes in atmospheric circulation. During summer 2007 anomalously strong southerly winds over the PaCific sector of the Arctic Ocean strengthen the ocean circulation and bring more Pacific water into the Arctic than the recent （2000-2006） average. The simulated summer （3 months ） 2007 mean Pacific water inflow at Bering Strait is 1.2 Sv, which is the highest in the past three decades of the simulation and is 20% higher than the recent average. Particularly, the Pacific water inflow in September 2007 is about 0.5 Sv or 50% above the 2000-2006 average. The strengthened warm Pacific water inflow carries an additional 1.0 x 1020 Joules of heat into the Arctic, enough to melt an additional 0.5 m of ice over the whole Chukchi Sea. In the model the extra summer oceanic heat brought in by the Pacific water mainly stays in the Chukchi and Beaufort region, contributing to the warming of surface waters in that region. The heat is in constant contact with the ice cover in the region in July through September. Thus the Pacific water plays a role in ice melting in the Chukchi and Beaufort region all summer long in 2007, likely contributing to up to O. 5 m per month additional ice melting in some area of that region. 相似文献
8.
A 3.8-kin Coupled Ice-Ocean Model （C1OM） was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches： Alaska Coastal Water （ACW） , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current （BSC） , the Beaufort Gyre, the East Siberian Current （ ESC）, mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution CIOM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with Solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which include the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast. 相似文献
9.
Summary of results from a high - resolution pan - Arctic ice - ocean model are presented for the northern North Pacific, Bering, Chukchi, and Beaufort seas. The main focus is on the mean circulation, communication from the Gulf of Alaska across the Bering Sea into the western Arctic Ocean and on mesoscale eddy activity within several important ecosystems. Model results from 1979 -2004 are compared to observations whenever possible. The high spatial model resolution at 1/12o （or -9 - km） in the horizontal and 45 levels in the vertical direction allows for representation of eddies with diameters as small as 36 km. However, we believe that upcoming new model integrations at even higher resolution will allow us to resolve even smaller eddies. This is especially important at the highest latitudes where the Rossby radius of deformation is as small as 10 km or less. 相似文献
10.
The elemental and isotopic signatures in the sediments influenced by seal excrement on Antarctic Fildes Peninsula are examined for their potential palaeoecologlcal applications. The seal hair abundance in sediments exhibits remarkable fluctuation versus depth, indicating similar changes in historical populations of the seals visiting the marine terrace. The combination of δ^13 C, total organic carbon concentration （TOC）, total nitrogen concentration （TN） and atomic C/N ratio shows that the organic matters in sediments with numerous seal hairs have a marine origin and are predominantly derived from seal excrements. The large δ15 N values in sediments are attributed to trophic enrichment and NH3 vollatilization processes. The large variations in the δ^15 N values and the negative correlation between the δ15 N values and the seal hair abundances seem to be the results of changes in the paleoclimates and the volatilization rates of the ammonia produced in the seal excrements. The 87 Sr/86 Sr ratios in the acid-soluble fraction of sediments are interpreted as a mixture of the ones from the seal excrements （30%-50%） and the chemically weathered local bedrocks （70%-50%）. The calculated proportion of seal-derived Sr based on the ^87 Sr/^86 Sr ratios has a significant correlation with seal hair abundances in sediments. These results suggest that δ15 N values and the ^87 Sr/^86 Sr ratios in the acid-soluble fraction of sediments were influenced by seal excrements, similar to seal halt numbers, and thus can potentially be used to estimate the historical seal population in the Antarctic region. 相似文献
11.
Sediment samples were cored from 3 locations representing the inner bay, the outer bay and the bay mouth of Jiaozhou Bay in September 2003 to study the source and biogeochemical characteristics of nitrogen and phosphorus in the bay. The content and vertical distributions of total nitrogen （TN）, total phosphorus （TP）, organic nitrogen （ON）, organic phosphorus （OP）, inorganic nitrogen （IN）, inorganic phosphorus （IP）, the ratio of organic carbon and total nitrogen （OC/TN）, and the ratio of total nitrogen and total phosphorus （TN/TP） in the sediments were analyzed. The results show that both TN and TP in surface sediments decrease from the inner bay to the outer bay. In general, ON occupies 50%-70% of TN and IP accounts for more than 60% of TP. In ratio of OC：TN, the nitrogen accumulated in the sediments from the inner bay and the bay mouth came mainly from terrestrial sources, and the portion of autogenetic nitrogen was 28.9% and 13.1%, respectively. However, in the outer bay, nitrogen was mainly autogenetic, accounting for 62.1% of TN, whereas phosphorus was mainly land-derived. The sedimentation fluxes of nitrogen and phosphorus varied spatially. The overall diagenesis rate of nitrogen was higher than that of phosphorus. Specifically, the diagenesis rate of OP was higher than that of IP. However, the diagenesis rate of ON was not always higher than that of IN. In species, the diagenesis rate of IN is sometimes much higher than that of the OC. In various environments, the diagenesis rate is, to some degree, affected by OC, pH, Eh, and Es. 相似文献
12.
Totally 2472 grains of Radiolaria belonging to 36 Genera and 45 species are distinguished from 12 surface sediments in the Bering Sea. The distribution characteristics of Radiolaria fossils in the surface sediments are as follows: (1) From the shelf of shallow water to the upper of continental slope, there are a few Radiolaria fossils and monotonous genus and species; (2) In the lower of continental slope, Radiolaria fossils are poor in the volcanic cinders and turbidite; (3) The abundance and diversity of Radiolaria fossils are high in clay of the basin. The dominant species of Radiolaria is Spongotrochus glacialis on the continental shelf. Current, topography, water depth, and temperature etc. are key factors influencing Radiolaria distribution. The sources of sediments mainly are terrigenous, biogenic and volcanic sediments in the survey area and they are mostly from the Kamchatka peninsula in the east of Russia and the Aleutian Islands. 相似文献
13.
The purpose of this study was to assess the effect of long-term cultivation and water erosion on the soil organic carbon （OC） in particle-size fractions. The study site is located at Nihegou Watershed in the Southern Loess Plateau, China. The soil at this site is loess with loose and silty structure, and contains macropores. The results showed that the OC concentrations in sediments and in the particle-size fractions of sediments were higher than those in soils and in the particle-size fractions of soils. The OC concentration was highest in the clay particles and was lowest in the sand particles. Clay particles possessed higher OC enrichment ability than silt and sand particles. The proportions of OC in the silt fractions of soil and sediment were the highest （mean value of 53.87% and 58.48%, respectively）, and the total proportion of OC in the clay and silt fractions accounted for 96% and 98% of the total OC in the soil and sediment, respectively. The loss of OC was highest in silt particles, with an average value of 0.16 Mg ha^-1 y^-1, and was lowest in the sand （0.003 Mg ha^-1 y^-l）. This result suggests that the fine particle-size fraction in the removed sediment may be an important indicator to assess soil OC losses. 相似文献
14.
LI Jianbing REN Jingling ZHANG Jing LIU Sumei 《中国海洋大学学报(英文版)》2008,7(1):48-54
Water samples containing dissolved aluminum were collected from the Yellow and East China Seas in October-November 2000. The average concentrations of dissolved AI in the Yellow Sea （YS） and East China Sea （ECS） were 0.042 and 0.056 μ molL^-1, respectively. The concentration of dissolved aluminum decreased gradually across the continental shelf. The lower concentrations appeared in the YS cold water center and in the bottom layer at the shelf edge of the ECS, where they were 0.016 and 0.011 μmolL^-1, respectively. The distribution of dissolved Al was controlled by physical mixing processes rather than biological uptake processes. The impact of different water masses along the PN transect was calculated based on the mass balance model. The results show that the impact of the Changjiang River was mainly concentrated on the coastal area and the top thermocline water on the ECS shelf, where the impact percentage decreased from 12.6% to 1.1% in the surface water, while the contribution of the Kuroshio water was dominant on the ECS shelf in this survey, increasing from 77.6% to 97,8% along the PN transect from the Changjiang River Estuary to the Ryukyu Islands. It is concluded that aluminum can serve as a proper tracer for studying the impact of Changjiang terrestrial matter on the ECS shelf water. 相似文献
15.
Motoyoshi Ikeda 《极地研究(英文版)》2008,19(2):212-217
The sea ice cover in the Arctic Ocean has been reducing and hit the low record in the summer of 2007. The anomaly was extremely large in the Pacific sector. The sea level height in the Bering Sea vs. the Greenland Sea has been analyzed and compared with the current meter data through the Bering Strait. A recent peak existed as a consequence of atmospheric circulation and is considered to contribute to inflow of the Pacific Water into the Arctic Basin. The timing of the Pacific Water inflow matched with the sea ice reduction in the Pacific sector and suggests a significant increase in heat flux. This component should be included in the model prediction for answering the question when the Arctic sea ice becomes a seasonal ice cover. 相似文献
16.
DONG Linsen SHI Xuefa LIU Yanguang FANG Xisheng CHEN Zhihua WANG Chunjuan ZOU Jianjun HUANG Yuanhui 《极地研究(英文版)》2014,(3):192-203
Mineralogical analysis was performed on bulk sediments of 79 surface samples using X-ray diffraction. The analytical results, combined with data on ocean currents and the regional geological background, were used to investigate the mineral sources. Mineral assemblages in sediments and their distribution in the study area indicate that the material sources are complex. （1） Feldspar is abundant in the sediments of the middle Chukchi Sea near the Bering Strait, originating from sediments in the Anadyr River carried by the Anadyr Current. Sediments deposited on the western side of the Chukchi Sea are rich in feldspar. Compared with other areas, sediments in this region are rich in hornblende transported from volcanic and sedimentary rocks in Siberia by the Anadyr Stream and the Siberian Coastal Current. Sediments in the eastern Chukchi Sea are rich in quartz sourced from sediments of the Yukon and Kuskokwim rivers carried by the Alaska Coastal Current. Sediments in the northern Chukchi Sea are rich in quartz and carbonates from the Mackenzie River sediments. （2） Sediments of the southern and central Canada Basin contain little calcite and dolomite, mainly due to the small impact of the Beaufort Gyre carrying carbonates from the Canadian Arctic Islands. Compared with other areas, the mica content in the region is high, implying that the Laptev Sea is the main sediment source for the southern and central Canada Basin. In the other deep sea areas, calcite and dolomite levels are high caused by the input of large amounts of sediment carried by the Beaufort Gyre from the Canadian Arctic Islands （Banks and Victoria）. The Siberian Laptev Sea also provides small amounts of sediment for this region. Furthermore, the Atlantic mid-water contributes some fine-grained material to the entire deep western Arctic Ocean. 相似文献
17.
Examination of solvent-extractable lipids in sediments from Beibu Gulf, South China Sea by capillary gas chromatography (GC)
and capillary gas chromatography-mass spectrometry (GC-MS) resulted in the first identifications of β, γ-carotanes and their
C19 to C31 homologs in the modern sediments from the China Seas. Distributional features of these (mainly triterpenoid and steroid hydrocarbons)
biomarkers are discussed and the possibility of using these compounds as indicators of source of materials, diagenesis and
depositional conditions is explored. It was found that the biomarkers in this region are mixtures of allochthonous (terrigenous
and/or crude oil leak or pollution) and antochthonous (marine) organic components. The biomarders have proved to be of value
for understanding sedimentation.
Contribution No. 1888 from the Institute of Oceanology, Academia Sinica.
This research is partially funded by the Organic Geochemistry Laboratory, Institute of Geochemistry. Academia Sinica. 相似文献
18.
Huanxin Li Huijun He Shifeng Yang Yanli Liu Hong Che Mujian Li Jing Zhang 《中国海洋大学学报(英文版)》2018,17(3):571-580
To improve the burial flux calculations of bioavailable phosphorus(P) and study opal-associated P(Opal-P) in the East China Sea(ECS), surface and core sediments were collected in the Changjiang Estuary(CE) and the south of the Cheju Island. In this study, sedimentary P was operationally divided into seven different forms using modified sedimentary extraction(SEDEX) technique: LSor-P(exchangeable or loosely sorbed P), Fe-P(easily reducible or reactive ferric Fe-bound P), CFA-P(authigenic carbonate fluorapatite and biogenic apatite and CaCO_3-bound P), Detr-P(detrital apatite), Org-P(organic P), Opal-P and Ref-P(refractory P). The data revealed that the concentrations of the seven different P forms rank as Detr-P CFA-P Org-P Ref-P Opal-P Fe-P LSor-P in surface sediments and CFA-P Detr-P Org-P Ref-P Fe-P Opal-P LSor-P in core sediments. The distributions of the total phosphorus(TP), TIP, CFA-P, Detr-P are similar and decrease from the CE to the south of the Cheju Island. Meanwhile, Org-P and Opal-P exhibit different distribution trends; this may be affected by the grain size and TOM. The concentrations of potentially bioavailable P are 9.6-13.0 μmol g~(-1) and 10.0-13.6 μmol g~(-1), representing 61%-70% and 41%-64% of the TP in surface and core sediments, respectively. The concentrations of Opal-P are 0.6-2.3 μmol g~(-1) and 0.6-1.4 μmol g~(-1) in surface and core sediments, accounting for 5.3%-19.8% and 4.2%-10.6% of bioavailable P, respectively. The total burial fluxes of Opal-P and bioavailable P are 1.4×10~9 mol yr~(-1) and 1.1×10~10 mol yr~(-1) in the ECS, respectively. Opal-P represents about 12.7% of potentially bioavailable P, which should be recognized when studying P cycling in marine ecosystems. 相似文献
19.
张相君 《广东海洋大学学报》2011,31(2):7-12
东亚海区域是中国周边海域之一,区域内的海洋环境状况关系到中国海洋利益的实现。基于区域内复杂的政治利益和经济利益格局,区域海洋环境保护在法律上的进展几近停滞。在对区域内海洋环境状况、政治利益格局和经济利益格局分析之后,提出区域内的海洋环境保护虽然面临重重障碍,但海洋环境保护法律制度的构建不可或缺。在构建该法律制度时,本区域可向具有类似特点的地中海汲取经验;中国也应该积极参与并推进海洋环境保护法律制度的构建,以保障本国在此区域内利益的最佳实现。 相似文献
20.
Evaporation duct is an ubiquitous natural phenomenon over the ocean and can be diagnosed by evaporation duct model. The model proposed by Paulus and Jeske and another model established by the American naval postgraduate school are the most widely used. They are called PJ model and NPS model, respectively. Two methods are used to investigate the global sensitivity of PJ model and NPS model in China Seas. The first method is based on meteorological and oceanographic observation data in China Seas. Considering the system random error caused by sensor measurement inaccuracies, the mean relative error and mean absolute error are used as criterion for sensitivity analysis. The second method, called Extended Fourier Amplitude Sensitivity Test(EFAST), takes into account the interaction between input parameters and is used for sensitivity analysis. The results show that NPS model is more sensitive to the random errors of sensors than PJ model. The mean relative errors of PJ model and NPS model are 11.43% and 14.81%, respectively. The results of global sensitivity parameter analysis indicate that wind speed is the key factor of PJ model, while all input parameter of NPS model have relatively large total sensitivity index. In addition, sensitivity analysis results confirm that wind speed is one of main driving factors for the formation of evaporation duct. These results are valuable for the selection of diagnosis models for evaporation duct, the evaluation of radio wave propagation in the marine atmospheric surface layer, and the prediction technique of evaporation duct based on numerical weather prediction(NWP) in China seas. 相似文献