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Long-Chain Alkenones in the South Yellow Sea Sediments and Their Indicative Significance for Haptophytes Species
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作者 XU Yakun YANG Xinxin +1 位作者 XIAO Rui XING Lei 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第5期1287-1296,共10页
Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic studies.However,the commonly used LCAs proxies are mainly based on C_(37) alkenones,and it is still lack of the studies abo... Long-chain alkenones(LCAs)have been widely used as important biomarkers in palaeoceanographic studies.However,the commonly used LCAs proxies are mainly based on C_(37) alkenones,and it is still lack of the studies about the distribution and in-dications of LCAs with different chain lengths other than C_(37) alkenones.Here,the composition and distribution of LCAs were ana-lyzed in surface sediments from the southern Yellow Sea(SYS)and a sedimentary core(A02-C)from the central Yellow Sea(YS)mud area.The results showed that C_(37),C_(38) and C_(39) alkenones were the major LCAs in surface sediments of the SYS,and the relative contents of C_(38:2)Et,C_(37:2)Me,C_(37:3)Me,C_(38:2)Me,C_(38:3)Et,C_(38:3)Me,C_(39:2)Et and C_(39:3)Et were 18.3%-59.8%,22.6%-41.2%,7.4%-23.0%,6.6%-15.4%,3.8%-13.3%,3.6%-8.7%,2.8%-6.0% and 0.7%-3.0%,respectively.Then the relationships of U_(38Me)^(K)-U_(38Et)^(K) and U_(37)^(K')-U_(38Et)^(K) indicate that LCAs are mainly derived from Emiliania huxleyi(E.huxleyi).High ratios of total C_(37) alkenones to total C_(38) alkenones(K_(37)/K_(38))(1-1.2)were found in the central SYS,corresponding to the relatively high abundance of E.huxleyi;while low ratios of K_(37)/K_(38)(0.7-0.9)were observed at nearshore area of the SYS where Gephyrocapsa oceanica(G.oceanica)has rela-tively high abundance.The spatial distribution of K_(37)/K_(38) ratio is also consistent with that of coccolithophores nannofossil in the sediments.In addition,K_(37)/K_(38) ratio in core A02-C varied from 0.7 to 1.1 with a gradual decreasing trend during the past 5.5 kyr.This suggests that the relative abundance of E.huxleyi decreased gradually,caused by the changes in the Yellow Sea Warm Current(YSWC)and the East Asian Winter Monsoon(EAWM)during this period. 展开更多
关键词 alkenoneS southern Yellow Sea SEDIMENT Yellow Sea Warm Current
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Application of long-chain alkenones and U_(37)~k values for paleotemperature estimation in the Arctic Chukchi Sea-Bering Sea area 被引量:4
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作者 Lu Bing, Chen Ronghua, Wang Zipan, Chen Jianfang, Liu Zhensheng 1. Key Laboratory of Submarine Geosciences, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2001年第3期371-381,共11页
Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is predominate in the long-c... Long-chain alkenones were detected in samples of sea surface sediments from the Chukchi Sea and the Bering Sea areas, the Arctic Pole. The analysis result indicates that C37:3 methylketone is predominate in the long-chain alkenones from the Chukchi and Bering Sea sediments. The abundance of C37 to C39 unsaturated alkenones changes in an order of C37 > C38 > C39. Based on C37 /C38 ratio, the detected organism precursors of the long-chain alkenones are mainly coccolithophrid (Emiliania huxleyi). By the calibration relationship between U37k and U37k indices, the sea surface paleotemperature in these seas is estimated. The estimated values of U37k vary from 4.147℃ to 5.706℃ , with a mean value of 5.092℃. 展开更多
关键词 Long-chain alkenone SST U37k the Chukchi Sea the Bering Sea PALEOTEMPERATURE
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Major Mid-Late Holocene Cooling in the East China Sea Revealed by an Alkenone Sea Surface Temperature Record 被引量:8
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作者 ZHAO Meixun DING Ling +2 位作者 XING Lei QIAO Shuqing YANG Zuosheng 《Journal of Ocean University of China》 SCIE CAS 2014年第6期935-940,共6页
Although the mid-late Holocene cold and dry event about 4000years ago (the 4ka event) has been observed almost globally, it was most prominent in terrestrial climate proxies from the lower latitudes. Here we evaluat... Although the mid-late Holocene cold and dry event about 4000years ago (the 4ka event) has been observed almost globally, it was most prominent in terrestrial climate proxies from the lower latitudes. Here we evaluate the oceanic response to this event in terms of a Holocene sea surface temperature (SST) record reconstructed using the U^7 index for Core B3 on the continen- tal shelf of the East China Sea. The record reveals a large temperature drop of about 5~C from the mid-Holocene (24.7~C at 5.6ka) to the 4ka event (19.2~C at 3.8ka). This mid-late Holocene cooling period in Core B3 correlated with (i) decreases in the East Asia summer monsoon intensity and (ii) the transition period with increased E1 Nifio/Southern Oscillation activities in the Equatorial Pa- cific. Our SST record provides oceanic evidence for a more global nature of the mid-late Holocene climate change, which was most likely caused by a southward migration of the Intertropical Converge Zone in response to the decreasing summer solar insolation in the Northern Hemisphere. However, the large SST drop around Core B3 indicates that the mid-late Holocene cooling was regionally amplified by the initiation/strengthening of eddy circulation/cold front which caused upwelling and resulted in additional SST de- crease. Upwelling during the mid-late Holocene also enhanced with surface productivity in the East China Sea as reflected by higher alkenone content around Core B3. 展开更多
关键词 sea surface temperature alkenone East China Sea 4 ka ITCZ
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Long-chain alkenones in Hotong Qagan Nur Lake sediments and its paleoclimatic implications 被引量:15
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作者 Guoying Sheng Keqin Cai +4 位作者 Xuexian Yang Jialan Lu Guodong Jia Ping’an Peng Jiamo Fu 《Chinese Science Bulletin》 SCIE EI CAS 1999年第3期259-263,共5页
The long-chain alkenones present in the shallow sediment of Hotong Qagan Nur Lake in China are reported. According to the similarity of compositions and distributions of the alkenones determined commonly in the sedime... The long-chain alkenones present in the shallow sediment of Hotong Qagan Nur Lake in China are reported. According to the similarity of compositions and distributions of the alkenones determined commonly in the sediment section to those of marine sediment, it is reasonably referred that the alkenones might also originate from Prymnesiophyceae. ln addition, the parameter U<sub>37</sub><sup>k</sup>'of alkenone is in positive correlation to δ<sup>18</sup>O values of authigenic calcium and magnesium minerals. This indicates that the parameter U<sub>37</sub><sup>k</sup>'of long-chain alkenone is also available to indicate paleoclimate of high-salinity alkaline lake. 展开更多
关键词 ALKALINE LAKE sediment LONG-CHAIN alkenone paleoclimate.
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Kuroshio Intrusion Combined with Coastal Currents Affects Phytoplankton in the Northern South China Sea Revealed by Lipid Biomarkers
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作者 WANG Yaoyao BI Rong +5 位作者 GAO Jiawei ZHANG Hailong LI Li DING Yang JIN Gui’e ZHAO Meixun 《Journal of Ocean University of China》 SCIE CAS CSCD 2023年第2期576-586,共11页
The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here... The northern South China Sea(NSCS)is significantly influenced by the Kuroshio intrusion and the coastal currents.Our knowledge on the roles of both currents on phytoplankton spatial variations is still inadequate.Here,we investigated the concentrations of phytoplankton biomarkers and their proportions in surface suspended particles from 47 sites of the NSCS during summer of 2017 and 2019.Brassicasterol/epi-brassicasterol,dinosterol,and C37 alkenones were used as proxies of biomass for diatoms,dinoflagellates,and haptophytes,respectively,and their sum indicating total phytoplankton biomass.A three end-member mixing model was applied to quantitatively assess the influence extent of the Kuroshio intrusion and the coastal currents.Our results showed that the Kuroshio intrusion and the coastal currents contributed equally to the overall surface water masses in the study area;however,the two currents had distinct effects on the spatial distribution of phytoplankton.For phytoplankton biomass,the eutrophic coastal currents were likely to be the main controlling factors,while the impact of the Kuroshio intrusion was weak and stimulated significant increases in phytoplankton biomass only at certain boundary sites.For phytoplankton community structures,the Kuroshio and its intrusion were the main factors,resulting in an increase in the proportions of dinoflagellates and haptophytes.The proportion of diatoms slightly increased due to the influence of the coastal currents.Our study quantifies the effects of the Kuroshio and the coastal currents on phytoplankton in the NSCS in terms of hydrological parameters,providing an important basis for the understanding of ecological functions and biogeochemical cycles in marginal sea-open ocean boundary regions. 展开更多
关键词 STEROLS alkenoneS PHYTOPLANKTON northern South China Sea KUROSHIO coastal currents
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Sea surface temperature variations in the southwestern South China Sea over the past 160 ka 被引量:3
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作者 XIE Hongqin JIA Guodong +1 位作者 PENG Ping'an SHAO Lei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2007年第2期49-55,共7页
Sea surface temperatures (SSTs) in the southwestern South China Sea have been reconstructed for the past 160 ka using the U37^k paleothermometer from the core MD01 - 2392. The temperature differences between glacial... Sea surface temperatures (SSTs) in the southwestern South China Sea have been reconstructed for the past 160 ka using the U37^k paleothermometer from the core MD01 - 2392. The temperature differences between glacial times ( MISs 6 and 2) and interglacial times ( MISs 5.5 and 1) are 2.2 ~ 2.5 ℃. Younger Dryas event during the last deglaciation was documented in both the planktonic foraminiferal δ^18 and SST records. After MIS 5.5, SSTs displayed a progressive cooling from 28.6 to 24.5 ℃ culminating at the LGM. During this gradual cooling period, warm events such as MISs 5.3, 5.1 and 3 were also clearly documented. By comparison of SST between the study core and Core 17954, a pattern of low or no meridional SST gradients during the interglacial periods and high meridional SST gradients during the glacial periods was exhibited. This pattern indicates the much stronger East Asian winter monsoon at the glacial than at the interglacial periods. Spectral analysis gives two prominent cycles:41 and 23 ka, with the former more pronounced, suggesting that SSTs in the southern SCS varied in concert with high-latitude processes through the connection of East Asian winter monsoon. 展开更多
关键词 sea surface temperature alkenone Late Quaternary South China Sea East Asian monsoon
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Assessing the U^(K′)_(37)-sea surface temperature relationship in shallow marine waters
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作者 Mengyuan WANG Haixian XIONG +4 位作者 Shouye YANG Fengling YU Deming KONG Yongqiang ZONG Zhonghui LIU 《Science China Earth Sciences》 SCIE EI CAS CSCD 2023年第4期918-928,共11页
To investigate the relationship between the alkenone unsaturation index(U^(K′)_(37)) and sea surface temperature(SST) in coastal and continental shelf waters, 58 surface sediment samples were collected from the South... To investigate the relationship between the alkenone unsaturation index(U^(K′)_(37)) and sea surface temperature(SST) in coastal and continental shelf waters, 58 surface sediment samples were collected from the South China Sea(SCS), Taiwan Strait,and East China Sea(ECS). We combined the new results with the previously published 71 data points from the SCS, the shallow water areas of the Yellow Sea(YS) and northern ECS, to form a dataset with sample sites spanning across 6°N and 37°N(including annual SST calibration between 14.3℃ and 28.6℃). With this dataset, we examined the U^(K′)_(37)-SST relationship based on 129 samples from the Western North Pacific(WNP) margin as well as using 85 samples from specific WNP shallow water.The U^(K′)_(37)index from the low-mid latitudinal WNP margin demonstrated a good correlation with the surface annual mean SST(0–50 m water depth;R^(2)=0.89). The slope of linear regression(U^(K′)_(37)-SST) based on the coastal-continental shelf samples with water depth less than 200 m is similar to that of the published global open ocean regression equation. These results confirm that U^(K′)_(37)can be used as a shallow sea water SST proxy in mid-low latitudes of the WNP marginal seas. In addition, our reintegrated U^(K′)_(37)-SST results based on 172 global shallow water samples are similar(similar slopes and intercepts) to the shallow ocean results in the WNP marginal seas. However, the similarity of the regression formula to the open ocean does not imply that the formula is applicable. For example, of the 85 data in the shallow waters from the marginal sea in this study, the majority of data points lie above the regression line, showing positive residuals for U^(K′)_(37). This regression bias appears to be caused by specific marine environments, such as warm ocean currents and/or high nutrient conditions that result in positive U^(K′)_(37)residuals. Taken together,considering the specific temperature and environmental factors in the shallow waters of the low-mid-latitude WNP margin, we propose a nonlinear U^(K′)_(37)-SST regression formula: U^(K′)_(37)=-1.2488+0.1740×SST-0.0035×(SST)2, R2=0.93, N=85, specifically for the environments with SST below 24℃. 展开更多
关键词 alkenone U^(K′)_(37) Sea surface temperature Western North Pacific margin Shallow marine waters
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Exceptional terrestrial warmth around 4200-2800 years ago in Northwest China 被引量:2
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作者 Qingfeng Jiang Bowen Meng +10 位作者 Zheng Wang Peng Qian Jianan Zheng Jiawei Jiang Cheng Zhao Juzhi Hou Guanghui Dong Ji Shen Weiguo Liu Zhonghui Liu Fahu Chen 《Science Bulletin》 SCIE EI CSCD 2022年第4期427-436,M0004,共11页
One of the Holocene abrupt events around 4200 years ago,lasting for~200 years,is thought to have caused cultural disruptions,yet terrestrial climatic status right after the cold/dry event remains poorly defined and is... One of the Holocene abrupt events around 4200 years ago,lasting for~200 years,is thought to have caused cultural disruptions,yet terrestrial climatic status right after the cold/dry event remains poorly defined and is often presumed that a generally cool condition prevailed during the Bronze Age(~4000-2200 years ago).Here we report an alkenone-based summer temperature record over the past~12,000 years,in addition to two updated alkenone records,from Northwest China,providing new insights into the climatic status right after the event.Our results indicate that exceptional terrestrial warmth,up to~6°C,occurred around 4200-2800 years ago during the Bronze Age,superimposed on the long-term Holocene cooling trend.The exceptional warmth in Northwest China,together with other climate anomalies elsewhere,suggests an unusual large-scale climatic reorganization at 4200-2800 years ago when solar activity remained high,with important implications to the climate background for cultural developments during the Bronze Age. 展开更多
关键词 Terrestrial temperature HOLOCENE The Bronze Age Northwest China alkenoneS
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