Owing to the significant differences in environmental characteristics and explanatory factors among estuarine and coastal regions,research on diatom transfer functions and database establishment remains incomplete.Thi...Owing to the significant differences in environmental characteristics and explanatory factors among estuarine and coastal regions,research on diatom transfer functions and database establishment remains incomplete.This study analysed diatoms in surface sediment samples and a sediment core from the Lianjiang coast of the East China Sea,together with environmental variables.Principal component analysis of the environmental variables showed that sea surface salinity(SSS)and sea surface temperature were the most important factors controlling hydrological conditions in the Lianjiang coastal area,whereas canonical correspondence analysis indicated that SSS and pH were the main environmental factors affecting diatom distribution.Based on the modern diatom species–environmental variable database,we developed a diatom-based SSS transfer function to quantitatively reconstruct the variability in SSS between 1984 and 2021 for sediment core HK3 from the Lianjiang coastal area.The agreement between the reconstructed SSS and instrument SSS data from 1984 to 2021 suggests that diatombased SSS reconstruction is reliable for studying past SSS variability in the Lianjiang coastal area.Three low SSS events in AD 2019,2013,and 1999,together with an increased relative concentration of freshwater diatom species and coarser sediment grain sizes,corresponded to two super-typhoon events and a catastrophic flooding event in Lianjiang County.Thus,a diatom-based SSS transfer function for reconstructing past SSS variability in the estuarine and coastal areas of the East China Sea can be further used to reflect the paleoenvironmental events in this region.展开更多
We analyzed the biogenic silica(BSi)content and produced a diatom-based summer sea-surface temperature(SST)reconstruction for sediment core GC4 from the Holsteinsborg Dyb,West Greenland.Our aim was to reconstruct mari...We analyzed the biogenic silica(BSi)content and produced a diatom-based summer sea-surface temperature(SST)reconstruction for sediment core GC4 from the Holsteinsborg Dyb,West Greenland.Our aim was to reconstruct marine productivity and climatic fluctuations during the last millennium.Increased BSi content and diatom abundance suggest relatively high marine productively during the interval of AD 1000–1400,corresponding in time to the Medieval Warm Period(MWP).The summer SST reconstruction indicates relatively warm conditions during AD 900–1100,followed by cooling after AD 1100.An extended cooling period during AD 1400–1900 is characterized by prolonged low in reconstructed SST and high sea-ice concentration.The BSi values fluctuated during this period,suggesting varying marine productivity during the Little Ice Age(LIA).There is no significant correlation between the BSi content and SST during the last millennium,suggesting that the summer SST has little influence on marine productively in the Holsteinsborg Dyb.A good correspondence between the BSi content and the element Ti counts in core GC4 suggests that silicate-rich meltwater from the Greenland ice sheet was likely responsible for changes in marine productively in the Holsteinsborg Dyb.展开更多
基金The National Natural Science Foundation of China under contract Nos 42376236 and 42176226.
文摘Owing to the significant differences in environmental characteristics and explanatory factors among estuarine and coastal regions,research on diatom transfer functions and database establishment remains incomplete.This study analysed diatoms in surface sediment samples and a sediment core from the Lianjiang coast of the East China Sea,together with environmental variables.Principal component analysis of the environmental variables showed that sea surface salinity(SSS)and sea surface temperature were the most important factors controlling hydrological conditions in the Lianjiang coastal area,whereas canonical correspondence analysis indicated that SSS and pH were the main environmental factors affecting diatom distribution.Based on the modern diatom species–environmental variable database,we developed a diatom-based SSS transfer function to quantitatively reconstruct the variability in SSS between 1984 and 2021 for sediment core HK3 from the Lianjiang coastal area.The agreement between the reconstructed SSS and instrument SSS data from 1984 to 2021 suggests that diatombased SSS reconstruction is reliable for studying past SSS variability in the Lianjiang coastal area.Three low SSS events in AD 2019,2013,and 1999,together with an increased relative concentration of freshwater diatom species and coarser sediment grain sizes,corresponded to two super-typhoon events and a catastrophic flooding event in Lianjiang County.Thus,a diatom-based SSS transfer function for reconstructing past SSS variability in the estuarine and coastal areas of the East China Sea can be further used to reflect the paleoenvironmental events in this region.
基金The Open Research Fund of State Key Laboratory of Estuarine and Coastal Research under contract No.SKLECKF201708the Project of Laboratory for Marine Geology,Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.MGQNLM201707+2 种基金the National Natural Science Foundation of China under contract Nos 41776193,41876215,41876070 and 41406209the Natural Science Foundation of Zhejiang Province under contract Nos LY17D060001 and LQ15D020001the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2018SDKJ0104-3.
文摘We analyzed the biogenic silica(BSi)content and produced a diatom-based summer sea-surface temperature(SST)reconstruction for sediment core GC4 from the Holsteinsborg Dyb,West Greenland.Our aim was to reconstruct marine productivity and climatic fluctuations during the last millennium.Increased BSi content and diatom abundance suggest relatively high marine productively during the interval of AD 1000–1400,corresponding in time to the Medieval Warm Period(MWP).The summer SST reconstruction indicates relatively warm conditions during AD 900–1100,followed by cooling after AD 1100.An extended cooling period during AD 1400–1900 is characterized by prolonged low in reconstructed SST and high sea-ice concentration.The BSi values fluctuated during this period,suggesting varying marine productivity during the Little Ice Age(LIA).There is no significant correlation between the BSi content and SST during the last millennium,suggesting that the summer SST has little influence on marine productively in the Holsteinsborg Dyb.A good correspondence between the BSi content and the element Ti counts in core GC4 suggests that silicate-rich meltwater from the Greenland ice sheet was likely responsible for changes in marine productively in the Holsteinsborg Dyb.
