Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its ad...Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its adjacent area,the eastern Leizhou Peninsula upwelling(ELPU)were illustrated.It is found that a significant cold tongue with high salinity and low temperature along the eastern Hainan coast driven by upwelling-favorable summer monsoon.The ELPU was relative weaker than the EHU because of its wide and gentle continental slope.Due to mixing by tides and waves,DO concentration with high value(>6.0 mg/L)were almost homogenous from surface to 30 m depth at the EHU.Beneath that,low DO water(<6.0 mg/L,anoxia)were pumped upward from bottom by the upwelling.The ELPU has worse DO condition compared with the EHU where bottom DO were lower than 3.5 mg/L owing to abundant DO consumption.The phytoplankton biomass reached maximal value about 1.5 mg/m3 at 30 m depth layer rather than surface layer at the EHU indicating the impact limit of upwelling on phytoplankton growth and DO distribution.Nourished by rich nutrient input,the phytoplankton biomass at the ELPU were much higher than the EHU where the maximal value can reach about 4.0 mg/m3.The phytoplankton biomass were reduced to about 0.2–0.3 mg/m3 at the offshore areas of the EHU and ELPU which were close to the value at open sea.At the inshore of the EHU,the phytoplankton community was dominated by diatom which accounted for about 50%of phytoplankton biomass.And prokaryotes(about 40%),green algae(about 20%)and prochlorococcus(about 20%)became main species at the offshore of the EHU.At the ELPU,diatom accounted for about 80%of phytoplankton biomass followed by green algae,indicating a different ecosystem at this region compared with the EHU.展开更多
Some of the islets in the eastern Beibu Gulf are covered by Quaternary volcano strata. The rock samples from these islets mainly consist of quartz tholeiites （at Shenjiandao）, olivine tholeiites （at Linshidao and X...Some of the islets in the eastern Beibu Gulf are covered by Quaternary volcano strata. The rock samples from these islets mainly consist of quartz tholeiites （at Shenjiandao）, olivine tholeiites （at Linshidao and Xieyang- dao） and alkali basalts （at Yangpubi and Jianshidao）, and basically represent four periods of the Quaternary volcanism of Hainan Island and its adjacent regions. Except for the samples from Shenjiandao, most of the Quaternary volcanics of these islets belong to alkali magma series. The trace element characteristics of all of these samples show they are OIB （oceanic island basalt） -like, which implies that their deep geodynamic setting may be related to a mantle plume. The Sr-Nd-Pb isotopic compositions show that the mantle source beneath the Quaternary strata can be regarded as a result of binary mixing between a depleted, DMM （de- pleted MORB mantle）-like source and an enriched mantle type 2 （EM2）. The EM2 may be originated from the Hainan mantle plume, and has been metasomatized by carbonaceous fluids released from ancient re- cycled oceanic crust at an asthenospheric mantle level. These features, together with typical trace element ratios, reflect that the parent magma was not subjected to crustal contamination during its ascent to the surface. This study provides further petrological and geochemical evidence for the existence of the Hainan mantle plume.展开更多
Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in ...Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island(19?12'28.4''N, 110?37'38.8''E) were analyzed using inductively coupled plasma-optic emission spectrometry(ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol^(-1) in 1903 to a maximum of 10.064 μmol mol^(-1) in 1944, with an average of 5.256 μmol mol^(-1). Mn/Ca ratios varied from 0.206 to 5.708 μmol mol^(-1) with an annual average of 1.234 μmol mol^(-1), with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future.展开更多
基金The National Key Research and Development Program of China under contract No.2018YFC0309800the National Natural Science Foundation of China under contract Nos 41666001,41576006,41976014,41776045+1 种基金the Chinese Academy of Sciences Frontier Basic Research Project under contract No.QYJC201910the Sanya Governmental Academy-Locality S&T Cooperation Program under contract No.2015YD28。
文摘Based on satellite remote sensing dataset and survey data during upwelling season of 2015,the spatial structures of phytoplankton biomass and community for the first time in the eastern Hainan upwelling(EHU)and its adjacent area,the eastern Leizhou Peninsula upwelling(ELPU)were illustrated.It is found that a significant cold tongue with high salinity and low temperature along the eastern Hainan coast driven by upwelling-favorable summer monsoon.The ELPU was relative weaker than the EHU because of its wide and gentle continental slope.Due to mixing by tides and waves,DO concentration with high value(>6.0 mg/L)were almost homogenous from surface to 30 m depth at the EHU.Beneath that,low DO water(<6.0 mg/L,anoxia)were pumped upward from bottom by the upwelling.The ELPU has worse DO condition compared with the EHU where bottom DO were lower than 3.5 mg/L owing to abundant DO consumption.The phytoplankton biomass reached maximal value about 1.5 mg/m3 at 30 m depth layer rather than surface layer at the EHU indicating the impact limit of upwelling on phytoplankton growth and DO distribution.Nourished by rich nutrient input,the phytoplankton biomass at the ELPU were much higher than the EHU where the maximal value can reach about 4.0 mg/m3.The phytoplankton biomass were reduced to about 0.2–0.3 mg/m3 at the offshore areas of the EHU and ELPU which were close to the value at open sea.At the inshore of the EHU,the phytoplankton community was dominated by diatom which accounted for about 50%of phytoplankton biomass.And prokaryotes(about 40%),green algae(about 20%)and prochlorococcus(about 20%)became main species at the offshore of the EHU.At the ELPU,diatom accounted for about 80%of phytoplankton biomass followed by green algae,indicating a different ecosystem at this region compared with the EHU.
基金The National Natural Science Foundation of China under contract Nos 41322036,41230960,40906034 and 41276003China Ocean Mineral Resources R&D Association (COMRA) under contract No.DY125-12-R-05+1 种基金China Postdoctoral Science Foundation under contract No.201104616the Taishan Scholar Program of Shandong Province
文摘Some of the islets in the eastern Beibu Gulf are covered by Quaternary volcano strata. The rock samples from these islets mainly consist of quartz tholeiites （at Shenjiandao）, olivine tholeiites （at Linshidao and Xieyang- dao） and alkali basalts （at Yangpubi and Jianshidao）, and basically represent four periods of the Quaternary volcanism of Hainan Island and its adjacent regions. Except for the samples from Shenjiandao, most of the Quaternary volcanics of these islets belong to alkali magma series. The trace element characteristics of all of these samples show they are OIB （oceanic island basalt） -like, which implies that their deep geodynamic setting may be related to a mantle plume. The Sr-Nd-Pb isotopic compositions show that the mantle source beneath the Quaternary strata can be regarded as a result of binary mixing between a depleted, DMM （de- pleted MORB mantle）-like source and an enriched mantle type 2 （EM2）. The EM2 may be originated from the Hainan mantle plume, and has been metasomatized by carbonaceous fluids released from ancient re- cycled oceanic crust at an asthenospheric mantle level. These features, together with typical trace element ratios, reflect that the parent magma was not subjected to crustal contamination during its ascent to the surface. This study provides further petrological and geochemical evidence for the existence of the Hainan mantle plume.
基金supported by the National Ocean Welfare Research Funds of State Ocean Administration (No.201105012)
文摘Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set(1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island(19?12'28.4''N, 110?37'38.8''E) were analyzed using inductively coupled plasma-optic emission spectrometry(ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol^(-1) in 1903 to a maximum of 10.064 μmol mol^(-1) in 1944, with an average of 5.256 μmol mol^(-1). Mn/Ca ratios varied from 0.206 to 5.708 μmol mol^(-1) with an annual average of 1.234 μmol mol^(-1), with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future.
