The use of ocean bottom seismometers provides an effective means of studying the process and the dynamic of cold seeps by continuously recording micro-events produced by sub-seafloor fluid migration.We deployed a four...The use of ocean bottom seismometers provides an effective means of studying the process and the dynamic of cold seeps by continuously recording micro-events produced by sub-seafloor fluid migration.We deployed a four-component Ocean Bottom Seismometer(OBS)at an active site of the Haima cold seep from 6 November to 19 November in 2021.Here,we present the results of this short-term OBS monitoring.We first examine the OBS record manually to distinguish(by their distinctive seismographic signatures)four types of events:shipping noises,vibrations from our remotely operated vehicle(ROV)operations,local earthquakes,and short duration events(SDEs).Only the SDEs are further discussed in this work.Such SDEs are similar to those observed in other sea areas and are interpreted to be correlated with sub-seafloor fluid migration.In the OBS data collected during the 14-day monitoring period.We identify five SDEs.Compared to the SDE occurrence rate observed in other cold seep regions,five events is rather low,from which it could be inferred that fluid migration,and subsequent gas seepage,is not very active at the Haima site.This conclusion agrees with multi-beam and chemical observations at that site.Our observations thus provide further constraint on the seepage activity in this location.This is the first time that cold seep-related SDEs have been identified in the South China Sea,expanding the list of sea areas where SDEs are now linked to cold seep fluid migration.展开更多
Microplastics(MPs)are important exempla of the Anthropocene and are exerting an increasing impact on Earth’s carbon cycle.The huge imbalance between the MPs floating on the marine surface and those that are estimated...Microplastics(MPs)are important exempla of the Anthropocene and are exerting an increasing impact on Earth’s carbon cycle.The huge imbalance between the MPs floating on the marine surface and those that are estimated to have been introduced into the ocean necessitates a detailed assessment of marine MP sinks.Here,we demonstrate that cold seep sediments,which are characterized by methane fluid seepage and a chemosynthetic ecosystem,effectively capture and accommodate small-scale(<100μm)MPs,with 16 types of MPs being detected.The abundance of MPs in the surface of the sediment is higher in methane-seepage locations than in non-seepage areas.Methane seepage is beneficial to the accumulation,fragmentation,increased diversity,and aging of MPs.In turn,the rough surfaces of MPs contribute to the sequestration of the electron acceptor ferric oxide,which is associated with the anaerobic oxidation of methane(AOM).The efficiency of the AOM determines whether the seeping methane(which has a greenhouse effect 83 times greater than that of CO_(2)over a 20-year period)can enter the atmosphere,which is important to the global methane cycle,since the deep-sea environment is regarded as the largest methane reservoir associated with natural gas hydrates.展开更多
A new prenylated indole alkaloid 11,17-epi-mangrovamide A(1),a new natural occurring product,1,7-dihydroxy-6-methyl-8-hydroxymethyl-xanthone(2),two known alkaloids,mangrovamide A(3)and mangrovamide G(4),and four known...A new prenylated indole alkaloid 11,17-epi-mangrovamide A(1),a new natural occurring product,1,7-dihydroxy-6-methyl-8-hydroxymethyl-xanthone(2),two known alkaloids,mangrovamide A(3)and mangrovamide G(4),and four known polyketide derivatives(5–8)were isolated and identified from the cold-seep sediment derived fungal strain Talaromyces funiculosus SD-523.Their structures were elucidated by combination of nuclear magnetic resonance(NMR),high resolution electrospray ionization mass spectroscopy(HRESIMS),quantum chemical electronic circular dichroism(ECD),and DP4+probability analysis as well as by comparison of the data with literature reports.All isolated compounds were tested for antibacterial activities.展开更多
Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the l...Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the leaked gases frequently exhibit a flame-like structure.We numerically modelled the relationship between the seismic response characteristic and bubble volume fraction to establish the bubble volume fraction in the submarine seep plume.Results show that our models are able to invert and predict the bubble volume fraction from field seismic oceanography data,by which synthetic seismic sections in different dominant frequencies could be numerically simulated,seismic attribute sections(e.g.,instantaneous amplitude,instantaneous frequency,and instantaneous phase)extracted,and the correlation between the seismic attributes and bubble volume fraction be quantitatively determined with functional equations.The instantaneous amplitude is positively correlated with bubble volume fraction,while the instantaneous frequency and bubble volume fraction are negatively correlated.In addition,information entropy is introduced as a proxy to quantify the relationship between the instantaneous phase and bubble volume fraction.As the bubble volume fraction increases,the information entropy of the instantaneous phase increases rapidly at the beginning,followed by a slight upward trend,and finally stabilizes.Therefore,under optimal noise conditions,the bubble volume fraction of submarine seep plumes can be inverted and predicted based on seismic response characteristics in terms of seismic attributes.展开更多
Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in ...Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in the Haima cold seeps at a water depth of 1381 m.Based on the scanning electron microscope(SEM)analyses,the prismatic layer and nacreous layer were identified,which are characterized by prismatic structure and stratified structure,respectively.In addition,the profile can be subdivided into two parts:altered and unaltered zones.Laser inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping shows that the element concentrations of the altered zones were influenced by the authigenic carbonate rocks,whereas the element concentrations of unaltered zones remain stable.In-situ X-ray diffraction(XRD)analyses show that the mineral constituent of the prismatic layer is mainly composed of aragonite.Along with the growth profile,Mg/Ca ratios of unaltered zones have minor variations,ranging 0.72-0.97 mmol/mol(mean=0.87 mmol/mol),with estimated temperatures of 3.8-4.1℃,indicating that the temperature of the surrounding seawater remains constant and agree with the measured data of 3.9℃which was conducted by a conductivity-temperature-depth system(CTD).The minor variations of Ba/Ca ratios(0.01-0.06 mmol/mol;mean=0.04 mmol/mol)indicate a relatively stabilized salinity of the surrounding seawater.S/Ca ratios show large variations of 0.04-4.15 mmol/mol(mean=1.37 mmol/mol).S/Ca ratios have regular variations which generally correspond to the variations of the Mg/Ca ratios,highlighting that the S/Ca ratios of bivalve shells show the potential to reflect the growth rate of the Gigantides.However,further studies should be carried out on the understanding of the links between the S/Ca ratios and seepage intensity of cold-seep fluids.展开更多
Cold seeps spread worldwide along the continental margins,which are closely related to the exploration of gas hydrates.Cold-seep carbonates have been reported to record the nature of seepage,including fluid source,sed...Cold seeps spread worldwide along the continental margins,which are closely related to the exploration of gas hydrates.Cold-seep carbonates have been reported to record the nature of seepage,including fluid source,sedimentary environment,and variation of seepage activity.We investigated the morphology,mineralogy,element compositions,and carbon and oxygen isotopes of 15 cold-seep carbonates collected from the Shenhu area,and compared them with 2 carbonates from the Haima cold seep,the South China Sea(SCS),to promote our knowledge of cold-seep system in SCS.Most of the Shenhu carbonates exhibit crust morphology,and some are in the form of chimneys and blocks.Their absolute(20%–65%)and relative carbonate mineral contents(mainly aragonite and calcite,with minor samples containing dolomite)vary significantly,indicating the multi-stage methane leakage in our study area.Some samples show a slight negative Ce anomaly,suggesting either the mixing of seawater or variation of the redox condition during the precipitation;the cooccurrence of strongly enriched U and Mo demonstrates anoxic condition during precipitation.The mixed genetic methane source was interpreted by δ^(13)C of the Shenhu carbonates to range from-22.34‰to-59.30‰Vienna PeeDee Belemnite(VPDB),and the slight ^(18)O-enrichment imprinted on the carbonates suggests the possible influence from hydrate dissociation.The Haima carbonates,with biogenic methane as the main gas source,were presumably formed in a stronger fluid flux by compared with our Shenhu samples.展开更多
Four massive brecciated, chimney-like, and slender pipe network carbonate samples(JA-4, JA-5, JX-8 and BG-12) were collected from southwestern Taiwan, which were suggested to have formed as a result of anaerobic oxidi...Four massive brecciated, chimney-like, and slender pipe network carbonate samples(JA-4, JA-5, JX-8 and BG-12) were collected from southwestern Taiwan, which were suggested to have formed as a result of anaerobic oxidization of methane(AOM). Considering that the environmental conditions of the carbonates precipitation and the sources of carbon and organic matter need to be further declared, molecular fossils and compound-specific carbon isotopic investigations of the carbonates were conducted in this study. According to lipid biomarkers of 2,6,10,15,19-pentamethyleicosane(PMI) and squalane diagnostic to methanotrophic archaea, as well as the extremely low δ^(13)C values(as low as -1^(13).4‰) detected in samples JA-4, JA-5 and JX-8, these carbonates were revealed to be a result of AOM. Based on the varied δ^(13)C values of characteristic archaea biomarkers in specific samples, biogenic methane was proposed to be responsible for the formation of samples JA-4 and JA-5, whereas a mixed carbon source of ^(13)C-depleted methane and ^(13)C-enriched residual CO_2 from methanogenesis was suggested for the carbonate of JX-8 due to the co-occurrence of a highly positive δ^(13) C_(carb) value(+8‰) and a moderate ^(13)C depletion of PMI. The low content of AOM-related biomarkers and the absence of indicators for ANME-2 suggested that these carbonates were formed in weak seep settings. By comparison, no typical lipid biomarkers for methanotrophic archaea was detected in carbonate BG-12. The short-chain and long-chain n-alkanes accounted for 30% and 45% of all hydrocarbons, respectively, with a CPI value of 1.2, suggesting that the n-alkanes were derived from both marine organisms and terrestrial inputs. A low thermal maturity could be revealed by the incomplete equilibrium value of the C^(31)αβ 22S/(22S+22R) ratio(0.5), and the carbonate BG-12 was probably deposited in a suboxic condition indicated by a value of Pr/Ph ratio(2.5).展开更多
South China Sea （SCS） is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, ＂SONNE＂ 177 cruise found two cold seep areas ...South China Sea （SCS） is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, ＂SONNE＂ 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diver- sity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abun- dance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment （wet weight）. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diver- sity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.展开更多
基金supported by the Key Research and Development Project of Guangdong Province(Grant:2020B1111510001)supported by the Project of Sanya Yazhou Bay Science and Technology City(Grant No:SCKJ-JYRC-2022-14)the National Natural Science Foundation of China(Grant No:92262304).
文摘The use of ocean bottom seismometers provides an effective means of studying the process and the dynamic of cold seeps by continuously recording micro-events produced by sub-seafloor fluid migration.We deployed a four-component Ocean Bottom Seismometer(OBS)at an active site of the Haima cold seep from 6 November to 19 November in 2021.Here,we present the results of this short-term OBS monitoring.We first examine the OBS record manually to distinguish(by their distinctive seismographic signatures)four types of events:shipping noises,vibrations from our remotely operated vehicle(ROV)operations,local earthquakes,and short duration events(SDEs).Only the SDEs are further discussed in this work.Such SDEs are similar to those observed in other sea areas and are interpreted to be correlated with sub-seafloor fluid migration.In the OBS data collected during the 14-day monitoring period.We identify five SDEs.Compared to the SDE occurrence rate observed in other cold seep regions,five events is rather low,from which it could be inferred that fluid migration,and subsequent gas seepage,is not very active at the Haima site.This conclusion agrees with multi-beam and chemical observations at that site.Our observations thus provide further constraint on the seepage activity in this location.This is the first time that cold seep-related SDEs have been identified in the South China Sea,expanding the list of sea areas where SDEs are now linked to cold seep fluid migration.
基金financially supported by the National Natural Science Foundation of China(42022046)the National Key Research and Development Program of China(2021YFF0502300)+1 种基金the Key Special Project for Introduced Talent Teams of the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0403 and GML2019ZD0401)Guangdong Natural Resources Foundation(GDNRC[2022]45)。
文摘Microplastics(MPs)are important exempla of the Anthropocene and are exerting an increasing impact on Earth’s carbon cycle.The huge imbalance between the MPs floating on the marine surface and those that are estimated to have been introduced into the ocean necessitates a detailed assessment of marine MP sinks.Here,we demonstrate that cold seep sediments,which are characterized by methane fluid seepage and a chemosynthetic ecosystem,effectively capture and accommodate small-scale(<100μm)MPs,with 16 types of MPs being detected.The abundance of MPs in the surface of the sediment is higher in methane-seepage locations than in non-seepage areas.Methane seepage is beneficial to the accumulation,fragmentation,increased diversity,and aging of MPs.In turn,the rough surfaces of MPs contribute to the sequestration of the electron acceptor ferric oxide,which is associated with the anaerobic oxidation of methane(AOM).The efficiency of the AOM determines whether the seeping methane(which has a greenhouse effect 83 times greater than that of CO_(2)over a 20-year period)can enter the atmosphere,which is important to the global methane cycle,since the deep-sea environment is regarded as the largest methane reservoir associated with natural gas hydrates.
基金Supported by the National Natural Science Foundation of China(No.U2006203)the National Natural Science Foundation of Jiangsu Province(No.BK20201211)the Senior User Project of R/V Kexue(No.KEXUE2020GZ02)。
文摘A new prenylated indole alkaloid 11,17-epi-mangrovamide A(1),a new natural occurring product,1,7-dihydroxy-6-methyl-8-hydroxymethyl-xanthone(2),two known alkaloids,mangrovamide A(3)and mangrovamide G(4),and four known polyketide derivatives(5–8)were isolated and identified from the cold-seep sediment derived fungal strain Talaromyces funiculosus SD-523.Their structures were elucidated by combination of nuclear magnetic resonance(NMR),high resolution electrospray ionization mass spectroscopy(HRESIMS),quantum chemical electronic circular dichroism(ECD),and DP4+probability analysis as well as by comparison of the data with literature reports.All isolated compounds were tested for antibacterial activities.
基金Supported by the Natural Science Foundation of Shandong Province(No.ZR2022MD074)the Laboratory for Marine Mineral Resources+3 种基金Qingdao National Laboratory for Marine Science and Technology(No.MMRKF201810)the National Natural Science Foundation of China(No.41606077)the National Key R&D Program of China:HighPrecision Characterization Technology of Gas Hydrate Reservoir(No.2017YFC0307406-03)supported by the Shandong Province Taishan Scholar Construction Project。
文摘Submarine seep plumes are a natural phenomenon in which different types of gases migrate through deep or shallow subsurface sediments and leak into seawater in pressure gradient.When detected using acoustic data,the leaked gases frequently exhibit a flame-like structure.We numerically modelled the relationship between the seismic response characteristic and bubble volume fraction to establish the bubble volume fraction in the submarine seep plume.Results show that our models are able to invert and predict the bubble volume fraction from field seismic oceanography data,by which synthetic seismic sections in different dominant frequencies could be numerically simulated,seismic attribute sections(e.g.,instantaneous amplitude,instantaneous frequency,and instantaneous phase)extracted,and the correlation between the seismic attributes and bubble volume fraction be quantitatively determined with functional equations.The instantaneous amplitude is positively correlated with bubble volume fraction,while the instantaneous frequency and bubble volume fraction are negatively correlated.In addition,information entropy is introduced as a proxy to quantify the relationship between the instantaneous phase and bubble volume fraction.As the bubble volume fraction increases,the information entropy of the instantaneous phase increases rapidly at the beginning,followed by a slight upward trend,and finally stabilizes.Therefore,under optimal noise conditions,the bubble volume fraction of submarine seep plumes can be inverted and predicted based on seismic response characteristics in terms of seismic attributes.
基金Supported by the Key Research and Development Project of Guangdong Province(No.2020B1111510001)the National Natural Science Foundation of China(No.U2244224)+1 种基金the PI Project of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2020GD0802)the Guangdong Special Support Team Program(No.2019BT02H594)。
文摘Bivalve shell fossils,cemented by authigenic carbonates,are widely spread in the Haima cold seep,Qiongdongnan Basin of the South China Sea(SCS).In this study,we examined an element profile of Gigantidas platifrons in the Haima cold seeps at a water depth of 1381 m.Based on the scanning electron microscope(SEM)analyses,the prismatic layer and nacreous layer were identified,which are characterized by prismatic structure and stratified structure,respectively.In addition,the profile can be subdivided into two parts:altered and unaltered zones.Laser inductively coupled plasma mass spectrometry(LA-ICP-MS)mapping shows that the element concentrations of the altered zones were influenced by the authigenic carbonate rocks,whereas the element concentrations of unaltered zones remain stable.In-situ X-ray diffraction(XRD)analyses show that the mineral constituent of the prismatic layer is mainly composed of aragonite.Along with the growth profile,Mg/Ca ratios of unaltered zones have minor variations,ranging 0.72-0.97 mmol/mol(mean=0.87 mmol/mol),with estimated temperatures of 3.8-4.1℃,indicating that the temperature of the surrounding seawater remains constant and agree with the measured data of 3.9℃which was conducted by a conductivity-temperature-depth system(CTD).The minor variations of Ba/Ca ratios(0.01-0.06 mmol/mol;mean=0.04 mmol/mol)indicate a relatively stabilized salinity of the surrounding seawater.S/Ca ratios show large variations of 0.04-4.15 mmol/mol(mean=1.37 mmol/mol).S/Ca ratios have regular variations which generally correspond to the variations of the Mg/Ca ratios,highlighting that the S/Ca ratios of bivalve shells show the potential to reflect the growth rate of the Gigantides.However,further studies should be carried out on the understanding of the links between the S/Ca ratios and seepage intensity of cold-seep fluids.
基金Supported by the Guangdong Province Marine Economic Development(Six Major Marine Industries)Special Fund Project(No.[2021]No.58)the National Key R&D Program of China(No.2018YFC0310000)the National Natural Science Foundation of China(Nos.41776056,42076054)。
文摘Cold seeps spread worldwide along the continental margins,which are closely related to the exploration of gas hydrates.Cold-seep carbonates have been reported to record the nature of seepage,including fluid source,sedimentary environment,and variation of seepage activity.We investigated the morphology,mineralogy,element compositions,and carbon and oxygen isotopes of 15 cold-seep carbonates collected from the Shenhu area,and compared them with 2 carbonates from the Haima cold seep,the South China Sea(SCS),to promote our knowledge of cold-seep system in SCS.Most of the Shenhu carbonates exhibit crust morphology,and some are in the form of chimneys and blocks.Their absolute(20%–65%)and relative carbonate mineral contents(mainly aragonite and calcite,with minor samples containing dolomite)vary significantly,indicating the multi-stage methane leakage in our study area.Some samples show a slight negative Ce anomaly,suggesting either the mixing of seawater or variation of the redox condition during the precipitation;the cooccurrence of strongly enriched U and Mo demonstrates anoxic condition during precipitation.The mixed genetic methane source was interpreted by δ^(13)C of the Shenhu carbonates to range from-22.34‰to-59.30‰Vienna PeeDee Belemnite(VPDB),and the slight ^(18)O-enrichment imprinted on the carbonates suggests the possible influence from hydrate dissociation.The Haima carbonates,with biogenic methane as the main gas source,were presumably formed in a stronger fluid flux by compared with our Shenhu samples.
基金supported by Qingdao National Laboratory for Marine Science and Technology(No.QNLM2016ORP0210)the NSF of China(No.41473080 and 41673029)
文摘Four massive brecciated, chimney-like, and slender pipe network carbonate samples(JA-4, JA-5, JX-8 and BG-12) were collected from southwestern Taiwan, which were suggested to have formed as a result of anaerobic oxidization of methane(AOM). Considering that the environmental conditions of the carbonates precipitation and the sources of carbon and organic matter need to be further declared, molecular fossils and compound-specific carbon isotopic investigations of the carbonates were conducted in this study. According to lipid biomarkers of 2,6,10,15,19-pentamethyleicosane(PMI) and squalane diagnostic to methanotrophic archaea, as well as the extremely low δ^(13)C values(as low as -1^(13).4‰) detected in samples JA-4, JA-5 and JX-8, these carbonates were revealed to be a result of AOM. Based on the varied δ^(13)C values of characteristic archaea biomarkers in specific samples, biogenic methane was proposed to be responsible for the formation of samples JA-4 and JA-5, whereas a mixed carbon source of ^(13)C-depleted methane and ^(13)C-enriched residual CO_2 from methanogenesis was suggested for the carbonate of JX-8 due to the co-occurrence of a highly positive δ^(13) C_(carb) value(+8‰) and a moderate ^(13)C depletion of PMI. The low content of AOM-related biomarkers and the absence of indicators for ANME-2 suggested that these carbonates were formed in weak seep settings. By comparison, no typical lipid biomarkers for methanotrophic archaea was detected in carbonate BG-12. The short-chain and long-chain n-alkanes accounted for 30% and 45% of all hydrocarbons, respectively, with a CPI value of 1.2, suggesting that the n-alkanes were derived from both marine organisms and terrestrial inputs. A low thermal maturity could be revealed by the incomplete equilibrium value of the C^(31)αβ 22S/(22S+22R) ratio(0.5), and the carbonate BG-12 was probably deposited in a suboxic condition indicated by a value of Pr/Ph ratio(2.5).
基金supported by the National Program on Key Basic Research Project(973 Program)(Grant No.2009CB219502)National Special Foundation(Grant No.GZH200200203-02-01)Non-profit Industry Financial Program of Ministry of Land and Resources of the PRC(Grant No.200811014-02)
文摘South China Sea （SCS） is the largest Western Pacific marginal sea. However, microbial studies have never been performed in the cold seep sediments in the SCS. In 2004, ＂SONNE＂ 177 cruise found two cold seep areas with different water depth in the northern SCS. Haiyang 4 area, where the water depth is around 3000 m, has already been confirmed for active seeping on the seafloor, such as microbial mats, authigenic carbonate crusts and bivalves. We investigated microbial abundance and diver- sity in a 5.55-m sediment core collected from this cold seep area. An integrated approach was employed including geochemistry and 16S rRNA gene phylogenetic analyses. Here, we show that microbial abun- dance and diversity along with geochemistry profiles of the sediment core revealed a coupled reaction between sulphate reduction and methane oxidation. Acridine orange direct count results showed that microbial abundance ranges from 105 to 106 cells/g sediment （wet weight）. The depth-related variation of the abundance showed the same trend as the methane concentration profile. Phylogenetic analysis indicated the presence of sulphate-reducing bacteria and anaerobic methane-oxidizing archaea. The diver- sity was much higher at the surface, but decreased sharply with depth in response to changes in the geochemical conditions of the sediments, such as methane, sulphate concentration and total organic carbon. Marine Benthic Group B, Chloroflexi and JS1 were predominant phylotypes of the archaeal and bacterial libraries, respectively.
