Pollution from heavy metals(HMs)(Cd,As,Cr,and Ni,etc.)has become a serious environmental issue in urban wetland ecosystems with more and more attention.Previous studies conducted in agricultural soils,rivers,and lakes...Pollution from heavy metals(HMs)(Cd,As,Cr,and Ni,etc.)has become a serious environmental issue in urban wetland ecosystems with more and more attention.Previous studies conducted in agricultural soils,rivers,and lakes demonstrated that microbial communities exhibit a response to HM pollution.Yet,little is known about the response of microbial communities to HM pollution in urban wetland ecosystems.We examined how heavy metals affect the stability of the microbial networks in the sediments of Sanyang wetland,Wenzhou,China.Key environmental parameters,including HMs,TC(total carbon),TN(total nitrogen),TP(total phosphorus),S,and pH,varied profoundly between moderately and heavily polluted areas in shaping microbial communities.Specifically,the microbial community composition in moderately polluted sites correlated significantly(P<0.05)with Ni,Cu,Cd and TP,whereas in heavily polluted sites,they correlated significantly with Cd,TN,TP,and S.Results show that the heavily polluted sites demonstrated more intricate and more stable microbial networks than those of the moderately polluted area.The heavily polluted sites exhibited higher values for various network parameters including total nodes,total links,average degree,average clustering coefficient,connectance,relative modularity,robustness,and cohesion.Moreover,the structural equation modeling analysis demonstrated a positive correlation between the stability of microbial networks and Cd,TN,TP,and S in heavily polluted sites.Conversely,in moderately polluted sites,the correlation was positively linked to Cd,Ni,and sediment pH.It implies that Cd could potentially play a crucial role in affecting the stability of microbial networks.This study shall enhance our comprehension of microbial co-occurrence patterns in urban wetland ecosystems and offer insights into the ways in which microbial communities respond to environmental factors in varying levels of HM pollution.展开更多
Large phosphorite deposits in Central Guizhou,China,were formed around the Precambrian/Cambrian boundary(PC/C),including the Ediacaran(Doushantuo stage)and early Cambrian(Gezhongwu stage).Among them,Gezhongwu phosphor...Large phosphorite deposits in Central Guizhou,China,were formed around the Precambrian/Cambrian boundary(PC/C),including the Ediacaran(Doushantuo stage)and early Cambrian(Gezhongwu stage).Among them,Gezhongwu phosphorite from Zhijin are enriched in rare earth elements(REE)plus yttrium(REY),reaching 3.503 million tons.Although phosphorites have attracted great attention,the specific sources P and REY remained unclear.To determine the P and REY sources and establish a phosphogenic model of PC/C phosphorite,we present an integrated dataset of Mo and phosphate O isotopes for the first time,along with carbonate C and O isotopes,geology,petrology,and geochemistry.In all samples,d18Op,Y/Ho,and Zr/Hf decreased from the Ediacaran to the early Cambrian,indicating increased terrigenous weathering fluxes while decreased upwelling water input.Furthermore,terrigenous weathering delivery significantly elevated marine REY concentrations in the Cambrian in Zhijin.The Ceanom and d98/95Mo suggest that seawater was oxidized in the later Ediacaran and became entirely oxic in the early Cambrian.The positive feedback between oxygen levels in atmosphere and primary productivity caused progressive oxygenation in ocean-atmosphere system and enable phosphorites to be formed by different mechanisms.Results show that the Lower Doushantuo consist of abiotic intraclasts and exhibited“seawaterlike”REY types,indicating abiological and mechanical reworking phosphogenesis.The Upper Doushantuo and Gezhongwu Formation contained mainly microbial debris and abiogenic intraclasts,and exhibit “hat-shaped”REY plots,suggesting microbially mediated phosphogenesis.Based on this data set,we developed a phosphogenic model illustrating formation of these two phosphorite deposits,wherein the Lower Doushantuo phosphorite formed through the reworking of pre-existing phosphatic sediments in anoxic and abiotic ocean,whereas the Upper Doushantuo and Gezhongwu phosphorite formed via microbial metabolisms in oxic and biotic conditions.Our study has implications on the PC/C phosphorite generative processes,as well as paleoenvironmental conditions.展开更多
Yttrium(Y)is a critical metallic element that is used widely in modern scientific,technological,and industrial applications.Phosphorites in the Zhijin area of Guizhou Province,China,are famous for Y enrichment,but the...Yttrium(Y)is a critical metallic element that is used widely in modern scientific,technological,and industrial applications.Phosphorites in the Zhijin area of Guizhou Province,China,are famous for Y enrichment,but the enrichment characteristics and sources remain unclear.Previous studies suggested that the sources of rare earth elements(REEs,La-Lu)and Y(REYs,La-Lu+Y)were related to hydrothermal deposition.However,this study presents evidence refuting that hypothesis,with major and trace elemental data collected with quadrupoleinductively coupled plasma-mass spectrometry(Q-ICPMS)analysis.These data show that Y in Zhijin REYscontaining phosphorites has a normal distribution and is particularly enriched relative to other REYs.The Y enrichment degree is different at different∑REY intervals.Specifically,the Y enrichment degree is higher at lower∑REY values and lower at higher∑REY values.The REYs-containing phosphorites show features of primary phosphorites.Both REEs and Y have good correlations with P2 O5 in the phosphorites with low REYs contents(total REYs<535 ppm),whereas at high REYs contents(total REYs>535 ppm),REEs have a good correlation with P2 O5 but Y does not.Inconsistent enrichment processes of REYs are suggestive of complex sources of Y.Thus,seafloor hydrothermal fluids were not the direct source of Y.Normal seawater mixed with terrestrial sources might have contributed to the origin of Y here.This study could lead to improvements in Y mineral resource explorations and the situation involving the global REYs supply crisis.展开更多
With the global vigorous development of high-tech industries,the market demand for rare earth elements and Yttrium(REY)have experienced explosive growth.In recent years,phosphate associated REY resources(up to 18,000 ...With the global vigorous development of high-tech industries,the market demand for rare earth elements and Yttrium(REY)have experienced explosive growth.In recent years,phosphate associated REY resources(up to 18,000 ppm)found in modern deep-sea muds have attracted significant attentions.It is believed that their REY originated directly from porewater in deep-sea sediments,with a process of detrital dissolution releasing REY into the porewater.However,it remains unclear whether this model could be applied to REY-rich phosphorites from geological history,which contrasts sharply with the widely accepted Fe-oxide redox pump model at the seawater-sediment interface.Here,we present the mineralogy and REY geochemistry of clay minerals,and whole-rock Si-Fe isotopic compositions(δ^(30)Si and δ^(56)Fe)from early Cambrian REY-rich Zhijin phosphorite(∑REY,~2000 ppm)and REY-poor Meishucun phosphorite(∑REY,<400 ppm)in South China.In the Zhijin samples,illite formed around the edges of muscovite,exhibiting seawater-like REY patterns.In contrast,muscovite and orthoclase in the Meishucun samples show no contact relationship and display REY patterns typical of granite-forming minerals.The REY contents(reach 310 ppm)of muscovites from Zhijin samples are much higher than that of detrital muscovite(REY,0.09-5.86 ppm)and orthoclase(REY,2.69-6.45 ppm)from Meishucun samples.Furthermore,the data can be classified into two categories based on the correlation between δ^(30)Si values and phosphate-hosted REY enrichment in Zhijin and Meishucun samples.One is characterized by higher δ^(30)Si values(average 0.6‰)and Y/Ho ratios(average 56),and lower SiO_(2)and REY contents(average 8.10% and 1076 ppm,respectively).The other group exhibits lower δ^(30)Si values(average 0.2‰)and Y/Ho ratios(average 52),and higher SiO_(2)and REY contents(average 17.45% and 2085 ppm,respectively).In addition,compared to the Meishucun phosphorites formed in well oxidized marine environment(δ^(56)Fe,~0‰),the Zhijin phosphorites developed under fluctuating oxic-suboxic marine condition exhibit a significant negative correlation between Fe and Si isotopic compositions.These findings indicate Zhijin muscovite underwent REY exchange with seawater under fluctuating redox marine conditions,leading to REY release into the porewater and the formation of authigenic illite.This process did not occur in the Meishucun samples.It's well known that continental weathering transformed feldspar into REY-rich muscovite or illite.These REY-rich clays,transported to the seawater-sediment interface,were dissolved and released REY into the porewater within a fluctuating oxic-suboxic marine environment.We proposed for the first time that fluctuating marine redox conditions acted as a trigger for REY enrichment in ancient phosphorites,with the primary REY source being terrigenous REY-rich clay.This perspective not only provides an insight into the mechanism of REY enrichment in phosphorites,but could also account for the lack of anomalous REYenrichment in phosphorites exhibiting the precipitation of extensive pyrites if only Fe-oxide redox processes are considered.展开更多
基金Supported by the Major Program of Institute for Eco-environmental Research of Sanyang Wetland(No.SY2022ZD-1001-05)。
文摘Pollution from heavy metals(HMs)(Cd,As,Cr,and Ni,etc.)has become a serious environmental issue in urban wetland ecosystems with more and more attention.Previous studies conducted in agricultural soils,rivers,and lakes demonstrated that microbial communities exhibit a response to HM pollution.Yet,little is known about the response of microbial communities to HM pollution in urban wetland ecosystems.We examined how heavy metals affect the stability of the microbial networks in the sediments of Sanyang wetland,Wenzhou,China.Key environmental parameters,including HMs,TC(total carbon),TN(total nitrogen),TP(total phosphorus),S,and pH,varied profoundly between moderately and heavily polluted areas in shaping microbial communities.Specifically,the microbial community composition in moderately polluted sites correlated significantly(P<0.05)with Ni,Cu,Cd and TP,whereas in heavily polluted sites,they correlated significantly with Cd,TN,TP,and S.Results show that the heavily polluted sites demonstrated more intricate and more stable microbial networks than those of the moderately polluted area.The heavily polluted sites exhibited higher values for various network parameters including total nodes,total links,average degree,average clustering coefficient,connectance,relative modularity,robustness,and cohesion.Moreover,the structural equation modeling analysis demonstrated a positive correlation between the stability of microbial networks and Cd,TN,TP,and S in heavily polluted sites.Conversely,in moderately polluted sites,the correlation was positively linked to Cd,Ni,and sediment pH.It implies that Cd could potentially play a crucial role in affecting the stability of microbial networks.This study shall enhance our comprehension of microbial co-occurrence patterns in urban wetland ecosystems and offer insights into the ways in which microbial communities respond to environmental factors in varying levels of HM pollution.
基金supported by the United Foundation of National Natural Science Foundation of China(Grant Numbers:41972095,U181240004,9206220039)the Public Beneficial,Basic Geological Project of Department of Land and Resources of Guizhou Province(Grant Number:2016-09-1).
文摘Large phosphorite deposits in Central Guizhou,China,were formed around the Precambrian/Cambrian boundary(PC/C),including the Ediacaran(Doushantuo stage)and early Cambrian(Gezhongwu stage).Among them,Gezhongwu phosphorite from Zhijin are enriched in rare earth elements(REE)plus yttrium(REY),reaching 3.503 million tons.Although phosphorites have attracted great attention,the specific sources P and REY remained unclear.To determine the P and REY sources and establish a phosphogenic model of PC/C phosphorite,we present an integrated dataset of Mo and phosphate O isotopes for the first time,along with carbonate C and O isotopes,geology,petrology,and geochemistry.In all samples,d18Op,Y/Ho,and Zr/Hf decreased from the Ediacaran to the early Cambrian,indicating increased terrigenous weathering fluxes while decreased upwelling water input.Furthermore,terrigenous weathering delivery significantly elevated marine REY concentrations in the Cambrian in Zhijin.The Ceanom and d98/95Mo suggest that seawater was oxidized in the later Ediacaran and became entirely oxic in the early Cambrian.The positive feedback between oxygen levels in atmosphere and primary productivity caused progressive oxygenation in ocean-atmosphere system and enable phosphorites to be formed by different mechanisms.Results show that the Lower Doushantuo consist of abiotic intraclasts and exhibited“seawaterlike”REY types,indicating abiological and mechanical reworking phosphogenesis.The Upper Doushantuo and Gezhongwu Formation contained mainly microbial debris and abiogenic intraclasts,and exhibit “hat-shaped”REY plots,suggesting microbially mediated phosphogenesis.Based on this data set,we developed a phosphogenic model illustrating formation of these two phosphorite deposits,wherein the Lower Doushantuo phosphorite formed through the reworking of pre-existing phosphatic sediments in anoxic and abiotic ocean,whereas the Upper Doushantuo and Gezhongwu phosphorite formed via microbial metabolisms in oxic and biotic conditions.Our study has implications on the PC/C phosphorite generative processes,as well as paleoenvironmental conditions.
基金supported by the National Natural Science Foundation of China (No. U1812402)the Public Beneficial and Basic Geological Project from the Department of Land and Resources of Guizhou Province (No. 2016-09-1)。
文摘Yttrium(Y)is a critical metallic element that is used widely in modern scientific,technological,and industrial applications.Phosphorites in the Zhijin area of Guizhou Province,China,are famous for Y enrichment,but the enrichment characteristics and sources remain unclear.Previous studies suggested that the sources of rare earth elements(REEs,La-Lu)and Y(REYs,La-Lu+Y)were related to hydrothermal deposition.However,this study presents evidence refuting that hypothesis,with major and trace elemental data collected with quadrupoleinductively coupled plasma-mass spectrometry(Q-ICPMS)analysis.These data show that Y in Zhijin REYscontaining phosphorites has a normal distribution and is particularly enriched relative to other REYs.The Y enrichment degree is different at different∑REY intervals.Specifically,the Y enrichment degree is higher at lower∑REY values and lower at higher∑REY values.The REYs-containing phosphorites show features of primary phosphorites.Both REEs and Y have good correlations with P2 O5 in the phosphorites with low REYs contents(total REYs<535 ppm),whereas at high REYs contents(total REYs>535 ppm),REEs have a good correlation with P2 O5 but Y does not.Inconsistent enrichment processes of REYs are suggestive of complex sources of Y.Thus,seafloor hydrothermal fluids were not the direct source of Y.Normal seawater mixed with terrestrial sources might have contributed to the origin of Y here.This study could lead to improvements in Y mineral resource explorations and the situation involving the global REYs supply crisis.
基金supported by the National Natural Science Foundation of China(Grant Nos.92062221,42121003)Jiangxi Province Key Laboratory of Exploration and Development of Critical Mineral Resources(Grant No.GJKC2024ZZ07)+1 种基金Guizhou Provincial Science and Technology Subsidies(Grant Nos.GZ2020SIG,GZ2021SIG)Geological Exploration Fund of Guizhou Province(Grant No.2024-2)。
文摘With the global vigorous development of high-tech industries,the market demand for rare earth elements and Yttrium(REY)have experienced explosive growth.In recent years,phosphate associated REY resources(up to 18,000 ppm)found in modern deep-sea muds have attracted significant attentions.It is believed that their REY originated directly from porewater in deep-sea sediments,with a process of detrital dissolution releasing REY into the porewater.However,it remains unclear whether this model could be applied to REY-rich phosphorites from geological history,which contrasts sharply with the widely accepted Fe-oxide redox pump model at the seawater-sediment interface.Here,we present the mineralogy and REY geochemistry of clay minerals,and whole-rock Si-Fe isotopic compositions(δ^(30)Si and δ^(56)Fe)from early Cambrian REY-rich Zhijin phosphorite(∑REY,~2000 ppm)and REY-poor Meishucun phosphorite(∑REY,<400 ppm)in South China.In the Zhijin samples,illite formed around the edges of muscovite,exhibiting seawater-like REY patterns.In contrast,muscovite and orthoclase in the Meishucun samples show no contact relationship and display REY patterns typical of granite-forming minerals.The REY contents(reach 310 ppm)of muscovites from Zhijin samples are much higher than that of detrital muscovite(REY,0.09-5.86 ppm)and orthoclase(REY,2.69-6.45 ppm)from Meishucun samples.Furthermore,the data can be classified into two categories based on the correlation between δ^(30)Si values and phosphate-hosted REY enrichment in Zhijin and Meishucun samples.One is characterized by higher δ^(30)Si values(average 0.6‰)and Y/Ho ratios(average 56),and lower SiO_(2)and REY contents(average 8.10% and 1076 ppm,respectively).The other group exhibits lower δ^(30)Si values(average 0.2‰)and Y/Ho ratios(average 52),and higher SiO_(2)and REY contents(average 17.45% and 2085 ppm,respectively).In addition,compared to the Meishucun phosphorites formed in well oxidized marine environment(δ^(56)Fe,~0‰),the Zhijin phosphorites developed under fluctuating oxic-suboxic marine condition exhibit a significant negative correlation between Fe and Si isotopic compositions.These findings indicate Zhijin muscovite underwent REY exchange with seawater under fluctuating redox marine conditions,leading to REY release into the porewater and the formation of authigenic illite.This process did not occur in the Meishucun samples.It's well known that continental weathering transformed feldspar into REY-rich muscovite or illite.These REY-rich clays,transported to the seawater-sediment interface,were dissolved and released REY into the porewater within a fluctuating oxic-suboxic marine environment.We proposed for the first time that fluctuating marine redox conditions acted as a trigger for REY enrichment in ancient phosphorites,with the primary REY source being terrigenous REY-rich clay.This perspective not only provides an insight into the mechanism of REY enrichment in phosphorites,but could also account for the lack of anomalous REYenrichment in phosphorites exhibiting the precipitation of extensive pyrites if only Fe-oxide redox processes are considered.
