Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we ...Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we report a flame-retard ant cross-linked sp^(3)boron-based single-ion gel polymer electrolyte(BSIPE).BSIPE was prepared by a simple one-step photoinitiated in situ thiol-ene click reaction.Due to the boron-based anions being immobilized in the cross-linking network,the developed BSIPE/PFN exhibits a high t_(Li^(+))(0.87),which can mitigate concentration polarization phenomenon and suppress the growth of lithium dendrites.BSIPE/PFN plasticized with triethyl phosphate(TEP),fluoroethylene carbonate(FEC)and LiNO_(3)exhibits enhanced ionic conductivity of 4.25×10^(-4)S cm^(-1)at 30℃ and flame retardancy.FEC and LiNO_(3) are conducive to form a stable solid electrolyte interphase(SEI)rich in Li_(3)N and LiF to improve interface stability.As expected,the dendrite-free Li‖BSIPE/PFN‖Li symmetric cell exhibits considerable cycling life over 1500 h.BSIPE/PFN significantly boosts the performance of LFP‖Li cell,which displays a capacity retention of 84.6%after 500 cycles.The BSIPE/PFN has promising applications in highsafety and high-performance lithium metal batteries.展开更多
The long persistent phosphors of Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)with Nd^(3+)as sensitized ions and Tb^(3+)as emission centers were synthesized using high temperature solid state reaction.The crystal st...The long persistent phosphors of Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)with Nd^(3+)as sensitized ions and Tb^(3+)as emission centers were synthesized using high temperature solid state reaction.The crystal structure and defects,excitation and emission spectra,decay curves and thermoluminescence(TL) curves of the phosphors were investigated.The synthesized Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)is essentially in line with the standard card PDF#49-1079.The emission band with main peak at 548 nm exhibits the characteristic transitions of ^(5)D_(3)-^(7)F_(j)(j=5,4) and ^(5)D_(3)-^(7)F_(j)(j=6,5,4,3) of Tb^(3+).The analysis of excitation and emission spectra shows that there exists the overlap between the emission peaks of Nd^(3+)at 466 and 485 nm and the excitation of Tb^(3+)at 443 and 485 nm,and the energy transfer from Nd^(3+)to Tb^(3+)plays an important role in the improvement of luminescence properties.The decay curves shows that Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)has longer afterglow time than ZrP_(2)O_(7) and Zr_(0.982)P_(2)O_(7):0.018 Tb^(3+).Additionally,the TL curves indicate that the trap depth at 0.72 eV in Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)is to the benefit of the afterglow time.The possible luminescence mechanism of ZrP_(2)O_(7):Tb^(3+),Nd^(3+)is proposed on the basis of the XPS spectra,EPR spectra,excitation and emission spectra,decay curves,TL curves and the analysis of defect equations.展开更多
Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT a...Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.展开更多
The co-occurrence of bacteria and microeukaryote species is a ubiquitous ecological phenomenon,but there is limited cross-domain research in aquatic environments.We conducted a network statistical analysis and visuali...The co-occurrence of bacteria and microeukaryote species is a ubiquitous ecological phenomenon,but there is limited cross-domain research in aquatic environments.We conducted a network statistical analysis and visualization of microbial cross-domain co-occurrence patterns based on DNA sampling of a typical subtropical bay during four seasons,using high-throughput sequencing of both 18S rRNA and 16S rRNA genes.First,we found obvious relationships between network stability and network complexity indices.For example,increased cooperation and modularity were found to weaken the stability of cross-domain networks.Secondly,we found that bacterial operational taxonomic units(OTUs)were the most important contributors to network complexity and stability as they occupied more nodes,constituted more keystone OTUs,built more connections,more importantly,ignoring bacteria led to greater variation in network robustness.Gammaproteobacteria,Alphaproteobacteria,Bacteroidetes,and Actinobacteria were the most ecologically important groups.Finally,we found that the environmental drivers most associated with cross-domain networks varied across seasons(in detail,the network in January was primarily constrained by temperature and salinity,the network in April was primarily constrained by depth and temperature,the network in July was mainly affected by depth,temperature,and salinity,depth was the most important factor affecting the network in October)and that environmental influence was stronger on bacteria than on microeukaryotes.展开更多
Background Ecological floating beds can restore eutrophic water,but few studies have focused on changes in microbial communities during the remediation process.To gain a deeper understanding of the restoration process...Background Ecological floating beds can restore eutrophic water,but few studies have focused on changes in microbial communities during the remediation process.To gain a deeper understanding of the restoration process,we used 16S/18S rRNA gene metabarcoding and metagenomic sequencing to investigate the changes in the structure and function of protist and bacterial communities.Results By comparing seawater with or without floating beds,we found that Sesuvium portulacastrum can effectively remove nutrients and dissolved solids from water,with nitrate removal above 52%and phosphate removal above 34%within 33 days.S.portulacastrum increased the alpha diversity of both protists and bacteria,changed their community composition,and improved the community stability.The stochastic processes were critical in shaping the community assembly,and the contribution of stochastic processes in floating beds was lower in the treatment group than in the control group.In addition,changes in aquatic community structure further led to changes in community function,particularly nitrogen cycle processes.Among all nitrogen cycle-related functional genes,dissimilatory nitrate reduction genes(44.50%)and denitrification genes(62.44%)were the most common on day 1 and day 33,respectively.The enhanced denitrification process promoted the nitrogen removal in eutrophic water,contributing to ecological restoration and water quality improvement.Conclusions Our results suggested that S.portulacastrum and associated microbial communities exhibited a synergistic role in the restoration process.The well-developed root system of S.portulacastrum acted as a carrier for microorganisms to play a crucial role in the removal of nutrients and other dissolved solids.This study can provide a reference for the optimization of ecological management of eutrophic seawater.Restoration efforts should integrate considerations of water physicochemical properties with the structure and function of aquatic community.展开更多
Climate change may threaten the survival of corals due to ocean warming and increased occurrence of extreme weather events.Yet,marginal coral communities demonstrate remarkable adaptability,largely due to stress-toler...Climate change may threaten the survival of corals due to ocean warming and increased occurrence of extreme weather events.Yet,marginal coral communities demonstrate remarkable adaptability,largely due to stress-tolerant species.The mechanisms underlying their resilience to environmental fluctuations remains largely unexplored.Here,we investigated 3 coral species(Cyphastrea serailia,Dipsastraea speciosa,and Duncanopsammia peltata)living at the northern edge of their distribution along the South China coast(Dongshan).Combining physiological and stable isotope analysis,we assessed their traits(symbiont characteristics,C:N ratio,and biomass)and trophic flexibility(i.e.,shifts in isotopic niche or nutritional mode)in response to environmental fluctuations across seasons(autumn,winter,and late spring).Our results revealed distinct physiological traits among these corals,but consistently showed lower symbiont density,higher biomass,and increased chlorophyll content in winter.All corals highly relied on heterotrophy as a crucial adaptive response(consistently no overlap between host and symbiont isotopic niches),but they differed in the degree of trophic plasticity,with D.speciosa showing the highest variability in heterotrophic contribution(36.3%across seasons),followed by C.serailia(21.8%)and D.peltata(8.6%).Notably,the species-specific differences in trophic plasticity well corresponded to the variation in overall isotopic niche and coral distribution.As such,trophic plasticity may play a role in shaping spatial distribution of corals in the marginal community.Overall,this study enhances our understanding of coral resilience in marginal communities and offer new insights into possible mechanisms driving the distribution of reef-building corals in the changing ocean.展开更多
Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but sto...Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but stock enhancement programs and seasonal fishery closures have failed to recover populations of the commercially important species,Larimichthys crocea.We want to figure out the potential reason of unsuccessful L.crocea resource in recent 30 years.In this study,the trophic status of L.crocea,the food source proportions of L.crocea and zooplankton,and the food web structure and functioning of Sansha Bay was analyzed.A high nutrient low chlorophyll phenomenon was observed:this prevented harmful algal blooms,and phytoplankton growth was restrained by intensive macroalgal culture,resulting in a low abundance of zooplankton in Sansha Bay.Phytoplankton was the most important food source of zooplankton,and zooplankton was the greatest food source of juvenile L.crocea.Analyzed L.crocea suffered from starvation.Crucially,most of the phytoplan kton was not used efficiently in the Sansha Bay ecosystem.This study suggests that trophic bottleneck,caused by food limitation,is a potential reason for unsuccessful fishery recovery in enclosed bay with macroalgal culture.展开更多
Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but sto...Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but stock enhancement programs and seasonal fishery closures have failed to recover populations of the commercially important species,Larimichthys crocea.We want to figure out the potential reason of unsuccessful L.crocea resource in recent 30 years.In this study,the trophic status of L.crocea,the food source proportions of L.crocea and zooplankton,and the food web structure and functioning of Sansha Bay was analyzed.A high nutrient low chlorophyll phenomenon was observed:this prevented harmful algal blooms,and phytoplankton growth was restrained by intensive macroalgal culture,resulting in a low abundance of zooplankton in Sansha Bay.Phytoplankton was the most important food source of zooplankton,and zooplankton was the greatest food source of juvenile L.crocea.Analyzed L.crocea suffered from starvation.Crucially,most of the phytoplankton was not used efficiently in the Sansha Bay ecosystem.This study suggests that trophic bottleneck,caused by food limitation,is a potential reason for unsuccessful fishery recovery in enclosed bay with macroalgal culture.展开更多
Assessment of microzooplankton and copepods grazing pressure on picoplankton is a key requirement for resolving the microbial food web efficiency.Although microzooplankton grazing on picoplankton has been extensively ...Assessment of microzooplankton and copepods grazing pressure on picoplankton is a key requirement for resolving the microbial food web efficiency.Although microzooplankton grazing on picoplankton has been extensively studied,the impact of microzooplankton on different groups of picoplankton,i.e.,heterotrophic bacteria,Synechococcus and picoeukaryotes have rarely been compared.Furthermore,in the very few existing studies there is no consistent evidence of an enhancing or restraining effect of copepods on picoplankton.More studies are needed to improve our understanding of the influence of microzooplankton and copepod on picoplankton.Dilution incubations and copepod addition incubations were performed during a cruise to the southern Yellow Sea on May 16-29,2007.The bulk grazing of microzooplankton and the calanoid copepod Cal anus sinicus on phytoplankton,flagellates and picoplankton was estimated.Stations were divided into either eutrophic or oligotrophic according to the nutrient and biological parameters.Picoplankton comprised a large part of the diet of microzooplankton in the central oligotrophic area,while phytoplankton was the main food of microzooplankton in the coastal eutrophic area.In the central oligotrophic area,microzooplankton preferred grazing on Synechococcus.After copepod addition,ciliate abundance decreased while Synechococcus abundance increased(382%,64%and 64%at three experimental stations,respectively),indicating strong grazing pressure of microzooplankton on Synechococcus.Our results suggest that Synechococcus might be an essential carbon source the planktonic food web in the oligotrophic waters of southern Yellow Sea.展开更多
Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous s...Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear.Sansha Bay is an enclosed bay with ongoing eutrophication,located in the southeast coast of China.We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes.Results:Diversity analyses revealed that the bacterial community composition among seasons differed significantly.By contrast,there was little difference in the community composition between the two depths.The temperature was the key environmental factor influencing the community composition.The null model indicated that the relative importance of homogeneous selection decreased in the following order:spring>winter>autumn>summer.Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay.The effects of pure spatial variables on the community assembly were prominent in autumn and winter.Conclusions:Our results showed the seasonal influence of eutrophication on bacterial community diversity.The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability.Eutrophication could enhance the importance of homogeneous selection in the assembly processes,but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes.Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay.The bacterial community was the most complex in summer,because the composition differed from other seasons,and the assembly process was the most intricate.These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.展开更多
基金supported by the National Natural Science Foundation of China(22179149,22075329,51573215,and 21978332)Research and Development Project of Henan Academy Sciences China(232018002)。
文摘Single ion gel polymer electrolyte has the advantages of high Li^(+)conductivity and dendrite mitigation.However,the addition of organic solvent makes the electrolyte flammable,posing serious safety hazards.Herein,we report a flame-retard ant cross-linked sp^(3)boron-based single-ion gel polymer electrolyte(BSIPE).BSIPE was prepared by a simple one-step photoinitiated in situ thiol-ene click reaction.Due to the boron-based anions being immobilized in the cross-linking network,the developed BSIPE/PFN exhibits a high t_(Li^(+))(0.87),which can mitigate concentration polarization phenomenon and suppress the growth of lithium dendrites.BSIPE/PFN plasticized with triethyl phosphate(TEP),fluoroethylene carbonate(FEC)and LiNO_(3)exhibits enhanced ionic conductivity of 4.25×10^(-4)S cm^(-1)at 30℃ and flame retardancy.FEC and LiNO_(3) are conducive to form a stable solid electrolyte interphase(SEI)rich in Li_(3)N and LiF to improve interface stability.As expected,the dendrite-free Li‖BSIPE/PFN‖Li symmetric cell exhibits considerable cycling life over 1500 h.BSIPE/PFN significantly boosts the performance of LFP‖Li cell,which displays a capacity retention of 84.6%after 500 cycles.The BSIPE/PFN has promising applications in highsafety and high-performance lithium metal batteries.
基金Project supported by the Guiding Project of Science and Technology Department of Fujian Province(2019N0016)Key Project of Advanced Industry of Science and Technology Department of Fujian Province(2017Y0067)+1 种基金the Foundation of Education Department of Fujian Province(JT180293)Natural Science Foundation of Zhangzhou Science&Technology Bureau(2017G02010028)。
文摘The long persistent phosphors of Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)with Nd^(3+)as sensitized ions and Tb^(3+)as emission centers were synthesized using high temperature solid state reaction.The crystal structure and defects,excitation and emission spectra,decay curves and thermoluminescence(TL) curves of the phosphors were investigated.The synthesized Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)is essentially in line with the standard card PDF#49-1079.The emission band with main peak at 548 nm exhibits the characteristic transitions of ^(5)D_(3)-^(7)F_(j)(j=5,4) and ^(5)D_(3)-^(7)F_(j)(j=6,5,4,3) of Tb^(3+).The analysis of excitation and emission spectra shows that there exists the overlap between the emission peaks of Nd^(3+)at 466 and 485 nm and the excitation of Tb^(3+)at 443 and 485 nm,and the energy transfer from Nd^(3+)to Tb^(3+)plays an important role in the improvement of luminescence properties.The decay curves shows that Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)has longer afterglow time than ZrP_(2)O_(7) and Zr_(0.982)P_(2)O_(7):0.018 Tb^(3+).Additionally,the TL curves indicate that the trap depth at 0.72 eV in Zr_(0.97)P_(2)O_(7):0.018 Tb^(3+),0.012 Nd^(3+)is to the benefit of the afterglow time.The possible luminescence mechanism of ZrP_(2)O_(7):Tb^(3+),Nd^(3+)is proposed on the basis of the XPS spectra,EPR spectra,excitation and emission spectra,decay curves,TL curves and the analysis of defect equations.
基金Supported by the National Key Basic Research Development Program of China(973 Program)(No.2015CB453303)the National Science Foundation for Young Scientists of China(No.41606195)。
文摘Fish otolithδ^(15) N(δ^(15) N_(oto))is a demonstrated source of information of dietary history for marine fi sh as it is available iN_(oto)lith archives and sedimentary deposits unlike white muscle tissue(WMT).WMT and stomach content data are insufficient for trophic level(TL)data of past fi shes which is important for the changes of marine fi shery resources over long time scales.To determine the correlation betweenδ^(15) N_(oto) and fi sh WMTδ^(15) N(δ^(15) N_(wmt))and the feasibility of usingδ^(15) N_(oto) in characterizing the TLs of marine fi shes,we conducted nitrogen stable isotope analysis(SIA)in the otolith and WMT of 36 marine fi sh species sampled from the Yellow Sea and northern East China Sea in 2011-2014.Bothδ^(15) N_(oto) andδ^(15) N_(wmt) were analyzed using an elemental analyzer coupled with an isotope ratio mass spectrometer(EA-IRMS).Multiple otoliths were combined to make each otolith measurement and were analyzed as-is without a carbonate dissolution pre-processing step.δ^(15) N_(oto) andδ^(15) N_(wmt) comparisons for species in the Yellow Sea and northern East China Sea are currently lacking and would be helpful for both regional studies and for increasing the number of species for whichδ^(15) N_(oto) andδ^(15) N_(wmt) have been compared.Additionally,to determine the relative accuracy of trophic level calculated usingδ^(15) N_(oto),we compared TL calculated fromδ^(15) N_(oto) to traditional trophic level metrics calculated usingδ^(15) N_(wmt).The results showed a positive and highly signifi cant correlation(R=0.780,P<0.001)betweenδ^(15) N_(oto) andδ^(15) N_(wmt).Trophic level estimation using WMT(TL wmt)and otolith(TL oto)showed congruence in our study,which is not entirely surprising given thatδ^(15) N_(oto) was regressed againstδ^(15) N_(wmt) and the resulting regression coefficient was used to convertδ^(15) N_(oto) toδ^(15) N_(wmt) prior to calculating TL oto.This conversion was required in order to be consistent with previousδ^(15) N_(wmt)-based calculations of TL for comparison.TL oto calculations resulted in TL values that were largely within 5%-10%of TL values calculated withδ^(15) N_(wmt).Our fi ndings show thatδ^(15) N_(oto) is a feasible technique for characterizing the TLs of marine fi sh and can also assist in food web and marine ecosystem studies.
基金Supported by the National Natural Science Foundation of China(Nos.42141003,42176147)the National Key Research and Development Program of China(No.2022YFF0802204)the Natural Science Foundation of Fujian Province of China(No.2021J01025)。
文摘The co-occurrence of bacteria and microeukaryote species is a ubiquitous ecological phenomenon,but there is limited cross-domain research in aquatic environments.We conducted a network statistical analysis and visualization of microbial cross-domain co-occurrence patterns based on DNA sampling of a typical subtropical bay during four seasons,using high-throughput sequencing of both 18S rRNA and 16S rRNA genes.First,we found obvious relationships between network stability and network complexity indices.For example,increased cooperation and modularity were found to weaken the stability of cross-domain networks.Secondly,we found that bacterial operational taxonomic units(OTUs)were the most important contributors to network complexity and stability as they occupied more nodes,constituted more keystone OTUs,built more connections,more importantly,ignoring bacteria led to greater variation in network robustness.Gammaproteobacteria,Alphaproteobacteria,Bacteroidetes,and Actinobacteria were the most ecologically important groups.Finally,we found that the environmental drivers most associated with cross-domain networks varied across seasons(in detail,the network in January was primarily constrained by temperature and salinity,the network in April was primarily constrained by depth and temperature,the network in July was mainly affected by depth,temperature,and salinity,depth was the most important factor affecting the network in October)and that environmental influence was stronger on bacteria than on microeukaryotes.
基金funded by the National Key Research and Development Program of China(2022YFF0802204)the National Natural Science Foundation of China(42176147 and 42141003)Xiamen Key Laboratory of Urban Sea Ecological Conservation and Restoration(USER)(USER2021-1 and USER2021-5)
文摘Background Ecological floating beds can restore eutrophic water,but few studies have focused on changes in microbial communities during the remediation process.To gain a deeper understanding of the restoration process,we used 16S/18S rRNA gene metabarcoding and metagenomic sequencing to investigate the changes in the structure and function of protist and bacterial communities.Results By comparing seawater with or without floating beds,we found that Sesuvium portulacastrum can effectively remove nutrients and dissolved solids from water,with nitrate removal above 52%and phosphate removal above 34%within 33 days.S.portulacastrum increased the alpha diversity of both protists and bacteria,changed their community composition,and improved the community stability.The stochastic processes were critical in shaping the community assembly,and the contribution of stochastic processes in floating beds was lower in the treatment group than in the control group.In addition,changes in aquatic community structure further led to changes in community function,particularly nitrogen cycle processes.Among all nitrogen cycle-related functional genes,dissimilatory nitrate reduction genes(44.50%)and denitrification genes(62.44%)were the most common on day 1 and day 33,respectively.The enhanced denitrification process promoted the nitrogen removal in eutrophic water,contributing to ecological restoration and water quality improvement.Conclusions Our results suggested that S.portulacastrum and associated microbial communities exhibited a synergistic role in the restoration process.The well-developed root system of S.portulacastrum acted as a carrier for microorganisms to play a crucial role in the removal of nutrients and other dissolved solids.This study can provide a reference for the optimization of ecological management of eutrophic seawater.Restoration efforts should integrate considerations of water physicochemical properties with the structure and function of aquatic community.
基金supported by the National Key Research and Development Program of China(2022YFF0802202)the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources of China(no.2019017)+2 种基金the Shenzhen Science and Technology Program(grant number KCXFZ20211020165547011)the National Natural Science Foundation of China(no.42376110,41976127)the Fujian Provincial Natural Science Funds for Distinguished Young Scholar(2023J06043)
文摘Climate change may threaten the survival of corals due to ocean warming and increased occurrence of extreme weather events.Yet,marginal coral communities demonstrate remarkable adaptability,largely due to stress-tolerant species.The mechanisms underlying their resilience to environmental fluctuations remains largely unexplored.Here,we investigated 3 coral species(Cyphastrea serailia,Dipsastraea speciosa,and Duncanopsammia peltata)living at the northern edge of their distribution along the South China coast(Dongshan).Combining physiological and stable isotope analysis,we assessed their traits(symbiont characteristics,C:N ratio,and biomass)and trophic flexibility(i.e.,shifts in isotopic niche or nutritional mode)in response to environmental fluctuations across seasons(autumn,winter,and late spring).Our results revealed distinct physiological traits among these corals,but consistently showed lower symbiont density,higher biomass,and increased chlorophyll content in winter.All corals highly relied on heterotrophy as a crucial adaptive response(consistently no overlap between host and symbiont isotopic niches),but they differed in the degree of trophic plasticity,with D.speciosa showing the highest variability in heterotrophic contribution(36.3%across seasons),followed by C.serailia(21.8%)and D.peltata(8.6%).Notably,the species-specific differences in trophic plasticity well corresponded to the variation in overall isotopic niche and coral distribution.As such,trophic plasticity may play a role in shaping spatial distribution of corals in the marginal community.Overall,this study enhances our understanding of coral resilience in marginal communities and offer new insights into possible mechanisms driving the distribution of reef-building corals in the changing ocean.
基金supported by the Ministry of Science and Technology of the People's Republic of China under Grant number[2018YFC1406306]
文摘Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but stock enhancement programs and seasonal fishery closures have failed to recover populations of the commercially important species,Larimichthys crocea.We want to figure out the potential reason of unsuccessful L.crocea resource in recent 30 years.In this study,the trophic status of L.crocea,the food source proportions of L.crocea and zooplankton,and the food web structure and functioning of Sansha Bay was analyzed.A high nutrient low chlorophyll phenomenon was observed:this prevented harmful algal blooms,and phytoplankton growth was restrained by intensive macroalgal culture,resulting in a low abundance of zooplankton in Sansha Bay.Phytoplankton was the most important food source of zooplankton,and zooplankton was the greatest food source of juvenile L.crocea.Analyzed L.crocea suffered from starvation.Crucially,most of the phytoplan kton was not used efficiently in the Sansha Bay ecosystem.This study suggests that trophic bottleneck,caused by food limitation,is a potential reason for unsuccessful fishery recovery in enclosed bay with macroalgal culture.
基金This work was supported by the Ministry of Science and Technology of the People’s Republic of China under Grant number[2018YFC1406306].
文摘Low biological productivity causes ecosystem energy deficiency.Sansha Bay is an important spawning and nursery ground for migratory fish in the East China Sea(ECS).There is significant mariculture in this area,but stock enhancement programs and seasonal fishery closures have failed to recover populations of the commercially important species,Larimichthys crocea.We want to figure out the potential reason of unsuccessful L.crocea resource in recent 30 years.In this study,the trophic status of L.crocea,the food source proportions of L.crocea and zooplankton,and the food web structure and functioning of Sansha Bay was analyzed.A high nutrient low chlorophyll phenomenon was observed:this prevented harmful algal blooms,and phytoplankton growth was restrained by intensive macroalgal culture,resulting in a low abundance of zooplankton in Sansha Bay.Phytoplankton was the most important food source of zooplankton,and zooplankton was the greatest food source of juvenile L.crocea.Analyzed L.crocea suffered from starvation.Crucially,most of the phytoplankton was not used efficiently in the Sansha Bay ecosystem.This study suggests that trophic bottleneck,caused by food limitation,is a potential reason for unsuccessful fishery recovery in enclosed bay with macroalgal culture.
文摘Assessment of microzooplankton and copepods grazing pressure on picoplankton is a key requirement for resolving the microbial food web efficiency.Although microzooplankton grazing on picoplankton has been extensively studied,the impact of microzooplankton on different groups of picoplankton,i.e.,heterotrophic bacteria,Synechococcus and picoeukaryotes have rarely been compared.Furthermore,in the very few existing studies there is no consistent evidence of an enhancing or restraining effect of copepods on picoplankton.More studies are needed to improve our understanding of the influence of microzooplankton and copepod on picoplankton.Dilution incubations and copepod addition incubations were performed during a cruise to the southern Yellow Sea on May 16-29,2007.The bulk grazing of microzooplankton and the calanoid copepod Cal anus sinicus on phytoplankton,flagellates and picoplankton was estimated.Stations were divided into either eutrophic or oligotrophic according to the nutrient and biological parameters.Picoplankton comprised a large part of the diet of microzooplankton in the central oligotrophic area,while phytoplankton was the main food of microzooplankton in the coastal eutrophic area.In the central oligotrophic area,microzooplankton preferred grazing on Synechococcus.After copepod addition,ciliate abundance decreased while Synechococcus abundance increased(382%,64%and 64%at three experimental stations,respectively),indicating strong grazing pressure of microzooplankton on Synechococcus.Our results suggest that Synechococcus might be an essential carbon source the planktonic food web in the oligotrophic waters of southern Yellow Sea.
基金funded by the National Natural Science Foundation of China(42176147)the Natural Science Foundation of Fujian Province of China(2021J01025)the National Key Research and Development Program of China(2018YFC1406306).
文摘Background:Previous studies have found that coastal eutrophication increases the influence of homogeneous selection on bacterial community assembly.However,whether seasonal changes affect the dominance of homogenous selection in bacterial community assembly in eutrophic bays remains unclear.Sansha Bay is an enclosed bay with ongoing eutrophication,located in the southeast coast of China.We investigated the bacterial community composition at two depths of the enclosed bay across seasons and the seasonal variation in community assembly processes.Results:Diversity analyses revealed that the bacterial community composition among seasons differed significantly.By contrast,there was little difference in the community composition between the two depths.The temperature was the key environmental factor influencing the community composition.The null model indicated that the relative importance of homogeneous selection decreased in the following order:spring>winter>autumn>summer.Homogeneous selection did not always dominate the community assembly among seasons in the eutrophic bay.The effects of pure spatial variables on the community assembly were prominent in autumn and winter.Conclusions:Our results showed the seasonal influence of eutrophication on bacterial community diversity.The seasonal variation in composition and structure of bacterial communities eclipsed the vertical variability.Eutrophication could enhance the importance of homogeneous selection in the assembly processes,but the seasonal environmental differences interfered with the steady-state maintained by ongoing eutrophication and changed the community assembly processes.Homogeneous selection was not always important in bacterial community in the eutrophic enclosed bay.The bacterial community was the most complex in summer,because the composition differed from other seasons,and the assembly process was the most intricate.These findings have contributed to understanding bacterial community composition and assembly processes in eutrophic coastal ecosystems.
