The utilization of discarded coral debris in cementitious material is a prominent research area for island construction projects.The aim of this study is to explore the use of environment-friendly cement and waste cor...The utilization of discarded coral debris in cementitious material is a prominent research area for island construction projects.The aim of this study is to explore the use of environment-friendly cement and waste coral sand in the preparation of coral mortar,while investigating its performance when exposed to a chloride environment.Three types of low-carbon cements were employed,such as rapid hardening sulphoaluminate(RCSA)cement,high belite sulphoaluminate(HBCSA)cement,and slag sulphoaluminate cement(SSC).The coulomb electric flux,mechanical properties,free chloride content,and mass change of the cement mortar under exposed to 3.5 wt%NaCl solution were examined at various time intervals.X-ray diffraction analysis was conducted to identify the mineral phases present in the mortar samples.The results demonstrate that the flexural and compressive strength of the mortar consistently increase throughout the 360 days chloride exposure period.Incorporating coral sand into SSC-based mortars enhances their compressive strength from day 28 up until day 360.However,it adversely affects the strength of HBCSA-based mortars.The behavior of mortars exposed to a chloride-rich environment is closely associated with the amount of C-S-H gel present within them.SSC generates a significant quantity of C-S-H gel which possesses a large specific surface area capable of absorbing more chloride ions thereby reducing their concentration within the mortar matrix as well as increasing its mass and improving resistance against chloride ion penetration.展开更多
Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of re...Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.展开更多
Chase the Dream of Coral is an inspiring book that shines a light on the brave scientists dedicated to saving our coral reefs.Coral reefs are often called the rainforests of the sea because they support a vast number ...Chase the Dream of Coral is an inspiring book that shines a light on the brave scientists dedicated to saving our coral reefs.Coral reefs are often called the rainforests of the sea because they support a vast number of marine species.However,they are facing serious threats from climate change,pollution and overfishing.This book highlights the urgent need to protect these beautiful and vital ecosystems.展开更多
The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology,utilizing Microbially Induced Carbonate Precipitation(MICP)to consolidate a specific volume of coral sand...The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology,utilizing Microbially Induced Carbonate Precipitation(MICP)to consolidate a specific volume of coral sand within the foundation into piles with defined strength,thereby enabling them to collaboratively bear external loads with the surrounding unconsolidated coral sand.In this study,a series of shaking table model tests were conducted to explore the dynamic response of the biocemented coral sand pile composite foundation under varying seismic wave types and peak accelerations.The surface macroscopic phenomena,excess pore water pressure ratio,acceleration response,and vertical settlement were measured and analysed in detail.Test results show that seismic wave types play a decisive role in the macroscopic surface phenomena and the response of the excess pore water pressure ratio.The cumulative settlement of the upper structure under the action of Taft waves was about 1.5 times that of El Centro waves and Kobe waves.The most pronounced liquefaction phenomena were recorded under the Taft wave,followed by the El Centro wave,and subsequently the Kobe wave.An observed positive correlation was established between the liquefaction phenomenon and the Aristotelian in-tensity of the seismic waves.However,variations in seismic wave types exerted minimal influence on the ac-celeration amplification factor of the coral sand foundation.Analysis of the acceleration amplification factor revealed a triphasic pattern-initially increasing,subsequently decreasing,and finally increasing again-as burial depth increased,in relation to the peak value of the input acceleration.This study confirms that the biocemented coral sand pile composite foundation can effectively enhance the liquefaction resistance of coral sand foundations..展开更多
As the main geomaterials for coral reefs oil or gas extraction and underground infrastructure construction,coral reef limestone demonstrates significantly distinct mechanical responses compared to terrigenous rocks.To...As the main geomaterials for coral reefs oil or gas extraction and underground infrastructure construction,coral reef limestone demonstrates significantly distinct mechanical responses compared to terrigenous rocks.To investigate the mechanical behaviour of coral reef limestone under the coupling impact of size and strain rate,the uniaxial compression tests were conducted on reef limestone samples with length-to-diameter(L/D)ratio ranging from 0.5 to 2.0 at strain rate ranging from 10^(−5)·s^(−1)to 10^(−2)·s^(−1).It is revealed that the uniaxial compressive strength(UCS)and residual compressive strength(RCS)of coral reef limestone exhibits a decreasing trend with L/D ratio increasing.The dynamic increase factor(DIF)of UCS is linearly correlated with the logarithm of strain rate,while increasing the L/D ratio further enhances the DIF.The elastic modulus increases with strain rate or L/D ratio increasing,whereas the Poisson’s ratio approximates to a constant value of 0.24.The failure strain increases with strain rate increasing or L/D ratio decreasing,while the increase in L/D ratio will inhibit the enhancing effect of the strain rate.The high porosity and low mineral strength are the primary factors contributing to a high RCS of 16.7%–64.9%of UCS,a lower brittleness index and multiple irregular fracture planes.The failure pattern of coral reef limestone transits from the shear-dominated to the splitting-dominated failure with strain rate increasing or L/D ratio decreasing,which is mainly governed by the constrained zones induced by end friction and the strain rate-dependent crack propagation.Moreover,a predictive formula incorporating coupling effect of size and strain rate for the UCS of reef limestone was established and verified to effectively capture the trend of UCS.展开更多
Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological s...Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological structures,the underlying micro-behaviors involving time-dependent deformation are poorly understood.For this,an abnormal phenomenon was observed where the axial and lateral creep deformations were mutually independent by a series of triaxial tests under constant stress and strain rate conditions.The significantly large lateral creep deformation implies that the creep process cannot be described in continuum mechanics regime.Herein,it is hypothesized that sliding mechanism of crystal cleavages dominates the lateral creep deformation in coral reef limestone.Then,approaches of polarizing microscope(PM)and scanning electronic microscope(SEM)are utilized to validate the hypothesis.It shows that the sliding behavior of crystal cleavages combats with conventional creep micro-mechanisms at certain condition.The former is sensitive to time and strain rate,and is merely activated in the creep regime.展开更多
Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experime...Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experimental testing,digital core technology,and theoretical modelling.Two CRL types with contrasting mesostructures were characterized across three scales.Macroscopically,CRL-I and CRL-II exhibited mean compressive strengths of 8.46 and 5.17 MPa,respectively.Mesoscopically,CRL-I featured small-scale highly interconnected pores,whilst CRL-II developed larger stratified pores with diminished connectivity.Microscopically,both CRL matrices demonstrated remarkable similarity in mineral composition and mechanical properties.A novel voxel average-based digital core scaling methodology was developed to facilitate numerical simulation of cross-scale damage processes,revealing network-progressive failure in CRL-I versus directional-brittle failure in CRL-II.Furthermore,a damage statistical constitutive model based on digital core technology and mesoscopic homogenisation theory established quantitative relationships between microelement strength distribution and macroscopic mechanical behavior.These findings illuminate the fundamental mechanisms through which mesoscopic structure governs the macroscopic mechanical properties of CRL.展开更多
Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef Natio...Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef National Nature Reserve,in Leizhou Peninsula,Zhanjiang,China.Sediment samples were taken in seven locations at 5-cm intervals from the surface to a depth of 30 cm.The vertical distribution of microplastic particles ranged from 0 to 1340 particles per kg on average of 119.05particles per kg.The most prevalent material was fibers(76%),followed by film(12%),fragments(11.2%),and foam(0.8%).The microplastics in size of 1-2 mm constituted the largest percentage(40%)of the total,followed by those in size of<1 mm(26.4%),2-3 mm(21.2%),3-4 mm(9.6%),and 4-5 mm(2.81%).Site S1 observed maximum sizes between 1 and 2 mm,S2 reported higher availability of microplastics with sizes ranging from 0.3 to 1 mm.Six different types of polymers were identified in the investigation,and mostly were polyethylene(PE)and polypropylene(PP).In general,the observation of microplastics in deeper sediments indicates that they have the ability to last for prolonged periods in the marine environment,which may present long-term hazards to benthic creatures.In conclusion,the discovery of microplastics in deep layers of coastal sediments highlights the necessity of minimizing plastic waste and enhancing management strategies to safeguard marine environments.展开更多
The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining season...The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining seasonal fluctuations in coral-associated Symbiodiniaceae communities.In this study,we investigated the seasonal dynamics of Symbiodiniaceae communities associated with coral species in the Luhuitou coral reef using high-throughput sequencing techniques and SymPortal analytical framework.The results indicated that the genus Cladocopium exhibited dominance(averaging 82%),followed by Durusdinium(18%)and Breviolum(0.01%)within the examined coral species.Among the 521 Symbiodiniaceae ITS2 sequence types,C15 emerged as the prevalent type(13.24%),trailed by C3u(9.51%)and D1(8.57%).Interestingly,Symbiodiniaceae communities varied among different coral species.Pocillopora damicornis displayed a predominant association with Durusdinium,while Porites lutea,Goniastrea retiformis,Montipora truncata,Montipora aequituberculata,and Acropora divaricata were entirely dominated by the genus Cladocopium(100%),showcasing distinct host specificity.In the cases of Hydnophora exesa,Acropora latistella,Acropora digitifera,and seawater,both Cladocopium and Durusdinium were concurrently detected.Moreover,the diversity of Symbiodiniaceae associated with P.damicornis,P.lutea,G.retiformis,M.truncata,M.aequituberculata,and A.digitifera exhibited significant variations across different seasons.Notably,the results revealed that the alterations in Symbiodiniaceae community compositions were primarily driven by nutrient concentrations and seawater temperature.The network analysis of Symbiodiniaceae revealed the dominant Symbiodiniaceae types C15,C17f,C3u,C3,and D4 were exclusive.This study provided the seasonal variation characteristics of Symbiodiniaceae communities among different coral species,which may be a potential adaptive mechanism to environmental conditions.展开更多
Acute respiratory distress syndrome(ARDS)is a common respiratory emergency,but current clinical treatment remains at the level of symptomatic support and there is a lack of effective targeted treatment measures.Our pr...Acute respiratory distress syndrome(ARDS)is a common respiratory emergency,but current clinical treatment remains at the level of symptomatic support and there is a lack of effective targeted treatment measures.Our previous study confirmed that inhalation of hydrogen gas can reduce the acute lung injury of ARDS,but the application of hydrogen has flammable and explosive safety concerns.Drinking hydrogen-rich liquid or inhaling hydrogen gas has been shown to play an important role in scavenging reactive oxygen species and maintaining mitochondrial quality control balance,thus improving ARDS in patients and animal models.Coral calcium hydrogenation(CCH)is a new solid molecular hydrogen carrier prepared from coral calcium(CC).Whether and how CCH affects acute lung injury in ARDS remains unstudied.In this study,we observed the therapeutic effect of CCH on lipopolysaccharide(LPS)induced acute lung injury in ARDS mice.The survival rate of mice treated with CCH and hydrogen inhalation was found to be comparable,demonstrating a significant improvement compared to the untreated ARDS model group.CCH treatment significantly reduced pulmonary hemorrhage and edema,and improved pulmonary function and local microcirculation in ARDS mice.CCH promoted mitochondrial peripheral division in the early course of ARDS by activating mitochondrial thioredoxin 2(Trx2),improved lung mitochondrial dysfunction induced by LPS,and reduced oxidative stress damage.The results indicate that CCH is a highly efficient hydrogen-rich agent that can attenuate acute lung injury of ARDS by improving the mitochondrial function through Trx2 activation.展开更多
Objective To investigate the chemical constituents and biological activities of soft coral Lemnalia sp.from the South China Sea.Methods The chemical constituents were isolated and purified by various chromatographic t...Objective To investigate the chemical constituents and biological activities of soft coral Lemnalia sp.from the South China Sea.Methods The chemical constituents were isolated and purified by various chromatographic techniques.The structures of all compounds were elucidated by using the modern spectrum analysis methods and comparison with the literature data.The antibacterial,immunosuppressive,and enzyme inhibitory activities of these compounds were evaluated.Results A new cembranoid diterpene,lemnaliaterpenoid A(1),and three known compounds,sinulaparvalide A(2),dihydrosinuflexolide(3),and capillolide(4)were isolated from the soft coral Lemnalia sp..Compound 1 showed antibacterial activity against Staphylococcus aureus and Escherichia coli with minimal inhibitory concentration(MIC)values of 16,16μg/mL,respectively.Compounds 1−3 displayed immunosuppressive activity against ConA-induced T cell(Jurkat cell)proliferation with inhibitory rates of 64.0%,67.8%,and 49.4%,respectively,at a concentration of 5μg/mL.Compounds 1−4 did not demonstrate enzyme inhibitory activity against the aldose reductase.Conclusion Four diterpenoid compounds were isolated from the soft coral Lemnalia sp.derived from the South China Sea,including one new cembranoid diterpene.Among them,the new compound 1 exhibitsed antibacterial and cytotoxic activities.The soft coral Lemnalia sp.from the South China Sea were prolific resources that produced structurally novel and biologically active secondary metabolites.展开更多
To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundati...To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.展开更多
The environments of tropical and subtropical coral reef regions(CRR)differ from each other;however,it is not known if these environmental differences influence coral polyp and skeleton microbiome composition.In this s...The environments of tropical and subtropical coral reef regions(CRR)differ from each other;however,it is not known if these environmental differences influence coral polyp and skeleton microbiome composition.In this study,Coelastrea palauensis corals were collected from tropical and subtropical CRR in the South China Sea,and bacterial,archaeal,and fungal communities in polyps and skeletons were analyzed.Results showed that the microbial diversity and composition of C.palauensis significantly differed between the polyps and skeletons,and between the tropical and subtropical CRR.Regarding bacteria associated with corals,C.palauensis was mainly associated with bacteria closely related to the nitrogen cycle in the subtropical CRR.The relative abundances of Terasakiellaceae and Chlorobium in both coral polyps and skeletons in the subtropical CRR were higher than those in the tropical CRR.In the tropical CRR,C.palauensis was mainly associated with opportunistic pathogenic bacteria.The relative abundances of Tenacibaculum and Vibrio in coral polyps and skeletons in the tropical CRR were higher than those in the subtropical CRR.Regarding archaea associated with corals,polyps and skeletons of C.palauensis in both tropical and subtropical reef areas were dominated by n_Woesearchaeales,and the relative abundance of n_Woesearchaeales in skeletons is significantly higher than that in polyps.In addition,the relative abundances of n_Woesearchaeales in polyps and skeletons in the subtropical CRR were significantly higher than those in the tropical CRR.Regarding fungi associated with corals,Ascomycota was dominant in polyps and skeletons in the subtropical CRR,while Sordariomycetes,Periconia,Cladosporium,and Aspergillus were dominant in polyps and skeletons in the tropical CRR.Besides,the diversity differences of coral-associated microorganisms were related to environmental factors such as nutrients and temperature that may affect the survival of coral-associated microorganisms.These results implied that corals may adjust the composition of microorganisms,conducive the coral holobiont to better adapting the environment.Our research will be beneficial in understanding the differences and adaptations of coral polyp and skeletal microbiome.展开更多
Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit...Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit plant growth and development,and reduce species richness comparing to tropical continental islands with mesophytic habitats(Li et al.,2024;Ren et al.,2017;Tu et al.,2022,2024).Coupled with global climate changes,these adverse conditions have been being exacerbated,leading to extensive degradation of ecosystems throughout the tropical coral islands(Li et al.,2021).Native insular plant resources provide enormous potentials in island greening and ecological restoration,since they have colonized and become well adapted to the specialized habitat on tropical coral islands,evolving a series of functional traits and molecular strategies to accommodate the abiotic stresses.Thus,understanding the genomic make-up of these plants will help uncover molecular mechanisms underlying adaptation to tropical coral islands.However,contrary to the numerous genomic studies done for other extreme habitats,such as deserts(Hu et al.,2021;Ma et al.,2013),alpine regions(Zhang et al.,2023),intertidal habitats(Feng et al.,2021;Hu et al.,2020;Natarajan et al.,2021),and karst caves(Feng et al.,2020),molecular adaptation of plants on the tropical coral islands remains to be elucidated.展开更多
Reef limestone is buried in the continental shelf and marine environment.Understanding the mechanisms governing filter cake formation in coral reef limestone strata is essential for various engineering activities in c...Reef limestone is buried in the continental shelf and marine environment.Understanding the mechanisms governing filter cake formation in coral reef limestone strata is essential for various engineering activities in coastal areas,including slurry pressure balanced(SPB)shield tunneling,which are currently not well understood.This study systematically investigates the slurry infiltration characteristics of different coral reef limestone types with inherent anisotropy,identified by growth line orientations,through a series of micro-infiltration column tests.Multiple slurry concentrations and pressures were used to analyze their effects on slurry infiltration dynamics and filter cake formation.Pre-and post-infiltration CT scanning was conducted to examine skeletal morphology and reconstruct the pore network structure of coral reef limestone samples.The results show that while increased slurry concentrations and pressures generally improve filter cake formation,excessive pressure can compromise filter cake integrity.By employing Dijkstra’s algorithm in a pore network model,the study identified primary seepage pathways,highlighting the significant role of near-vertical throat clusters in the infiltration process.A comprehensive analysis of pore structure and connectivity indices before and after infiltration revealed that the orientation of growth lines in coral reef limestone is the primary factor influencing macroscopic slurry infiltration behavior.These findings offer valuable insights for the design and execution of tunneling projects through coral reef limestone formations,especially in coastal regions.展开更多
Coralline soils,specialized materials found extensively in the South China Sea,are playing an increasingly vital role in engineering projects.However,like most terrigenous soils,fine-grained coral soil is prone to shr...Coralline soils,specialized materials found extensively in the South China Sea,are playing an increasingly vital role in engineering projects.However,like most terrigenous soils,fine-grained coral soil is prone to shrinkage and cracking,which can significantly affect its engineering properties and ultimately jeopardize engineering safety.This paper presents a desiccation cracking test of fine-grained coral soil,with a particular focus on the thickness effect.The study involved measuring the water content and recording the evolution of desiccation cracking.Advanced image processing technology is employed to analyze the variations in crack parameters,clod parameters,fractal dimensions,frequency distributions,and desiccation cracking propagation velocities of fine-grained coral soil.Furthermore,the dynamic evolution of desiccation cracking under the influence of layer thickness is analyzed.A comprehensive crack evolution model is proposed,encompassing both top-down and bottom-up crack propagation,as well as internal tensile cracking.This work introduces novel metrics for the propagation velocity of the total crack area,the characteristic propagation velocities of desiccation cracks,and the acceleration of crack propagation.Through data fitting,theoretical formulas for soil water evaporation,propagation velocities of desiccation cracks,and crack propagation acceleration are derived,laying a foundation for future soil cracking theories.展开更多
Coral gardening has become a promising technique for restoring reefs worldwide in the Anthropocene era.The microbiome plays an important role in enhancing adaptive resilience in situ nursery propagation of corals.Howe...Coral gardening has become a promising technique for restoring reefs worldwide in the Anthropocene era.The microbiome plays an important role in enhancing adaptive resilience in situ nursery propagation of corals.However,little is known about the response patterns of bacterial community dynamics,co-occurrence networks and assembly processes of different species in coral restoration nurseries over time.Here,we collected two Acropora coral samples from transplanted fragments and source colonies at 1-month and 3-month post-transplantation(May and July 2022)in an upwelling-affected fragmented reef.Full-length 16S rRNA gene sequencing revealed that bacterial communities of coral fragments in nurseries exhibited consistent temporal shifts compared to those of the source colonies.High host specificity was observed in the bacterial community and network structure associated with source colonies.In contrast,for the two coral species within nurseries,there were no differences in bacterial diversity,composition and core microbiome.Stochastic assembly processes were identified as the primary drivers of bacterial communities in all May samples,whereas deterministic processes played a more prominent role in July.Seawater properties(e.g.,temperature and ammonium concentration)partially explained the compositional changes in the bacterial communities of these coral samples.Our findings suggested that coral nurseries contributed to the homogenization of bacterial communities in different Acropora corals,despite the apparent temporal dynamics of bacteria.These results enhance our understanding of the coral microbiome,ecological interactions and assembly principles in different host within in situ nurseries.展开更多
The world’s coral reefs are threatened by the cumulative impacts of global climate change and local stressors.Driven largely by a desire to understand the interactions between corals and their symbiotic microorganism...The world’s coral reefs are threatened by the cumulative impacts of global climate change and local stressors.Driven largely by a desire to understand the interactions between corals and their symbiotic microorganisms,and to use this knowledge to eventually improve coral health,interest in coral microbiology and the coral microbiome has increased in recent years.In this review,we summarize the role of the coral microbiome in maintaining a healthy metaorganism by providing nutrients,support for growth and development,protection against pathogens,and mitigation of environmental stressors.We explore the concept of coral microbiome engineering,that is,precise and controlled manipulation of the coral microbiome to aid and enhance coral resilience and tolerance in the changing oceans.Although coral microbiome engineering is clearly in its infancy,several recent breakthroughs indicate that such engineering is an effective tool for restoration and preservation of these valuable ecosystems.To assist with identifying future research targets,we have reviewed the common principles of microbiome engineering and its applications in improving human health and agricultural productivity,drawing parallels to where coral microbiome engineering can advance in the not-too-distant future.Finally,we end by discussing the challenges faced by researchers and practitioners in the application of microbiome engineering in coral reefs and provide recommendations for future work.展开更多
Thermal stress causes the overproduction and toxic accumulation of reactive oxygen species(ROS),which seems to be correlated with coral bleaching and,ultimately,death.The reduction of ROS concentration within the cora...Thermal stress causes the overproduction and toxic accumulation of reactive oxygen species(ROS),which seems to be correlated with coral bleaching and,ultimately,death.The reduction of ROS concentration within the coral holobiont could minimize the effects of thermal stress and support efforts to reduce coral decline globally.In the current study,we explored the physiological responses of Pocillopora damicornis to ROS-scavenging bacteria inoculation as well as the microbiome restructuring that correlates with P.damicornis’s resilience to thermal stress after probiotic inoculation.Inoculation of corals with ROS-scavenging bacteria enhanced coral health and reduced ROS concentration.Furthermore,the enhanced coral thermal resistance promoted by ROS-scavenging bacteria was also correlated with an overall coral microbiome restructuring.In addition,the complex network relationships between bacteria and Symbiodiniaceae in corals after ROS-scavenging bacteria inoculation contributed to corals’resilience to high temperatures.Besides,coral heat tolerance bacterial biomarkers,such as Myxococcota,were enriched in corals with added ROS-scavenging bacteria.Collectively,our findings validate the selected ROS-scavenging bacteria as coral probiotics that could help corals resist thermal stress on a short timescale.Additionally,our data contribute to our understanding of the potential interactions between different members of the coral holobiont and the use of probiotics as tools to aid coral restoration efforts.展开更多
In this study we assessed the current status of coral reefs along the Saudi Arabian coast of the Red Sea. Among the three growth forms of Acroporid corals, the branching forms were found to dominate in the Farassan Is...In this study we assessed the current status of coral reefs along the Saudi Arabian coast of the Red Sea. Among the three growth forms of Acroporid corals, the branching forms were found to dominate in the Farassan Islands （44.55%±11.10% cover） fol-lowed by tabular forms in the Doga Islands （ranging between 18%±6.47% and 18.30%±9.47% cover）. Digitate forms were rarely found along the coast except at Maqna. Among the five growth forms of non-Acroporid corals, we observed maximum cover of branching forms in the Yanbu offshore area （58.89%±15.11% cover） followed by the Jeddah coast （24.76%±14.04% cover）. The Millepora spp., a non-Scleractinian coral, was abundant at all the near-shore sites, such as Jeddah （10.70%±8.21%） and A1-Wajh （9.81%±6.69%）. The live coral cover （including both Scleractinian and non-Scleractinian corals） of Saudi Red Sea coast was seen to be higher in the north and gradually decrease towards the south. Principal Component analysis showed that the contribution of Acro- porid corals was greater in the southern region than in the northem and middle regions, but vice-versa in the case of non-Acroporid corals. Bray-Curtis cluster analysis categorized all the study sites into two major clusters with 60% similarity. Among them, one cluster-forming sites from Maqna to Masturah （Northem region） and the second one comprised the middle and southem regions （Jeddah to Farassan Islands）, and one outlier Rabigh.展开更多
基金Funded by the National Natural Science Foundation of China(No.51708290)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘The utilization of discarded coral debris in cementitious material is a prominent research area for island construction projects.The aim of this study is to explore the use of environment-friendly cement and waste coral sand in the preparation of coral mortar,while investigating its performance when exposed to a chloride environment.Three types of low-carbon cements were employed,such as rapid hardening sulphoaluminate(RCSA)cement,high belite sulphoaluminate(HBCSA)cement,and slag sulphoaluminate cement(SSC).The coulomb electric flux,mechanical properties,free chloride content,and mass change of the cement mortar under exposed to 3.5 wt%NaCl solution were examined at various time intervals.X-ray diffraction analysis was conducted to identify the mineral phases present in the mortar samples.The results demonstrate that the flexural and compressive strength of the mortar consistently increase throughout the 360 days chloride exposure period.Incorporating coral sand into SSC-based mortars enhances their compressive strength from day 28 up until day 360.However,it adversely affects the strength of HBCSA-based mortars.The behavior of mortars exposed to a chloride-rich environment is closely associated with the amount of C-S-H gel present within them.SSC generates a significant quantity of C-S-H gel which possesses a large specific surface area capable of absorbing more chloride ions thereby reducing their concentration within the mortar matrix as well as increasing its mass and improving resistance against chloride ion penetration.
基金Funded by Natural Science Foundation of Guangxi(No.2025GXNSFBA069565)Guangxi Science and Technology Program(No.AD25069101)Guangxi Bagui Scholars Fund。
文摘Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.
文摘Chase the Dream of Coral is an inspiring book that shines a light on the brave scientists dedicated to saving our coral reefs.Coral reefs are often called the rainforests of the sea because they support a vast number of marine species.However,they are facing serious threats from climate change,pollution and overfishing.This book highlights the urgent need to protect these beautiful and vital ecosystems.
基金supported by the National Natural Science Foundation of China(No.51978103,No.52308340,No.52408355)the Postdoctoral Fellowship Program of CPSF(No.BX20240450)Chongqing Talent Innovation and Entrepreneurship Demonstration Team Project(No.cstc2024ycjh-bgzxm0012).
文摘The biocemented coral sand pile composite foundation represents an innovative foundation improvement technology,utilizing Microbially Induced Carbonate Precipitation(MICP)to consolidate a specific volume of coral sand within the foundation into piles with defined strength,thereby enabling them to collaboratively bear external loads with the surrounding unconsolidated coral sand.In this study,a series of shaking table model tests were conducted to explore the dynamic response of the biocemented coral sand pile composite foundation under varying seismic wave types and peak accelerations.The surface macroscopic phenomena,excess pore water pressure ratio,acceleration response,and vertical settlement were measured and analysed in detail.Test results show that seismic wave types play a decisive role in the macroscopic surface phenomena and the response of the excess pore water pressure ratio.The cumulative settlement of the upper structure under the action of Taft waves was about 1.5 times that of El Centro waves and Kobe waves.The most pronounced liquefaction phenomena were recorded under the Taft wave,followed by the El Centro wave,and subsequently the Kobe wave.An observed positive correlation was established between the liquefaction phenomenon and the Aristotelian in-tensity of the seismic waves.However,variations in seismic wave types exerted minimal influence on the ac-celeration amplification factor of the coral sand foundation.Analysis of the acceleration amplification factor revealed a triphasic pattern-initially increasing,subsequently decreasing,and finally increasing again-as burial depth increased,in relation to the peak value of the input acceleration.This study confirms that the biocemented coral sand pile composite foundation can effectively enhance the liquefaction resistance of coral sand foundations..
基金supported by the National Natural Science Foundation of China(Nos.52222110,52401354,and 52301353).
文摘As the main geomaterials for coral reefs oil or gas extraction and underground infrastructure construction,coral reef limestone demonstrates significantly distinct mechanical responses compared to terrigenous rocks.To investigate the mechanical behaviour of coral reef limestone under the coupling impact of size and strain rate,the uniaxial compression tests were conducted on reef limestone samples with length-to-diameter(L/D)ratio ranging from 0.5 to 2.0 at strain rate ranging from 10^(−5)·s^(−1)to 10^(−2)·s^(−1).It is revealed that the uniaxial compressive strength(UCS)and residual compressive strength(RCS)of coral reef limestone exhibits a decreasing trend with L/D ratio increasing.The dynamic increase factor(DIF)of UCS is linearly correlated with the logarithm of strain rate,while increasing the L/D ratio further enhances the DIF.The elastic modulus increases with strain rate or L/D ratio increasing,whereas the Poisson’s ratio approximates to a constant value of 0.24.The failure strain increases with strain rate increasing or L/D ratio decreasing,while the increase in L/D ratio will inhibit the enhancing effect of the strain rate.The high porosity and low mineral strength are the primary factors contributing to a high RCS of 16.7%–64.9%of UCS,a lower brittleness index and multiple irregular fracture planes.The failure pattern of coral reef limestone transits from the shear-dominated to the splitting-dominated failure with strain rate increasing or L/D ratio decreasing,which is mainly governed by the constrained zones induced by end friction and the strain rate-dependent crack propagation.Moreover,a predictive formula incorporating coupling effect of size and strain rate for the UCS of reef limestone was established and verified to effectively capture the trend of UCS.
基金supported by the National Natural Science Foundation of China(Grant Nos.41877267,41877260)the Priority Research Program of the Chinese Academy of Science(Grant No.XDA13010201).
文摘Catastrophic failure in engineering structures of island reefs would occur when the tertiary creep initiates in coral reef limestone with a transition from short-to long-term load.Due to the complexity of biological structures,the underlying micro-behaviors involving time-dependent deformation are poorly understood.For this,an abnormal phenomenon was observed where the axial and lateral creep deformations were mutually independent by a series of triaxial tests under constant stress and strain rate conditions.The significantly large lateral creep deformation implies that the creep process cannot be described in continuum mechanics regime.Herein,it is hypothesized that sliding mechanism of crystal cleavages dominates the lateral creep deformation in coral reef limestone.Then,approaches of polarizing microscope(PM)and scanning electronic microscope(SEM)are utilized to validate the hypothesis.It shows that the sliding behavior of crystal cleavages combats with conventional creep micro-mechanisms at certain condition.The former is sensitive to time and strain rate,and is merely activated in the creep regime.
基金National Key Research and Development Program of China (No.2021YFC3100800)the National Natural Science Foundation of China (Nos.42407235 and 42271026)+1 种基金the Project of Sanya Yazhou Bay Science and Technology City (No.SCKJ-JYRC-2023-54)supported by the Hefei advanced computing center
文摘Coral reef limestone(CRL)constitutes a distinctive marine carbonate formation with complex mechanical properties.This study investigates the multiscale damage and fracture mechanisms of CRL through integrated experimental testing,digital core technology,and theoretical modelling.Two CRL types with contrasting mesostructures were characterized across three scales.Macroscopically,CRL-I and CRL-II exhibited mean compressive strengths of 8.46 and 5.17 MPa,respectively.Mesoscopically,CRL-I featured small-scale highly interconnected pores,whilst CRL-II developed larger stratified pores with diminished connectivity.Microscopically,both CRL matrices demonstrated remarkable similarity in mineral composition and mechanical properties.A novel voxel average-based digital core scaling methodology was developed to facilitate numerical simulation of cross-scale damage processes,revealing network-progressive failure in CRL-I versus directional-brittle failure in CRL-II.Furthermore,a damage statistical constitutive model based on digital core technology and mesoscopic homogenisation theory established quantitative relationships between microelement strength distribution and macroscopic mechanical behavior.These findings illuminate the fundamental mechanisms through which mesoscopic structure governs the macroscopic mechanical properties of CRL.
基金Supported by the Southern Marine Science and Engineering Guangdong Laboratory、Zhanjiang(No.ZJW-2019-08)APN、CRRP2019-09MYOnodera、Shinichi Onodera、and the SCS Scholar Grant(No.002029002008/2019)。
文摘Plastic pollution and microplastics in sediments are a growing concern for marine ecosystems worldwide.We examined the vertical distribution and properties of microplastics in beach sediments of Xuwen Coral Reef National Nature Reserve,in Leizhou Peninsula,Zhanjiang,China.Sediment samples were taken in seven locations at 5-cm intervals from the surface to a depth of 30 cm.The vertical distribution of microplastic particles ranged from 0 to 1340 particles per kg on average of 119.05particles per kg.The most prevalent material was fibers(76%),followed by film(12%),fragments(11.2%),and foam(0.8%).The microplastics in size of 1-2 mm constituted the largest percentage(40%)of the total,followed by those in size of<1 mm(26.4%),2-3 mm(21.2%),3-4 mm(9.6%),and 4-5 mm(2.81%).Site S1 observed maximum sizes between 1 and 2 mm,S2 reported higher availability of microplastics with sizes ranging from 0.3 to 1 mm.Six different types of polymers were identified in the investigation,and mostly were polyethylene(PE)and polypropylene(PP).In general,the observation of microplastics in deeper sediments indicates that they have the ability to last for prolonged periods in the marine environment,which may present long-term hazards to benthic creatures.In conclusion,the discovery of microplastics in deep layers of coastal sediments highlights the necessity of minimizing plastic waste and enhancing management strategies to safeguard marine environments.
文摘The symbiotic association between reef-building corals and Symbiodiniaceae is pivotal for coral reef ecosystems,yet remains susceptible to environmental factors.Currently,there is a dearth of research examining seasonal fluctuations in coral-associated Symbiodiniaceae communities.In this study,we investigated the seasonal dynamics of Symbiodiniaceae communities associated with coral species in the Luhuitou coral reef using high-throughput sequencing techniques and SymPortal analytical framework.The results indicated that the genus Cladocopium exhibited dominance(averaging 82%),followed by Durusdinium(18%)and Breviolum(0.01%)within the examined coral species.Among the 521 Symbiodiniaceae ITS2 sequence types,C15 emerged as the prevalent type(13.24%),trailed by C3u(9.51%)and D1(8.57%).Interestingly,Symbiodiniaceae communities varied among different coral species.Pocillopora damicornis displayed a predominant association with Durusdinium,while Porites lutea,Goniastrea retiformis,Montipora truncata,Montipora aequituberculata,and Acropora divaricata were entirely dominated by the genus Cladocopium(100%),showcasing distinct host specificity.In the cases of Hydnophora exesa,Acropora latistella,Acropora digitifera,and seawater,both Cladocopium and Durusdinium were concurrently detected.Moreover,the diversity of Symbiodiniaceae associated with P.damicornis,P.lutea,G.retiformis,M.truncata,M.aequituberculata,and A.digitifera exhibited significant variations across different seasons.Notably,the results revealed that the alterations in Symbiodiniaceae community compositions were primarily driven by nutrient concentrations and seawater temperature.The network analysis of Symbiodiniaceae revealed the dominant Symbiodiniaceae types C15,C17f,C3u,C3,and D4 were exclusive.This study provided the seasonal variation characteristics of Symbiodiniaceae communities among different coral species,which may be a potential adaptive mechanism to environmental conditions.
基金supported by the Nanjing Medical Science and Technology Development Project,China(Project No.:YKK23221)Open Project of Immune Cell Translational Research Center of Jiangning Hospital,Nanjing Medical University,China(Project No.:JNYYZXKY202216)+1 种基金General Project of Medical Education Collaborative Innovation Fund of Jiangsu University,China(Project No.:JDYY2023094)China Red Cross Foundation Medical Empowerment Charity Special Fund Project(Project No.:CRCF-YXFN-202302028).
文摘Acute respiratory distress syndrome(ARDS)is a common respiratory emergency,but current clinical treatment remains at the level of symptomatic support and there is a lack of effective targeted treatment measures.Our previous study confirmed that inhalation of hydrogen gas can reduce the acute lung injury of ARDS,but the application of hydrogen has flammable and explosive safety concerns.Drinking hydrogen-rich liquid or inhaling hydrogen gas has been shown to play an important role in scavenging reactive oxygen species and maintaining mitochondrial quality control balance,thus improving ARDS in patients and animal models.Coral calcium hydrogenation(CCH)is a new solid molecular hydrogen carrier prepared from coral calcium(CC).Whether and how CCH affects acute lung injury in ARDS remains unstudied.In this study,we observed the therapeutic effect of CCH on lipopolysaccharide(LPS)induced acute lung injury in ARDS mice.The survival rate of mice treated with CCH and hydrogen inhalation was found to be comparable,demonstrating a significant improvement compared to the untreated ARDS model group.CCH treatment significantly reduced pulmonary hemorrhage and edema,and improved pulmonary function and local microcirculation in ARDS mice.CCH promoted mitochondrial peripheral division in the early course of ARDS by activating mitochondrial thioredoxin 2(Trx2),improved lung mitochondrial dysfunction induced by LPS,and reduced oxidative stress damage.The results indicate that CCH is a highly efficient hydrogen-rich agent that can attenuate acute lung injury of ARDS by improving the mitochondrial function through Trx2 activation.
文摘Objective To investigate the chemical constituents and biological activities of soft coral Lemnalia sp.from the South China Sea.Methods The chemical constituents were isolated and purified by various chromatographic techniques.The structures of all compounds were elucidated by using the modern spectrum analysis methods and comparison with the literature data.The antibacterial,immunosuppressive,and enzyme inhibitory activities of these compounds were evaluated.Results A new cembranoid diterpene,lemnaliaterpenoid A(1),and three known compounds,sinulaparvalide A(2),dihydrosinuflexolide(3),and capillolide(4)were isolated from the soft coral Lemnalia sp..Compound 1 showed antibacterial activity against Staphylococcus aureus and Escherichia coli with minimal inhibitory concentration(MIC)values of 16,16μg/mL,respectively.Compounds 1−3 displayed immunosuppressive activity against ConA-induced T cell(Jurkat cell)proliferation with inhibitory rates of 64.0%,67.8%,and 49.4%,respectively,at a concentration of 5μg/mL.Compounds 1−4 did not demonstrate enzyme inhibitory activity against the aldose reductase.Conclusion Four diterpenoid compounds were isolated from the soft coral Lemnalia sp.derived from the South China Sea,including one new cembranoid diterpene.Among them,the new compound 1 exhibitsed antibacterial and cytotoxic activities.The soft coral Lemnalia sp.from the South China Sea were prolific resources that produced structurally novel and biologically active secondary metabolites.
基金Projects(51878103,52208370)supported by the National Natural Science Foundation of ChinaProject(cstc2020jcyjcxtt X0003)supported by the Innovation Group Science Foundation of the Natural Science Foundation of Chongqing,ChinaProject(2022CDJQY-012)supported by the Fundamental Research Funds for the Central Universities,China。
文摘To understand the specific behaviors of coastal coral sand slope foundations,discrete element method(DEM)was employed to examine the effect of breakable particle corners on the performance of coral sand slope foundations under a strip footing,from macro to micro scales.The results demonstrate that the bearing characteristics of coral sand slope foundations can be successfully modeled by utilizing breakable corner particles in simulations.The dual effects of interlocking and breakage of corners well explained the specific shallower load transmission and narrower shear stress zones in breakable corner particle slopes.Additionally,the study revealed the significant influence of breakable corners on soil behaviors on slopes.Furthermore,progressive corner breakage within slip bands was successfully identified as the underling mechanism in determining the unique bearing characteristics and the distinct failure patterns of breakable corner particle slopes.This study provides a new perspective to clarify the behaviors of slope foundations composed of breakable corner particle materials.
基金The National Natural Science Foundation of China under contract Nos 42206157,42030502,and 42090041the Natural Science Foundation of Guangxi Province under contract No.2022GXNSFBA035449the Self-Topic Project of Guangxi Laboratory on the Study of Coral Reefs in the South China Sea under contract No.GXLSCRSCS2022103.
文摘The environments of tropical and subtropical coral reef regions(CRR)differ from each other;however,it is not known if these environmental differences influence coral polyp and skeleton microbiome composition.In this study,Coelastrea palauensis corals were collected from tropical and subtropical CRR in the South China Sea,and bacterial,archaeal,and fungal communities in polyps and skeletons were analyzed.Results showed that the microbial diversity and composition of C.palauensis significantly differed between the polyps and skeletons,and between the tropical and subtropical CRR.Regarding bacteria associated with corals,C.palauensis was mainly associated with bacteria closely related to the nitrogen cycle in the subtropical CRR.The relative abundances of Terasakiellaceae and Chlorobium in both coral polyps and skeletons in the subtropical CRR were higher than those in the tropical CRR.In the tropical CRR,C.palauensis was mainly associated with opportunistic pathogenic bacteria.The relative abundances of Tenacibaculum and Vibrio in coral polyps and skeletons in the tropical CRR were higher than those in the subtropical CRR.Regarding archaea associated with corals,polyps and skeletons of C.palauensis in both tropical and subtropical reef areas were dominated by n_Woesearchaeales,and the relative abundance of n_Woesearchaeales in skeletons is significantly higher than that in polyps.In addition,the relative abundances of n_Woesearchaeales in polyps and skeletons in the subtropical CRR were significantly higher than those in the tropical CRR.Regarding fungi associated with corals,Ascomycota was dominant in polyps and skeletons in the subtropical CRR,while Sordariomycetes,Periconia,Cladosporium,and Aspergillus were dominant in polyps and skeletons in the tropical CRR.Besides,the diversity differences of coral-associated microorganisms were related to environmental factors such as nutrients and temperature that may affect the survival of coral-associated microorganisms.These results implied that corals may adjust the composition of microorganisms,conducive the coral holobiont to better adapting the environment.Our research will be beneficial in understanding the differences and adaptations of coral polyp and skeletal microbiome.
基金supported by the National Natural Science Foundation of China(32170232,32070222,32271613)the National Key R&D Programof China(Key Special Project for Marine Environmental Security and Sustainable Development of Coral Reefs 2021-400)+1 种基金Guangdong Science and Technology Program(2024B1212050007)the National Key Research and Development Program of China(2021YFC3100405)。
文摘Tropical coral islands represent one of the extremely stressful ecosystems,characterized by high salinity,seasonal drought,heat,strong ultraviolet radiation,and infertile soil,which constraint species occurrence,limit plant growth and development,and reduce species richness comparing to tropical continental islands with mesophytic habitats(Li et al.,2024;Ren et al.,2017;Tu et al.,2022,2024).Coupled with global climate changes,these adverse conditions have been being exacerbated,leading to extensive degradation of ecosystems throughout the tropical coral islands(Li et al.,2021).Native insular plant resources provide enormous potentials in island greening and ecological restoration,since they have colonized and become well adapted to the specialized habitat on tropical coral islands,evolving a series of functional traits and molecular strategies to accommodate the abiotic stresses.Thus,understanding the genomic make-up of these plants will help uncover molecular mechanisms underlying adaptation to tropical coral islands.However,contrary to the numerous genomic studies done for other extreme habitats,such as deserts(Hu et al.,2021;Ma et al.,2013),alpine regions(Zhang et al.,2023),intertidal habitats(Feng et al.,2021;Hu et al.,2020;Natarajan et al.,2021),and karst caves(Feng et al.,2020),molecular adaptation of plants on the tropical coral islands remains to be elucidated.
文摘Reef limestone is buried in the continental shelf and marine environment.Understanding the mechanisms governing filter cake formation in coral reef limestone strata is essential for various engineering activities in coastal areas,including slurry pressure balanced(SPB)shield tunneling,which are currently not well understood.This study systematically investigates the slurry infiltration characteristics of different coral reef limestone types with inherent anisotropy,identified by growth line orientations,through a series of micro-infiltration column tests.Multiple slurry concentrations and pressures were used to analyze their effects on slurry infiltration dynamics and filter cake formation.Pre-and post-infiltration CT scanning was conducted to examine skeletal morphology and reconstruct the pore network structure of coral reef limestone samples.The results show that while increased slurry concentrations and pressures generally improve filter cake formation,excessive pressure can compromise filter cake integrity.By employing Dijkstra’s algorithm in a pore network model,the study identified primary seepage pathways,highlighting the significant role of near-vertical throat clusters in the infiltration process.A comprehensive analysis of pore structure and connectivity indices before and after infiltration revealed that the orientation of growth lines in coral reef limestone is the primary factor influencing macroscopic slurry infiltration behavior.These findings offer valuable insights for the design and execution of tunneling projects through coral reef limestone formations,especially in coastal regions.
基金supported by the Fundamental Research Funds for the Central Universities(Grant No.2022CDJQY-012)the Innovation Group Science Foundation of the Natural Science Foundation of Chongqing,China(Grant No.cstc2020jcyj-cxttX0003).
文摘Coralline soils,specialized materials found extensively in the South China Sea,are playing an increasingly vital role in engineering projects.However,like most terrigenous soils,fine-grained coral soil is prone to shrinkage and cracking,which can significantly affect its engineering properties and ultimately jeopardize engineering safety.This paper presents a desiccation cracking test of fine-grained coral soil,with a particular focus on the thickness effect.The study involved measuring the water content and recording the evolution of desiccation cracking.Advanced image processing technology is employed to analyze the variations in crack parameters,clod parameters,fractal dimensions,frequency distributions,and desiccation cracking propagation velocities of fine-grained coral soil.Furthermore,the dynamic evolution of desiccation cracking under the influence of layer thickness is analyzed.A comprehensive crack evolution model is proposed,encompassing both top-down and bottom-up crack propagation,as well as internal tensile cracking.This work introduces novel metrics for the propagation velocity of the total crack area,the characteristic propagation velocities of desiccation cracks,and the acceleration of crack propagation.Through data fitting,theoretical formulas for soil water evaporation,propagation velocities of desiccation cracks,and crack propagation acceleration are derived,laying a foundation for future soil cracking theories.
基金The Innovative Talent Foundation of Hainan Province under contract No.KJRC2023C39the National Natural Science Foundation of China under contract Nos 42161144006 and 42076108.
文摘Coral gardening has become a promising technique for restoring reefs worldwide in the Anthropocene era.The microbiome plays an important role in enhancing adaptive resilience in situ nursery propagation of corals.However,little is known about the response patterns of bacterial community dynamics,co-occurrence networks and assembly processes of different species in coral restoration nurseries over time.Here,we collected two Acropora coral samples from transplanted fragments and source colonies at 1-month and 3-month post-transplantation(May and July 2022)in an upwelling-affected fragmented reef.Full-length 16S rRNA gene sequencing revealed that bacterial communities of coral fragments in nurseries exhibited consistent temporal shifts compared to those of the source colonies.High host specificity was observed in the bacterial community and network structure associated with source colonies.In contrast,for the two coral species within nurseries,there were no differences in bacterial diversity,composition and core microbiome.Stochastic assembly processes were identified as the primary drivers of bacterial communities in all May samples,whereas deterministic processes played a more prominent role in July.Seawater properties(e.g.,temperature and ammonium concentration)partially explained the compositional changes in the bacterial communities of these coral samples.Our findings suggested that coral nurseries contributed to the homogenization of bacterial communities in different Acropora corals,despite the apparent temporal dynamics of bacteria.These results enhance our understanding of the coral microbiome,ecological interactions and assembly principles in different host within in situ nurseries.
基金supported by the National Natural Science Foundation of China(42122045,41890853,and 42106197)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(GML2019ZD0401 and GML2019ZD0402)Strategic Priority Research Program of Chinese Academy of Sciences(XDA13020300).
文摘The world’s coral reefs are threatened by the cumulative impacts of global climate change and local stressors.Driven largely by a desire to understand the interactions between corals and their symbiotic microorganisms,and to use this knowledge to eventually improve coral health,interest in coral microbiology and the coral microbiome has increased in recent years.In this review,we summarize the role of the coral microbiome in maintaining a healthy metaorganism by providing nutrients,support for growth and development,protection against pathogens,and mitigation of environmental stressors.We explore the concept of coral microbiome engineering,that is,precise and controlled manipulation of the coral microbiome to aid and enhance coral resilience and tolerance in the changing oceans.Although coral microbiome engineering is clearly in its infancy,several recent breakthroughs indicate that such engineering is an effective tool for restoration and preservation of these valuable ecosystems.To assist with identifying future research targets,we have reviewed the common principles of microbiome engineering and its applications in improving human health and agricultural productivity,drawing parallels to where coral microbiome engineering can advance in the not-too-distant future.Finally,we end by discussing the challenges faced by researchers and practitioners in the application of microbiome engineering in coral reefs and provide recommendations for future work.
基金Supported by the National Key Research and Development Program of China(No.2022YFC3103602)the National Natural Science Foundation of China(No.41976147)+4 种基金the NSFC-Shandong Joint Fund(No.U 2106208)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0402)the National Key Research and Development Program of China(No.2018FY100105)the Innovation Academy of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences(No.ISEE2021ZD03)the Science and Technology Planning Project of Guangdong Province,China(No.2020B1212060058)。
文摘Thermal stress causes the overproduction and toxic accumulation of reactive oxygen species(ROS),which seems to be correlated with coral bleaching and,ultimately,death.The reduction of ROS concentration within the coral holobiont could minimize the effects of thermal stress and support efforts to reduce coral decline globally.In the current study,we explored the physiological responses of Pocillopora damicornis to ROS-scavenging bacteria inoculation as well as the microbiome restructuring that correlates with P.damicornis’s resilience to thermal stress after probiotic inoculation.Inoculation of corals with ROS-scavenging bacteria enhanced coral health and reduced ROS concentration.Furthermore,the enhanced coral thermal resistance promoted by ROS-scavenging bacteria was also correlated with an overall coral microbiome restructuring.In addition,the complex network relationships between bacteria and Symbiodiniaceae in corals after ROS-scavenging bacteria inoculation contributed to corals’resilience to high temperatures.Besides,coral heat tolerance bacterial biomarkers,such as Myxococcota,were enriched in corals with added ROS-scavenging bacteria.Collectively,our findings validate the selected ROS-scavenging bacteria as coral probiotics that could help corals resist thermal stress on a short timescale.Additionally,our data contribute to our understanding of the potential interactions between different members of the coral holobiont and the use of probiotics as tools to aid coral restoration efforts.
文摘In this study we assessed the current status of coral reefs along the Saudi Arabian coast of the Red Sea. Among the three growth forms of Acroporid corals, the branching forms were found to dominate in the Farassan Islands （44.55%±11.10% cover） fol-lowed by tabular forms in the Doga Islands （ranging between 18%±6.47% and 18.30%±9.47% cover）. Digitate forms were rarely found along the coast except at Maqna. Among the five growth forms of non-Acroporid corals, we observed maximum cover of branching forms in the Yanbu offshore area （58.89%±15.11% cover） followed by the Jeddah coast （24.76%±14.04% cover）. The Millepora spp., a non-Scleractinian coral, was abundant at all the near-shore sites, such as Jeddah （10.70%±8.21%） and A1-Wajh （9.81%±6.69%）. The live coral cover （including both Scleractinian and non-Scleractinian corals） of Saudi Red Sea coast was seen to be higher in the north and gradually decrease towards the south. Principal Component analysis showed that the contribution of Acro- porid corals was greater in the southern region than in the northem and middle regions, but vice-versa in the case of non-Acroporid corals. Bray-Curtis cluster analysis categorized all the study sites into two major clusters with 60% similarity. Among them, one cluster-forming sites from Maqna to Masturah （Northem region） and the second one comprised the middle and southem regions （Jeddah to Farassan Islands）, and one outlier Rabigh.
