Oyster reefs and their spatial patterns are deemed to change the local hydrodynamic condition and exert profound impacts on the grain size,concentration and transportation of suspended sediments.Meanwhile,high suspend...Oyster reefs and their spatial patterns are deemed to change the local hydrodynamic condition and exert profound impacts on the grain size,concentration and transportation of suspended sediments.Meanwhile,high suspended sediment concentration often results in excess mortality among oysters.Oyster reefs are rare and vital ecosystem in Liyashan national marine park,Jiangsu Coast,China.However,urgent conservation efforts should be made on account of the drastic reduction in reef areas.To investigate the sediment dynamics and the geomorphology,two tripod observation systems were deployed and UAV aerial surveys with elevation measurement using Real Time Kinematic(RTK)were also carried out.High mud content(60%)was found in the bed sediment at the reef ridge,causing much lower drag coefficient than other recorded values of living oyster reefs,indicating the death of oysters and the degradation of reefs in Liyashan.Ridgelines of the string reefs at 45°to the current direction and high suspended sediment concentration in the water body(50–370 mg/L)that exceeds the threshold(200 mg/L),which would affect nutrient uptake efficiency and further result in gill saturation,decrease of clearance rate and associated deposition,were probably crucial causes of the death of oysters.The findings are useful for restoring natural oyster reefs and designing artificial reefs for nature-based coastal defense.展开更多
Oyster reefs have an equivalent, complex 3-dimensional structure to vegetated habitats and may provide similar functions in estuarine environments. Nevertheless, few studies have compared oyster reefs with adjacent na...Oyster reefs have an equivalent, complex 3-dimensional structure to vegetated habitats and may provide similar functions in estuarine environments. Nevertheless, few studies have compared oyster reefs with adjacent natural shallow-water habitats. Here the resident benthic macroinvertebrate communities in an artificial oyster （Crassostrea ariakensis） reef and in adjacent natural estuarine shallow-water habitats （salt marsh, intertidal mudflat, and subtidal soft bottom） in the Changjiang （Yangtze） River estuary were described. The mean total densities and biomass, Margalef＇s species richness, Pielou＇s evenness and Shannon-Weaver biodiversity indices of the resident benthic macroinvertebrate communities differed significantly among the habitats. Significantly higher densities and biomass of benthic macroinvertebrates occurred in the oyster reef compared with the other three habitats. Ordination plots showed a clear separation in benthic macroinvertebrate communities among the four habitat types. The results demonstrated that the artificial oyster reef supported distinct and unique benthic communities, playing an important role in the complex estuarine habitat by supplying prey resources and contributing to biodiversity. In addition, the results suggested that the oyster reef had been restored successfully.展开更多
With 85% of the global oyster reefs destroyed, there is an urgent need for large scale restoration to benefit from the ecosystem services provided by biogenic oyster reefs and their associated biodiversity, including ...With 85% of the global oyster reefs destroyed, there is an urgent need for large scale restoration to benefit from the ecosystem services provided by biogenic oyster reefs and their associated biodiversity, including microorganisms that drive marine biogeochemical cycles. This experiment established a baseline for the monitoring of the bacterial and archaeal community associated with wild oysters, using samples from their immediate environment of the Voordelta, with cohabiting Crassostrea gigas and Ostrea edulis, Duikplaats with only C. gigas attached to rocks, and the Dansk Skaldyrcentre, with no onsite oysters. The microbial profiling was carried out through DNA analysis of samples collected from the surfaces of oyster shells and their substrate, the sediment and seawater. Following 16S rRNA amplicon sequencing and bioinformatics, alpha indices implied high species abundance and diversity in sediment but low abundance in seawater. As expected, Proteobacteria, Bacteroidetes, Firmicutes and Thaumarchaeota dominated the top 20 OTUs. In the Voordelta, OTUs related to Colwellia, Shewanella and Psychrobium differentiated the oysters collected from a reef with those attached to rocks. Duikplaats were distinct for sulfur-oxidizers Sulfurimonas and sulfate-reducers from the Sva 0081 sediment group. Archaea were found mainly in sediments and the oyster associated microbiome, with greater abundance at the reef site, consisting mostly of Thaumarchaeota from the family Nitrosopumilaceae. The oyster free site displayed archaea in sediments only, and algal bloom indicator microorganisms from the Rhodobacteraceae, Flavobacteriaceae family and genus [Polaribacter] huanghezhanensis, in addition to the ascidian symbiotic partner, Synechococcus. This study suggests site specific microbiome shifts, influenced by the presence of oysters and the type of substrate.展开更多
牡蛎礁是蓝色碳汇的重要组成部分,其通过钙化作用、生物同化作用以及生物沉积作用等来完成对碳的封存,以达到碳中和的目的。目前我国关于热带天然牡蛎礁碳库储量的研究较少。文章评估了海南岛近岸4处典型天然牡蛎礁(文昌龙楼、文昌会文...牡蛎礁是蓝色碳汇的重要组成部分,其通过钙化作用、生物同化作用以及生物沉积作用等来完成对碳的封存,以达到碳中和的目的。目前我国关于热带天然牡蛎礁碳库储量的研究较少。文章评估了海南岛近岸4处典型天然牡蛎礁(文昌龙楼、文昌会文、昌江昌化和儋州海头)的碳库储量,并分析了其时空变化特征及其原因。结果表明,4处礁区的现存总碳库储量为18734.6 t C,长期总碳库储量为16883.08 t C。其中海头、昌化、龙楼和会文的现存碳库储量及单位面积平均碳库储量分别为15923.42 t C(3.46 kg C/m^(2))、2119.01 t C(6.09 kg C/m^(2))、494.53 t C(2.49 kg C/m^(2))和197.63 t C(3.67 kg C/m^(2)),长期碳库储量分别为14334.11、1898.99、460.08和189.91 t C。海头和昌化牡蛎礁单位面积碳库储量可能受到高温或低温的影响,在7月和12月出现下降趋势,而在水温适宜的10月和2月,牡蛎快速生长,同时导致单位面积碳库储量的上升,值得注意的是牡蛎的繁殖可能是10月份单位面积碳库储量上升的另一重要因素。2022年6~12月龙楼地区的牡蛎遗壳脱落导致牡蛎礁单位面积碳库储量连续下降,而2022年7月、10月和2023年2月会文地区牡蛎的死亡率升高,牡蛎活体壳和软体部分固碳量下降。研究表明,海南岛近岸天然牡蛎礁总体固碳效率较高,固碳潜力大,其碳储量受温度、海况及周边养殖活动的影响较大。研究同时发现上述区域仍面临人为干扰和系统退化的风险,亟需制订相关保护政策并开展有效的人工增殖,以保证其良好的固碳功能。展开更多
讨论了早全新世晚期以来渤海湾西岸贝壳堤平原成堤、西北岸牡蛎礁平原(及毗邻浅海区)建礁过程的同时性特征和气候变化与这一特征之间的关系,以及堤、礁记录的相对海面变化。堤、礁大致同时发育,可分为6期,依次分别被寒冷事件5、4、3、2...讨论了早全新世晚期以来渤海湾西岸贝壳堤平原成堤、西北岸牡蛎礁平原(及毗邻浅海区)建礁过程的同时性特征和气候变化与这一特征之间的关系,以及堤、礁记录的相对海面变化。堤、礁大致同时发育,可分为6期,依次分别被寒冷事件5、4、3、2和1分隔。堤底板前、后缘高差大致对应3m的大潮差、礁顶板大致对应海平面。据二者分别重建了南部贝壳堤平原、北部牡蛎礁平原的相对海面变化:南部自7ka cal BP以来基本与现代海平面等高,小的波动在±1m之间,压实固结作用抵消了中全新世的相对高海面;北部中全新世的相对海平面位置因新构造和固结压实双重下沉作用的影响,已位于现代海平面2～3m以下。展开更多
基金The National Natural Science Foundation of China under contract Nos 42076172,41676077 and 41530962。
文摘Oyster reefs and their spatial patterns are deemed to change the local hydrodynamic condition and exert profound impacts on the grain size,concentration and transportation of suspended sediments.Meanwhile,high suspended sediment concentration often results in excess mortality among oysters.Oyster reefs are rare and vital ecosystem in Liyashan national marine park,Jiangsu Coast,China.However,urgent conservation efforts should be made on account of the drastic reduction in reef areas.To investigate the sediment dynamics and the geomorphology,two tripod observation systems were deployed and UAV aerial surveys with elevation measurement using Real Time Kinematic(RTK)were also carried out.High mud content(60%)was found in the bed sediment at the reef ridge,causing much lower drag coefficient than other recorded values of living oyster reefs,indicating the death of oysters and the degradation of reefs in Liyashan.Ridgelines of the string reefs at 45°to the current direction and high suspended sediment concentration in the water body(50–370 mg/L)that exceeds the threshold(200 mg/L),which would affect nutrient uptake efficiency and further result in gill saturation,decrease of clearance rate and associated deposition,were probably crucial causes of the death of oysters.The findings are useful for restoring natural oyster reefs and designing artificial reefs for nature-based coastal defense.
基金Supported by the Special Fund of Chinese Central Government for Basic Scientific Research Operations in Commonweal Research Institutes(East China Sea Fisheries Research Institute)(No.2011M01)the National Natural Science Foundation of China(No.31170508)the National Basic Research Program of China(973 Program)(No.2010CB429005)
文摘Oyster reefs have an equivalent, complex 3-dimensional structure to vegetated habitats and may provide similar functions in estuarine environments. Nevertheless, few studies have compared oyster reefs with adjacent natural shallow-water habitats. Here the resident benthic macroinvertebrate communities in an artificial oyster （Crassostrea ariakensis） reef and in adjacent natural estuarine shallow-water habitats （salt marsh, intertidal mudflat, and subtidal soft bottom） in the Changjiang （Yangtze） River estuary were described. The mean total densities and biomass, Margalef＇s species richness, Pielou＇s evenness and Shannon-Weaver biodiversity indices of the resident benthic macroinvertebrate communities differed significantly among the habitats. Significantly higher densities and biomass of benthic macroinvertebrates occurred in the oyster reef compared with the other three habitats. Ordination plots showed a clear separation in benthic macroinvertebrate communities among the four habitat types. The results demonstrated that the artificial oyster reef supported distinct and unique benthic communities, playing an important role in the complex estuarine habitat by supplying prey resources and contributing to biodiversity. In addition, the results suggested that the oyster reef had been restored successfully.
文摘With 85% of the global oyster reefs destroyed, there is an urgent need for large scale restoration to benefit from the ecosystem services provided by biogenic oyster reefs and their associated biodiversity, including microorganisms that drive marine biogeochemical cycles. This experiment established a baseline for the monitoring of the bacterial and archaeal community associated with wild oysters, using samples from their immediate environment of the Voordelta, with cohabiting Crassostrea gigas and Ostrea edulis, Duikplaats with only C. gigas attached to rocks, and the Dansk Skaldyrcentre, with no onsite oysters. The microbial profiling was carried out through DNA analysis of samples collected from the surfaces of oyster shells and their substrate, the sediment and seawater. Following 16S rRNA amplicon sequencing and bioinformatics, alpha indices implied high species abundance and diversity in sediment but low abundance in seawater. As expected, Proteobacteria, Bacteroidetes, Firmicutes and Thaumarchaeota dominated the top 20 OTUs. In the Voordelta, OTUs related to Colwellia, Shewanella and Psychrobium differentiated the oysters collected from a reef with those attached to rocks. Duikplaats were distinct for sulfur-oxidizers Sulfurimonas and sulfate-reducers from the Sva 0081 sediment group. Archaea were found mainly in sediments and the oyster associated microbiome, with greater abundance at the reef site, consisting mostly of Thaumarchaeota from the family Nitrosopumilaceae. The oyster free site displayed archaea in sediments only, and algal bloom indicator microorganisms from the Rhodobacteraceae, Flavobacteriaceae family and genus [Polaribacter] huanghezhanensis, in addition to the ascidian symbiotic partner, Synechococcus. This study suggests site specific microbiome shifts, influenced by the presence of oysters and the type of substrate.
文摘牡蛎礁是蓝色碳汇的重要组成部分,其通过钙化作用、生物同化作用以及生物沉积作用等来完成对碳的封存,以达到碳中和的目的。目前我国关于热带天然牡蛎礁碳库储量的研究较少。文章评估了海南岛近岸4处典型天然牡蛎礁(文昌龙楼、文昌会文、昌江昌化和儋州海头)的碳库储量,并分析了其时空变化特征及其原因。结果表明,4处礁区的现存总碳库储量为18734.6 t C,长期总碳库储量为16883.08 t C。其中海头、昌化、龙楼和会文的现存碳库储量及单位面积平均碳库储量分别为15923.42 t C(3.46 kg C/m^(2))、2119.01 t C(6.09 kg C/m^(2))、494.53 t C(2.49 kg C/m^(2))和197.63 t C(3.67 kg C/m^(2)),长期碳库储量分别为14334.11、1898.99、460.08和189.91 t C。海头和昌化牡蛎礁单位面积碳库储量可能受到高温或低温的影响,在7月和12月出现下降趋势,而在水温适宜的10月和2月,牡蛎快速生长,同时导致单位面积碳库储量的上升,值得注意的是牡蛎的繁殖可能是10月份单位面积碳库储量上升的另一重要因素。2022年6~12月龙楼地区的牡蛎遗壳脱落导致牡蛎礁单位面积碳库储量连续下降,而2022年7月、10月和2023年2月会文地区牡蛎的死亡率升高,牡蛎活体壳和软体部分固碳量下降。研究表明,海南岛近岸天然牡蛎礁总体固碳效率较高,固碳潜力大,其碳储量受温度、海况及周边养殖活动的影响较大。研究同时发现上述区域仍面临人为干扰和系统退化的风险,亟需制订相关保护政策并开展有效的人工增殖,以保证其良好的固碳功能。
文摘讨论了早全新世晚期以来渤海湾西岸贝壳堤平原成堤、西北岸牡蛎礁平原(及毗邻浅海区)建礁过程的同时性特征和气候变化与这一特征之间的关系,以及堤、礁记录的相对海面变化。堤、礁大致同时发育,可分为6期,依次分别被寒冷事件5、4、3、2和1分隔。堤底板前、后缘高差大致对应3m的大潮差、礁顶板大致对应海平面。据二者分别重建了南部贝壳堤平原、北部牡蛎礁平原的相对海面变化:南部自7ka cal BP以来基本与现代海平面等高,小的波动在±1m之间,压实固结作用抵消了中全新世的相对高海面;北部中全新世的相对海平面位置因新构造和固结压实双重下沉作用的影响,已位于现代海平面2～3m以下。
