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1.
Homeward sound     
Despite spending weeks at sea as larvae, potentially scattered over many kilometers, young coral reef fish find suitable settlement habitat and in some cases return to their natal reefs. We report that some dominant families of larval reef fish use the sounds made by fish and shrimp resident on reefs to help them locate and settle on reefs and that some fish groups use specific components of the reef sound to guide their behavior. These findings could offer potential for active management of reef fisheries.  相似文献   

2.
To examine the problem of how far coral larvae disperse from their natal reef, coral recruitment densities were experimentally determined at distances up to 5 kilometers from a small, relatively isolated platform reef, Helix Reef, on the central Great Barrier Reef for 7 months. High concentrations of recruits, accounting for up to 40 percent of all recruitment, were found downstream of the reef in areas of high water residence time, suggesting that near-field(proximal) circulation has a profound influence on dispersal and recruitment of coral larvae. Coral recruitment declined logarithmically with distance from the reef, decreasing by an order of magnitude at radial distances of only 600 to 1200 meters. On an ecological time scale, advective dispersal of semipassive marine larvae with relatively short planktonic lives(minimally days) may be extensive, but success of recruitment is highly limited. Through evolutionary time, sufficient dispersal occurs to ensure gene flow to reef tracts hundreds or possibly thousands of kilometers apart. In the short term, however, coral reefs appear to be primarily self-seeded with respect to coral larvae.  相似文献   

3.
Coral reefs under rapid climate change and ocean acidification   总被引:13,自引:0,他引:13  
Atmospheric carbon dioxide concentration is expected to exceed 500 parts per million and global temperatures to rise by at least 2 degrees C by 2050 to 2100, values that significantly exceed those of at least the past 420,000 years during which most extant marine organisms evolved. Under conditions expected in the 21st century, global warming and ocean acidification will compromise carbonate accretion, with corals becoming increasingly rare on reef systems. The result will be less diverse reef communities and carbonate reef structures that fail to be maintained. Climate change also exacerbates local stresses from declining water quality and overexploitation of key species, driving reefs increasingly toward the tipping point for functional collapse. This review presents future scenarios for coral reefs that predict increasingly serious consequences for reef-associated fisheries, tourism, coastal protection, and people. As the International Year of the Reef 2008 begins, scaled-up management intervention and decisive action on global emissions are required if the loss of coral-dominated ecosystems is to be avoided.  相似文献   

4.
广东省澄海莱芜拟建礁区建礁可行性研究   总被引:3,自引:0,他引:3  
根据2003年5月广东省澄海菜芜拟建人工鱼礁区海域和对比区海域本底调查所获资料,从水文、水质、底质、生物环境等方面分析了在拟建礁区建礁的优越性。结果表明,莱芜拟建人工鱼礁区海域水深8.5-11.0m,海面波高小于1m,拟建礁区相对于对比I墨具有明显的建礁优越性:流速较平缓,投礁后礁体所受到的波流影响较小、稳定性较强;拟建礁区的海水透明度高于对比区,更适合营光合作用的浮游生物和礁体附着生物生长;各站位pH值的平面分布和垂直分布都比较均匀;海水质量基本达到国家二类海水水质标准;表层沉积物类型主要为细砂、粘土-砂质粉砂、粉砂质砂和粘土质粉砂,属于硬质底质泥沙底,可减缓礁体投放下沉时的冲击力,投礁后礁体稳定性较强;浮游植物、浮游动物和底栖生物的栖息密度和生物多样性均高于同期调查的对比区;拟建礁区游泳生物的栖息密度明显比对比区高;鱼卵仔鱼数量较多;拟建礁海域以前是良好的渔场,附近无工业废水排放。因此,在澄海菜芜拟建礁区建礁是可行的。  相似文献   

5.
The scale of larval dispersal of marine organisms is important for the design of networks of marine protected areas. We examined the fate of coral reef fish larvae produced at a small island reserve, using a mass-marking method based on maternal transmission of stable isotopes to offspring. Approximately 60% of settled juveniles were spawned at the island, for species with both short (<2 weeks) and long (>1 month) pelagic larval durations. If natal homing of larvae is a common life-history strategy, the appropriate spatial scales for the management and conservation of coral reefs are likely to be much smaller than previously assumed.  相似文献   

6.
The suppression of overwintering population is essential in integrated pest management, but little is known about the biological mortality factors that reduce the overwintering density of Chilo suppressalis. Here, we examine the parasitism of overwintering larvae, and assume that key parasitoids strengthen the over-wintering population suppression. The natural parasitism incidence and related dominant parasitoids in overwintering larvae were investigated in two successive winters, in 2015–2016 and 2016–2017. Parasitism rates were also assessed in larvae collected from 15 different counties in 2016. The results showed that the parasitism incidence and dominant parasitoids in overwintering C. suppressalis larvae were significantly different for different sampling dates and sites. Overwintering larvae of C. suppressalis were mainly parasitized by Cotesia chilonis, and less often by Eriborus sinicus and Microgaster russata. Regression analysis indicated that the natural incidence of parasites in overwintering C. suppressalis larvae was positively correlated with the over-wintering larval density. The current work provides support for overwintering pest management strategies by showing the effectiveness of parasitoid communities as a bio-mortality factor for suppressing overwintering density.  相似文献   

7.
Regional-scale assembly rules and biodiversity of coral reefs   总被引:2,自引:0,他引:2  
Tropical reef fishes and corals exhibit highly predictable patterns of taxonomic composition across the Indian and Pacific Oceans. Despite steep longitudinal and latitudinal gradients in total species richness, the composition of these key taxa is constrained within a remarkably narrow range of values. Regional-scale variation in reef biodiversity is best explained by large-scale patterns in the availability of shallow-water habitat. Once habitat area is accounted for, there is surprisingly little residual effect of latitude or longitude. Low-diversity regions are most vulnerable to human impacts such as global warming, underscoring the urgent need for integrated management at multinational scales.  相似文献   

8.
The type of larval development in echinoids (Phylum Echinodermata) was found to determine crystal patterns in adult apical skeletal plates. This relation between larvae and adults will allow fossil species to be examined to determine the effects of developmental mode on evolutionary patterns, such as species longevity and speciation rate. Independent tests of hypotheses of such patterns now shown among fossil mollusks with and without feeding larvae can thus be performed.  相似文献   

9.
本文基于Ansys Fluent平台,采用湍流模型中的大涡模拟方法(large eddy simulation, LES)对双层十字翼型人工鱼礁四种子礁的流场效应进行了数值模拟,采用比混凝土体积法分析其背涡流体积、上升流体积、向上水体输运通量等流场效应数据,得到双层十字翼型鱼礁的最优礁体构造,以期为人工鱼礁的设计和选型提供科学依据。结果表明:双层十字翼型鱼礁加顶板对流场效应并无增益,上升流和背涡流相对体积变小;侧板结构对礁体的上升流和背涡流效应有明显的增益,上升流和背涡流相对体积逐渐变大,全侧板D型礁体的上升流和背涡流效应最强,上升流相对体积可达无侧板B型礁体的13.50~25.48倍,背涡流相对体积达1.40~1.61倍;向上水体输运通量约在一倍礁高处达到最大值,约在两倍礁高处降为最大值的1/2左右。迎流角度的改变,对D型礁体流场效应的影响无显著差异,表明本型礁体对自然海域的潮流流向有很好的适应性。  相似文献   

10.
Temperatures above those normally present in larval sites of certain mosquitoes (for example, Aedes stimulans) cause larvae of potential males to be feminized in all degrees. Certain combinations of temperatures will affect these larvae so that an abnormal pair of genital appendages consistently appears in addition to the usual pair. These appendages appear to be masculine and are presumed to come from imaginal discs that are latent in present-day Diptera.  相似文献   

11.
南海重要珊瑚礁过渡性水域软骨鱼类的组成与分布   总被引:4,自引:0,他引:4  
2004年5—7月和2005年3—4月采用深水三重刺网在南海的羚羊礁、华光礁、银砾滩、东岛、滨湄滩、排洪滩、本固暗沙、比微暗沙、武勇暗沙、海鸠暗沙、双子群礁、中业群礁、鲎藤礁、美济礁、仁爱礁、仙宾礁、南方浅滩、棕滩、大渊滩、永署礁、南薰礁、牛轭礁、道明群礁等23座重要珊瑚礁过渡性水域进行了2个航次专业调查,其中有21座岛礁共渔获到7目15科33种408尾软骨鱼类,而美济礁和南方浅滩没有渔获到软骨鱼类。根据调查资料,通过物种各分类阶元的分布、优势度(IRI)和单位努力量渔获量等几个方面分析南海重要珊瑚礁过渡性水域软骨鱼类的组成与分布,旨在为南海珊瑚礁渔业资源的开发和管理提供科学依据。结果表明,西沙群岛的重量单位努力量渔获量范围为73~499kg/10^4m^2,其优势种类是迈氏条尾虹、灰六鳃鲨和黑梢真鲨;中沙群岛的重量单位努力量渔获量范围为114~245kg/10^4m^2,其优势种类是迈氏条尾虹、灰三齿鲨;南沙群岛除了美济礁和南方浅滩外其重量单位努力量渔获量范围为51~846kg/10^4m^2,其优势种类是黑梢真鲨、灰三齿鲨。  相似文献   

12.
礁体沉降作为人工鱼礁投放后普遍产生的现象,对人工鱼礁周围流场会产生影响。为研究多孔方型人工鱼礁不同沉降情况下流场效应的变化,采用计算流体动力学(Computational fluid dynamics,CFD)技术,利用Fluent软件模拟在固定来流流速为0.8 m/s时,5种不同沉降程度下单体鱼礁周围的流场情况。结果显示:与无沉降时(初始状态)相比,在沉降程度为20%时,上升流最大高度降低约1.0 m,最大上升流流速增大约0.015 m/s,侧向流速增大区域(大于来流速度)扩大至1.5倍左右,同时礁体背流面透水区域增大,背涡流区域沿水流方向移动约2 m,礁体周围流场情况一定程度上变得更加复杂;在沉降程度为40%时,上升流流速最大值与初始状态相比减少约为0.010 m/s,侧向流增大区域基本一致,此时礁体背流面透水区变化较大,有形成一个逆时针涡旋的趋势;当沉降程度达到60%时,礁体周围流场效应开始明显下降,上升流最大高度相较于初始状态降低约3.2 m,上升流最大流速降低约0.600 m/s,侧向流速增大区域与壁面间距缩短约0.4 m,背涡流区域有消失的迹象;在沉降程度达到80%时,礁体流场效应基本丧失。研究表明,对于多孔方型人工鱼礁,在沉降程度40%以内,人工鱼礁仍然能够发挥着较好的流场效应;礁体在沉降程度达到60%时,礁体周围流场复杂程度相较于初始状态有明显损失,之后随着沉降深度增加,礁体流场效应逐渐消失。  相似文献   

13.
2004年5—7月和2005年3—4月采用深水三重刺网在南海的羚羊礁、华光礁、银砾滩、东岛、滨湄滩、排洪滩、本固暗沙、比微暗沙、武勇暗沙、海鸠暗沙、双子群礁、中业群礁、鲎藤礁、美济礁、仁爱礁、仙宾礁、南方浅滩、棕滩、大渊滩、永署礁、南薰礁、牛轭礁、道明群礁等23座重要珊瑚礁过渡性水域进行了2个航次专业调查,其中有21座岛礁共渔获到7目15科33种408尾软骨鱼类,而美济礁和南方浅滩没有渔获到软骨鱼类。根据调查资料,通过物种各分类阶元的分布、优势度(IRI)和单位努力量渔获量等几个方面分析南海重要珊瑚礁过渡性水域软骨鱼类的组成与分布,旨在为南海珊瑚礁渔业资源的开发和管理提供科学依据。结果表明,西沙群岛的重量单位努力量渔获量范围为73~499kg/10^4m^2,其优势种类是迈氏条尾虹、灰六鳃鲨和黑梢真鲨;中沙群岛的重量单位努力量渔获量范围为114~245kg/10^4m^2,其优势种类是迈氏条尾虹、灰三齿鲨;南沙群岛除了美济礁和南方浅滩外其重量单位努力量渔获量范围为51~846kg/10^4m^2,其优势种类是黑梢真鲨、灰三齿鲨。  相似文献   

14.
Daily otolith increments were used to determine the daily pattern of settlement of the bluehead wrasse (Thalassoma bifasciatum), a Caribbean coral reef fish. Recruitment occurs in brief and sporadic episodes even though bluehead wrasses spawn every day. Patterns of recruitment do not correspond to patterns of mortality on the reef. The composition of the adult population directly reflects the relative rates of recruitment of juveniles the year before. The population dynamics of this species may therefore be determined by the supply of recruits and not by the supply of space or some other resource on the reef.  相似文献   

15.
[目的]研究家蚕Polycomb蛋白家族基因BmSu(z)12在家蚕幼虫中的表达情况.[方法]根据家蚕基因组预测的BmSu(z)12基因序列,设计特异引物,利用qRT-PCR对该基因在家蚕不同龄期幼虫中的表达进行研究.[结果]BmSu(z)12基因在5龄幼虫蜕皮后2d和变态前2d有较高表达,而在1~5龄取食中期表达量较低,表达特征具有一定的规律性.[结论]BmSu(z)12基因在家蚕幼虫生长发育中具有重要作用,该研究为进一步研究家蚕SU(Z)12蛋白的功能奠定基础.  相似文献   

16.
A bacterial pathogen of coralline algae was initially observed during June 1993 and now occurs in South Pacific reefs that span a geographic range of at least 6000 kilometers. The occurrence of the coralline algal pathogen at Great Astrolabe Reef sites (Fiji) increased from zero percent in 1992 to 100 percent in 1993, which indicates that the pathogen may be in an early stage of virulence and dispersal. Because of the important role played by coralline algae in reef building, this pathogen, designated coralline lethal orange disease (CLOD), has the potential to greatly influence coral reef ecology and reef-building processes.  相似文献   

17.
斜纹夜蛾种群空间动态   总被引:4,自引:0,他引:4  
利用频次分布法和分布型指数研究了斜纹夜蛾低中龄幼虫在菜芯Brassica parachinensis Bailey地内和种群空间分布图式,并研究了各龄幼虫在菜株上的垂直分布。结果表明:斜纹夜蛾 龄幼虫在菜株上呈聚集颁上,频次分布拟事的结果大部分样本符合负二项分布,半产本符合奈曼分布,而不符合泊松分布,频次分布拟事的结果大部样本符合负二项分布,半数样本符合奈曼分布,而不符合泊松分布,幼虫在菜株上的分  相似文献   

18.
蜂王浆对雌性蜜蜂幼虫dynactin p62甲基化影响   总被引:1,自引:1,他引:0  
【目的】研究蜂王浆对雌性蜜蜂幼虫dynactin p62甲基化水平影响。【方法】以意大利蜜蜂(Apis mellifera ligustica)和中华蜜蜂(A. cerana cerana)1日龄幼虫为试验材料,分别饲喂意大利蜜蜂蜂王浆和中华蜜蜂蜂王浆,并提取每组3日龄和6日龄幼虫样品的基因组DNA,利用Sequenom MassARRAY技术检测dynactin p62甲基化水平。【结果】饲喂异种蜂王浆可以更显著降低雌性蜜蜂幼虫dynactin p62整体甲基化水平;饲喂同一种蜂王浆,均为6日龄幼虫dynactin p62整体甲基化水平显著低于3日龄;2种蜂王浆对雌性蜜蜂幼虫dynactin p62各位点甲基化水平影响不同。【结论】2种蜂王浆对雌性蜜蜂幼虫dynactin p62整体甲基化水平和各位点甲基化水平影响不同,这说明不同蜂王浆具有不同的生物学效应。  相似文献   

19.
航道整治工程对河流生态环境的影响分析   总被引:3,自引:1,他引:2  
内河航道整治工程一般包括疏浚工程、炸礁工程、护岸工程、桥梁拆除及跨过河管线改建工程、航标工程、配套设施工程及环境保护工程。其中疏浚工程、炸礁工程等将会对河道内的水生生态造成一定的影响,通过分析施工期施工活动对浮游植物、浮游动物、底栖生物和渔业资源的影响,特别是关注工程炸礁对河流生态环境的影响,以及施工对珍稀水生生物的栖息地、洄游通道的影响分析,并按照预防、减轻、修复和补偿的顺序提出针对性地水生生态保护措施,以避免和减轻内河航道整治工程对河流生态环境的影响,为其他内河航道整治工程的环境保护工作提供一些经验。  相似文献   

20.
本文采用扩散系数C,Morisita扩散指标I_δ,聚集度指标I,Cassie指标Ca,Lloyd聚块性指标L和Iwao平均拥挤度X与平均数X回归分析法,测定了日本龟蜡蚧越冬雌成虫和1龄固定若虫的空间分布型属于聚集分布,同时探讨了其在确定最适抽样数及序贯抽样中的应用。  相似文献   

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