Chemical diversity of scleractinian corals revealed by untargeted metabolomics and molecular networking

The chemical diversity of scleractinian corals is closely related to their physiological,ecological,and evolutionary status,and can be influenced by both genetic background and environmental variables.To investigate intraspecific variation in the metabolites of these corals,the metabolomes of four species(Pocillopora meandrina,Seriatopora hystrix,Acropora formosa,and Fungia fungites)from the South China Sea were analyzed using untargeted mass spectrometry-based metabolomics.The results showed that a variety of metabolites,including amino acids,peptides,lipids,and other small molecules,were differentially distributed among the four species,leading to their significant separation in principal component analysis and hierarchical clustering plots.The higher content of storage lipids in branching corals(P.meandrina,S.hystrix,and A.formosa)compared to the solitary coral(F.fungites)may be due to the high densities of zooxanthellae in their tissues.The high content of aromatic amino acids in P.meandrina may help the coral protect against ultraviolet damage and promote growth in shallow seawater,while nitrogen-rich compounds may enable S.hystrix to survive in various challenging environments.The metabolites enriched in F.fungites,including amino acids,dipeptides,phospholipids,and other small molecules,may be related to the composition of the coral's mucus and its life-history,such as its ability to move freely and live solitarily.Studying the chemical diversity of scleractinian corals not only provides insight into their environmental adaptation,but also holds potential for the chemotaxonomy of corals and the discovery of novel bioactive natural products.

Diversity of symbiotic algae of the genus Symbiodinium in scleractinian corals of the Xisha Islands in the South China Sea

Symbiotic algae （Symbiodinium sp.） in scleractinian corals are important in understanding how coral reefs will respond to global climate change. The present paper reports on the diversity of Symbiodinium sp. in 48 scleractinian coral species from 25 genera and 10 families sampled from the Xisha Islands in the South China Sea, which were identified with the use of restriction fragment length polymorphism （RFLP） of the nuclear ribosomal DNA large subunit gene （rDNA）. The results showed that： （i） Symbiodinium Clade C was the dominant zooxanthellae in scleractinian corals in the Xisha Islands; （ii） Symbiodinium Clade D was found in the corals Montipora aequituberculata, Galaxea fascicularis, and Plerogyra sinuosa; and （iii） both Symbiodinium Clades C and D were found simultaneously in Montipora digitata, Psammocora contigua, and Galaxeafascicularis. A poor capacity for symbiosis polymorphism, as uncovered by RFLP, in the Xisha Islands indicates that the scleractinian corals have low adaptability to environmental changes. Further studies are needed to investigate zooxanthellae diversity using other molecular markers.

Triassic Scleractinian Corals in China：A Review of Present Knowledge

Scleractinian corals appeared during the Anisian period of the Triassic after the end-Permian mass extinction, which in Triassic were distinct from the Jurassic-Cretaceous scleractinian corals. The study on Triassic scleractinian coral fauna as a separate field is significant for exploring the development and evolution of modern corals and investigating environmental changes since the Mesozoic. The first Triassic coral in China was reported in 1925, and since then, nearly 25 articles dealing with taxonomy and 17 papers about fossil reports on Triassic scleractinian corals in China have been published, which refer to 60 genera and 312 species, 49 localities and 25 strata. In this paper, the history, taxonomy, localities, stratigraphic distribution, current research, and existing knowledge gaps of the Triassic scleractinian corals in China are reviewed. More specifically, the research findings of the Triassic scleractinain coral in China since 1925 are discussed; the species of the Triassic scleractian coral fossil reported in China, has been examined and its synonyms have been sorted out; the geographical distributions of the Middle and Late Triassic scleractinian corals in China are systematically treated; the Triassic coral biostratigraphy in China has been improved; and the stratigraphic ranges of existing genera and species are provided. The above conclusions are presented in the form of complete figures. At the same time, we analyzed shortcomings in current research and identified productive future research directions of the Triassic scleractinian corals in China.

Involvement of the ammonium assimilation mediated by glutamate dehydrogenase in response to heat stress in the scleractinian coral Pocillopora damicornis

Glutamate dehydrogenase(GDH)plays an important role in the ammonium assimilation and nitrogen metabolism by catalyzing the reversible oxidative deamination of L-glutamate toα-ketoglutarate.In the present study,the potential functions of GDH in response to heat stre ss were explored in the scleractinian coral Pocillopora damicornis(designated as PdGDH).The cDNA of PdGDH contained an open reading frame of 1611 bp encoding a polypeptide of 536 amino acids,which exhibited the highest sequence identity to GDH of Stylophora pistillata(96%identity),and the deduced PdGDH protein was predicted to contain one GdhA domain(from Val95 to Tyr525).The recombinant protein of PdGDH(rPdGDH)was expressed in Escherichia coli BL21(DE3)-Transetta,and its catalytic activity was measured under different temperatures,pH conditions and epigallocatechin-3-gallate(EGCG,a GDH inhibitor)concentrations.The purified rPdGDH only used reduced coenzyme nicotinamide adenine dinucleotide(NADH)as coenzyme,and its highe st activity was observed at 35℃and pH 7.5,re spectively.The rPdGDH activity was negatively correlated with the concentration of EGCG,and was inhibited by more than half(65%,P<0.05)at 10mol/L EGCG.No significant alteration of PdGDH mRNA expression was detected at 12 h after exposure to heat and ammonium(P>0.05).Furthermore,the activities of NADH-GDH in the scleractinian coral P.damicornis increased significantly at 12 h after the heat and ammonium stress,and the NADH-GDH activity in the heat stress group(32.66 U/mg,P<0.05)was significantly higher than that in the heat and ammonium stress group(11.26 U/mg).These results collectively suggested that PdGDH,as a homologue of glutamate dehydrogenase in the scleractinian coral P.damicornis,could respond to heat stress at the protein level,which would have ability to further promote ammonium assimilation to increase the heat acclimatization of the coral-Symbiodiniaceae symbiotic association.

Scleractinian coral communities of Hormuz Island in the PersianGulf

The abundance and health of scleractinian coral communities of Hormuz Island were investigated.For this purpose,we employed 20 m line intercept transects—12 in the intertidal zone and 15 subtidally to evaluate coral cover and community composition.The estimated dead coral coverage was 6.21%±0.81%,while live coral coverage was 16.93%±1.81%,considered as very poor.Totally,12 genera were recorded,of which Porites with 11.9%±1.4%live cover was the dominant,while Goniopora had the least cover(0.07%±0.08%).Based on Mann-Whitney U-test,live coral coverage,dead coral coverage,algal coverage,cover of other benthic organisms and abiotic components showed significant univariate differences between zones(p<0.05).The Spearman correlation test between the abundance of biotic and abiotic components indicated significant negative correlation of live coral and sand with zoantharian and significant positive correlation of algae and other benthic organisms with rubble.The reef health indices used for the corals indicated that,in general,the environmental conditions were not suitable,which could be attributed to both natural and anthropogenic factors,the most important of which was zoantharian’overgrowth on the scleractinian corals in this region.

A Rapid Assessment of Scleractinian and Non-Scleractinian Coral Growth Forms Along the Saudi Arabian Coast, Red Sea

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) followed 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 Al-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 Acroporid corals was greater in the southern region than in the northern 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(Northern region) and the second one comprised the middle and southern regions(Jeddah to Farassan Islands), and one outlier Rabigh.

三亚凤凰岛造礁石珊瑚迁移效果研究

造礁石珊瑚既是构成珊瑚礁生态系统中的关键功能生物,也是国家二级保护野生动物,其数量的快速衰退已引起了广泛关注,因此近年来我国对造礁石珊瑚以及珊瑚礁生态系统的保护正在逐步加强。海岸工程易对周边的珊瑚礁造成严重影响,实施保护性迁移是降低工程对造礁石珊瑚影响的重要手段。为研究海南热带海域造礁石珊瑚迁移方法以及迁移保护的效果,我们对三亚凤凰岛二期项目拆除工程影响海域内的造礁石珊瑚实施了保护性迁移及监测。迁移造礁石珊瑚个体共计16634株,包括鹿角珊瑚属、牡丹珊瑚属、滨珊瑚属等18属造礁石珊瑚种类。迁移个体分别迁移至鹿回头海域6210株与西岛海域10424株。迁移珊瑚采用了三种移植方法,分别为铆钉移植、小型移植礁体移植与直接摆放。在迁移至鹿回头和西岛两地8个月后,迁移珊瑚平均存活率均在80%以上,两地迁移珊瑚的总存活率为86.24%。调查的结果显示,铆钉移植的方法存活率最高,小型移植礁体和直接摆放的两种移植方法存活率稍低。迁移至西岛的珊瑚8个月平均生长了3.03cm,的增长率为23.31%,而鹿回头迁入的珊瑚平均生长了6.15cm,增长率为58.74%,高于迁移至西岛的珊瑚。迁移采用的三种移植方法的8个月的存活率均高于75%,并且珊瑚的生长速率较好,说明珊瑚适应迁入区环境。由以上结果来看,此次保护性迁移珊瑚数量多,涉及的珊瑚种类广,在迁移后经受过两次台风的影响,迁移结果具有一定的代表性。本研究中,珊瑚迁移的效果达到了保护受拆除工程影响的造礁石珊瑚的目的,可为未来的珊瑚迁移性保护提供重要经验。

厦门湾大佰屿、小佰屿海域石珊瑚物种多样性

为了解厦门湾内大佰屿、小佰屿附近海域石珊瑚的物种多样性,于2017、2021年在大佰屿、小佰屿附近海域设置了11个站位进行潜水调查,共获得196株珊瑚样本,其中石珊瑚样本17株。采用形态学方法对石珊瑚样本进行鉴定。结果显示,在大小佰屿海域共栖息有1科3属4种石珊瑚,分别为筒星珊瑚属的Tubastraea tagusensis及T.coccinea,枝沙珊瑚属的Cladopsammia gracilis,以及木珊瑚属待定种Dendrophyllia sp.,其中枝沙珊瑚C.gracilis是厦门湾海域的新纪录种。

Antagonism between coral pathogen Vibrio coralliilyticus and other bacteria in the gastric cavity of scleractinian coral Galaxea fascicularis

Scleractinian corals host numerous microbial symbionts with different types of interactions. The gastric cavity of scleractinian coral, as a semiclosed subenvironment with distinct chemical characteristics(e.g., dissolved O2, pH, alkalinity, and nutrients), harbors a distinct microbial community and a diverse array of bacteria that can be pathogenic or beneficial. Galaxea fascicularis is one of the dominant massive scleractinian coral species on inshore fringing reefs in the northern South China Sea.Although the abundance of coral-associated bacteria has been investigated in G. fascicularis, less is known about the microorganisms in the gastric cavity. In this study, we specially isolated cultivable bacterial strains from the gastric cavity of G.fascicularis collected from Hainan Island using a noninvasive sampling approach. Among the 101 representative bacterial strains, one Vibrio coralliilyticus strain, SCSIO 43001, was found to be a temperature-dependent opportunistic pathogen of G.fascicularis. The antagonistic activity between the 100 strains and V. coralliilyticus SCSIO 43001 was tested using a modified Burkholder diffusion assay. Our results showed that V. coralliilyticus SCSIO 43001 inhibits the growth of Erythrobacter flavus and Sphingomonas yabuuchiae. Additionally, we found that three Pseudoalteromonas strains showed moderate to high antibacterial activity against V. coralliilyticus SCSIO 43001 and several other coral-associated Gram-negative bacterial strains.These results suggest that competition between the coral pathogen and other bacteria also occurs in the gastric cavity of coral, and Pseudoalteromonas strains in the gastric cavity of G. fascicularis may provide a protective role in the defense against coinhabiting coral pathogens at elevated temperature.

南海北部珊瑚群落结构特征及其对海洋热浪事件的响应

全球变暖背景下,造礁石珊瑚大规模白化的频度和强度日益加大,其生存也面临严峻的危机。南海北部海域被认为是气候变暖背景下我国造礁石珊瑚生存的避难所。综合分析该海域珊瑚群落的空间格局、历史演变及其对夏季高温的响应,有利于深入认识我国造礁石珊瑚的适应性及相应的保护与养护。本研究于2020年夏季对大亚湾、涠洲岛、徐闻和三亚鹿回头的珊瑚礁/珊瑚群落开展了较为全面的生态调查,并追踪了2020年海洋热浪的效应。结果显示,珊瑚群落的优势种组成、物种数量和α多样性指数呈现明显的区域差异,活珊瑚覆盖度在三亚鹿回头和大亚湾相对更高(分别为37.78%和17.97%);珊瑚白化率和白化死亡率在徐闻海域最高(84.78%和10.68%),其次是涠洲岛海域(65.52%和0.70%),大亚湾和三亚鹿回头海域均未监测到珊瑚白化。结合历史数据分析表明,南海北部海域珊瑚群落的活珊瑚覆盖度自1980年代以来发生大幅度下降,但近年来趋于稳定并呈现出恢复的态势;珊瑚群落结构演变上整体呈现出热耐受型物种和热中度适应型物种占比增加(大亚湾除外)的趋势。总体而言,目前南海北部海域的珊瑚群落对海洋热浪具有一定的抵抗能力,加强珊瑚礁区的保护和管理对于促进珊瑚群落的恢复和热敏感珊瑚物种避难所潜力的发挥至关重要。

Twenty-five years of change in scleractinian coral communities of Daya Bay (northern South China Sea) and its response to the 2008 AD extreme cold climate event

世界范围的珊瑚礁石逐渐地正在变得并且有害地影响在之上由包括的许多因素，重要气候变化，例如全球温暖和增加的 El Nino 南部的摆动活动。通常，珊瑚礁石的坚持，在特别低纬度，部分地，海运被管理不超过集体死亡能在发生的批评限制(&#8764;30 ° C ) 的表面温度。因此，它被想珊瑚那生活在高纬度(即，当前更凉爽的海表面温度) 将多半比珊瑚生活在对假设未来温度增加更有利作出回应低纬度(即，当前更温暖的海表面温度) 。因而，高纬度的珊瑚社区可以有潜力在面临潜在的未来时为许多珊瑚种类充当 refugia 的区域全球温暖。Daya 海湾(22 ° 3 1 &#8242;22 ° 5 0 &#8242;N ) ，北华南海，包含几个高纬度的 non-reefal 珊瑚社区并且在这个区域以内代表 scleractinian 珊瑚的最在北方的分布之一。显著地， Daya 海湾经历了在整个过去的 50 年的在空和海表面温度中的戏剧的温暖。在这篇论文，我们在 Daya 海湾珊瑚社区分析 25 年变化，把两个基于历史性的调查并且我们的最近 2006 2008 地区性的生态的调查。我们的结果建议与预言相反，在过去的 25 年期间在在 Daya 海湾以内的珊瑚盖子有重要衰落(即，在到在 2008 的 15.3% 仅仅珊瑚盖子的 1983/1984 的 76.6% 珊瑚盖子) 。如此的变化也在最丰富的珊瑚种类反映重要移动，从 Acropora pruinosa 到 Favites abdita。大多数现代珊瑚社区变得以前在 15 和 30 年之间建立了，相应于增加的冬季海表面温度的一个时期。然而，很少的殖民地变得在最后 15 年以内建立了，尽管有温暖的一个更强烈的时期。由考虑另外的因素，我们假设那直接人为的影响，而非气候的事件，限制了发展，并且驾驶了衰落，最后 15 年里的 Daya 海湾珊瑚社区。Daya 海湾也在过去的 50 年期间受到了偶尔的极端冷事件，与最近的发生在 2008 年初(13 年 1 月 13 日 2 月) 。在 2008 冷事件期间，最低空气温度到达仅仅 6.6 ° C，和吝啬的海表面温度 2 月秋天，包括在 12.3 ° C 的六连续的天 【 14 ° C。显著地，海表面温度在通常在 scleractinian 珊瑚社区导致集体死亡的假设批评更低的温度阀值(&#8764;13 ° C ) 下面掉落。令人惊讶地，我们的珊瑚社区调查，以前进行了两个(2007 年 8 月) 并且在以后(2008 年 2 月下旬) 极端 2008 冷事件，证明 Daya 海湾珊瑚生态系统恰好被影响在之上在冷时期期间。那些观察建议 Daya 海湾 scleractinian 珊瑚社区开发了改编到低海表面温度。总的来说，我们的数据支持高纬度的珊瑚社区例如 Daya 海湾，有的假设在潜在的未来的来临为 scleractinian 珊瑚充当 refugia 的区域的潜力全球温暖。

Estimate of carbonate production by scleractinian corals at Luhuitou fringing reef,Sanya,China

Carbonate production by scleractinian corals not only maintains coral reef growth, but also represents an important source of atmospheric carbon dioxide. In this paper the carbonate production by scler-actinian corals at Luhuitou fringing reef, Sanya, Hainan Island, China, is investigated with an ecological census-based method. Averaged carbonate production is 1.16 ± 0.55 kg·m-2·a-1 and 3.52 ± 1.32 kg·m-2·a-1 on the reef flat and reef slope, respectively, depending on the composition and distribution of corals and the intergeneric difference of skeletal growth. In response to the rapidly increasing human impacts, coral carbonate production has decreased by 80%―89% at this fringing reef since the 1960s; as a result, the reef accretion rate declined and became lower than the rate of sea level rise. Further development of the Luhuitou fringing reef will switch significantly from lateral extension sea-wards to vertical growth, reflecting a response of coral reef biogeomorphic process to strong human impacts under the background of global sea level rise. In addition, decrease in coral carbonate production reduced CO2 release from this fringing reef. In the future, it is likely that the role played by coral reefs, especially of fringing reefs, in the ocean and even in the global carbon cycle will be modified or weakened by the increasing human impacts.

近40年来大亚湾造礁石珊瑚群落结构的演变分析

本研究采用文献调研、现场调查和室内模拟试验等方法对大亚湾造礁石珊瑚的种群结构演变及其成因进行了探讨。2020年7月现场调查共发现造礁石珊瑚39种,块状的扁脑(Platygyra)、蜂巢(Favia)和角蜂巢(Favites)等是湾内优势珊瑚。1983/1984-2020年,大亚湾珊瑚群落演变的主要特征是曾经优势的鹿角珊瑚(Acropora)和蔷薇珊瑚(Montipora)从湾内基本消失。综合全球珊瑚礁退化大背景和大亚湾独特的水环境分析发现:大亚湾珊瑚群落退化是多方面因素共同作用的结果,其中珊瑚本身的脆弱性和环境中持续的夏季异常高温与低溶解氧含量的共同作用可能是湾内霜鹿角珊瑚(A.pruinosa)退化的主要原因。从湾内珊瑚群落恢复的种源考量,建议加强对刷洲东岛珊瑚群落的保护。

福建东山石珊瑚伴生物种多样性

本文记录了福建东山锯齿刺星珊瑚（Ｃｙｐｈａｓｔｒｅａｓｅｒｒａｉｌｉａ）、标准菊花珊瑚（Ｆａｖｉａｓｐｅｃｉｏｓａ）和盾形陀螺珊瑚（Ｔｕｒｂｉｎａｒｉａｐｅｌｔａｔａ）等６种造礁石珊瑚。石珊瑚的立体生境中，栖息着埋栖、穴栖、缝栖、附着和游动等５种栖息习性的１５４种伴生物种。埋栖的连贵藤壶和穴栖的羽膜石蛏、珊瑚绒贻贝等是造礁石珊瑚伴生物种的表征。

海南岛西北部海域珊瑚礁造礁石珊瑚种类组成与分布

调查了海南岛西北部海域造礁石珊瑚种类的多样性及分布。结果表明:共发现50种造礁石珊瑚和1种多孔螅。海南岛西北部造礁石珊瑚优势种为澄黄滨珊瑚(Porites lutea)和丛生盔形珊瑚(Galaxea fascicularis),与历史资料相比优势种发生明显变化;海南岛西北部海域造礁石珊瑚覆盖率急剧下降,是由自然因素和人为活动共同造成;海南岛西北部海域是北部湾、琼州海峡和南海的重要交汇点,可能是造礁石珊瑚幼虫扩散的重要通道,对华南沿岸造礁石珊瑚资源自然恢复起到重要作用。因此,未来的海洋管理应该加强对珊瑚礁的保护力度,开发利用与环境保护并重,这样才能有效保护海南岛西北部海域的珊瑚礁。

珠江口万山群岛海域造礁石珊瑚群落分布与保护

通过2008年对珠江口万山群岛造礁石珊瑚群落结构和分布的调查研究,结合走访资料以及历史文献和数据的分析,对比了2005年佳蓬列岛造礁石珊瑚群落的调查结果,掌握了珠江口万山群岛造礁石珊瑚群落的现状,造礁石珊瑚覆盖率从以前的48.2%降低到20%以下。同时讨论了珠江口万山群岛造礁石珊瑚群落面临的生存威胁和亟待加强保护的迫切需要,提出保护和管理珠江口万山群岛造礁石珊瑚群落的建议,希望完善可持续的生态开发与和谐的生态保护的管理体系。

珊瑚共生虫黄藻密度的季节变化及其与珊瑚白化的关系--以大亚湾石珊瑚为例

定量分析了2006年6月、2007年8月和2008年2月采自南海北部大亚湾海域的共8科、13属、23种170个石珊瑚样品的共生虫黄藻密度,探讨了石珊瑚共生虫黄藻密度的季节变化及其与珊瑚白化的关系。结果显示,所有珊瑚种属的共生虫黄藻密度都显示出明显的季节性波动,总体上夏季低、冬季高(约为夏季的2倍),是海表水温和太阳辐射协同作用的结果。夏季大规模的珊瑚白化(热白化)可能是珊瑚共生虫黄藻密度逐渐降低(排出)到一定阈值的外观表征,而非突发的生态现象;冬季珊瑚白化(冷白化)则可能是极端低温直接致珊瑚死亡,进而快速排出虫黄藻的突发现象;高共生虫黄藻密度对冬季低温乃至极端低温条件下的珊瑚生存起到一定的保护作用。

广东大亚湾石珊瑚群落的分布及动态变化

2006年6月对位于南海北部亚热带的大亚湾和大鹏湾石珊瑚群落的分布、种类和覆盖率进行了调查,结果显示大亚湾共有石珊瑚24种,以秘密角蜂巢珊瑚(Favites abdita)为优势种,总覆盖率为20%,大鹏湾有石珊瑚21种,以精巧扁脑珊瑚(Platygyra daedalea)为优势种,总覆盖率为7.9%。大亚湾石珊瑚群落健康状况良好,但生长稀疏,群落密度低,空间结构简单,生长带窄;与1964年、1983年、1984年和1991年的调查结果相比,覆盖率从76.6%下降到20%,优势种从枝状的霜鹿角珊瑚(Acropora Pruinosa)转变成块状或皮壳状的秘密角蜂巢珊瑚,群落生态退化严重,主要原因可能是人为破坏活动对珊瑚本身以及生长环境造成的压力所致,包括过度捕捞、盗采珊瑚、沿岸施工和水体污染等,建议采取相应的保护措施。

深圳海域造礁石珊瑚分布特点与多样性

2015年7月,采用国际通用的截线样带法对大亚湾海域的造礁石珊瑚进行普查,并采用ShannonWeaver多样性指数(H')和均匀度指数(J)分析大亚湾海域造礁石珊瑚多样性情况,通过统计造礁石珊瑚覆盖率、死亡率、白化率和基底岩石、碎石、沙子覆盖率来分析大亚湾海域石珊瑚分布特点。结果表明:调查海域共记录54种珊瑚,调查海域主要优势种珊瑚以块状居多,主要为厚板页表孔珊瑚(Montipora incrassata)、团状滨珊瑚(Porites lobata)、隐形角菊珊瑚(Favites abdita)。统计分析数据表明:西涌海域所获珊瑚覆盖率(55%±3%)、多样性(3.039)都较高,但近期珊瑚白化率也较高(6%±2%);东山海域珊瑚覆盖率(13%±2%)、多样性(0.618)均最低。调查海域整体珊瑚覆盖度较高达到41.15%,最高覆盖率为55%,最低覆盖率仅为13%,覆盖度差异较大,近3年内珊瑚死亡率较高,建议加强大亚湾海域珊瑚生态系统的保护。

虫黄藻的分类和遗传多样性研究进展

综述了虫黄藻的分类研究,其中与造礁石珊瑚共生的虫黄藻主要是共生藻属(Symbiodinium)的种类,重点概述了共生藻的分类和遗传多样性研究进展,特别综述了分子生物学技术在造礁石珊瑚共生藻的分类和遗传多样性方面的研究近况,并对未来共生藻的分类和遗传多样性研究作了展望。目前多采用分子生物学手段进行共生藻的分类和遗传多样性研究,PCR-RFLP是解决共生藻系群水平分类的有效分子标记,而DNA序列分析是目前进行共生藻分子进化和系统发育研究最有效的方法。目前应用于共生藻分子系统发生研究的DNA信息主要为核糖体RNA。对共生藻进行分类和遗传多样性研究,将有助于理解造礁石珊瑚共生藻共生系统对外界环境变化的生态响应机制。