徐闻珊瑚礁礁栖无脊椎动物分布

采用均匀定点潜水观察和采集标本调查表明，徐闻珊瑚自然保护区除分布有40多种珊瑚外，尚分布有隶属于软体动物门、节肢动物门、棘皮动物门、环节动物门、腔肠动物门和海绵动物门的55科115种礁栖无脊椎动物，分布的方式主要有穴居、附着和固着等3种方式，部分种类在礁丛中索饵而隐蔽或躲避在礁缝隙中。     

珠海庙湾岛海域造礁石珊瑚的分布及种类多样性

【目的】对珠海庙湾岛海域进行造礁石珊瑚分布及种类多样性调查。【方法】采用石珊瑚群落边界摸查和截线样条法开展石珊瑚群落的面积分布及生态资源调查。【结果与结论】造礁石珊瑚分布区共有14个,分布面积共42.33 hm~2,分布区主要集中在庙湾岛滃崖礁东、下风湾、庙湾岛西中、水坑湾、钳虫尾湾及庙湾岛东南近岸海域;珠海庙湾岛海域共有造礁石珊瑚11科23属50种及2个未定种,优势种为澄黄滨珊瑚、翼形蔷薇珊瑚和秘密角蜂巢珊瑚;庙湾岛活造礁石珊瑚覆盖率显著下降,珊瑚礁资源退化严重,其中水坑湾降幅达43.56%,下风湾及钳虫尾湾珊瑚覆盖率降低20%～30%。     

广西二叠纪生物礁的特征和分布规律

广西二叠纪生物礁（丘）非常发育，自栖霞期至长兴期均有分布，以茅口期最繁盛。生物礁主要发育于具陡斜坡的孤立浅水台地边缘，包括堤礁、马蹄形礁、环礁、链状礁和块状礁。逅礁生物以钙质海绵为主，另有水熄、管壳石、苔藓虫及红藻等。包覆粘结生物以古石孔藻、层纹状蓝绿藻为主，附礁生物为底栖生物和藻类。礁岩类型以复合型为主，包括包覆骨架岩、粘结骨架岩、包覆障积粘结岩、包覆粘结岩等。生物丘则主要产在碳酸盐缓坡、孤立台地缓斜坡及台凹环境，包括珊瑚丘、海绵丘、荷叶藻丘、生物屑藻灰泥丘和藻泥丘，常与陆棚相深灰色泥岩、生物屑粒泥岩、泥粒岩及风暴岩构成旋回组合。生物礁、丘的分布受古特提斯海的扩张和同沉积断裂所控制。     

隆林中泥盆统发现礁相地层

笔者从一九八一至一九八三年在隆林地区进行地层及古生物工作期间,发现该地区的者艾、德峨、蛇场、榜纳、隆或、马窑等背斜构造群中均出露有层孔虫礁相地层。本区礁岩中由60%以上原地生长的块状—丘状层孔虫与一些块状、饼状、枝状板珊瑚、苔藓虫、四射珊瑚等共同组成礁的骨架。还常见一些喜礁生物腕足类、棘皮类。礁岩中充填着不少生物碎屑(包括棘屑、层孔虫屑、珊瑚屑等)与泥晶、亮晶胶结物和藻粘结岩一起构成抗浪构造。     

红藻石和蓝藻石概念及分类归属的综述和修订

在分析和总结前人对红藻石和蓝藻石研究成果基础上,结合岩石薄片显微镜下观察实例,发现在以往碳酸盐岩颗粒分类中没有红藻石和蓝藻石的合适位置.鉴于红藻石重要的成因意义和造礁作用,有必要明确红藻石的概念和归属.珊瑚藻本身极易钙化,经生物矿化作用最终保存下来的珊瑚藻屑一直放在生物碎屑中,而红藻石是由非固着的珊瑚藻构成的钙质独立结...     

广西来宾早石炭世叠层石藻礁

广西早石炭世生物礁研究甚少,仅有方少仙、侯方浩(1986)曾报道过田林浪平珊瑚—苔藓虫礁,而来宾叠层石藻礁的发现为早石炭世生物礁增添了新的内容。本文通过对叠层石的形态、礁岩组合及沉积序列的描述,探讨成礁环境,认为来宾叠层石礁属于发育在台缘缓斜坡上的丘礁群;并说明叠层石仅局限于潮坪和潮下浅水环境。     

塔西南阿尔塔什剖面下石炭统和什拉甫组生物礁地质特征

生物礁研究对沉积环境与油气勘探具有重要意义,但目前对于塔西南石炭系生物礁研究相对较少。深入解析了塔西南阿尔塔什剖面早石炭世维宪期中-晚期和什拉甫组生物礁地质特征,并在此基础上深入探讨了塔西南早石炭世沉积环境以及该生物礁在全球早石炭世生物礁演化中的意义。结果表明：该套生物礁的造礁生物主要为各种群体珊瑚以及少量单体珊瑚,附礁生物主要为棘皮动物等,造礁和附礁生物类型相对单一。礁体的生长受陆源物质的影响而中断,这和塔西南山前早石炭世频繁的海平面变化有关。该生物礁是继晚泥盆世生物大灭绝后,伴随着维宪期中-晚期气候变暖、全球海平面上升,全球范围内后生动物骨架礁开始复苏的产物之一,该生物礁的地质特征在全球早石炭世维宪期生物礁中具有普遍性。此外,根据对阿尔塔什剖面和什拉甫组以及相邻的库山河剖面罕铁热克组的整体沉积相分析,推测早石炭世维宪期,受当时全球海平面上升的影响以及塔西南地区在早石炭世开始形成被动大陆边缘并开始下沉,使得塔西南地区从早石炭世开始发生自南西向北东方向的海侵,在塔西南山前也逐渐形成了狭长的台地边缘相带,这有利于生物礁的发育,并在和什拉甫组时期自陆向海形成了“滨岸相-泻湖相-台地边缘相-...     

运用ITS基因分析大鹏半岛海域石珊瑚系统发育关系

通过ITS基因特异扩增测序,对大鹏半岛海域46种石珊瑚ITS基因片段序列进行了比较分析。结果表明,该片段序列长度在674~806碱基对(bp)之间,A、T含量在40%~55.5%之间,大部分物种的序列碱基A、T含量小于G、C含量。46种造礁珊瑚的平均遗传距离为0.261。采用邻位连接(NJ)和最小进化(ME)法分别构建15种复合型珊瑚的5.8S r DNA系统发育树和28种坚实型珊瑚的ITS2系统发育树,结果显示15种复合型珊瑚的5.8S r RNA序列系统进化聚类结果较符合传统形态学分类结果,而28种坚实型珊瑚的ITS2序列系统进化聚类结果与传统形态学存在较大的差异,提示石珊瑚表型的变异性可能对传统分类存在影响。     

深海珍宝——珊瑚

珊瑚是一种海洋动物。珊瑚虫分泌的骨骼,其主要成分为碳酸钙,另有少量碳酸镁、氧化铁及蛋白质等,硬度3.2～3.5,比重2.6～2.7。珊瑚虫只生长在温暖、清澈的海域,大多在南北纬30°之间,水温25～30℃的热带海洋中。建造珊瑚礁的珊瑚广泛分布在热带浅海里,它们骨骼粗糙,像模样奇特的石头。贵重珊瑚不会造礁,生长在热带深海礁岩上,一般高数尺,条柯坚挺,枝干扶疏;红如火,白如玉,丰富多彩,蕴润秀丽。由于其生存条件受水温、海流、光度、水压、沉淀物之沉降状态及盐份浓度等大自然诸多因素限制,生长速度极缓,至今无法人工养殖;因此数量稀少,价格昂贵…     

中国南海珊瑚岛礁第四系覆盖层钻探取心技术

中国南海珊瑚岛礁拥有巨大的资源潜力和科研价值。珊瑚岛礁第四系覆盖层结构为珊瑚砂和珊瑚骨架的松散堆积物,无胶结,钻探取心、成井极端困难。通过南海诸岛礁数百口钻井的施工实践,总结出"套管连续跟进干钻取心技术",工艺要点为4个步骤循环操作,称为"四步法"。使用该技术:①能确保珊瑚岛礁第四系覆盖层岩心采取率达到95%以上,并基本保持岩心原状性;②能实现在珊瑚岛礁第四系覆盖层中不使用泥浆护壁情况下安全钻进成井,达到避免地层过水通道堵塞、满足抽水试验要求的效果。研究成果对于珊瑚岛礁钻探具有重要的借鉴作用。      

基于多时间序列Landsat-8遥感影像的珊瑚礁白化监测

近年来, 受人类活动和全球变暖的双重影响, 我国南海区域珊瑚礁生态系统退化, 发生白化现象。利用遥感技术监测和掌握珊瑚礁的白化情况, 对南海生态环境的保护和治理具有重大价值。首先通过多期海表温度数据获取珊瑚礁白化预警的区域, 选定西沙群岛永乐环礁中的羚羊礁作为研究对象; 然后, 提出了一种新型的珊瑚礁白化监测模型, 分别采取水深校正、珊瑚礁分类、反射率调整以及阈值选择等方式对2013-2018年的Landsat-8遥感影像开展了多时间序列的珊瑚礁白化监测研究。最终的结果显示, 该模型能够较为准确地获取珊瑚礁白化区域, 为南海珊瑚礁白化现象的长时间序列监测提供依据。      

Regional hard coral distribution within geomorphic and reef flat ecological zones determined by satellite imagery of the Xisha Islands,South China Sea

Coral reefs in the Xisha Islands(also known as the Paracel Islands in English), South China Sea, have experienced dramatic declines in coral cover. However, the current regional scale hard coral distribution of geomorphic and ecological zones, essential for reefs management in the context of global warming and ocean acidification, is not well documented. We analyzed data from field surveys, Landsat-8 and GF-1 images to map the distribution of hard coral within geomorphic zones and reef flat ecological zones. In situ surveys conducted in June 2014 on nine reefs provided a complete picture of reef status with regard to live coral diversity, evenness of coral cover and reef health(live versus dead cover) for the Xisha Islands. Mean coral cover was 12.5% in 2014 and damaged reefs seemed to show signs of recovery. Coral cover in sheltered habitats such as lagoon patch reefs and biotic dense zones of reef flats was higher, but there were large regional differences and low diversity. In contrast, the more exposed reef slopes had high coral diversity, along with high and more equal distributions of coral cover. Mean hard coral cover of other zones was 10%. The total Xisha reef system was estimated to cover 1 060 km~2, and the emergent reefs covered ~787 km~2. Hard corals of emergent reefs were considered to cover 97 km~2. The biotic dense zone of the reef flat was a very common zone on all simple atolls, especially the broader northern reef flats. The total cover of live and dead coral can reach above 70% in this zone, showing an equilibrium between live and dead coral as opposed to coral and algae. This information regarding the spatial distribution of hard coral can support and inform the management of Xisha reef ecosystems.     

Numerical Simulation for Shallow Strata Stability of Coral Reef in the Southwest of Yongshu Reef (South China Sea)

In recent years, infrastructure construction on coral reefs has been increasingly developed. Therefore, the shallow strata stability of coral reefs in the South China Sea should be evaluated. This study aims to investigate the profiles for the shallow strata of coral reefs in the southwest of the Yongshu Reef, particularly in the hydrodynamic marine environment, and to establish a geological model for numerical simulation using Geo-Studio. The shallow strata of the coral reefs include mass gravel, sand gravel, mid-coarse sand, silty sand, fine sand, and reef limestone. The shallow reef slope near the lagoon is similar to a ‘layer cake', in which the side close to the sea is analogous to a ‘block cake'. The simulation results showed that coral reef stability depends on wave loads and earthquake strength and on the physical properties of coral reefs. The factor of safety for the outer reef is greater than 10.0 under static, wave, and seismic conditions; this indicated that the outer reefs were less affected by waves and earthquakes. However, the factor of safety next to the lagoon varied from 0.1 to 5.3. The variation was primarily caused by the thick strata of coral reefs close to the sea(reef limestone, typically with the thickness 10 m and equivalent to a block). The soil and rock layers in the coral reef strata with thicknesses 10 m showed weak engineering geological characteristics. Our findings can provide useful information to future construction projects on coral reefs.     

Performance of ecological restoration in an impaired coral reef in the Wuzhizhou Island,Sanya, China

Coral restoration is becoming popular to help restoring degraded coral reefs.However,few studies have tried to monitor the long-term recovery of coral reefs,which makes it difficult to assess the performance of the restoration.We monitored the growth of three transplanted Acropora corals and naturally-attached Pocillopora damicornis on artificial reefs(ARs) from October 2014 to September 2018 during which there were several attacks of typhoons.Results show that two staghorn Acropora species had the highest growth rate s(11.0-12.1 cm/a),followed by table coral A.divaricate(5.6 cm/a) and P.damicornis(4.8 cm/a).A linear growth pattern was found for the three Acropora species;the pattern gradually slowed in P.damicornis.There was a strong interspecific competition for space among the corals on ARs,and it led to the sharply declined occurrence of slow-growing P.darmicornis colonies in 2017.Coral recovery was successful at the Wuzhizhou Island and quickly increased AR complexity.However,the ARs made of metal frames fail to resist the direct attack from a catastrophic typhoon.Therefore,concrete and environmentalfriendly materials should be used in future restoration.This study is the first report on long-term monitoring and assessment of coral reef restoration in China.The results offer future guide of reef restoration for impaired coral reefs in regions easily affected by typhoons.     

Theoretical Analysis of Coral Reef Stability in South Sea

In this paper, we utilize the variational limiting equilibrium (LE) procedure to theoretically determine the slope stability of homogeneous coral sand in the South China Sea. By establishing a reasonable functional and calculating its extremum, we can deduce the stability factor of a coral reef identical to that obtained by upper bound analysis. To determine the accuracy of the results obtained using the variational LE procedure, we present some classical examples of homogeneous sand slopes without a hard shell and compare our results with those obtained by the upper bound theorem of plasticity. A series of extensive calculations and comparisons reveal that the results obtained by our proposed analysis method and those obtained using classical methods are slightly different, but the variational results are believable. On the other hand, our method solves some stability factors for reef slopes covered with a hard shell, which indicates that the existence of a hard reef shell may significantly enhance the stability of a reef slope, and that there is strong nonlinear relationship between reef stability and the mechanical characteristics of the reef shell, such as its thickness and strength. Finally, based on the variational results presented in this paper, we present a useful chart that offers a convenient and straightforward way to determine the maximum stability factor of reef slopes. Taking into account the influence of the hard reef shell, we found that, in some limit equilibrium cases, the limit stability factor and critical height of a coral slope could be improved significantly. Therefore, this issue deserves careful attention in engineering practice.     

Trend in coral-algal phase shift in the Mandapam group of islands,Gulf of Mannar Marine Biosphere Reserve,India

The present study revealed proliferation of macro-algae modifying coral reef ecosystems in a different manner due to diseases and sedimentations in the Mandapam group of islands in the Gulf of Mannar. Benthic surveys were conducted with major attack of seven coral reefs diseases with high sedimentation rate, nine species of fleshy macro-algae(Turbinaria ornata, Turbinaria conaides, Caulerpa scalpelliformis, Caulerpa racemosa, Kappaphycus alvarezii, Padina gymnosphora, Sargassum wightii, Ulva reticulata and Calurpa lentillifera) proliferation against major corals life forms(Acropora branching, Acropora digitate, Acropora tabulate, coral massive, coral submassive, coral foliose and coral encrusting). The results confirm that diseased corals most favor to macro-algae growth(15.27%) rather than the sedimentation covered corals(8.24 %). In the degradation of coral life forms, massive corals were more highly damaged(7.05%) than any other forms. Within a short period of time(May to September), coral coverage shrank to 17.4% from 21.9%, macro-algae increased 23.51% and the average sedimentation rate attained 77.52 mg cm~(-2) d~(-1) with persisting coral reef diseases of 17.59%. The Pearson correlation showed that the coral cover decreased with increasing macro-algae growth, which was statistically significant(r =-0.774, n = 100, P 0.0005). The proliferation of the various macro-algae C. scalpellifrmis, T. ornata, C. racemosa, T. conaides, U. reticulata, S. wightii, K. alvarezii, P. gymnosphora and C. lentillifera increased with percentages of 6.0, 5.8, 5.7, 4.9, 4.2, 3.7, 2.7 and 1.9, respectively. If this trend continues, the next generation of new recruit corals will undoubtedly lead to a phase shift in Gulf of Mannar corals.     

面向对象的南海珊瑚礁地貌单元提取

南海珊瑚礁地貌信息的提取是珊瑚礁资源利用、生态保护与管理及可持续发展的重要地学基础。本文提出了面向对象的珊瑚礁地貌单元提取模型,针对不同的地貌单元,以不同地貌单元的最优分割尺度、光谱参数、形状参数来分割影像并合并成不同对象,从而获得相应的地貌单元。通过大量实验得出自然地貌的最优分割尺度区间为[140,600],其中附礁生物稀疏带及丛生带、礁坑发育带的光谱参数和形状参数分别为0.9和0.1,其他自然地貌单元的光谱参数和形状参数分别为0.8和0.2;人工地貌的最优分割尺度区间为[25,170],其光谱参数和形状参数分别为0.8和0.2。进一步以南沙群岛簸箕礁WorldView-2高分辨率遥感影像为例提取地貌单元,并结合混淆矩阵和Kappa系数对分类结果进行了精度评价,地貌单元提取总体精度达到了85.75%,Kappa系数为0.8349。结果表明,该方法可有效运用南海珊瑚礁遥感影像的光谱特征、纹理特征,以及影像数据不同波段的组合特性,综合了影像和珊瑚礁地貌的关联特性,充分利用了珊瑚礁不同地貌相带的异质性,获得了理想的南海珊瑚礁地貌的整体信息,满足了我国南海珊瑚礁地貌信息提取和地貌数字产品生成的需求。     

Type and evolution of landscapes of Nansha Islands

ＴＹＰＥＡＮＤＥＶＯＬＵＴＩＯＮＯＦＬＡＮＤＳＣＡＰＥＳＯＦＮＡＮＳＨＡＩＳＬＡＮＤＳＺｈａｏＨｕａｎｔｉｎｇ（赵焕庭）ＳｏｕｔｈＣｈｉｎａＳｅａＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｌｏｇｙ,ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ,Ｇｕ...     

Improvement on the Effectiveness of Marine Stock Enhancement in the Artificial Reef Area by a New Cage-Based Release Technique

The release technique, affecting the survival rate of fish species released for stock enhancement, plays a vital role in the effectiveness of the enhancement. In order to improve the probability of released fish settling down to bottom, a new cage-based release technique was designed and tested via a water tank with artificial reef models. Two coral reef fish species, Sebastes schlegelii and Paralichthys olivaceus were assessed using this technique. Fish behavior and distribution in water tank were recorded and compared with the traditional release release techniques. Results showed that in the case of cage-based release technique: 1) when the release process is just finished, the distribution index(DI) of juveniles S. schlegelii and P. olivaceus were 97.8% and 98.9% at reef area, 40% and 71.1% at release point, respectively, which was higher than those using two alternative techniques; 2) its impact duration was less than that in the other two conditions, where the DI within 4 hours was higher after releasing, especially for S. schiegelii. These findings indicated that the new cage-based technique could release the fish into the specified location, and has a potential to mitigate the stress reaction of fish caused by releasing process.     

Type and evolution of landscapes of Nansha Islands

Landscapes of the Nansha Islands may be divided into five types: tropical marine organism-breeding landscape of reef knoll like Zengmu Shoal, Wan’an Bank and so on; tropical marine organism-breeding landscape of atoll including all emerged reefs and most submerged reefs; tropical evergreen arbor-bush forest and phosphorous lime soil landscape of limesand Islets like Taiping Islet, Nanwei islet and so on; tropical shallow sea marine organism-breeding landscape of southern continental shelf; tropical oceanic and deep-sea marine organism landscape in middle and north parts of the Nansha Islands area. These five landscape types may be also summed up as two categories, one is tropical sea landscape including those in shallow and deep sea, the other is tropical coral reef landscape including those of reef knoll, atoll and limesand islet. This paper outlines the evolutional model of landscapes of the Nansha Islands. The distribution and evolution of landscape types are related with palaeogeography and modern environmental conditions. The former shallow sea of the Nansha islands was coastal zone in the Late Pleistocene epoch. Deep sea is evolved from shallow sea due to long and slow subsidence of crust. Modern coral reefs develop on old reef top of the Late pleistocene epoch or on baserock of continental shelf in the Holocene due to the rise of sea level in postglacial. Limesand islet is in the peak of developmental stage.