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1.
Studies on the coral reefs of the South China Sea (SCS) was the theme of the 6th Session of the 3rd Conference on Earth System Science (CESS) in Shanghai, 2014. This session discussed the most recent study developments on the SCS coral reefs, including coral reefs’ responses to global changes, coral reefs’ records on past climatic variations, and the activities about constructions and oil gas explorations in the coral reefs areas of the SCS. Disturbed by intensive anthropogenic activities and global climate warming, coral reefs in the SCS have declined dramatically, reflecting the up to 80% decrease of living coral cover and many areas having less than 20% of living coral cover. Geochemical data of SCS coral skeletons clearly show that since the Industry Revolution, the pollution situation of the SCS have dramatically increased and the seawater pH values have been continuously lowering, i.e. oceanic acidification. All these environmental phenomenon are further stressing the healthy development of the coral reef ecosystem in the SCS. Meanwhile, the poor coral reef ecosystems in the SCS are facing more anthropogenic disturbances such as coastal developments and engineering constructions. Obviously, the SCS coral reefs will be faced with more environmental challenges in the coming future. We therefore suggest that the policy makers should realize the extreme importance and the fragile of the coral reef ecosystems, and scientifically and with great cautions design construction project when in coral reef areas. We initiated the concept of “green engineering” for future developments in coral reef areas. Coral reefs are widely spreading in the whole SCS, and most of them developed since Miocene. Variations in coral reef structures provide good future oil-gas exploration. Because the SCS coral reefs have a long-developing history and a wide spatial distribution, they provide great potential in recording past environmental changes. 相似文献
2.
珊瑚礁支持了对全球气候变化响应最敏感的生态系统之一,其部分特征地貌是海面变化记录的重要载体.目前,无论是对珊瑚礁现代地貌还是埋藏古地貌的研究多以定性为主,定量研究相对匮乏.基于2017年8～9月采集的浅层地震剖面数据,结合遥感影像研究显示,道明群礁目前是发育有1个岛、4个沙洲、7个干出礁和若干座暗礁的典型珊瑚群礁,其形... 相似文献
3.
珊瑚礁是发育于热带海洋环境中由生物作用和地质作用共同形成的地质体,具有独特的新构造运动意义。南海西北部珊瑚礁记录所反映的新构造运动主要有火山活动、地壳升降运动和地震活动等。珊瑚礁区第四纪火山活跃,到现代已停止活动,部分火山构成珊瑚礁的基座,个别出露海面为火山岛;地壳升降运动差异较大,雷州半岛西南部珊瑚礁呈上升趋势,上升率为0.02~0.05mm/a;西沙群岛等岛礁地壳运动则呈下降趋势,下降率为-0.07~-0.10mm/a,岛礁中的造礁石珊瑚生长率、礁顶和灰沙岛的堆积率均相当于或大于地壳下降率与现代海平面上升率的总和;南海西北部珊瑚礁区内地震活动较强,尤其是1994年12月31日和1995年1月10日在雷州半岛西南部海域发生了6.1级和6.2 级地震,这两次地震对该区珊瑚礁的发育有较大的影响。 相似文献
4.
海南岛南岸的珊瑚礁,是我国全新世珊瑚岸礁最为发育的地区之一,仅次于台湾岛南端的恒春半岛沿岸。前人从生物学[1-5]、地貌学[6-8]和地质学[9-12]角度对海南岛南岸的珊瑚礁进行过较为广泛的研究。作者报道过崖县鹿回头水尾岭剖面珊瑚礁样品的C14年代测定结果[13,14]。1979年底至1980年初,作者在海南岛南岸东起小东海沿岸西至西瑁岛西岸地区进行了野外调查与采样。根据野外和室内分析资料,本文公布了一批新测试的C14年代数据,并进一步讨论了全新世珊瑚礁的发育历史及其与海岸变迁、海面变化和地壳运动的关系等问题。 相似文献
5.
Coral reefs are often constrained by diagenesis as a sound environmental archive. The correct understanding and evaluation of diagenesis is the key to the paleoenvironmental reconstruction of coral reefs. The diagenesis of coral reefs mainly includes cementation, dissolution, neomorphism and dolomitization etc. On the one hand, the diagenesis itself can record the paleoenvironment that coral reefs underwent, such as sea-level fluctuation, climate change, change of sea water, hydrothermal alteration, microbial activity and so on. The diagenetic evolution thus can be used for the reconstruction of paleoenvironment change. On the other hand, diagenesis also destroys the original environmental information which recorded of coral reefs recard, and it is necessary to know the degree of the impact of diagenesis. In the future, we should pay more attention to the study on the relationships among diagenesis, modern climate, sea-level change, atmospheric water transformation and microbial activity. It can provide more accurate and longer time series of paleoenvironmental information that coral reefs recorded. 相似文献
6.
本文以政府间气候变化专业委员会（IPCC）于2001年专门报告中关于21世纪内全球气候变化的温度和海平面变化的预估为前提。简要介绍了中国珊瑚礁的定位、类型和分布,对其进行了成熟度分类,评估了全球海平面变化对中国珊瑚礁的影响。据预测,21世纪我国各海域海平面上升以南海最大,为32 ~ 98cm,其平均上升速率为0.32 ~ 0.98cm/a。从海平面上升速率与珊瑚礁生长速率的理论对比分析,中国珊瑚礁基本上能与前者同步生长,即使海平面以预估高值上升,也不会威胁其生存。从中国珊瑚礁成熟度较高、其生长趋势以侧向生长为主的现实状况出发,未来全球海平面上升能为其创造向上生长的有利条件。从古地理学“将古论今”观点出发,自全新世6000aBP以来曾存在过的高海平面和较高表层海水温度的历史,也可以佐证,21世纪的全球海平面上升不会对中国珊瑚礁的存在和发育造成威胁。现存的珊瑚礁岛应对于全球海平面上升,可以做到“水涨岛高”,它们能够屹立于上升了的未来海平面之上;但对于岛上的人工建筑物则会被浸、被淹,或被淘蚀和破坏,因此必须根据海平面上升的幅度和速率,采取相应的防御措施。 相似文献
7.
中国南海珊瑚岛礁泻湖砂层钻探取心技术 总被引：3，自引：0，他引：3
中国南海珊瑚岛礁拥有巨大的资源潜力和科研价值。科学钻探是珊瑚岛礁研究工作中获取地层资料的重要技术手段。南海珊瑚岛礁地下普遍存在多层厚层泻湖砂层，主要结构为无胶结或轻微胶结的细粒珊瑚砂，这种层位钻探取心极端困难，是影响钻探成果的主要难题之一。南海两个岛礁所实施的3口千米以上深井施工过程中，为解决泻湖砂层钻探取心难题，在分析泻湖砂层性状的基础上，综合研究钻具合理选用、钻进参数控制、钻井液性能控制等钻探工程核心内容，形成了较完整的适用于泻湖砂层钻探取心的“多要素组合钻探取心技术”。使用该技术能确保珊瑚岛礁泻湖砂层岩心采取率达到95%以上，并基本保持岩心原状性。该研究成果对于珊瑚岛礁钻探具有重要的借鉴作用。 相似文献
8.
石炭纪生物礁在晚古生代礁体演化序列中处于特殊地位。石炭纪是生物礁地史演化过程中一个非常关键的时期,发育的生物礁类型有:(1)叶状藻礁丘;(2)叠层石礁丘;(3)珊瑚礁;(4)Waulsortian灰泥丘;(5)Chaetetes礁丘;(6)钙质微生物—藻礁丘。石炭纪生物礁总体上表现为礁相结构、造礁群落组成及礁体建造阶段的造礁作用相对比较简单,这些都体现出生物礁在石炭纪的发展受到生物灭绝事件的影响。在以藻礁占主导地位的宾夕法尼亚亚纪,中国后生动物骨架礁发育,尤其是发育有Fomitchevella大型珊瑚礁,成为世界石炭纪生物礁的一个亮点。从石炭纪整个生物礁的发展情况来看,后生动物骨架礁与以微生物和钙藻为主导的生物礁或许是两个平行发展的礁系统,后生动物骨架礁的发展在大规模生物灭绝事件之后有明显的演化滞后现象,以钙藻和微生物为主导的造礁群落的复苏在生物灭绝事件之后更为迅速。从石炭纪生物礁古地理分布来看,石炭纪生物礁基本上分布在南北纬30°之间的区域,因此,它们代表了在相对温暖的气候条件下生长的礁体,与现代珊瑚礁的分布相近似。 相似文献
9.
许红 史国宁 廖宝林 陈刚 董树义 邱隆伟 李琦 罗进雄 申剑 曾晓起 王亚民 贺静 董刚 闫桂京 王宇喆 周星蕾 胡喜鹏 罗乔乔 陈竹 陶萌 纳琴 王晴 王英 沈江远 马骁 付和平 吴汉儒 马亚增 陈舒 《古地理学报》2021,23(4):771-788
珊瑚是地球上最古老的原住民,具有近6×108年的发育史,弱势群居、喜温和原地长成是珊瑚的基本特征。作者介绍了珊瑚-珊瑚礁的基本特征,综述了跨十年调查的研究区珍贵照片资料和相关认识,指出中国是全球主要的珊瑚-珊瑚礁国家,地位举足轻重;珊瑚-珊瑚礁作为地球生物多样性的代表,造岛、固礁、护鱼、防护岛岸流失,形成南海四大群岛280余座岛、礁、滩、沙,所构建庞大海洋生态系统是无与伦比的海洋生态资源和寸土寸金的南海海洋国土。提出划分南海珊瑚-珊瑚礁为中央区和周缘区2个分布区,阐述了南海中央区珊瑚-珊瑚礁的基本特征,系统汇集报道了间隔10年2个科考航次调查在浅水礁盘浮潜、至20 m水深浅潜-深潜和礁盘及开展岛、礁、滩、沙地质调查的发现,包括科学定名46种六放石珊瑚和6种八放软珊瑚等成果,同时,收集了西沙、中沙、东沙和南沙群岛海域的相关调查航次珊瑚照片;进一步阐述了单体环礁和复合环礁的特征及分布,并进行了初步对比,指出永乐环礁是南海唯一一个真正的切合达尔文模式的环礁,也是环礁发展到最高阶段的产物,构成现代海洋珊瑚-珊瑚礁形成演化研究最好的天然实验室。 相似文献
10.
Pinxian Wang 《地球科学进展》2019,34(12):1222-1233
The discovery of deep sea coral forests in the spring of 2018 filled a significant gap in the benthos research and even in carbon cycling in the South China Sea. Previously, the researches of deep-sea benthos were restricted to the sediment-covered soft bottom due to the technical limitations, and the rocky hard bottom was believed to be barren of life. Using submersible technique in the mid-1990s, deep-water coral reefs were first discovered in the Atlantic Ocean, which opened a new research direction in marine sciences. Two groups of deep sea corals have been recognized: scleractinian hexacorals and gorgonian octocorals. The aragonite skeleton of the former group build up deep sea coral reefs, while the latter make up deep sea coral forests with high-Mg calcite skeleton in many gorgonian corals. All kinds of carbonate coral skeletons can record environment changes of the deep sea and provide excellent material for high-resolution paleoceanography. Although the development of deep sea coral reefs in the Pacific Ocean is hampered by its extremely shallow aragonite compensation depth, deep sea coral forests are ubiquitous in the ocean. Up to now, most parts of the Pacific have not yet explored in this respect, and deep sea corals remain outside the research scope. The present paper is a literature review and calls for attention to the deep sea forests. It starts with the composition and distribution of deep sea coral reefs and forests, followed by discussions on the significance of deep sea coral forests in marine ecology and in paleoceanographic reconstructions. 相似文献
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海南岛排浦礁区由珊瑚岸礁和堤礁及其间水域组成。因堤礁的障壁作用和丰富的陆源物质供应,研究区内形成清水和浑水两类沉积环境,产出清水碳酸盐和浑水碳酸盐两列沉积体系,并形成礁源沉积、陆源沉积和混合沉积三类沉积物。文中详细论述了各类沉积的特征,讨论了沉积体系的演化过程:全新世早期是单一的陆源碎屑沉积体系,全新世中期海侵,气温转暖,形成早期排浦岸礁与大铲堤礁的雏型,全新世晚期堤礁进入成熟阶段,其障壁作用加强,最终形成清水与浑水两种沉积环境和两列沉积体系。 相似文献
13.
《Comptes Rendus Geoscience》2014,346(1-2):45-51
In southern Corsica, three successive Upper Burdigalian coral reef episodes (R1, R2 subdivided into R2A and R2B subunits, and R3) developed within the Cala di Labra Formation. Tabular corals dominated under high water energy and siliciclastic input conditions. The R1 reefs show the highest coral diversity with 16 species described for the first time. A coral impoverishment was recorded in the R2 and R3 reefal episodes. The reefs did not reach a climax growth stage, except the R1 ones. Analogous to North Sardinian reefs, they reflect local vanishing conditions in the Corsican–Sardinian block through Upper Burdigalian because of constant siliciclastic inputs and deepening of the Bonifacio straight. 相似文献
14.
Alina M. Szmant 《Estuaries and Coasts》2002,25(4):743-766
Coral reefs are degrading worldwide at an alarming rate. Nutrient over-enrichment is considered a major cause of this decline because degraded coral reefs generally exhibit a shift from high coral cover (low algal cover) to low coral cover with an accompanying high cover and biomass of fleshy algae. Support for such claims is equivocal at best. Critical examination of both experimental laboratory and field studies of nutrient effects on corals and coral reefs, including the Elevated Nutrient on Coral Reefs Experiment (ENCORE) enrichment experiment conducted on the Great Barrier Reef, does not support the idea that the levels of nutrient enrichment documented at anthropogenically-enriched sites can affect the physiology of corals in a harmful way, or for most cases, be the sole or major cause of shifts in coralalgal abundance. Factors other than nutrient enrichment can be significant causes of coral death and affect algal cover, and include decreased abundance of grazing fishes by fishing, and of grazing sea urchins to disease; grazing preferences of remaining grazers; temperature stress that kills coral (i.e., coral bleaching) and creates more open substrate for algal colonization; sedimentation stress that can weaken adult corals and prevent coral recruitment; coral diseases that may be secondary to coral bleaching; and outbreaks of coral predators and sea urchins that may be secondary effects of overfishing. Any factor that leads to coral death or reduces levels of herbivory will leave more substrate open for algal colonization or make the effects of even low-level enrichment more severe. Factors that contribute to an imbalance between production and consumption will result in community structure changes similar to those expected from over-enrichment. Over-enrichment can be and has been the cause of localized coral reef degradation, but the case for widespread effects is not substantiated. 相似文献
15.
珊瑚礁工程地质研究进展 总被引：9，自引：0，他引：9
珊瑚礁是发育于热带海洋环境中由生物作用和地质作用共同形成的地质体,是一种特殊的岩土介质类型,有着独特的工程环境特性和工程地质性质。珊瑚礁工程地质研究是现代工程地质学的一个新课题,是近年来为适应珊瑚岛礁工程建设的需求而发展起来的。介绍了珊瑚礁工程地质研究的内容及意义,综述了国内外珊瑚礁工程地质研究的历史现状及其进展,指出应将珊瑚礁体作为工程岩体,进行工程地质环境区带划分及各区带工程地质条件评价;分析礁岩体结构特征和礁体稳定性及其影响因素;分析礁体工程适宜性、地基及其环境与工程活动相互关系。针对珊瑚礁岩土的土力学特点,加强珊瑚礁颗粒破碎机理及其对工程地质性质影响机制的研究;建立能够代表珊瑚礁应力—应变特性的本构关系。 相似文献
16.
基于TM和ETM+影像数据的东沙环礁珊瑚礁监测 总被引：1，自引：0，他引：1
以东沙环礁为研究区域,选取1999年Landsat-7 ETM+影像数据和2001年、2009年Landsat-5 TM影像数据为主要数据源,应用基于统计学习理论的支持向量机（SVM）分类技术,通过选择训练时间较短的“一对一”SVM方法和RBF核函数,对3个年度的影像数据进行珊瑚礁信息提取。结果表明：2009年东沙环礁珊瑚礁面积为140.93 km2;1999－2009年,东沙环礁珊瑚礁面积减少了17.54 km2,珊瑚礁破碎化、白化现象趋于明显,珊瑚礁退化处于中期阶段。空间分辨率的提高可得到更准确详尽的珊瑚礁信息,尤其对小面积珊瑚礁的信息提取。 相似文献
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Keiichi Sasaki Akio Omura Kazuo Murakami Natsume Sagawa Toru Nakamori 《Quaternary International》2004,120(1):51
Coral reef terraces are one of the best recorders of relative sea-level changes during the last glacial cycle. Thus far, knowledge of relative sea-level record based on coral reefs during the marine Oxygen Isotope Stage (OIS) 3 has been limited to studies of the Huon Peninsula, Papua New Guinea. High-precision a α-spectrometric 230Th/234U dating demonstrated an offlapping sequence of five coral reef complexes, ages of which are 66, 64, 62, 55 and 52 ka, in the northern part of Kikai Island, central Ryukyus of Japan. Interstadial reefs, characterized by deepening-upward sequences of coral assemblages, recorded three hemicycles from transgression to highstand at 52, 62, and 66 ka, during which these reefs were drowned. These highstands in the relative sea-level record can be correlated with the eustatic record reconstructed from the Huon reef terraces and with the interstadials 14, 18, and 19 of the GISP 2 oxygen isotope record. This consistency confirms the Huon sea-level record of OIS 3 and implies that the eustatic sea level responded to the millennial-scale climate changes even during the glacial period of OIS 4. 相似文献
19.
Jürgen Titschack Daniel Baum Ricardo De Pol‐Holz Matthias López Correa Nina Forster Sascha Flögel Dierk Hebbeln André Freiwald 《Sedimentology》2015,62(7):1873-1898
Cold‐water coral ecosystems present common carbonate factories along the Atlantic continental margins, where they can form large reef structures. There is increasing knowledge on their ecology, molecular genetics, environmental controls and threats available. However, information on their carbo‐nate production and accumulation is still very limited, even though this information is essential for their evaluation as carbonate sinks. The aim of this study is to provide high‐resolution reef aggradation and carbonate accumulation rates for Norwegian cold‐water coral reefs from various settings (sunds, inner shelf and shelf margin). Furthermore, it introduces a new approach for the evaluation of the cold‐water coral preservation within cold‐water coral deposits by computed tomography analysis. This approach allows the differentiation of various kinds of cold‐water coral deposits by their macrofossil clast size and orientation signature. The obtained results suggest that preservation of cold‐water coral frameworks in living position is favoured by high reef aggradation rates, while preservation of coral rubble prevails by moderate aggradation rates. A high degree of macrofossil fragmentation indicates condensed intervals or unconformities. The observed aggradation rates with up to 1500 cm kyr?1 exhibit the highest rates from cold‐water coral reefs so far. Reef aggradation within the studied cores was restricted to the Early and Late Holocene. Available datings of Norwegian cold‐water corals support this age pattern for other fjords while, on the shelf, cold‐water coral ages are reported additionally from the early Middle Holocene. The obtained mean carbonate accumulation rates of up to 103 g cm?2 kyr?1 exceed previous estimates of cold‐water coral reefs by a factor of two to three and by almost one order of magnitude to adjacent sedimentary environments (shelf, slope and deep sea). Only fjord basins locally exhibit carbonate accumulation rates in the range of the cold‐water coral reefs. Furthermore, cold‐water coral reef carbonate accumulation rates are in the range of tropical reef carbonate accumulation rates. These results clearly suggest the importance of cold‐water coral reefs as local, maybe regional to global, carbonate sinks. 相似文献
20.
Kekuewa Samuel A. H. Courtney Travis A. Cyronak Tyler Kindeberg Theodor Eyre Bradley D. Stoltenberg Laura Andersson Andreas J. 《Aquatic Geochemistry》2021,27(4):241-268
Globally, coral reefs are threatened by ocean warming and acidification. The degree to which acidification will impact reefs is dependent on the local hydrodynamics, benthic community composition, and biogeochemical processes, all of which vary on different temporal and spatial scales. Characterizing the natural spatiotemporal variability of seawater carbonate chemistry across different reefs is critical for elucidating future impacts on coral reefs. To date, most studies have focused on select habitats, whereas fewer studies have focused on reef scale variability. Here, we investigate the temporal and spatial seawater physicochemical variability across the entire Heron Island coral reef platform, Great Barrier Reef, Australia, for a limited duration of six days. Autonomous sensor measurements at three sites across the platform were complemented by reef-wide boat surveys and discrete sampling of seawater carbonate chemistry during the morning and evening. Variability in both temporal and spatial physicochemical properties were predominantly driven by solar irradiance (and its effect on biological activity) and the semidiurnal tidal cycles but were influenced by the local geomorphology resulting in isolation of the platform during low tide and rapid flooding during rising tides. As a result, seawater from previous tidal cycles was sometimes trapped in different parts of the reef leading to unexpected biogeochemical trends in space and time. This study illustrates the differences and limitations of data obtained from high-frequency measurements in a few locations compared to low-frequency measurements at high spatial resolution and coverage, showing the need for a combined approach to develop predictive capability of seawater physicochemical properties on coral reefs.
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