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1.
海洋生物礁是由具有造礁能力的海洋生物聚集而成的一种三维礁体结构,其形成改变了海底地貌、增加了不同尺度上的地形复杂性,为其他海洋生物提供了栖息地并维持了生物多样性。近年来,由于自然因素和人为因素影响,海洋生物礁受到了严重威胁,已成为海洋生态保护和修复领域的重要研究对象。综述了海洋生物礁的类型、生态功能及其生态修复的研究进展。根据形成海洋生物礁的优势造礁生物种类,将海洋生物礁分为海藻礁、海绵礁、刺胞动物礁、贝类礁和多毛类礁,其优势造礁生物分别是珊瑚藻和仙掌藻、钙质海绵和硅质海绵、造礁珊瑚、牡蛎、龙介虫。目前国内对海洋生物礁的全面了解相对较少,主要集中在珊瑚礁和牡蛎礁。海洋生物礁的生态功能主要有海岸防护、提供栖息地、净化水体、固碳作用和能量耦合等。全球变暖和海洋酸化等全球气候变化以及海洋污染、破坏性渔业捕捞、海岸工程、水产养殖和敌害生物等自然和人为因素对海洋生物礁构成了严重威胁。海洋生物礁的生态修复方法分为两类:在退化生物礁区投放造礁生物逐渐成礁,投放人工礁体补充造礁生物逐渐成礁。针对海洋生物礁保护和修复的需要,提出下一步应加强海洋造礁生物生态特征、海洋造礁生物种群丧失因素和海洋生物礁保护与...  相似文献   

2.
奥陶纪末的生物冰川灾变事件结束后,华南板块上扬子区进入志留纪初的海进期。黔东北志留纪初期香树园组(兰多维列统鲁丹阶上部-埃隆阶中部)是壳相动物群复苏时沉积的灰岩相地层,具有显著的生物-岩相分异。"白沙型"后生动物化石密集的礁滩沉积仅限于近岸正常浪基面附近的浅海区展布。同期石阡枫香铺沟村剖面远岸带"印江型"香树园组薄层灰岩中壳相动物大化石的生物多样性和丰度低,没有原地绑结岩型的生物礁和粗颗粒堆积的生屑滩,岩相和生物相特征显示各种细颗粒的生屑呈碎片堆积。尽管这里海水清澈度较高,但由于水深偏大且水动力偏低的环境指标抑制了"白沙型"造礁动物向广海区的空间拓展。这一实例凸显了黔东北陆表海区海水深度对香树园组底栖生态组合多样性的控制,导致志留纪最早复苏的生物礁古地理分布的局限性。  相似文献   

3.
桂林北郊灵川县岩山大村剖面和乌龟山剖面为中泥盆世吉维期沉积,其沉积构造、生物组成、微相序列反映出生物礁的特点,大量层孔虫为造礁的主要生物,其生长形式为:(1)厚板状;(2)半球状和穹窿状;(3)大型柱状和不规则状;(4)披覆状或薄板状。珊瑚有3层,或作为礁基,或参加造礁,前者为单体珊瑚,后者为复体珊瑚。刺毛虫主要为根茎状,常被层孔虫包统,也是造礁的主要生物。藻类生物很少。横向上可以分出礁核相,礁后相和礁前斜坡相。主要的微相类型有13种,纵向上可以识别出两个造礁旋回,从礁基-珊瑚、层孔虫礁-礁后外带-礁后内带,两个造礁旋回之上为礁坪所覆。根据礁的规模、礁体与上下沉积物的关系、礁生物组成的变化和古地理位置的讨论推测为一岸礁体系。  相似文献   

4.
桂林北郊灵川县岩山大村剖面和乌龟山剖面为中泥盆世吉维期沉积,其沉积构造、生物组成、微相序列反映出生物礁的特点,大量层孔虫为造礁的主要生物,其生长形式为:(1)厚板状;(2)半球状和穹窿状;(3)大型柱状和不规则状;(4)披覆状或薄板状。珊瑚有3层,或作为礁基,或参加造礁,前者为单体珊瑚,后者为复体珊瑚。刺毛虫主要为根茎状,常被层孔虫包统,也是造礁的主要生物。藻类生物很少。横向上可以分出礁核相,礁后相和礁前斜坡相。主要的微相类型有13种,纵向上可以识别出两个造礁旋回,从礁基-珊瑚、层孔虫礁-礁后外带-礁后内带,两个造礁旋回之上为礁坪所覆。根据礁的规模、礁体与上下沉积物的关系、礁生物组成的变化和古地理位置的讨论推测为一岸礁体系。  相似文献   

5.
塔里木中央隆起区中2井位于塔中南坡台缘带,上奥陶统凯迪阶良里塔格组频繁出现浅水粒屑滩沉积,以及由蓝藻、钙藻兼以少量珊瑚、苔藓虫等造礁生物以不等含量分别构成生物障积或粘结型礁灰岩,棘皮类、腕足类和三叶虫等壳相生物碎屑丰富。可分出数层典型的生物礁、滩组合序列,总体显示为原地生长和近源搬运的生物礁滩复合体建造。环境的动能条件略有变化,但皆属浪基面之上的沉积深度。礁、滩储层形成模式主要受于沉积相带、成岩改造的控制,储层以生屑灰岩、藻粘结灰岩、障积灰岩及砂屑灰岩为主,储集空间类型包括次生溶蚀孔隙、晶洞与裂缝,同时伴随少量的白云岩化作用,且孔隙以深埋藏溶蚀成因为主,次生胶结作用也十分强烈,礁相储层潜力好于滩相。  相似文献   

6.
浙赣交界地区上奥陶统三衢山组礁灰岩的分类   总被引:1,自引:0,他引:1  
本文讨论了礁灰岩的分类历史,特别对Tsien,H.H.的礁灰岩分类系统进行了介绍.浙赣交界地区上奥陶统三衢山组生物礁发育良好,通过对其所含造礁生物的形态及功能分析,区分出五大类礁灰岩,即格架岩、障积岩、盖复岩、绑结岩和生物粘结岩,并指出生物礁礁核相主要由以上各种礁灰岩的复合类型所组成.  相似文献   

7.
钙质海锦之古生态   总被引:4,自引:0,他引:4  
古生代生物礁中钙质海绵(纤维海绵、房室海绵、硬海绵)的生态位在中三叠世以后被生态竞争能力更强的六射珊瑚所占据。在古生代和中三叠世的钙质海绵礁上,0-10m深度内钙质海绵很发育。由于与钙藻共生,典型的造礁钙质海绵生活在透光带以内,并且在其上部更丰富。钙质海绵礁也会生长到破浪带内并受风浪的破坏而形成倒骨岩和骨屑岩。对古生代的钙质海绵礁而言,倒骨岩和骨屑岩形成于0-3m水深范围内,亮晶骨架岩形成于3-1  相似文献   

8.
华南板块古生代生物礁及其古地理控制因素   总被引:1,自引:0,他引:1  
华南板块在古生代处于中、低纬度,碳酸盐岩类型多样并形成不同时空背景下的多种生物礁建造,生物礁发展序列基本吻合于全球古生代生物礁的宏演化趋势,寒武纪生物群和古生代动物群演化过程中重要造礁生物门类的起源、辐射、灭绝与复苏事件是塑造礁群落基本生态结构的历史因素。寒武纪早期的古杯-藻礁和继之的微生物礁生长区域相当局限;早—中奥陶世的苔藓虫礁、藻礁以及瓶筐石-硬海绵礁群落分异明显;晚奥陶世珊瑚-层孔虫礁以及藻丘建造见于浙赣局限台地及台缘带,而扬子区志留纪兰多维列世生物礁的生长频繁受陆源碎屑岩覆盖;中泥盆世的珊瑚-层孔虫-藻礁群落结构相对稳定,晚泥盆世法门期—密西西比亚纪的微生物礁、苔藓虫-珊瑚礁、宾夕法尼亚亚纪—早二叠世的苔藓虫-海绵-藻礁、中—晚二叠世的珊瑚-苔藓虫-海绵-藻礁可诠释为与生物灭绝事件相关的幕式群落演替。区域构造活动导致的岩相分异和海平面变化显著制约生物礁的时空分布。中—晚奥陶世的偏深水环境、志留纪兰多维列世—早泥盆世早期扬子区整体抬升的古地理格局造成适宜于生物礁生长海域的缩减;泥盆纪较长的温室期促进了生物礁发展,而宾夕法尼亚亚纪—早二叠世偏凉的海洋水体对生物礁的规模影响力度明显。从华南板块古生界整体的视角看,海相碳酸盐岩具有量值优势,海水在时间尺度和空间展布上多维持较高的清澈度,陆源碎屑岩沉积在特定的时间段可视为生物礁生长的主控因素;海平面变化因其幅度有限可在单剖面或区域上控制生物礁群落的纵横迁移,碳酸盐岩沉积区多见基底沉降与沉积补偿速率基本均衡,具备不同规模的浅海相沉积空间,因此水深变化并非起到决定性作用。特定时段碳酸盐岩台地海水的盐度异常可造成大规模白云岩沉积可排除生物礁发育。  相似文献   

9.
中国南方二叠纪海绵礁的成礁模式   总被引:6,自引:0,他引:6  
广泛发育于我国南方碳酸盐岩台地区的二叠纪生物礁,其中绝大多数属于海绵生物礁。从该地区二叠纪海绵生物礁的内部成礁因素分析,即从主要造礁生物-钙质海绵和钙质藻类等的生物学和生态学特征、埋藏和保存特点等方面进行分析,提出了华南二叠纪海绵生物礁主要是由于其主要造礁生物钙质海绵和钙质藻类独特的生物学特征、生态学特征以及它们的共同作用所形成的。此模式与其它地质历史时期生物礁的成礁模式明显不同。  相似文献   

10.
黔西南兴义地区及邻区中三叠世安尼期台地边缘生物礁发育在上扬子台地西南缘,为大型堡礁。造礁生物主要为暗管管壳石Tubiphytes obscurus,鹿角状管壳石Tubiphytes alcicornis,以及脑型丛状管壳石Plexoramea cerebriformis,占造礁生物总量的90%以上。苔藓虫类Reptonoditrypa cautica,珊瑚类Pinacophyllum spizzensis,奥顿菌Ortonella sp.以及普拉塔拉丁管Ladinella porata等为次要造礁生物。此外,礁灰岩中还见棘皮动物、腹足动物、腕足动物和有孔虫等附礁生物。该生物礁为晚二叠世绝灭事件之后在中三叠世开始重新建立的台地边缘礁复合体。本次研究为中三叠世造礁生物种类的恢复提供了新材料,同时也填补了上扬子台地西南缘安尼期生物礁研究的空白。  相似文献   

11.
ECOLOGY AND MORPHOLOGY OF RECENT CORAL REEFS   总被引:7,自引:0,他引:7  
1. The classical ‘coral reef problem’ concerned the geological relationships of reefs as major topographical features; modern coral studies consider reefs both as complex biological systems of high productivity and as geological structures forming a framework for and being modified by coral growth. 2. Deep borings in reefs have conclusively confirmed the general arguments of Darwin, that oceanic reefs developed by progressive subsidence of their foundations. Darwin failed to take account of Pleistocene changes in sea level and their effect on the present surface features of reefs. Daly's alternative ‘glacial control theory’ was based on false assumptions concerning marine erosion rates during glacial periods, but if sea level during the Holocene was higher than at present, as Daly also supposed, the effects on reef features would be profound. 3. Reefs are complex biological systems in tropical seas, dominated by scleractinian corals. Coral faunas are larger and more diverse in the Indo-Pacific than in the Atlantic. Hermatypic corals are restricted to shallow water by the light requirements of their symbiotic algae, but temperature is a major control of worldwide distributions. Temperature, salinity and sediment tolerances of corals are wider than formerly supposed, and corals can survive brief emersion except when it coincides with heavy rainfall. Water turbulence is an important ecological control, but difficult to measure. 4. The trophic status of corals is still unclear, but in spite of their anatomical and physiological specialization as carnivores it is likely that they derive some nutrient substances from zooxanthellae. Suggestions that filamentous algae in coral heads play a major part in the economy of the corals have not been supported by later work, but biomass pyramids constructed on the basis by Odum and Odum remain the only ones available. Most reefs are apparently autotrophic, with 1500–3500 g. Carbon being fixed per m.2 per year. 5. Few animals eat corals, which may account for their success. Important predators are fish and the echinoderm Acanthaster. Quantitative estimates of biogenic erosion of organic skeletons on reefs are high. Fish affect not only corals but other invertebrates, algae and marine phanerogams. 6. Corals may be killed by ‘dark water’, intense rain or river floodwaters, earth movements, human interference and especially hurricanes. Reef recovery after hurricanes may take 10–20 years. 7. In addition to fringing, barrier and atoll reefs, intermediate types are recognised. The main types may consist of linear reefs or faros. Smaller lagoon reefs include pinnacles, patches and platforms, and submerged knolls. Complex cellular or mesh reef patterns are also found. 8. Reefs are conspicuously zoned, both laterally in response to changing exposure to waves to form windward and leeward reefs, and transversely, as a result of steep environmental gradients across reef flats from sea to lagoon. Topographic and ecological zones may be characterized by particular coral species, but these vary widely from reef to reef. A major distinction can be made between reefs with and without algal ridges, which are common on open-ocean trade-wind reefs, in the Indo-Pacific, but are absent on Caribbean reefs and on Indo-Pacific reefs in more sheltered waters. gorgonians are common on Caribbean reefs, alcyonaceans in the Indo-Pacific. 9. Much of the difficulty in comparing reefs stems from the lack of uniformity in surveying methods. Problems of describing the complex three-dimensional patterns of organisms on reefs have yet to be solved, and hence little progress has been made in explanation of these patterns. Explanation in terms of simple environmental controls is inadequate. 10. Understanding the distribution of corals is made more difficult both by taxo-nomic problems and by the plasticity of growth form in different situations. 11. Growth of corals and reefs may be estimated by measuring the growth of individual colonies, measuring rates of calcium carbonate deposition in the skeleton, measuring topographic change on the reef and deducing net rates of reef growth from geological evidence. Massive corals may increase in diameter by 1 cm./year, branches of branching corals may increase in length by 10 cm./year. Study of deposition rates shows variation within colonies, between species, in light and dark, and seasonally. Rates of reef growth extrapolated from colony measurements reach 2–5 cm./year, and contrast with figures as low as 0–02 cm/year averaged over 70 million years from borehole data. Both colony growth rates and geological data suggest worldwide variations in rates of reef growth. 12. In spite of clear evidence of long-continued subsidence, present surface features of reefs, often only thinly veneered by modern corals, have been much affected by recent sea level fluctuations. Many slightly raised reefs at 2–10 m. above sea level date at 90–160 thousand years B.P.; there is evidence for a sea level at about the present level at 30–35 thousand years B.P.; and controversy continues over whether sea level has stood higher than the present at any time since the last sea level rise began about 20,000 years ago. Evidence from many reefs suggests a slightly higher sea level in the last 4000 years, but on other reefs such evidence is lacking. 13. Several reef features (submerged terraces, groove-spur systems, algal ridge, reef flat, reef blocks and reef islands) have been interpreted either as relict features dating from a higher sea level in the last 5000 years, or contemporary features developed in response to present processes. In some cases the evidence is equivocal; in others it is clear that diverse features are being grouped together under the same name. If such features are referable to a higher sea level, this may have been of last Interglacial or even Interstadial age rather than Holocene. 14. A reef consists of a rigid framework defining several major depositional environments within and around it. Sediments are of biological, mainly skeletal origin, except in unusual environments such as the Bahama Banks. The characteristics of sediments derived from organisms depend partly on the breakdown patterns of particular skeletons, partly on transportation and sorting processes. Fine sediments may be either detrital, or physicochemical precipitates. 15. Organisms affect sediments after deposition, by disturbance, transportation and probably comminution. Fish and holothurians have been studied in detail. 16. While new theories of coral reefs are proposed from time to time, the need is less for new theories than for standardised procedures to ensure comparability of reef studies and the identification of variations in reefs both on local and regional scales. While reefs as biological systems adjust relatively rapidly to changes, reefs as geological systems adjust much more slowly. Because of the magnitude and recency of Pleistocene fluctuations in sea level, many biological features of reefs are out of phase with inherited geological features, and this had led to much controversy.  相似文献   

12.
Wolosz. T. H. 1992 07 15: Turbulence-controlled succession in Middle Devonian reefs of eastern New York State.
The Edgecliff Member ol the Middle Devonian Onondaga Formation contains numerous reefs comprised of two distinct facies. The Phaceloid Colonial Rugosan Facies consists of thickets and mounds, while the Favositid/Crinoidal Sand facies occurs as flank beds surrounding rugosan mounds and as low shield-shaped banks interbedded with thickets of the colonial rugosan facics. Three of these reefs - the North Coxsackie. Albrights and Roberts Hill reefs - have been studied in order to determine the factors that controlled their development and their preserved paleocommunity succession. Both the Roberts Hill and Albrights reefs display well-developed rugosan mounds with an internal succession of rugosan genera. The North Coxsackie reef is a crinoidal sand bank with rugosan thickets and a back-reef satellite mound. Based on the lithology of the underlying limestone in which the reefs are rooted, the North Coxsackie reef is considered to have grown in a shallow-water environment, landwards of the two other reefs. Successional sequences or partial sequences are common to the three reefs, and are found to be reversible - a response attributed to changes in sea-level. As a result, the successions preserved in these reefs are interpreted as having been controlled by degree ol water turbulence.  相似文献   

13.
黔北桐梓的戴家沟剖面和狮溪剖面志留系兰多维列统特列奇阶下部的韩家店组出露完好,该组泥岩、粉砂岩中夹有厚度1—3m、直径4—7m的小型点礁。礁核相多具典型的障积格架岩特征,但生长时限短暂,群落分异度低,仅见床板珊瑚、单体四射珊瑚、苔藓虫和海百合茎,礁间为珊瑚、苔藓虫和海百合茎碎片堆积的滩相,伴生丰富的遗迹化石。在陆源碎屑快速沉积的背景下,浑浊海水频繁的富营养化过程限制了礁体纵横向生长和朝高分异度群落发展的可能性。  相似文献   

14.
广西,贵州和川东二叠纪礁相岩石和礁后相岩层内获得了红藻Solenoporella,Gymnocodium,Permocalcu-lus;绿藻Anthracoporella,Mizzia以及显微疑难藻类化石Pseudovermiporella,Tubiphytes等,除了广西隆林有中二叠世茅口期藻类化石外,其它均属于晚二叠世乐平世的分子,这些藻类植物一般生活于热带和亚热带,正常盐度的浅海水内,其水深不大于30m,川东,鄂西晚二叠世礁属于浅水海绵礁,而非深水礁。  相似文献   

15.
Natural and anthropogenic catastrophes occurred at the end of the previous and in the beginning of the current centuries at the coral reefs of the World Ocean, and their consequences for the tropical shelf ecosystems have been described based on published data and our own investigations. It has been shown that in recent decades coral populations on reefs of tropical and subtropical regions of the World Ocean have been reduced by 80%, and in some areas have completely vanished. The biodiversity of reef ecosystems has been considerably reduced. The main reason for such changes is a 1-2°C increase in the temperature of surface waters in comparison with the monthly mean temperature in the hot season. The fate of the damaged coral reefs is under discussion. It is thought that in clean waters partially damaged coral reefs can recover, whereas in waters polluted as the result of human activity they collapse. The rate of coral reef restoration depends on the hydrological and hydrochemical conditions, frequency of natural calamities and competitive interrelation of algae and corals on the damaged sites of coral reefs. The nature of competitive interrelation between algae and corals is considered, viz., the dynamics of obliteration of damaged and dead coral colonies by various algal species, mechanisms of competitive interrelation, effects of the environment on the competitive ability of corals and algae, the internal and external conditions for victory in competitive activity. It has been suggested that coral reefs can be restored through temporary transformation into a vegetable reef. In the absence of natural calamities damaged reefs can be clearly restored to their original or altered state over several decades, but only in clean waters.  相似文献   

16.
塔里木板块塔中井区上奥陶统凯迪阶良里塔格组的沉积序列由碳酸盐岩台地区礁滩复合体灰岩构成,显示晚奥陶世由高生物多样性形成的暖水浅海域生态组合。根据滩相灰岩的颗粒组成,可次分为生屑为主、生屑-内碎屑混合、内碎屑为主的三大类型,其中灰泥充填和亮晶方解石胶结均有。部分滩相是礁相单元的近源沉积,而内碎屑和生屑经各种营力改造后多以不同比例混合独立形成滩相。滩中的颗粒粒径一般多小于厘米级,仅部分核形石、珊瑚等颗粒可达到砾级,这些滩多堆积于最大风暴浪基面之上的深度。  相似文献   

17.
Database on isolated low-latitude carbonate banks   总被引:1,自引:0,他引:1  
Dr. Adam Vecsei 《Facies》2000,43(1):205-221
Summary A database on modern isolated neritic carbonate banks from the tropical and subtropical oceans provides individual and collective data on the geography (distribution and coordinates), morphology (summit area, perimeter, depth, reefs). A bibliography is also provided. Maps illustrate the global distribution and the major clusters of the banks. The database allows to estimate the number of banks that were too small to be mapped, and gives insights into the global significance of carbonate bank summits and slopes.  相似文献   

18.
Halimeda bioherms of the northern Great Barrier Reef   总被引:2,自引:0,他引:2  
The reefless tract directly behind the ribbon reefs on the outer shelf off Cooktown supports a luxuriant growth of Halimeda that, during the Holocene, has developed into bioherms. These mounded biodies of unconsolidated sediment have formed banks that vary in height between 2 and 20 m. Combined shallow, high-resolution seismic reflection profiles and side-scan sonar have diferentiated three areas of biohermal complexes behind the ribbon reefs of Cooktown. Observations by SCUBA and submersible plus the sedimentology of the bioherms indicate that they are in situ accumulations. Evidence from dating of cores suggests that the Halimeda bioherms began to grow about 10 000 years B.P. and their growth has continued to the present time, even though their tops are presently restricted to a depth of -20 m. It is suggested that the origin and morphology of the bioherms are related to a specific hydrodynamic phenomenon, involving jets of nutrient-rich, upwelled oceanic water intruding onto the outer shelf via the narrow passes between the ribbon reefs, and forming eddies behind the ribbons.  相似文献   

19.
土壤种子库的研究进展及若干研究热点   总被引:98,自引:2,他引:96       下载免费PDF全文
 土壤种子库是指存在于表层土壤(包括凋落物)中的有生命的种子。土壤种子库的研究已是植物生态学研究不可缺少的一部分,现已成为植物种群生态学中比较活跃的领域。土壤种子库时期是植物种群生活史的一个重要阶段,有人称之为潜种群阶段。土壤种子库对一年生植物来说尤其重要。土壤种子库简单地可分为瞬时土壤种子库和长久土壤种子库,即使给予理想的萌发条件如季节、温度、湿度等,土壤种子库中也仍有部分种子保持休眠状态,休眠的种子组成了土壤长久种子库的成分。时空异质性是土壤种子库的基本特性之一,不仅不同植被类型的土壤种子库具有不同的组成、大小和多样性,而且微环境也影响土壤种子库的分布格局。由于萌发、捕食和衰老等原因,土壤种子库具有季节动态,一般在旧种子萌发之后,新种子散布之前达到最低点。在高等植物占据的大多数生境中,以休眠繁殖体形式存在的个体远远超过地上植株的数量;土壤种子库、幼苗库和成年植被相互联系相互影响。由于各种原因如群落类型的差异、群落的演替阶段、取样的时间等,地上植被和土壤种子库之间关系大体上可分为两种情况,即相似性和差异性;研究土壤种子库的方法通常有萌发法和物理分离法。土壤种子库能部分反应群落的历史,对退化生态系统的恢复起着重要的作用。目前土壤种子库的主要研究热点问题可分为以下几个方面:1)土壤种子库的研究方法,2)土壤种子库的分类问题,3)土壤种子库分布的时空格局,4)地上植被和土壤种子库的关系,5)土壤种子库的动态等。  相似文献   

20.
The blue starfish Linckia laevigata grazes coralline algae. The starfish populations studied were composed entirely of adults. Spawning takes place in October at the southern end of the Great Barrier Reef. On reefs which were unaffected by Acanthaster planci, L. laevigata was confined to algae covered reef tops and rubble banks. On reefs affected by A. planci, L. laevigata had extended its range and was feeding on and among the coralline algae covered dead hard coral skeletons on the reef perimeter. Coral regrowth, followingattack by A. planci , was found to be slower on reefs with populations of L. laevigata living on the reef perimeter than on reefs where they were absent from this region. It is suggested that grazing by L. laevigata destroys small coral colonies and newly settled larvae thus slowing down the rate of coral regeneration. The consequences of this reduced rate of recolonisation is also discussed.  相似文献   

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