南沙群岛封闭环礁空间结构的遥感信息与数学模型

阐述了造礁珊瑚生长发育的诸多条件,形成珊瑚环礁的地质背景与漫长的历史过程,珊瑚环礁的地貌特征与环境动力条件的密切关系,依据珊瑚环礁发育的规律及其表观的光谱响应特征,建立了封闭环环礁空间结构的数学模型,此模型与印证的结果是理想的,对于南沙群岛大片航行危险地带和暂不能入区进行研究有着重要的意义。     

动物的世外桃源——阿尔达布拉环礁

<正>在马达加斯加岛的西北部,有一个被称为"阿尔达布拉环礁"的地方,这里位置独特,人迹罕至,是动物们的世外桃源。独特的位置阿尔达布拉环礁位于马达加斯加西北约426千米处,距非洲东海岸640千米。在这片长34千米、宽14.5千米的海域里,有4座高出海平面约8米的珊瑚岛,它们彼此连接成环状。在珊瑚岛中间是一个浅浅的漏湖(即被沙坝或珊瑚分割而与外面的海域分离的局部海水水域),落潮时,部分珊瑚礁和岩石露出水面,而涨潮时水深也只有6米。这些     

日本列岛的形成及其构造体系

日本列岛处于亚洲大陆与太平洋之间,其地体的形成和构造体系,受亚洲大陆和太平洋的严重影响,因而是极其复杂的。现在加以论述。一、日本列岛的形成日本列岛古老地层很少,主要属古生代志留纪以后的地层。其形成的过程主要是由地槽发育经过海西运动(秋吉,佐川运动)、中生代运动(日高运动)和第三纪阿尔卑     

晚古生代右江盆地层序格架中的生物礁

通过对右江盆地泥盆纪、二叠纪生物礁的时空分布和成因类型的研究,结合层序地层研究的成果,将其划分为低位礁、陆棚边缘礁、海侵礁、高位礁.低水位礁仅发育于台盆背景,以加积丘礁或点礁为特色,常与混屑浊积岩、硅灰岩、硅泥岩共生.陆棚边缘礁发育于台盆和斜坡背景,与低水位礁相比,具有礁体大、数量多的特点.由于海平面的向陆超覆而形成的海侵型台盆礁、斜坡礁、台缘礁、台内礁组合,具加积-退积型堆积序列,礁顶发育硬底、生物挠动面、海底溶蚀面、淹没面、水下中止面等,礁盖包括硅岩、火山碎屑浊积岩、放射虫岩、骨针岩、深水退积相、生物密集层、浮游相灰岩、含锰磷酸盐灰泥岩等,生长方式主要是追补式和中止式,以宝塔礁、链状礁、点礁为主.高水位礁以进积礁、加积礁和混积礁组合为特征,广泛发育于台内、台缘、斜坡、台盆等环境,具向上变浅序列,礁顶发育暴露面、岩溶面、冲刷侵蚀面、钙化壳、白云岩帽等,礁盖主要有残积相、开阔台地相、浊积相、丘滩相等,规模大、分布广,以堤礁、环礁、马蹄形礁为主.     

从日本外大陆架划界案看冲之鸟礁之法律属性

联合国大陆架界限委员会(CLCS)对日本外大陆架划界案给出建议摘要,决定推迟对以冲之鸟礁为基点的九州帕劳海岭南部区块的审议。这一建议说明委员会并不认同日本以冲之鸟礁为基点主张外大陆架。从法律属性上看,冲之鸟礁是《联合国海洋法公约》第121条规定的不能维持人类居住和经济生活的岩礁,不能拥有专属经济区和大陆架。日本外务省声称日方以冲之鸟礁为基点主张的区块获得批准的言论是不符合《大陆架界限委员会第29届会议主席声明》和大陆架界限委员会《日本划界案建议摘要》原义的误导。     

黔南石炭纪珊瑚礁与南海现代珊瑚礁的对比研究

根据沉积环境和珊瑚礁的特征,分别对两种礁体进行了沉积相带的划分和建造过程的对比研究.分析表明:扁平村珊瑚礁中充填了大量的蜓、海百合茎和腕足碎屑等附礁生物组分,而现在珊瑚礁中的充填物大都以珊瑚碎屑为主;两种礁体虽形成于不同的时代,但具有类似的沉积相带分布和礁体形成过程,这与礁群落的盛衰状况密不可分.与晚石炭世的四射珊瑚相比,现代六射珊瑚对环境的适应能力更强,现代珊瑚礁的形成过程也更加曲折.     

湖相礁灰岩圈闭的成因类型及其对油气成藏的控制作用

沾化凹陷四扣洼陷及周缘地区在古近系沙四上亚段沉积时期发育了一套礁灰岩。在薄片观察和岩心分析测试的基础上,结合地层对比和储层物性分析,对礁灰岩储层特征及有效圈闭形成的控制因素进行研究,划分灰岩圈闭成因类型,探讨其在油气成藏中的控制作用。研究表明:湖相礁灰岩具有发育层位相对稳定、礁体规模不一、礁滩混杂、储层非均质性强等特点;礁灰岩圈闭的发育主要受沉积相带、成岩作用和构造运动的影响,可形成控制礁灰岩油气成藏的4类圈闭;礁灰岩圈闭类型在油气成藏过程中起双重控制作用,一方面控制了礁灰岩圈闭的有效性,另一方面控制了油气成藏的时间、输导体系类型和运移充注方式。     

四川北碚地区上二叠统长兴组生物礁成油条件浅析

本文通过北碚上二叠统长兴组生物礁成油条件的分析,认为川东西部地区长兴组生物礁的储集层段主要是晶间孔、溶蚀孔较发育的结晶白云岩和白云化礁灰岩,其发育程度与礁的成岩环境有关。油气主要来源于_上二叠统龙潭组,其次是长兴组。台地内的点礁面积虽小,但以群礁复合体形式展布,成油条件配置良好,含油有利。礁分布可能受隐伏基底断裂活动所形成的古构造控制。     

南海东沙环礁附近第二模态内孤立波生成过程的数值模拟

为了研究东沙环礁附近海域第二模态内孤立波的生成机制,基于非静压海洋模型SUNTANS,在南海实际地形条件下建立了南海东北部内孤立波三维数值模型,对该海域内孤立波的传播演变进行了数值模拟.模型模拟出了第二模态内孤立波,其垂向呈三层结构,即上层水体与下层水体水平向流速相同,并与中间层相反.第二模态内孤立波波速模拟值与理论计算值吻合较好.根据模拟结果,分析了东沙环礁附近海域第二模态内孤立波的生成过程,结果表明,该海域第二模态内孤立波源于从吕宋海峡附近海域传播而来的第一模态内孤立波和底部地形的相互作用,并与陆坡上部内潮的影响有关.     

我国的南海诸岛

南海诸岛,是南海上的珊瑚岛群。在祖国大陆以南,是一片还阔浩瀚的海洋,这个海洋,叫做“南海”。南海诸岛就是散布在碧波万顷的南海上的东沙群岛、西沙群岛、中沙群岛和南沙群岛的总称。它北起北纬21°以北,南至北纬4°以南,西起东经108°附近,东至东经118°以东。东沙群岛在汕头以南约140里,由东沙岛及其附近的几个滩、礁组成,是南海诸岛中位置最北,离大陆最近,岛礁数目最少的一群。东沙岛位于东沙环礁西部礁盘上,是东沙珠岛中唯一的岛屿,岛西原有二条沙堤包绕的小海湾,小海湾被人工填平后,全岛面积达1.8C平方公里。西沙群岛在海南岛榆林港东南约160里,是由一大群现代珊瑚礁和第四纪隆起珊瑚礁构成的群岛,其分布范围比东沙群岛大得多,由三十多个岛屿、摊、礁等组成。按照它们的集结情况可以分为东、西两群:较东的则宣德群岛,主要由七个岛屿组成,又叫东七岛,较西的叫永乐群岛,主要由八个岛屿组成,又叫西八岛。海南岛渔民来这里生产时,常先到宣德群岛,后到永乐群岛。所以,西沙群岛又被称为“上七下八的西沙群岛”。     

Crustal activities recorded in coral reefs in the northwestern South China Sea

Coral reefs in the northwest of South China Sea have recorded the information from not only the environmental variation but also the crustal activities there during their development. The main crustal activities correlated with the coral reef development include fault, seismic, and volcano activities, etc. The high-resolution spark seismic profiles in the northwestern South China Sea show that the fault activities in the coral reef region have been clearly recorded, and appear as neonatal faults incising reefs. Earthquakes in the coral reef region are rather intense, especially the two occurring on December, 31, 1994, and January, 10, 1995, around the southwest of Leizhou Peninsula, with the magnitude of 6.1 and 6.2, respectively. They have great influence on the growth of the local coral reefs. Quaternary volcanos are active in the northwestern South China Sea, especially around the southwest of Leizhou Peninsula, and they have obvious control of the coral reef development. Some submarine volcanoes form the substrates of coral reef, while a few emerge above the sea surface and form coral islands.     

热带岛礁型海洋牧场中珊瑚礁生境与资源的修复

我国南海的离岸岛礁以珊瑚礁生境为主。珊瑚礁在提升海洋生态资源和维护我国海洋国土权益上发挥了至关重要的作用。近年来,在全球气候变化以及人类活动的影响下,南海珊瑚礁生境和资源严重退化,威胁着渔业资源、海洋环境以及国土安全。现代化的海洋牧场被认为是实现南海资源可持续发展战略的新型海洋生物资源开发模式。珊瑚礁生境与资源的修复则是热带岛礁型海洋牧场建设的基础和关键。基于此,本文整理了珊瑚礁生境与资源修复的技术方法,详细介绍了珊瑚礁生境构建框架生物造礁石珊瑚的有性繁殖、断枝培育、底播移植等技术方法以及珊瑚礁其他特色生物资源人工放流技术,并提出了在珊瑚礁生境与资源修复中所面临的问题及相应对策。     

On biogeomorphology of Luhuitou fringing reef of Sanya City, Hainan Island, China

Based on comprehensive survey of 6 transects on Luhuitou fringing reef in Sanya City of Hainan Island, China, some features of its biogeomorphologic processes were found, including ( i ) three basic biogeomorphologic units: inner reef flat, outer reef flat and reef slope; (ii) two important biogeomorphologic boundary lines: up limit for live flat coral growing between inner and outer reef flats is Mean Lower Low Water of tropic tide ± 15 cm; the break in slope between reef flat and reef slope is Theoretical Lowest Tide±15 cm; (iii) three types of reef flat profiles in response to distinctive Holocene sea level changes and dynamic condition: Luhuitou type responds to falling sea level and low wave energy; Xiaodonghai type to falling sea sevel and high wave energy; type for atolls of Nansha Islands to stable sea level and low wave energy; (iv) hermatypic coral community is the most essential member in coral reef ecosystem and plays the most important role in biogeomorphologic process. Over the past 30 years Luhuitou fringing reef was severely destroyed by human activities, its biogeomorphologic function severely weakened, and it needs urgent management and protection.     

南海北部陆坡地形特征及其影响因素研究

南海北部陆坡位于南海北部大陆边缘,地质构造活动丰富,是大陆和深海进行物质和能量交换的重要过渡区。研究北部陆坡区复杂的地形地貌,有助于深化对南海北部陆缘海底地质活动与环境变化的认识,并为资源勘探与工程建设提供基础地质信息支撑。本研究基于全球水深地形图（General Bathymetric Chart of the Oceans,GEBCO）数据及实测多波束数据,对南海北部陆坡的地形地貌进行研究,识别出不同的地貌类型,并探讨其形成和发展的控制因素。研究表明,南海北部陆坡发育有海台、海山、海丘、海槽、海底峡谷以及冷泉地貌类型。南海北部陆坡地形地貌的发育和演化主要受控于构造活动及火山活动,而外动力地质作用如沉积输运、海平面变化及甲烷流体的活动等,都对研究区的地形地貌做了进一步的改造,使之更加复杂。     

一种适合珊瑚礁生态区用海项目的礁系生物群落调查方法

对国内常用的3种珊瑚礁生态系生物群落调查方法：ReefCheck、截线样条法、HY／T082—2005珊瑚礁生态监测技术规程方法的生物指标、主要调查内容、工作效率、适用范围等进行对比分析,提出一种适合珊瑚礁生态区用海项目的珊瑚礁生物群落的调查方法。     

Coral mucus functions as an energy carrier and particle trap in the reef ecosystem

Zooxanthellae, endosymbiotic algae of reef-building corals, substantially contribute to the high gross primary production of coral reefs, but corals exude up to half of the carbon assimilated by their zooxanthellae as mucus. Here we show that released coral mucus efficiently traps organic matter from the water column and rapidly carries energy and nutrients to the reef lagoon sediment, which acts as a biocatalytic mineralizing filter. In the Great Barrier Reef, the dominant genus of hard corals, Acropora, exudes up to 4.8 litres of mucus per square metre of reef area per day. Between 56% and 80% of this mucus dissolves in the reef water, which is filtered through the lagoon sands. Here, coral mucus is degraded at a turnover rate of at least 7% per hour. Detached undissolved mucus traps suspended particles, increasing its initial organic carbon and nitrogen content by three orders of magnitude within 2 h. Tidal currents concentrate these mucus aggregates into the lagoon, where they rapidly settle. Coral mucus provides light energy harvested by the zooxanthellae and trapped particles to the heterotrophic reef community, thereby establishing a recycling loop that supports benthic life, while reducing loss of energy and nutrients from the reef ecosystem.     

Coral reef ecosystems in the South China Sea as a source of atmospheric CO<Subscript>2</Subscript> in summer

Field measurements of air-sea CO2 exchange in three coral reef areas of the South China Sea (i.e. the Yongshu Reef atoll of the Nansha Islands, southern South China Sea (SCS); Yongxing Island of Xisha Islands, north-central SCS; and Luhuitou Fringing Reef in Sanya of Hainan Island, northern SCS) during the summers of 2008 and 2009 revealed that both air and surface seawater partial pressures of CO2 (pCO2) showed regular diurnal cycles. Minimum values occurred in the evening and maximum values in the morning. Air pCO2 in each of the three study areas showed small diurnal variations, while large diurnal variations were ob-served in seawater pCO2. The diurnal variation amplitude of seawater pCO2 was ~70 μmol mol–1 at the Yongshu Reef lagoon, 420–619 μmol mol–1 on the Yongxing Island reef flat, and 264–579 μmol mol–1 on the reef flat of the Luhuitou Fringing Reef, and 324–492 μmol mol–1 in an adjacent area just outside of this fringing reef. With respect to spatial relations, there were large differences in air-sea CO2 flux across the South China Sea (e.g. ~0.4 mmol CO2 m–2 d–1 at Yongshu Reef, ~4.7 mmol CO2 m–2 d–1 at Yongxing Island, and ~9.8 mmol CO2 m–2 d–1 at Luhuitou Fringing Reef). However, these positive values suggest that coral reef ecosystems of the SCS may be a net source of CO2 to the atmosphere. Additional analyses indicated that diurnal variations of surface seawater pCO2 in the shallow water reef flat are controlled mainly by biological metabolic processes, while those of deeper water lagoons and outer reef areas are regulated by both biological metabolism and hydrodynamic factors. Unlike the open ocean, inorganic metabolism plays a significant role in influencing seawater pCO2 variations in coral reef ecosystems.     

Organic geochemical studies of sinking particulate material in China sea area II

Conclusions We have for the first time studied the compositions of ketone, aldehyde and alcohol lipid compounds in sinking particulate materials from Yongshu Reef lagoon and the continental shelf of the East China Sea collected by sediment trap sampling apparatus. The results indicate that sinking particulate materials contain abundant isoprenoid ketone, aldehyde and alcohol lipid compounds which take part in marine chemical cycling. The compositional features of these compounds show that sinking particulate organic matter mainly comes from autochthonous marine organisms and Yongshu Reef lagoon has more submerged macrophytes-derived component, while the continental shelf of the East China Sea contains more dinoflagellate-derived constituent. The contribution of higher land plant to sinking particulate organic matter may be very small. In contrast, it is greater in Yongshu Reef lagoon than that in the continental shelf of the East China Sea. Sinking particulate organic matter in the two regions undergoes strong biochemical transformation processes before reaching the depth of 5 m to the sea floor, and its intensity is greater in Yongshu Reef lagoon than in the continental shelf of the East China Sea. These results have certain reference value to the researches of marine chemistry, marine biology and marine sedimentology in China, and reveal the importance of organic geochemistry to the study of oceanology.