深圳东部海域造礁石珊瑚资源分布及其群落健康评价

采用边界摸查与截线样条法对深圳东部海域的造礁石珊瑚资源分布及其多样性进行全面调查,并对其群落生态系统健康状况进行了分析评价。结果表明,深圳东部海域共有造礁石珊瑚群落密集分布区37片,其中23片为重点分布区,总分布面积为193.73 hm²;共有造礁石珊瑚67种,分隶于13科及1个未定类,25属;优势种前三位为澄黄滨珊瑚（Porites lutea）、肉质扁脑珊瑚（Platygyra carnosus）和翼形蔷薇珊瑚（Montipora peltiformis）;造礁石珊瑚覆盖度均值为37.58%,其中站位16的覆盖度最高,为57.33%;站位2最低,为14.89%;丰度（d）、种类多样性指数（H′）、均匀度（J）均值分别为5.32、2.71和0.81;死亡率均值为8.23%,平均补充量均值为3.66 ind/m²;深圳东部海域造礁石珊瑚群落生态系统健康状况良好,其中鹅公湾、大鹿湾、西涌—东涌及杨梅坑海域为健康状态,梅沙—溪涌、大澳湾及茅东湾海域为亚健康状态。本研究对深圳东部海域造礁石珊瑚资源进行全面调查和评估,并对资源保护和生态系统健康发展提出做好规划与布局,制定相应保护及修复规划,设立监测站位,加强研究并建立修复示范区,联动公众与社会科普等5条建议,可为区域造礁石珊瑚群落的保护、管理、恢复、重建和可持续发展提供参考。     

Supply of terrigenous organic matter from tidal flat to the marine environment: An example of neritic source rocks in the Eocene Pinghu Formation,Xihu Depression,East China Sea Shelf Basin

The terrigenously-dominated marine shales which were deposited in the lower Eocene Pinghu Formation were thought to be a potential source rock in the Xihu Depression of the East China Sea Shelf Basin. However, the exceptionally high total organic carbon content (TOC, >6% on average) of the tidal sand ridge samples was not compatible with their sedimentary environment, indicating coal-bearing sedimentary debris may have been transferred from the coast to the ocean. In this study, new sights into the origins and supply of organic materials in the coastal environment were proposed in the neritic organic matter of the Eocene Pinghu Formation. A discriminant model was developed using plynofacies analysis data to pinpoint the source of organic materials in marine source rocks. The discrimination results suggested that marine mudstones were associated with tidal flat mudstones rather than deltaic ones. The biomarker characteristics of mudstones deposited in various environments support this assertion, indicating that the supply of plant materials in tidal flats is the primary organic matter source for the marine environment. The organic matter abundance was elevated in tidal flats due to their superior preservation conditions. Additionally, the lithological assemblage of tidal flats suggests that tidal currents can scour marshes and then transport dispersed terrigenous organic materials to neritic areas. These findings indicate that coal-bearing sedimentary debris was likely transferred from the coast to the ocean, and tidal currents are thought to be the dominant mechanism driving organic matter from the tidal to the marine environment.     

On the small-scale fractal geometrical structure of a living coral reef barrier

The topographical complexity of coral reefs is of primary importance for a number of hydrodynamical and ecological processes. The present study is based on a series of high-resolution seabottom elevation measurements along the Maupiti Barrier Reef, French Polynesia. Several statistical metrics and spectral analysis are used to characterize the spatial evolution of the coral geometrical structure from the reef crest to the backreef. A consistent fractal-like power law exists in the spectral density of bottom elevation for length scales between 0.1 and 7 m, while at larger scale, the reef structure shows a different pattern. Such a fine characterization of the reef geometrical structure provides key elements to reconstruct the reef history, to improve the representation of reef roughness in hydrodynamical models and to monitor the evolution of coral reef systems in the context of global change. © 2020 John Wiley & Sons, Ltd.     

全球变暖和海洋酸化背景下珊瑚礁生态响应的研究进展

生物礁是由珊瑚虫、藻类等造礁生物组成、具有抗浪结构的海相碳酸盐岩,是全球主要碳库之一,也是观察热带海洋影响中-高纬度环境过程的重要窗口。近二、三十年以来,伴随着海洋水体的显著酸化和增温,全球热带海洋生物礁的主体——珊瑚礁系统遭受了不同程度的影响。其中,对于高温强迫而言,海水温度上升诱发珊瑚白化、抑制珊瑚的自我修复;海洋酸化可以显著改变珊瑚钙化率、抑制珊瑚幼虫发育、引发珊瑚礁的溶解;两大因素均可改变珊瑚礁的群落结构。针对这些环境要素的改变,珊瑚自身可以通过共生藻的种类转换以及调控基因表达等手段在一定程度上抵抗高温胁迫;但若温室气体的排放不受控制,绝大多数珊瑚礁到21世纪末都将遭受灾难性打击。为应对未来不同场景下的珊瑚礁变化,还需要对高温、酸化等关键因子响应特征进行更深入的研究;珊瑚礁长序列研究有可能为珊瑚的长周期演化特征提供关键认识,也为现代观测提供有益补充。     

西藏措勤断块中—上三叠统嘎热扎地组的建立

在西藏措勤断块新建了中三叠统—上三叠统卡尼阶岩石地层单位——嘎热扎地组.在建组剖面上,嘎热扎地组厚约485 m,下部岩性以碎屑岩为主,上部岩性为碎屑岩夹灰岩.嘎热扎地组与下伏上二叠统—下三叠统木纠错组、上覆上三叠统诺利阶麦龙岗组均为整合接触关系.该组尚未发现指示地层时代的化石,但前人在其下伏的木纠错组中发现了早三叠世牙...     

南沙群岛珊瑚砂工程性质研究

珊瑚砂是发育于热带海洋环境中的一种特殊的岩土介质类型 ,主要由珊瑚碎屑和其他海洋生物碎屑组成 ,碳酸钙含量高达 96 %。特殊的物质组成、结构和发育环境导致珊瑚砂具有独特的工程性质。文章综述了珊瑚砂的压缩性、破碎性、剪切特性和强度特性 ,指出了其显著的土力学特点 :高孔隙比、高摩擦角和低强度值。颗粒破碎是影响珊瑚砂变形和强度特性的主要因素 ,深入研究珊瑚砂的工程性质对珊瑚岛礁工程设计和施工、加强国防建设、开发热带海洋渔业资源和海底石油资源具有重要的意义。     

泉州市部分石材矿山地质灾害调查分析

针对泉州市4个主要石材采矿带的矿山分布特征及矿山开采状况进行调查分析,认为各矿山采矿场地普遍偏小,以个体开采经营为主,机械化程度低,开采作业较零乱,开采边坡大多数形成高陡的采掘面,缺少安全台阶。各矿山综合治理相对滞后,废石、废碴随意堆放,均存在不同程度安全隐患和潜在的地质灾害,通过分析研究,提出预防建议和对策。     

大渡河猴子岩水电站库尾段藏碉群斜坡巨型堆积体的成因分析

丹巴梭坡堆积体是一巨型第四纪堆积体,分布在大渡河的左右两岸,其上有114座珍贵藏碉。对堆积体的成因有冰川成因、冰水成因和泥石流成因等各种观点。在对堆积体现场进行详细勘察的基础上,对藏碉群斜坡巨型堆积体的成因进行了深入分析,得出左岸堆积体的成因主要以崩滑作用为主;右岸堆积体是冰源泥石流和崩塌、滑坡等作用的混杂堆积。并在后来的钻孔揭示中得以验证。这对于川西地区深厚覆盖层成因的揭示以及藏碉群文物的保护均具有重要的意义。     

南沙珊瑚礁生态系中元素的垂直转移途径

于１９９３年和１９９４年用沉积物捕捉器采集南沙永暑礁和渚碧礁内的沉降颗粒物,用中子活化法分析元素的含量并计算通量,通过对生源要素的统计相关分析,垂直沉降颗粒物中的元素人,非生源要素在泻湖中的停留时间的探讨,研究了南沙珊瑚礁生态系中元素的垂直转移途径,结果表明,在南沙珊胡礁泻湖中元素的停留时间较海水中短,元素的循环速率高,且尤以与生物作用有关的元素为甚;颗粒物中非生源要素的垂直转移主要是通过生物过程