Distribution and evolution of Carboniferous reefs in South China

Reefs are sensitive proxies for palaeontological, palaeoenvironmental, and palaeogeographical changes during geological history. In South China, after the collapse of the reef ecosystem during the Frasnian-Famennian and Hangenberg mass extinction events, Carboniferous reefs underwent evolutionary episodes of recovery, decline, and turnover, which were controlled by changes of reef-builders abundance, sedimentary facies, relative sea level, and even global climate. In Tournaisian times, only a few Waulsortian-like banks have been found in Liuzhou, Guangxi without metazoan reefs, which were caused by the lack of reef-builders, such as colonial rugose corals and bryozoans, and the dominant non-carbonate facies (shale, mud stone and sandstone) driven by low relative sea level. The absence of mud mounds in the early Viséan was attributed to the regression event during the Tournaisian-Viséan boundary. During Viséan times, bryozoan-coral reefs in Huishui, Guizhou and Tianlin, Guangxi occurred during a time of increasing biodiversity and carbonate facies resulting from relative sea-level rise. The number of potential reef-builders as colonial rugose coral and bryozoan genera significantly increased in Viséan times in South China. The reef abundance declined during Serpukhovian times in South China and the controlling factors were decreasing abundance of potential reef-builders and developing non-carbonate facies due to a relative sea-level fall. The sedimentary facies were characterized by shale, mud stone, sandstone, and dolostone during this time. A distinct change in reef types occurred after the Mississippian-Pennsylvanian boundary, when phylloid algae and red algae reefs (distributed in Ziyun, Guizhou and Beibuwan, Guangxi) replaced metazoan reefs and became the dominant role in reef ecosystem. This reef turnover event may be triggered by the dramatic relative sea-level fall during the mid-Carboniferous, and continued low relative sea level in South China and global flourish of phylloid and red algae during Pennsylvanian times. Grainstone and dolomitic limestone were the main composition of the platform sedimentary facies in South China during Pennsylvanian times. In addition, global climate cooling and warming, resulted from the waxing and waning of Gondwana glaciation, may also influence the reef evolution in South China, as evidenced from the consistent transgression and regression events and reef evolutionary pattern between South China and globe during the Carboniferous.     

2008年夏季南海北部浮游植物群落结构特征分析

根据2008年8月15日—2008年9月7日南海北部调查期间所获得的网采浮游植物资料,对该海域的4个断面共计13个站位的浮游植物群落结构特征进行了研究,包括种类组成、丰度、分布、多样性以及浮游植物群落结构与环境因子之间相关关系等基本状况。本次调查共鉴定出浮游植物4门53属169种(含变种和变型),主要以暖水性、广温性和广布性种为主,其中硅藻门(Bacillariophyceae)37属114种,占总种数的67.4%,甲藻门(Pyrrophyta)12属50种,占总种数的29.6%,蓝藻门(Cyanophyta)2属3种及金藻门(Chrysophyta)2属2种等。浮游植物丰度平均值为18.06×104cells/m3,其中硅藻丰度平均值为55.72×106cells/m3,甲藻丰度平均值为0.81×106cells/m3。调查区域内的优势种包括铁氏束毛藻(Trichodesmium thiebautii),洛氏角毛藻(Chaetoceros lorenzianus),柔弱菱形藻(Nitzschia delicatissima),红海束毛藻(Trichodesmium erythraeum)和菱形海线藻(Thalassionema nitzschioides)。藻类为聚类分析(UPMGA)将站点大致上分为4个生态区(珠江口生态区,吕宋海峡区,琼东上升流区和18°N断面区),结果表明,在地理位置上分布比较相近的站点具有较高的群落结构组成相似性。     

南海北部白姑鱼生长和死亡参数的估算

将南海北部白姑鱼分成南海北部大陆架和北部湾两个不同海域群体,根据20世纪60年代和90年代在南海北部底拖网渔业资源调查资料,利用ELEFAN技术估算了南海北部白姑鱼的生长和死亡参数.结果表明,北部湾和陆架区的生长参数L_∞、K、t₀分别为382mm、0.42、-0.16龄和315mm、0.35、-0.23龄.体重生长拐点年龄t_r分别为244和287龄;瞬时总死亡率(Z)、自然死亡率(MF)分别为3.55、0.93、2.62和3.12、0.85、2.27;当前开发率为074和073,资源处于过度利用状态.根据BevertonHolt动态综合模型,建议北部湾和陆架区白姑鱼的最适开捕年龄应大于190和195龄,相应的开捕体长大于2.11和168mm.     

2007年10月南海北部浮游纤毛虫的丰度和生物量

报道2007年10月南海北部海域(21°25.47′N 17°24.95′N,109°28.86′E 113°13.01′E)纤毛虫丰度和生物量的水平分布及砂壳纤毛虫的种丰富度。包括了13个断面的82个站位,Rosette采水器采水,水深低于15 m的站位采0,5 m和10 m;小于30 m站位,采0,10 m和底层;大于30 m的站位,采0,10,30 m和底层。纤毛虫丰度为0 5757 ind./L,平均(848±776)ind./L。无壳纤毛虫占绝对优势,其丰度占纤毛虫总丰度的比例平均为(91.9±9)%;纤毛虫生物量为0 12.09μg C/L,平均是(1.2±1.54)μg C/L,无壳纤毛虫的生物量平均为(0.94±1.27)μg C/L,占纤毛虫总生物量的78.6%。共发现砂壳纤毛虫16个属,49种,拟铃虫最多,具有一定的季节性。纤毛虫水体(40 m到表层)丰度为6.4×1069.1×107ind./m2,平均是(3.6×106±1.4×106)ind./m2;水体生物量3.6 195.8 mg C/m2,平均(48.1±33.7)mg C/m2。纤毛虫多分布于近岸浅水区(高温低盐,高Chl a),最大丰度要高于我国其他海区,不是Chl a最高的地方纤毛虫的丰度也最大,纤毛虫丰度最大时Chl a偏低。     

电阻率成像法在树干水分吸收过程研究中的应用

将地球物理学中广泛运用的电阻率成像法成功地运用于树干内部截面电阻率分布特性的监测,利用电阻率平面分布图来分析树干内水分的空间分布和动态变化特征。结果表明：截面内树干水分的含量具有从核心部沿径向向外逐渐递增的趋势;位置较高的截面比较低的截面具有更多的水分含量,但充足的水分补给能打破这种水分分布的规律性,靠近补给源的截面含水率上升幅度最高;即使是在水分补给充足的情况下,树干内水分的吸收并不是面状饱和推进的过程,而是存在着优先纵向流动的生理机制;利用电阻率的变化,可以实现水分在截面上的优势流的定位。     

渤海南部牙鲆的食性及摄食的季节性变化

1051尾渤海南部牙鲆的胃含物分析表明,渤海南部牙鲆为捕食性(游泳生物食性)鱼类,其食物成分有30余种,以底栖虾类中的口虾蛄、鲜明鼓虾、日本鼓虾、脊尾褐虾,软体动物的日本枪乌贼及鱼类中的斑(鱼祭)、鳀鱼、黄鲫、六丝矛尾虾虎鱼及焦氏舌鳎等动物为主要食物。牙鲆除冬季外,其余时间均强烈摄食,而且其摄食的季节性变化明显:春季以鱼类(重量占80.9％)及甲壳类(18.6％)为主要食物;夏季以鱼类(83.5％)及软体动物类(13.1％)为主要食物;秋季主要摄食鱼类(87.9％);冬季则主要摄食鱼类(73.2％)及甲壳类(19.7％)。     

广东东海岛与硇洲岛海域底栖贝类物种多样性及其地理分布

海洋底栖贝类是海洋底栖动物区系的重要组分之一, 也是影响海洋生态系统和海洋底质环境的关键类群之一。粤西岸段地处南海北部, 海洋底栖贝类物种丰富, 但却是我国海洋底栖贝类区系调查最为缺乏的区域之一, 严重妨碍了我国近海底栖动物地理区系区划工作的开展。东海岛与硇洲岛海域是粤西岸段中底栖贝类历史研究相对较多的地区, 也是揭示南海北部底栖动物地理格局的关键地区。本文基于中山大学地理科学与规划学院2021-2023年间在东海岛与硇洲岛潮间带及近海海域采集的底栖贝类标本的鉴定, 结合中国科学院南海海洋研究所馆藏标本记录及已发表文献中记载物种的整理, 更新了该海域的底栖贝类名录, 并对各物种在东亚大陆近海的地理分布类型进行了分析。本研究共采集贝类标本2,600余号, 分属73科144属207种, 其中38种为东海岛与硇洲岛海域新记录。结合中国科学院南海海洋研究所馆藏标本及历史文献资料记录的物种, 至本研究为止, 东海岛与硇洲岛海域共记录底栖贝类115科330属602种, 为目前南海北部大陆岸段海洋底栖贝类物种数最多的地区。区系成分上, 热带性暖水种占26.2%; 热带-亚热带性暖水种占49.3%; 余下24.4%为广温性种。地理格局上, 有89.0%的种类在海南岛也有分布记录, 80.2%的种类在北部湾也有分布记录, 粤东岸段有分布记录的种类也占80.2%。研究结果表明, 东海岛与硇洲岛海域的底栖贝类区系十分丰富, 热带性特征明显, 且与海南岛的联系最为密切, 在南海北部近海底栖生物地理区划上可考虑同海南岛划入同一生物地理地区。基于本文结果及近年来的南海北部底栖生物相关研究, 我们推测雷州半岛及琼州海峡对南海北部底栖生物扩散及生物地理格局的影响程度很有可能被高估了。本研究丰富了雷州半岛东侧海域的底栖贝类区系, 为开展整个南海北部的底栖生物地理格局与区系区划工作提供了数据支持。     

High-resolution sea surface temperature records derived from foraminiferal Mg/Ca ratios during the last 260 ka in the northern South China Sea

High-resolution sea surface temperatures (SST) derived from Mg/Ca ratios of Globeriginoides sacculifer at ODP Site 1144 were reported to reveal the SST changes during the last 260 ka in the northern South China Sea (SCS). The results indicate an average Holocene SST of about 26.7 °C, about 3.6 °C increase from LGM to the Holocene, and higher temperature during MIS 5.5 than the Holocene. These agree well with other foraminifer Mg/Ca and U^k₃₇ SST records in this region. The Mg/Ca records suggest warmer SSTs during MIS 3 in the northern SCS, compared with those in the eastern Pacific. Strong East Asian summer monsoon during MIS 3 indicated by paleoclimate records from nearby continents may account for it. Step-wise increases during terminations are shown in our SST record, and the beginning of deglacial warming occurs at about 19 ka, which precedes the change of oxygen isotopes, suggesting a tropical driven forcing for the SST change in the northern SCS. This is further supported by a robust semi-precessional cycle centering at  9.1 ka in the spectra of the SST record, which is absent in that of the oxygen isotopes. However, tropical driven forcing seems not to be indicated in another Mg/Ca SST record in the northern SCS [Oppo, D.W. and Sun, Y.B., 2005. Amplitude and timing of sea-surface temperature change in the northern South China Sea: Dynamic link to the East Asian monsoon. Geology, 33 (10): 785–788.]. The discrepancy may be caused by different post-deposition dissolutions of foraminifer tests at these two sites. Details about the modification of foraminifer Mg/Ca ratios after burial, however, are not well known in this region, and further studies are needed.     

南海北部莺歌海盆地新近纪古环境与层序地层格架再认识

利用莺歌海盆地钻井中获得的丰富的有孔虫、钙质超微化石等微体古生物资料,对研究区新近纪各地层沉积时期的古环境及演化进行了研究。结合古环境及地震资料分析,重新认识了莺歌海盆地新近纪各层序界面。S40、S30、S28、S27等界面都具明显的峡谷侵蚀特征。另外,①号断层上升盘地层受峡谷侵蚀搬运后在下部S29界面上形成较好的储层,是下一步油气勘探的重要方向之一。     

A Code of Conduct for Human and Regional Security Around the South China Sea

In the past decade, there have been calls for a regional code of conduct for the South China Sea to ensure peace and stability in a region replete with conflicting territorial claims over offshore geographical features. This paper will distinguish between the process of codification of rules and principles in one document, on the one hand, and the process of implementing existing rules and principles, on the other hand. It will be argued that rules and principles governing conduct for human and regional security around the South China Sea already exist in many forms and that the South China Sea states are obligated by international law to implement them without waiting for their consolidation in one document.     

黄、东海生态系统中鱼卵、仔稚幼鱼种类组成与数量分布

2000年秋季和2001年春季“北斗号”生物资源调查船利用大型浮游生物网采用表层水平拖网的调查方式对黄、东海鱼卵、仔稚幼鱼种类组成与数量分布进行了调查。秋季和春季分别设置66个(黄海26个,东海40个)和98个(黄海46个,东海52个)调查站。每站拖网10min,拖网速度为3.0nmile/h。调查结果表明:秋季和春季所采集到的鱼卵和仔稚幼鱼样品共62种以及鳗鲡目和飞鱼类两大类,鉴定到种的44种,隶属于9目33科40属;还有10种仅能鉴定到属,6种和飞鱼类仅能鉴定到科,1种和鳗鲡目一大类仅能鉴定到目以及1种不能识别。优势种为、鲐、带鱼、棱、黑鳃梅童鱼、绿鳍鱼以及多鳞、鼠、大泷六线鱼、细纹狮子鱼等。2000年秋季,从黄海和东海分别采集到16粒鱼卵、107尾仔稚幼鱼和495粒鱼卵、116尾仔稚幼鱼。鱼卵、仔稚幼鱼的出现频率分别为26.92%、38.46%和65.00%、40.46%,平均密度分别为0.6粒/站、3.6尾/站和12.4粒/站、2.8尾/站。2001年春季,从黄海和东海分别采集到3粒鱼卵、61尾稚幼鱼和17587粒鱼卵和1560尾仔稚幼鱼,鱼卵、仔稚幼鱼的出现频率分别为2.17%、39.13%和57.69%、48.08%,平均密度仅分别为0.07粒/站、1.3尾/站和338.2粒/站、30.0尾/站。秋季,黄海区的硬骨鱼类进入产卵末期,而东海区才刚刚进入产卵末期。春季,黄海区的硬骨鱼类刚刚进入产卵初期,而东海区已进入产卵盛期。此外,对秋季和春季鱼卵和仔稚幼鱼的数量分布以及鼠、、棱、多鳞、少鳞、黑鳃梅童鱼、小黄鱼、鲐、带鱼、绿鳍鱼、大泷六线鱼和细纹狮子鱼等优势种类的鱼卵和仔稚幼鱼数量分布进行了详尽的描述。2000年和2001年黄海区鱼卵、仔稚幼鱼的种类组成与1985年和1986年发生了明显的变化,这与黄海区渔业资源和鱼类群落结构的变化是相符合的。从而说明人类的长期捕捞活动对海洋生态系统中鱼类资源的种群交替和鱼类群落结构的变化产生了较大的影响     

Coastal States in the South China Sea and Submissions on the Outer Limits of the Continental Shelf

The purpose of this article is to examine the outer continental shelf submissions made by the coastal states of the South China Sea and their potential impact on legal and political developments in the South China Sea. In accordance with the United Nations Convention on the Law of the Sea of 1982 and the guidelines of the Commission on the Limits of the Continental Shelf, coastal states are to establish the outer limits of their continental shelf where it extends beyond 200 nautical miles. Meeting this obligation is complicated in enclosed or semienclosed seas where there are maritime disputes such as in the South China Sea.     

南海北部海区浮游植物粒级结构生物光学反演模型的验证与评价

浮游植物粒级结构是海洋生态系统中的一个重要生物学因子。基于生物光学参数反演浮游植物粒级结构变化是当前水色遥感研究的热点问题。本文综合南海北部海区多年航次调查数据,对现有几类反演算法进行了区域性优化和验证评价。根据叶绿素 a 浓度（Chl a）或浮游植物吸收系数（aph （443））的阈值可实现南海北部海区小型（Micro）和微微型（Pico）浮游植物主导的划分,微型（Nano）的判别精度较差。基于归一化吸收光谱提取的粒级指数可定性地表征浮游植物粒级结构的综合变化趋势。基于叶绿素 a 浓度的三组分模型,较好地模拟浮游植物粒级结构的变化规律,可实现分粒级叶绿素 a 浓度的定量反演,Pico 粒级的反演精度较高;在此基础上,耦合浮游植物吸收光谱变化规律和总叶绿素 a 浓度定量反演粒级结构的模型,进一步提高了 Micro 和Nano 粒级的反演精度,且线性相关程度增强。     

China's Nine Dotted Lines in the South China Sea: The 2011 Exchange of Diplomatic Notes Between the Philippines and China

Important events relating to the sovereignty dispute over the Spratly Islands have arisen by fits and starts since 2009, marking the start of a new phase in the legal battle over territorial and maritime claims in the South China Sea. While the exchange of legal arguments between the parties has gradually laid bare their maritime claims, much still remains shrouded in uncertainty. Among the obscure claims wanting clarification is China's infamous nine-dotted-line map, which in 2011 elicited a response and counterresponse between the Philippines and China. This article examines the maritime and territorial claims of the Philippines and China as revealed in the recent discord over the nine-dotted-line map.     

Miltoncostaea marina gen. nov. sp. nov., and Miltoncostaea oceani sp. nov., a novel deep branching phylogenetic lineage within the class Thermoleophilia isolated from marine environments,and proposal of Miltoncostaeaceae fam. nov. and Miltoncostaeales ord. nov

Two novel marine actinobacteria, designated as SCSIO 60955^T and SCSIO 61214^T, were isolated from deep-sea sediment samples collected from the South China Sea. The cells of these organisms stained Gram-negative and were rod shaped. These strains were aerobic, and catalase- and oxidase-positive. Optimal growth occurred at 28 °C and pH 7 over 14 days of cultivation. Both strains possessed phospholipids and phosphoglycolipids. The main menaquinone was MK-7. The major fatty acid was C_16:0. The peptidoglycan structure was type A1γ′ (meso-Dpm). Analysis of genome sequences revealed that the genome size of SCSIO 60955^T was 3.37 Mbp with G + C content of 76.1%, while the genome size of SCSIO 61214^T was 3.67 Mbp with a G + C content of 74.8%. The ANI and 16S rRNA gene analysis results showed that the pairwise similarities between the two strains were 73.4% and 97.7% and that with other recognized Thermoleophilia species were less than 69.1% and 87.8%, respectively. Phylogenetic analysis of the 16S rRNA gene sequences showed that strains SCSIO 60955^T and SCSIO 61214^T were separately clustered together and formed a well-separated phylogenetic branch distinct from their most related neighbor Gaiella occulta. Based on the data presented here, these two strains are proposed to represent two novel species of a novel genus, for which the name Miltoncostaea marina gen. nov., sp. nov., with the type strain SCSIO 60955^T (=DSM 110281^T =CGMCC 1.18757^T), and Miltoncostaea oceani sp. nov., with the type strain SCSIO 61214^T (=KCTC 49527^T =CGMCC 1.18758^T) are proposed. We also propose that these organisms represent a novel family named Miltoncostaeaceae fam. nov. of a novel order Miltoncostaeales ord. nov.