A new coral reef province in the Gulf of Carpentaria, Australia: Colonisation, growth and submergence during the early Holocene

Multibeam sonar mapping, drill cores and underwater video data have confirmed the existence of a previously unknown coral reef province in the Gulf of Carpentaria, Australia. Seven reefs, comprised of coral limestone that support living corals have been mapped so far and as many as 50 other reefs may exist in the region. U/Th ages show that reef growth commenced shortly after limestone pedestals were submerged by rising sea level around 10.5 kyr BP, making them the oldest Holocene reefs known in Australia. Reef growth persisted for ~ 2.0 kyr but it had ceased at most locations by ~ 7.0 kyr BP. Measurements of reef growth rates (0.95 to 4 m kyr^− 1), indicate that the reefs were unable to keep pace with contemporaneous rapid sea level rise (> 10 m kyr^− 1), which is consistent with a “give up” reef growth history. Core samples from reef platforms demonstrate that Pleistocene limestone is exposed at depths of 27 and 30 m below present mean sea level. These depths represent regionally significant phases of reef growth during a prolonged sea level still stand. We conclude that the reefs are therefore mostly relict features, whose major phase of growth and development relates to an earlier, pre-Holocene sea level still stand.     

基于SLAMM模型的海平面上升对广西沿海红树林影响研究

本文基于SLAMM模型分析了不同情景下海平面上升对广西沿海红树林分布面积的影响及其空间差异,通过对比实验定量分析了潮差和沉积速率的作用。结果显示,与基准年2007年相比,2100年广西红树林面积在当前海平面上升速率、典型浓度路径RCP2.6、RCP4.5和RCP8.5情景下分别减少0.57%、4.99%、7.99%和17.39%,珍珠港、茅尾海、丹兜海和英罗港受影响程度较大。当地潮差与红树林面积减少率呈负相关关系。需维持红树林生长区域的沉积速率以应对未来的海平面加速上升。     

基于CMIP5模式的南海海平面未来变化预估

Future potential sea level change in the South China Sea(SCS) is estimated by using 24 CMIP5 models under different representative concentration pathway(RCP) scenarios. By the end of the 21 st century(2081–2100 relative to 1986–2005), the multimodel ensemble mean dynamic sea level(DSL) is projected to rise 0.9, 1.6, and 1.1 cm under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively, resulting in a total sea level rise(SLR) of 40.9, 48.6, and 64.1 cm in the SCS. It indicates that the SCS will experience a substantial SLR over the 21 st century, and the rise is only marginal larger than the global mean SLR. During the same period, the steric sea level(SSL) rise is estimated to be 6.7, 10.0, and 15.3 cm under the three scenarios, respectively, which accounts only for 16%, 21% and 24% of the total SLR in this region. The changes of the SSL in the SCS are almost out of phase with those of the DSL for the three scenarios. The central deep basin has a slightly weak DSL rise, but a strong SSL rise during the 21 st century, compared with the north and southwest shelves.     

南海及其周缘地区全新世海平面遗迹的构造含义

通过对海南岛海岸带野外考察,在文昌市铜鼓岭石头公园观察到高程为30m的海平面遗迹,在东方市黄流镇观察到高程为25~35m的海平面遗迹,在三亚市鹿回头观察到高程为2.5m的海平面遗迹。综合研究前人在该区关于海平面变化的研究成果,得出如下几点初步认识:(1)南海及其周缘地区中全新世以来海平面呈下降趋势,海平面最高位置出现在7000a左右、高于现代海平面3m左右的位置;(2)南海中全新世以来海平面遗迹所揭示的古海平面高程的差异性是古海平面本身持续下降和该区地壳差异性垂直运动共同作用的结果;(3)南海及其周缘地区中全新世期间中央海盆及其西缘的珠江口、红河、湄公河和昭披耶河4个河流三角洲地区为构造沉降区,而南海周缘的台湾岛、雷州半岛、印支半岛、南马来半岛、爪哇岛和苏拉威西岛6个地区为构造抬升区,抬升幅度最大的地方在台湾岛。     

涌潮沉积揭示长江河口湾全新世最高海面

海面变化对沿海地区的自然环境和社会经济有着重要影响,了解过去海面变化规律可以为预测未来海面上升情景提供参考依据。以长江古河口湾湾顶附近的扬州市昌建广场建筑工地所揭示的自然沉积剖面（CJGC剖面）为研究对象,通过详细调研,在剖面下部发现了保存有海相贝壳的涌潮沉积,为研究全新世最高海面和最大海侵提供了绝佳的地质材料。通过系统的沉积相与光释光（OSL）年代学研究,重建了古河口湾中全新世以来沉积环境的变化过程。结果表明,该地点中全新世以来经历了从陆相→潮滩→河口沙坝→河漫滩的沉积环境变迁,清晰显示了由海侵到海退的变化过程。OSL测年数据表明长江河口全新世最高海面和河口湾湾顶最大海侵出现的年代约为5.6 ka,当时对应的海面高度不低于海拔1.3 m,这一时期的高海面在世界多地均有记录。     

Late Cenozoic sea-level changes and the onset of glaciation: impact on continental slope progradation off eastern Canada

Late Cenozoic sedimentation from four varied sites on the continental slopes off southeastern Canada has been analysed using high-resolution airgun multichannel seismic profiles, supplemented with some single channel data. Biostratigraphic ties are available to exploratory wells at three of the sites. Uniform, slow accumulation of hemipelagic sediments was locally terminated by the late Miocene sea-level lowering, which is also reflected in changes in foraminiferan faunas on the continental shelf. Data are very limited for the early Pliocene but suggest a return to slow hemipelagic sedimentation. At the beginning of the late Pliocene, there was a change in sedimentation style marked by a several-fold increase in accumulation rates and cutting of slope valleys. This late Pliocene cutting of slope valleys corresponds to the onset of late Cenozoic growth of the Laurentian Fan and the initiation of turbidite sedimentation on the Sohm Abyssal Plain. Although it corresponds to a time of sea-level lowering, the contrast with the late Miocene lowstand indicates that there must also have been a change in sediment delivery to the coastline, perhaps as a result of increased rainfall or development of valley glaciers. High sedimentation rates continued into the early Pleistocene, but the extent of slope dissection by gullies increased. Gully-cutting episodes alternated with sediment-draping episodes. Throughout the southeastern Canadian continental margin, there was a change in sedimentation style in the middle Pleistocene that resulted from extensive ice sheets crossing the continental shelf and delivering coarse sediment directly to the continental slope.     

东海海平面变化的综合分析

利用1993年1月至2011年12月的卫星高度计数据,研究了东海海平面变化的季节信号、线性趋势和低频信号,并结合风应力资料、Ishii温盐数据和海表面温度数据分析了季节信号和低频信号的驱动机制。东海季节性海平面变化主要由年信号组成,其占海平面变化的大部分;年信号振幅和相位的分布具有明显的区域差异;东海季节性海平面变化主要受海面风和海水热膨胀驱动,而且在不同季节、不同区域,两种驱动机制的作用存在明显差异,主导地位也不断变化;季节信号还受到黑潮的一定影响。1993-2011年间东海海平面线性上升速率为3.28mm/a,各海域海平面上升速率不同。东海海平面变化低频信号与比容海平面变化低频信号具有显著相关性,最大相关系数为0.55;东海比容海平面变化低频信号与SOI低频信号同样具有一定的相关性,最大相关系数为0.3。ENSO通过大气环流和黑潮洋流等对东海海域的比容海平面变化产生影响,比容海平面变化进而对东海年际间海平面变化产生调制作用,因此ENSO可以通过东海年际间比容海平面变化对东海年际间海平面变化产生影响。     

海平面上升对海岸潮差响应的理论解析

应用海湾和半封闭矩形海域改进的Taylor问题的解研究海平面上升对M2分潮旋转潮波系统及沿岸潮差的变化.将南黄海概化为一等深矩形海域,初步研究在海平面上升3 m和5 m条件下该海域旋转潮波系统的演化趋势,继而分析沿岸潮差变化特征.初步分析研究表明:随着海平面上升,该海域M2分潮的无潮点有向东南方向偏移的趋势,受此影响,沿岸潮差呈现不同的变化特征,靠近无潮点的左侧及湾顶海岸变化明显,而远离无潮点的右侧及湾顶海岸则变化不大.     

The impact of mean dynamic topography on a sea-level anomaly assimilation in the South China Sea based on an eddy-resolving model

The sea-level anomaly (SLA) from a satellite altimeter has a high accuracy and can be used to improve ocean state estimation by assimilation techniques. However, the lack of an accurate mean dynamic topography (MDT) is still a bothersome issue in an ocean data assimilation. The previous studies showed that the errors in MDT have significant impacts on assimilation results, especially on the time-mean components of ocean states and on the time variant parts of states via nonlinear ocean dynamics. The temporal-spatial differences of three MDTs and their impacts on the SLA analysis are focused on in the South China Sea (SCS). The theoretical analysis shows that even for linear models, the errors in MDT have impacts on the SLA analysis using a sequential data assimilation scheme. Assimilation experiments, based on EnOI scheme and HYCOM, with three MDTs from July 2003 to June 2004 also show that the SLA assimilation is very sensitive to the choice of different MDTs in the SCS with obvious differences between the experimental results and observations in the centre of the SCS and in the vicinity of the Philippine Islands. A new MDT for assimilation of SLA data in the SCS was proposed. The results from the assimilation experiment with this new MDT show a marked reduction (increase) in the RMSEs (correlation coefficient) between the experimental and observed SLA. Furthermore, the subsurface temperature field is also improved with this new MDT in the SCS.     

珠江河口盐度和输运过程对未来海平面上升的响应

研究海平面上升对河口的影响情况有助于了解输运过程的变化,基于21世纪海平面上升预测研究(陈长霖,2012;张吉,2014),本文选取珠江河口这一径优型与潮优型并存的河口为研究区域,利用数值模拟的方法,研究其在未来海平面上升后可能出现的响应。结果表明,河口的平均盐度、咸潮上溯距离和层化强度都将随着海平面的上升而增加,这些因素的变化有着明显的季节性。伶仃洋平均盐度在4月和10月增加更多;伶仃洋枯水期咸潮上溯距离的增量大于丰水期,磨刀门则相反;伶仃洋丰水期层化强度及其增量都要大于枯水期。海平面上升后的输运过程响应结果显示:(1) 垂向输运时间将增加,虽然海平面上升带来的潮差潮流的增强将加强垂向混合,但是层化的加强会削弱垂向交换。垂向输运时间的增加是由于层化的加强,层化加强抑制了潮汐变化带来的影响,表层水更难交换到底层; (2) 南北向河口环流将加强,表层余流向海加强,底层余流向陆加强,南北向余流整体向海减小。造成这些现象的主要原因是海平面上升后水深增加带来的河道比降的减小和压力梯度力的改变。     

Development of a foraminifera-based transfer function in the Basque marshes, N. Spain: Implications for sea-level studies in the Bay of Biscay

In order to reconstruct former sea level we have developed a foraminifera-based transfer function using three models based on a modern dataset of 59 samples and 23 species obtained from four Basque marshes in Northern Spain. The relationship between observed and foraminifera-predicted elevation illustrated the strong performance of the transfer function (r²_jack ranges from 0.74 to 0.81). These results indicated that precise reconstructions of former sea levels are possible (error ranges from 0.11 to 0.19 m). The transfer function was used to calibrate the foraminiferal assemblages collected from a 50 cm salt marsh core. We placed the foraminifera-based reconstructions into a temporal framework using ¹³⁷Cs, Pb concentrations, and ²¹⁰Pb-derived sediment accumulation rates. The resulting relative sea-level curve is in good agreement with regional tide-gauge data. Both instrumental data and microfossil records suggest a rate of relative sea-level rise of approximately 2 mm yr^− 1 for the 20th century.     

Trend analysis of relative sea level rise or fall of the tide gauge stations in the Pacific

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Effect of sea level rise on tidal circulation in the Hooghly Estuary,Bay of Bengal

The issue of sea level rise is receiving considerable attention all over the world. Although the Indian stations have shown mixed trends, a positive sea level trend has been noticed in the Hooghly Estuary, situated on the east coast of India. The Hooghly River serves as a navigable waterway to Calcutta and Haldia ports. The river is tidal for nearly 250 km. To study the water levels and tidal currents in the lower part of the Hooghly Estuary, from sea face at Sagar to Hooghly Point, a vertically integrated numerical model has been used. The model is fully nonlinear and uses a semiexplicit finite‐difference scheme to solve the basic hydrodynamic equations on a staggered grid. This model is coupled with a one‐dimensional model, which has been used for the upper estuary from Hooghly Point to Swarupganj, where the flow is unidirectional. The computed water levels and currents are found to be in good agreement with the available observations. This model is applied to study the alterations in tidal circulation for a rise and fall in the sea level. The results have shown a substantial increase in the amplitude and velocities of the tidal wave due to the sea level rise.     

南海地区全新世高海平面遗迹高程的区域差异问题

本文较全面地列举南海地区6500～5000a(BP)期间的古海平面遗迹，共61个实例，其中正高程的或高程为0m的有45例．这些遗迹的现存高程差异很大，主要是受构造升降运动的影响．按照遗迹高程的分布，可分为5个区域，台湾为高程最大值。巽他群岛居其次，中南半岛和马来半岛居第三位，华南沿海的高程较小，南海海盆为最小值．负高程的实例主要分布在五大三角洲地区．     

Deviation of mean sea level from the mean geoid in the transition area between the North Sea and the Baltic Sea

The mean sea level along the coasts of the Skagerrak, the Kattegat, and the Danish Straits—i.e., the transition area between the North Sea and the Baltic Sea—has been computed geodetically. The basis consists of mean sea level data from Denmark, Norway, and Sweden in various more or less inappropriate height systems. These are transformed and unified into a common height system relevant for oceanographic purposes to show the deviation of the mean sea level (1960) from the mean geoid, with Normaal Amsterdams Peil (NAP) as zero. The geodetically determined mean sea surface is compared with oceanographic model results for parts of the area. Among other findings, the outflow of low‐salinity water from the Baltic Sea, as well as its separation from high‐salinity North Sea water along the Kattegat‐Skagerrak front are clearly revealed.     

A Re-Evaluation of the Offset in the Australian Height Datum Between Mainland Australia and Tasmania

Applications of Marine Geodesy in Support of National Objectives in Ocean Science, Engineering and Operations a study prepared for the Marine Technology Society, by Narendra Saxena, College of Engineering, University of Hawaii, 1980, 176 pages.

Plate Tectonics and Crustal Evolution by K.E. Condie (New York: Pergamon Press, 1979), 288 pages, $35.00.

Bottom‐Interacting Ocean Accoustics by W.A. Kuperman and F.B. Jensen (eds.). NATO Conference Series, Series IV: Marine Sciences, Volume 5 (New York: Plenum Press, 1980), 717 pages, hardcover, U.S. $75.00.     

南海及其周缘地区全新世海平面遗迹的构造含义南海及其周缘地区全新世海平面遗迹的构造含义

通过对海南岛海岸带野外考察,在文昌市铜鼓岭石头公园观察到高程为30 m的海平面遗迹,在东方市黄流镇观察到高程为25～35 m的海平面遗迹,在三亚市鹿回头观察到高程为25 m的海平面遗迹。综合研究前人在该区关于海平面变化的研究成果,得出如下几点初步认识：（1）南海及其周缘地区中全新世以来海平面呈下降趋势,海平面最高位置出现在7 000 a左右、高于现代海平面3 m左右的位置;（2）南海中全新世以来海平面遗迹所揭示的古海平面高程的差异性是古海平面本身持续下降和该区地壳差异性垂直运动共同作用的结果;（3）南海及其周缘地区中全新世期间中央海盆及其西缘的珠江口、红河、湄公河和昭披耶河4个河流三角洲地区为构造沉降区,而南海周缘的台湾岛、雷州半岛、印支半岛、南马来半岛、爪哇岛和苏拉威西岛6个地区为构造抬升区,抬升幅度最大的地方在台湾岛。     

Chronology of the sedimentary processes during the postglacial sea level rise in two estuaries of the Algarve coast,Southern Portugal

Four profiles of estuarine sediments obtained from boreholes drilled in the Algarve, Southern Portugal were studied in order to reconstruct the process of sediment accumulation driven by the postglacial sea level rise. In addition to the sedimentological analysis, the Foraminifera Index of Marine Influence (FIMI) permitted assessment of the nature and organization of sedimentary facies in the Beliche–Guadiana and Gilão–Almargem estuaries. The Beliche–Guadiana CM5 and Almargem G2 profiles accumulated in a sheltered environment, with the former presenting an almost continuous record of the sea level rise since ca 13?000 cal yr BP. The G1 and G3 profiles from the Gilão–Almargem area represent a more discontinuous record of the last 8000 years, which accumulated in the more dynamic environment of an outer estuary. The integration of all radiocarbon ages of dated levels, led to an estimate of sediment accumulation rates. Assuming a constant position of the sediment surface with respect to the tidal range and a negligible compaction of sediment, the sea level rose at the rate of 7 mm yr⁻¹ in the period from 13?000 to 7500 cal yr BP. This process slowed down to ca 0.9 mm yr⁻¹ from 7500 cal yr BP until the present. The marked historical change in the rate of sediment accumulation in these estuaries also occurred with the accumulation of organic matter and is, therefore, important data for global biogeochemical models of carbon. The main obstacle to obtain higher temporal resolution of the sedimentary processes was the intense anaerobic respiration of organic matter via sulphate reduction, which did not allow any accumulation of peat and, furthermore, led to erasure of the palaeontological record by acid formed from the subsequent oxidation of sulphides.     

A new eyeless species of Nicon (Annelida: Nereididae) from the deep Northwest Pacific Ocean

A new species of the nereidid annelid, genus Nicon Kinberg, 1866, from KIOST Seamount, Northwest Pacific deep water is described. Nicon is a genus characterized by lacking paragnaths or papillae on the pharynx and composed of nine species worldwide, distributed from shallow water to deep sea. Nicon ablepsia sp. nov. here described is characterized by the lack of eyes on the prostomium, prolonged tentacular cirri reaching to chaetiger6, notochaetae homogomph spinigers, neurochaetae homogomph spin...     

西北太平洋围线海绵科(海绵动物门:六放海绵纲:双盘海绵目)一新种

本文记录了西太平洋深海围线海绵科1新种——扭形白须海绵。该海绵共含2个标本,其中1个采集于雅浦海山932米处,另1个采集于卡罗琳海山775.3米处。该新种含有椭圆形大双盘骨针、3种类型的双盘骨针、棒状骨针和节杖骨针,使其很容易与该属下的现有8种区分开。该种为西北太平洋报道的第4种白须海绵属的种。