Estimates of mixing on the South China Sea shelf

1 Introduction The outer shelf of the South China Sea is a di- verse environment characterized by sharp changes in bottom topography (Wang et al., 2002). Internal wave and diapycnal mixing may be a vital mechanism con- trolling the distribution of physical water properties, nutrient fluxes, and concentrations of particulate mat- ter. Therefore, the research on diapycnal mixing on the outer shelf in the South China Sea is of great impor- tance to explore the level and variability of the abov…     

A new type of internal solitary waves with a re-appearance period of 23 h observed in the South China Sea

正The South China Sea (SCS), in particular the northern SCS, is one of ocean areas where energetic internal solitary waves (ISWs)occur most frequently (Cai et al., 2012; Zheng, 2017). Based on the re-appearance period (RP) at an observation station, Ramp et al.(2004) divided the ISWs into two types:Type-a and Type-b. Type-a ISWs arrive regularly at the same time every day, i.e., the RP is about 24 h, and Type-b ISWs arrive about one hour late every day, i.e., the RP is about 25 h. The discovery of the Types-a and b ISWs     

Potassium-argon/argon-40-argon-39 geochronology of Cenozoic alkali basalts from the South China Sea

Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activi- ty of the South China Sea after spreading were studied. The potassium - argon ages of eight alkali basalt samples from the South China Sea, and the argon - argon ages of two samples among them are reported. Apparent ages of the whole rock are 3.80 to 7. 91 Ma with an average value of 5.43 Ma （potassium- argon, whole rock）, and there is little difference among samples at the same location, e. g. , 4. 76 - 5.78 Ma for location S（M-12. The argon - argon ages for the two samples are 6.06 and 4. 71 Ma, which lie within the age scope of potassium - argon method. The dating results indicate that rock-forming age is from late Miocene to Pliocene, which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea. Volcanic activities occur after the cessation of spreading of the South China Sea, which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea. These dating results, combined with geochemical characteristics of these basalts, the published chronological data for the South China Sea and its adjacent regions, and the updated geophysical data near Hainan Island, suggest that after the cessation of spreading of the South China Sea, there occur widely distributing magmatic activities which primarily is alkali basalt, and the volcanic activity continues to Quaternary. The activity may be relative to Hainan mantle plume originated from core/mantle boundary.     

Study of the propagation direction of the internal waves in the South China Sea using satellite images

Internal wave propagation carries considerable vertical shear which can lead to turbulence and mixing. Based on the analysis of more than 2 500 synthetic aperture radar (SAR) and optical satellite images, the internal wave propagation in the whole South China Sea was investigated systematically. The results show that (1) in the northeastern South China Sea, most internal waves propagate westward from the Luzon Strait and are diffracted by coral reefs near the Dongsha Islands. Some impinge onto the shelf and a few are reflected; (2) in the northwestern South China Sea, most internal waves are generated at the shelf and propagate northwestward or westward to the coast; (3) in the western South China Sea, most internal waves propagate westward to the Vietnamese coast, except a few propagate southward to the deep sea; and (4) in the southern South China Sea, most internal waves propagate southwestward to the coast. Some propagate southeastward to the coast of Kalimantan Island, and a few propagate southeastward because of the influence of the Mekong River.     

New insight into the South China Sea: Rossby normal modes

<正>The South China Sea(SCS),the largest marginal sea of the Northwest Pacific Ocean,is characterized by frequent occurrence of energetic mesoscale eddies.The eddy diameters range from 100 to 300 km.The eddy lifespan varies from several days to several months with the longest time of seven months(Zheng et al.,2017).The eddy disturbance reaches down to the ocean bottom layer.     

NOTES ON THE HYDROMEDUSAE FAUNA OF THE CHINA SEA AREAS

Since the end of 19th century, large amounts of studies have been made on marinehydromedusae fauna all over the world. According to a preliminary statistical survey,there are about 450 species of marine hydromedusae in the world. The record of marine hydromedusae in the China Sea Areas began in 1879 andaltogether 21 species had been reported fragmentarily until 1940's. Beginning from1950's, the range of investigation had been enlarged to the whole China Sea Areas andthe study had been more systematically carried out. Qiu (1954), Zhou et al (1958),Gao et al (1958, 1962), Xu and Zhang (1964, 1974, 1978), Xu (1965) and Zhang (1977)respectively reported in detail hydromedusae species around China. Kramp (1965) also     

A numerical study of the South China Sea deep circulation and its relation to the Luzon Strait transport

A fine-resolution MOM code is used to study the South China Sea basin-scale circulationand its relation to the mass transport through the Luzon Strait. The model domain includes the South China Sea, part of the East China Sea, and part of the Philippine Sea so that the currents in the vicinity of the Luzon Strait are free to evolve. In addition, all channels between the South China Sea and the Indonesian seas are closed so that the focus is on the Luzon Strait transport. The model is driven by specified Philippine Sea currents and by surface heat and salt flux conditions. For simplicity, no wind-stress is applied at the surface.The simulated Luzon Strait transport and the South China Sea circulation feature a sandwich vertical structure from the surface to the bottom. The Philippine Sea water is simulated to enter the South China Sea at the surface and in the deep ocean and is carried to the southern basin by western boundary currents. At the intermediate depth, the net Luzon Strait transport is out of t     

Paleobiogeography of Ostracoda and Foraminifera in the China sea area

The distribution of ostracods and benthonic foraminifers in the China sea area is briefly reviewed from the paleobio-geographic viewpoint in this paper. Three regions can be distinguished in the area on the basis of modern distribution data: Region I (the Huanghai Sea and the Bohai Sea) with cool and temperate forms, Region I (the East China Sea and the northern part of the South China Sea) with subtropical warm-water forms and Region Ⅲ (central and southern parts of the South China Sea) with larger foraminifers and other tropical warm-water forms. The occurrence of Nummulites-Discocyclira fauna in the Eocene deposits of the East China Sea indicates a northward extension of tropical zoogeographical region at the time, whereas the distribution pattern of the Miocene Nephrolepidina-Miogypsiua-Austrotrillina fauna in the South China Sea resembles that of the present larger-foraminiferal fauna. In the South China Sea and Taiwan, a warm-water fauna with Asterorotalia and Pseudorotalia first appeared in late     

FIVE NEW SPECIES OF THE GENUS ACANTHOMYSIS (CRUSTACEA MYSIDACEA) FROM THE SOUTH CHINA SEA

A distinctive feature of the mysidacean fauna of the inshore waters of the China Seas is that it is rich in species of two genera, viz., Acanthomysis and Neomysis. Five new species of Acanthomysis are found in the zooplankton samples collected from the continental shelf region of the northern South China Sea in 1959—1960. In this paper an account of the new species (Acanthomysis laticauda sp. nov., A. crassispinosa sp.nov., A. leptura sp. nov., A. rotundicauda sp. nov., A. serrata sp. nov.) are presented. The type materials of new species are deposited in the Institute of Oceanology, Academia Sinica.     

中国南海中南部花水母亚纲一新属四新种记述

本文描述了采自中国南海中南部花水母亚纲一新属四新种：南海宽管水母,新属、新种Laticanna nanhaiensis gen.nov. et sp.nov.,芽拟原帽水母,新种Protiaropsis gemmifera sp.nov.,南海潜水母,新种Merga nanhaiensis sp.nov.和顶室无球水母,新种Rhabdoon apiciloculus sp.nov.。编制了深帽水母科已知属分属检索表和拟帽水母属、潜水母属以及无球水母属已知种分种检索表。模式标本保存于中国水产科学研究院南海水产研究所。     

中国南海水螅水母纲(刺胞动物门)分类研究Ⅳ:高手水母科(花水母亚纲)

本文复查了中国南海丝螅水母目高手水母科的所有属,解决了该科和一些属、种存在的分类问题,并给予更新的鉴别。以前,无手单肢水母Nubiella atentaculata Xu and Huang,2004包含在单肢水母属内,现变换为拟单肢水母新属Paranubiella n.gen.,隶属于高手水母科内,原无手单肢水母新组合为无手拟单肢水母Paranubiella atentaculata（Xu and Huang,2004） n.comb.。本文记述了二个新种：南海拟单肢水母,新种Paranubiella nanhaiensis sp.nov.和无突单肢水母,新种N.apapillaris sp.nov.。此外编制了高手水母科已知属和单肢水母属已知种的检索表,总结了中国南海高手水母科已知种名录。模式标本保存于国家海洋局第三海洋研究所。     

Five <Emphasis Type="Italic">Oncaea</Emphasis> species (Copepoda,Poecilostomatoida, Oncaeidae) from the Korean waters,with notes on the spatio-temporal distribution of Korean oncaeid species

Five Oncaea species were recorded on the basis of specimens collected using three type nets from the South Sea and the East Sea of Korea. These included the clevei-group of one species (O. clevei) and the venusta-group of four species (O. media, O. mediterranea, O. scottodicarloi, O. waldemari). The former has a dorsoposterior projection on the second pedigerous somite, while the latter do not bear any dorsal projection on the somite. Also, their spatio-temporal distribution are discussed in relation to temperature-salinity.     

Dissolved organic phosphorus utilization and alkaline phosphatase activity of the dinoflagellate <Emphasis Type="Italic">Gymnodinium impudicum</Emphasis> isolated from the South Sea of Korea

This study investigated alkaline phosphatase (APase) activity and dissolved organic and inorganic phosphorus utilization by the harmful dinoflagellate Gymnodinium impudicum (Fraga et Bravo) Hansen et Moestrup isolated from the South Sea of Korea. Under conditions of limited phosphorus, observation of growth kinetics in batch culture yielded a maximum growth rate (μ_max) of 0.41 /day and a half saturation constant (Ks) of 0.71 μM. In time-course experiments, APase was induced as dissolved inorganic phosphorus (DIP) concentrations fell below 0.83 μM, a threshold near the estimated Ks; APase activity increased with further DIP depletion to a maximum of 0.70 pmol/cell/h in the senescent phase. Thus, Ks may be an important index of the threshold DIP concentration for APase induction. G. impudicum utilizes a wide variety of dissolved organic phosphorus compounds in addition to DIP. These results suggest that DIP limitation in the Southern Sea of Korea may have led to the spread of G. impudicum along with the harmful dinoflagellate Cochlodinium polykrikoides in recent years.     

春季我国不同纬度河口浮游动物群落变化趋势

根据2010-2012年春季由南向北河口海域：北仑河口、九龙江口、瓯江口、长江口和灌河口的浮游动物调查资料;通过比较不同纬度河口浮游动物群落的生物多样性指数（H''）、物种更替率（R）和群落相似系数（S）;探讨了河口浮游动物群落特征沿着不同纬度变化的趋势。结果表明;自南向北5个河口可以划分为3个不同的浮游动物区系。北仑河口和九龙江口为南部亚热带区系;位于亚热带海域;以亚热带种为主;H''分别为1.01和2.18;两河口之间R值为65.52%;S值为51.28%;瓯江口和长江口为中部过渡区系;位于亚热带和温带过渡海域;亚热带种和暖温带种是主要出现的种类;H''分别为1.31和1.86;两河口之间R值为58.33%;S值为58.82%;灌河口单独为北部温带区系;位于温带海域;暖温带种是主要出现的种类;H''值为1.19;与其余河口物种更替率均高于80.00%;群落相似系数均低于32.00%;表明群落结构由南到北的变化非常显著。线性回归结果表明：我国不同河口之间浮游动物的物种更替率与纬度差（两河口所处纬度的差值;δN）呈正相关关系（R=0.026ΔN+0.608;p=0.002）;群落相似系数与纬度差呈负相关关系（S=0.034ΔN+0.578;p=0.001）。春季;我国不同纬度河口浮游动物群落结构的变化;主要是因为影响各河口的水温和水团存在较大差别所致。     

鱼耳石碳氧同位素在黄、渤海小黄鱼种群识别中的应用

Oxygen and carbon isotope ratios(δ~(18)O and δ~(13)C) in otoliths were used to identify the stock structure of small yellow croaker,Larimichthys polyactis.Otoliths were collected from fish at five locations across the Yellow Sea and the Bohai Sea representing most of their distributional range and fisheries areas.The significant differences in the isotopic signatures showed that the five locations could be chemically distinguished and clearly separated,indicating stock subdivision.Correlation of δ~(18)O and δ~(13)C values suggested that population of L.polyactis could be divided into the Bohai Sea group,the southern Yellow Sea group and the central Yellow Sea group.Discriminant analysis of δ~(18)O and δ~(13)C values demonstrated a high significant difference with 85.7% classification accuracy.The spatial separation of L.polyactis indicated a complex stock structure across the Yellow Sea and the Bohai Sea.These results indicate that optimal fisheries management may require a comprehensive consideration on the current spatial arrangements.This study has provided further evidence that measurement of the stable isotopes ratios in otolith can be a valuable tool in the delineation of fishery management units.     

Species composition and seasonal dynamics of the population density and biomass of the genus <Emphasis Type="Italic">Pyramimonas</Emphasis> (Prasinophyceae) from the Russian waters of East/Japan Sea

The species composition and seasonal dynamics of the population density and biomass of the prasinophycean algae of the genus Pyramimonas were investigated in the Russian waters of the East/Japan Sea. According to literature data and the results of our observations, eight species of the prasinophycean algae were identified, and some of them were new for the Russian waters of the East/Japan Sea as follows: P. aff. amylifera Ñonrad, P. aff. cordata McFadden, Hill et Wetherbee, and P. nansenii Braarud. An analysis of their seasonal dynamics showed that the most conspicuous winter peak of the population density of Pyramimonas species in the Amurskii Bay was clearly distinguishable in February. In winter and early spring, the prasinophycean algae made a considerable contribution of 28 to 60% into the total population density on the background of a relatively low biomass, 1.1–14.4% of the total phytoplankton biomass in the Amurskii Bay. In the Golden Horn Bay, the summer peak of the population density of Pyramimonas species was most intensive in June. In summer, during the period of mass development of the algae of the genus Pyramimonas in the Golden Horn Bay, the prasinophycean algae contributed up to 71% of the total population density and up to 84% of the total microalgal biomass. An increase was noted in the density and biomass of the Pyramimonas species in the polluted waters near the sewage water outlets in the Amurskii and Golden Horn bays.     

The trophic position of the alien crab <Emphasis Type="Italic">Rhithropanopeus harrisii</Emphasis> (crustacea decapoda panopeidae) in the Taman Bay,Sea of Azov community

This work concerns the trophic web positioning of the alien crab Rhithropanopeus harrisii and other common marine invertebrate species and fishes in the benthic ecosystem of the shallows of Taman Bay, Sea of Azov. The base of the trophic web in this system is composed of phytoplankton, macrophytes (algae and marine grasses), and reeds that use atmospheric carbon for photosynthesis. Analysis of the isotopic composition of nitrogen and carbon has shown that although marine grasses are dominating primary producers in the shallows of the bay, primary consumers (such as Cerastoderma glaucum, Porifera gen. sp., Gammarus aequicauda, Deshayesorchestia deshayesii and Idotea balthica) only partially use this organic source; instead, they use a combination of different sources of primary production. It has been shown that the food source of the alien crab is primarily of animal origin. In Taman Bay, R. harrisii is on the same trophic level as other carnivores/scavengers: benthic fishes Syngnathus nigrolineatus, Gobius spp. and native crab Pilumnus hirtellus and shrimp Palaemon adspersus.     

A Baseline Assessment of Coral Reef in Malacca Straits,Malaysia

Coral reefs along the Malacca Straits (MS) are poorly developed mainly due to turbidity and sedimentation. This study describes the health status and community structure of the corals in Cape Rachado, West Coast of Peninsular Malaysia (WCPM), utilizing the Coral Video Transect (CVT) technique. All the survey transects were categorized as ‘fair’ coral conditions (27.39 ± 5.41%–48.56 ± 18.96%) with the reef floor mainly covered by corals and sediment. Twelve families of coral comprised of 25 distinct genera were identified. Coral communities were differentiated into four clusters with each being predominated by Galaxea, Diploastrea, Fungia and Pectinia respectively. Among all, Pectinia is the most spectacular genera and dominated the survey area. Along the MS, Favia, Favites and Porites are commonly found while Porites and Pectinia dominated the reefs. Low coral cover and diversity was recorded in MS as compared to the reefs in the South China Sea (SCS). The most prominent results include changes in the dominant coral from Porites to Pectinia while some species such as Acropora were absent from the study area. Based on the presented data, the reef in the study area was predominantly occupied by sediment and the coral communities were formed by a species with a high tolerance to turbidity and sedimentation.     

南极西北威德尔海上层海洋湍流混合研究

Turbulent mixing in the upper ocean(30-200 m) of the northwestern Weddell Sea is investigated based on profiles of temperature,salinity and microstructure data obtained during February 2014.Vertical thermohaline structures are distinct due to geographic features and sea ice distribution,resulting in that turbulent dissipation rates(ε) and turbulent diffusivity(K) are vertically and spatially non-uniform.On the shelf north of Antarctic Peninsula and Philip Ridge,with a relatively homogeneous vertical structure of temperature and salinity through the entire water column in the upper 200 m,both ε and K show significantly enhanced values in the order of O(10~(-7))-O(10~(-6)) W/kg and O(10~(-3))-O(10~(-2)) m~2/s respectively,about two or three orders of magnitude higher than those in the open ocean.Mixing intensities tend to be mild due to strong stratification in the Powell Basin and South Orkney Plateau,where s decreases with depth from O(10~(-8)) to O(10~(-9)) W/kg,while K changes vertically in an inverse direction relative to s from O(10~(-6)) to O(10~(-5)) m~2/s.In the marginal ice zone,K is vertically stable with the order of10~(-4) m~2/s although both intense dissipation and strong stratification occur at depth of 50-100 m below a cold freshened mixed layer.Though previous studies indentify wind work and tides as the primary energy sources for turbulent mixing in coastal regions,our results indicate weak relationship between K and wind stress or tidal kinetic energy.Instead,intensified mixing occurs with large bottom roughness,demonstrating that only when internal waves generated by wind and tide impinge on steep topography can the energy dissipate to support mixing.In addition,geostrophic current flowing out of the Weddell Sea through the gap west of Philip Passage is another energy source contributing to the local intense mixing.