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1.
A recent island survey reveals that the Xuande Atoll and the Yongle Atoll in the Xisha Islands can be classified into one of two systems: the depleted atoll system and growth atoll system; the survey also indicates that the decreased area of several shoals is an unbearable burden for the Xisha Islands, of which the largest island area is 2.13 km2 and the minimum elevation is 1.4 m. According to a survey on the ecological characteristics of Halimeda in the Laolongtou breaker zone of Shidao Island in the Xisha Islands, the green and white living Halimeda are collected,the isotopic ages of 14 C contained in the Halimeda are shown to be 27 years and 55 years, respectively, and carbonate mainly occurs in five types, i.e., luster, segment, sand, sand grain, and marl in the formation. The Halimeda segments mainly provide the carbonate sediments of long-term biogenic deposits in the reef environment and the annual productivity per area is 60–100 g/m2; the characteristics of the microstructure of the Halimeda are analyzed, the aragonite raphide carbonate is deposited and enriched in the cortexes, medullas and cysts, and the Halimeda generally contain major elements such as C, O, Ca, Cl, Mg, K, Na, S and Al, and are rich in trace elements such as tellurium(Te), rhodium(Rh) and strontium. It is believed that the Halimeda grow slowly,including the biotic community of reef corals in the reef areas, thus they possess an environmental remediation capacity, but it takes much time to remedy the environment, and it is necessary to make the law to protect the diversity and vulnerability of the Xisha marine ecology, the ecology of the reef community and the island environment in a scientific way. As indicated in the survey, under the background of global warming and sea-level rise, the discovery of large amounts of Halimeda in the Laolongtou sea area is significant for the natural increase of the depleted atoll system of the Xuande Atoll, while the Halimeda segments represent the primary form of the fossil Halimeda, of which the species can be identified and preserved in great numbers under geological conditions. The Miocene was discovered in large amounts in the Xichen-1 well, therefore the study on the characteristics and mechanism of Halimeda carbonate sediments plays a pivotal role in the formation and construction of organic reefs in the South China Sea as well as oil and gas exploration.  相似文献   

2.
Epizoic diatoms on marine copepods are common in nature and may have a special ecological relationship with their hosts.However,this special ecological group is not well known,and it has only rarely been studied in the China seas.To address this knowledge gap,the species diversity and classification of epizoic diatoms on planktonic copepods were studied with samples collected from the East China Sea.In the present study,a marine araphid diatom genus Protoraphis and its type species,Pr.hustedtiana,were observed and identified by light and electron microscopy,thus representing the first record of this genus and its type species in China.This genus is characterized by a median sternum strongly bent to opposite sides and terminate in two transapical grooves at the valve ends.Protoraphis hustedtiana was found to be epizoic on the posterior body appendages and segments of the marine calanoid copepod Candacia bradyi.An internal view shows a complex,ear-shaped process that is close to the apical slit field.The ecological habitats and geographical distributions of Protoraphis were also discussed,and,together with complementary morphological studies,our results have increased the number of records for marine epizoic diatoms to three genera with three species in China,including Pseudohimantidium and Pseudofalcula.  相似文献   

3.
~IOXWith economic development and consumer demand, oil pollutants have been one of themain marine pollutants in the coastal regal Of China. The oil-contaminated area incrsharply to 69% in 1995 and its average criterion index reached up to 2. 17 in the ChangjiangEstuary (NBEP, 1996). TO assess the influences Of the oil POllutants on the marine ~tern, it is neceSSary to develOP a mathematical kinetic model of the tranSport, distribution andfate in the marine ~teln, espeCially to esthate …  相似文献   

4.
China(herein referred as China’s mainland,and excluding Hong Kong,Macao and Taiwan)ranks as the world’s leading fishing nation,with approximately 11.1 million tons of domestic marine catch acquired in 2017.Marine fisheries resources in China are mainly exploited by its 11 coastal provinces and municipalities,and the development of fishing industry varies among them.However,few studies have examined the exploitation history of the 11 coastal provinces and municipalities.In this paper,we systematically quantified the exploitation history of marine fishery resources in China and then measured the vulnerability of the 11 coastal provinces and municipalities of China to a reduction in marine catches.Our analysis suggested that Chinese marine fisheries experienced rapid growth from the mid-1980 s to the end of the 20 th century,and this rapid increase in marine catches were mainly promoted by increased fishing effort.The total primary production required level amounted to approximately 80%of the average primary productivity in 2017,and Zhejiang,Fujian,Shandong,Hainan and Guangdong provinces were the main fishing provinces in China.By assessing three dimensions of vulnerability(exposure,sensitivity and adaptive capacity)to the impacts of a reduction in marine catches in the 11 coastal provinces and municipalities,we found that Hainan,Guangxi,Zhejiang and Fujian provinces had high or very high vulnerability,while the municipalities of Shanghai and Tianjin had low vulnerability.Identifying suitable adaptation policies and management plans based on the differences in vulnerability among coastal provinces is important in sustainable fisheries management.  相似文献   

5.
A better understanding of bacterioplankton community shifts following change in marine environments is critical to predict the marine ecosystem function. In order to get a snapshot of the microbial taxonomy profiling of a wide range marine area, a quick, convenient and low cost method would be favorable. In this study, we developed a 16S rRNA gene-based microarray using ARB software, which contained 447 probes targeting 160 families of marine bacteria. The specificity, sensitivity and quantitative capability of this microarray were assessed by single cloned16S rRNA genes. The reliability of this microarray was tested by eight environmental samples. The results showed that the microarray was specific, only 1.16% false results were detected in five single-clone hybridization tests. The microarray could detect DNA samples as few as 1 ng/μL and the signal intensity could reflect the relative abundance of the bacteria in the range of 1 ng/μL to 100 ng/μL of DNA concentration. Hybridization with environmental samples showed that it can discriminate bacterioplankton communities by sites and time. High throughput sequencing results from the eight samples confirmed the hybridization results. It indicated that this developed microarray could be used as a convenient tool to monitor the bacterioplankton community in marine environment.  相似文献   

6.
A study of oil spill detection using ASAR images   总被引：5，自引：3，他引：2  
The oil spilled worldwide causes ecological disasters that result in enormous damages to the quality of marine environment, and great expenses on clear-up operations are needed. Due to its wide coverage and day-night all-weather observation capability, Synthetic Aperture Radar (SAR) is an important tool for oil spill monitoring and detection. C-band SAR is well adapted to detect oil pollution because oil slicks dampen the Bragg waves and reduce radar backscattering coefficients. In order to detect the area of oil slicks, the algorithm consists of these steps:Preprocessing, Masking of land areas, Detection of dark spots, Spot feature extraction, Dark spot classification. In this paper, the authors examined two coastal regions around Hong Kong and Yantai, China. The obtained results performed on Envisat ASAR images have demonstrated that it is efficient to detect oil spill around the coastal regions. The methodology still needs to be refined with the collection of more SAR data in the near future.  相似文献   

7.
Marine plastic debris has been a pervasive issue since the last century, and research on its sources and fates plays a vital role in the establishment of mitigation measures. However, data on the quantity of plastic waste that enters the sea on a certain timescale remain largely unavailable in China. Here, we established a model using material flow analysis method based on life cycle assessment to follow plastic product from primary plastic to plastic waste with statistical data and monitoring data from accurate sources. This model can be used to estimate and forecast the annual input of plastic waste into the sea from China until 2020. In 2011, 0.547 3–0.751 5 million tons of plastic waste entered the seas in China, with a growth rate of 4.55% per year until 2017. And the amount will decrease to0.257 1 to 0.353 1 million tons in 2020 under the influence of governmental management. The amount of plastic waste discharged from coastal areas calculated in this study was much larger than that from river, thus it is suggested to strengthen the governance and control of plastic waste in coastal fishery activities in China in order to reduce the amount of marine plastic waste input.  相似文献   

8.
Neomysis awatschensis was collected on the west coast of Jiaozhou Bay,Qingdao in 1992 and acclimated in the laboratory conditions.The acute toxicity method using 4 ～6 day juvenile mysid of this species is studied.The species is compared with M.bahia in taxonomy,geographic distribution,morphology,as well as the sensitivity to reference toxins,Based on the results,we recommend N.awatschensis to be a standard marine organism for toxicity test in China and the method to be applied in toxicity evaluation of drilling fluids.In this paper,we report the results of the above studies and the application of the method in the evaluation of several drilling fluid products.  相似文献   

9.
Halocyprid ostracods are appreciable part of ostracods floating through virtually everywhere in marine environment.In this study,we describe a new species of genus Polyconchoecia Xiang,Chen and Du,2018,tribe Conchoeciini Chavtur and Angel,2011,family Halocyprididae Dana,1853 from the middle of the South China Sea.Polyconchoecia chenii sp.nov.is very close to P.commixtus Xiang,Chen and Du,2018.But it differs from P.commixtus by the distinctions of locations of major glands of carapace and the characteristics of appendages:more posteriorly situated left asymmetric gland of carapace,no right asymmetric gland;segmented frontal organ;the endopod 2 of the first antenna with a very small seta;a-and c-setae of the first antenna with long end joint have long end joint,the b-and d-setae have no end joint,spinose e-seta without end joint;the e-seta of the second antenna is present;teeth side is distinctive;the setal counts of the mandible,maxilla,fifth limb,and sixth limb are individual.The locations of the major glands on carapace and the characteristics of the first antenna can be the key of the new species.This work is the second discovery of the genus Polyconchoecia from the world.  相似文献   

10.
In exploring new sources for economically important products, marine environment draws particular attention because of its remarkable diversity and extreme conditions; it is known to produce metabolic products of great value. It represents untapped source for the discovery of novel secondary metabolites with varying potential such as antibiotic, anti-tumor, antifouling and cytotoxic properties. Marine actinomycetes distributed throughout the marine environment from shallow to deep sea sediments have proved to be a finest source for this discovery. Secondary metabolites derived from marine actinomycetes have proved their worth in industries based on the research on their properties and wide range applications. Spotlight of the review is range of marine based actinomycetes products and significant research in this field. This shows the capability of marine actinomycetes as bioactive metabolite producers. Additionally, the present review addresses some effective and novel approaches of procuring marine microbial compounds utilizing the latest screening strategies of drug discovery from which traditional resources such as marine actinobacteria has decreased due to declining yields. The aim is in the context of promoting fruitful and profitable results in the near future. The recent surfacing of new technologies for bioprospection of marine actinomycetes are very promising, resulting in high quality value added products, and will be de? ning a new era for bioactive compounds with medical and biotechnological applications.  相似文献   

11.
The present work aimed to study the influence of mercuric chloride (HgCl2) on pigment content (chlorophyll a and pheophytin) in sediment traps on the basis of experimental data. The marine microalgal cultures of Conticribra weissflogii (Mediophyceae), Tetraselmis viridis (Chlorodendrophyceae), Amphidinium carterae (Dinophyceae), Nannochloropsis sp. (Eustigmatophyceae) were used. The obtained results revealed that the influence of mercury on pigment content as well as on photosynthetic activity was different in different species. The considerable decrease in phytopigments content was observed in Amphidinium carterae and Conticribra weissflogii, while the proportion of pheophytin increased. The pigment content of Tetraselmis viridis was not different from the control line, while for Nannochloropsis sp. the increase in pigment concentration was noticed. The complete immediate inhibition of photosynthetic activity was observed in Conticribra weissflogii, Tetraselmis viridis, Amphidinium carterae, while Nannochloropsis sp. responded only after 24 h of exposition. The pigment degradation rate was almost the same for diatoms and dinoflagellates. The equation for estimating the phytopigments content in sediment traps, that takes into consideration the exposition time, is proposed.  相似文献   

12.
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。  相似文献   

13.
本文审查了中国南海感棒水母科、触丝水母科、玛拉水母科和帽冠水母科有关种类。记述了二个新种：隆脊真唇水母，新种Eucheilota carinata sp.nov.和南海盐生水母，新种Halopsis nanhaiensis sp.nov.和二个新记录属种：十字胃水母Staurostoma sp.及阿弗罗八拟杯水母Octophialucium aphrodite（Bigelow，1928）。编制了触丝水母科和玛拉水母科所有已知属和分种的检索表。此外，还简介了中国南海感棒水母科、触丝水母科、玛拉水母科和帽冠水母科已知种类名录及分布。模式标本保存于国家海洋局第三海洋研究所。  相似文献   

14.
本文描述了采自南麂列岛小柴屿岩相潮间带的一海洋底栖硅藻新种，南麂侧链藻（Pleurosira nanjiensis sp.nov.）。本研究使用光学显微镜和扫描电子显微镜对该种进行了形态学观察，并基于SSU rRNA和rbcL基因重建了其系统发育关系。南麂侧链藻具有壳面橄榄形、椭圆形或圆形，壳面隆起，单眼突出于壳表面，2–3个唇状突（rimportulae），放射排列的线纹等特征，区别于其他侧链藻。  相似文献   

15.
Macrofauna in the Clarion-Clipperton Fracture Zone remain poorly understood, due both to gross undersampling and to the fact that most species collected from the area are new to science. Evaluation of the diversity and species distribution of the benthic fauna in this area is critical to predicting and managing the impacts of manganese nodule mining. In this study, we investigated the distribution of macrofauna to understand the natural variability in the macrobenthic community and, by extension, to establish a baseline for environmental risk assessment. Samples were collected from the KR5 block of the Korea Contract Area, within the abyssal area of the Clarion-Clipperton Fracture Zone in the northeastern Pacific Ocean, by the RV Onnuri from 2012–2014. A total of 36 core samples were examined in the survey, from which we identified 183 macrobenthic species in 25 faunal groups with a mean density of 257 ind/m2. Not taking into account meio-faunal groups such as nematodes and harpacticoid copepods, the highest percentage of individuals was represented by Arthropoda. The dominant species (> 1% of total density) were the tanaids Typhlotanais sp.1, and Akanthophoreus spp. and Stenotanais sp., the isopod Macrostylis sp.1, and the polychaetes Cirratulidae spp. and Levinsenia uncinata. The abundances of the two dominant species, the tanaid Typhlotanais sp1. and isopod Macrostylis sp.1., were positively correlated with total organic carbon (TOC). There were no differences in macrofaunal density and community structure between preserved areas (PRA), the potential benthic impacted site (BIS), and other areas near the BIS. In general, higher diversity was associated with homogeneous environmental conditions, with high nodule coverage (> 50%) and TOC.  相似文献   

16.
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。  相似文献   

17.
为节约成本和样品，一些学者同时分析海洋沉积物中的碳、氮及其同位素（TOC、TN、δ13C和δ15N）。分析沉积物中的δ13C，需要对样品进行酸化去除无机碳，但是这一酸化过程会使TN和δ15N的分析结果产生偏差，且偏差范围与沉积物中无机碳含量（CaCO3）有关。本研究选取了低CaCO3含量（1-16%）和高CaCO3含量（20-40%）的海洋沉积物样品，比较了酸化过程对TN和δ15N的影响。研究结果表明，酸化过程对海洋沉积物中TN和δ15N的分析结果产生了显著影响。对于低CaCO3含量的样品，酸化导致样品中TN流失了约0-40%，δ15N偏移了约0-2‰；而对于高CaCO3含量的样品，酸化导致样品中TN流失了约10-60%，δ15N偏移了约1-14‰。表明酸化对TN和δ15N的影响已经超过了仪器的误差范围0.002%（TN）和0.08‰（δ15N），将影响TN和δ15N的环境指示意义。因此，即使海洋沉积物样品中CaCO3含量很低，也必须用原样分析TN和δ15N以避免酸化过程的影响。  相似文献   

18.
Results obtained from simulating the propagation of infrasonic waves from the Chelyabinsk meteoroid explosion observed on February 15, 2013, are given. The pseudodifferential parabolic equation (PDPE) method has been used for calculations. Data on infrasonic waves recorded at the IS31 station (Aktyubinsk, Kazakhstan), located 542.7 km from the likely location of the explosion, have been analyzed. Six infrasonic arrivals (isolated clearly defined pulse signals) were recorded. It is shown that the first “fast” arrival (F) corresponds to the propagation of infrasound in a surface acoustic waveguide. The rest of the arrivals (T1–T5) are thermospheric. The agreement between the results of calculations based on the PDPE method and experimental data is satisfactory. The energy E of the explosion has been estimated using two methods. One of these methods is based on the law of conservation of the acoustic pulse I, which is a product of the wave profile area S/2 of the signal under analysis and the distance to its source E I [kt] = 1.38 × 10–10 (I [kg/s])1.482. The other method is based on the relation between the energy of explosion and the dominant period T of recorded signal E T [kt] = 1.02 × (T [s]2/σ)3/2, where σ is the dimensionless distance determining the degree of nonlinear effects during the propagation of sound along ray trajectories. According to the data, the explosion energy E I,T ranges from 1.87 to 32 kt TNT.  相似文献   

19.
The species compositions of the genus Chironomus in the Curonian and Vistula lagoons are very similar, represented by Ch. plumosus and Ch. balatonicus. In the Curonian Lagoon, in addition to these two species, Ch. muratensis and the first-generation interspecific hybrid Ch. muratensis × Ch. plumosus are also found. In this lagoon, Ch. plumosus occurs most frequently (84%); Ch. balatonicus is considered a subdominant species (24%). In the Vistula Lagoon, on the contrary, the high frequency of occurrence is typical of Ch. balatonicus (89%); for Ch. plumosus, it reaches only 11%. The Ch. plumosus population occupies most of the Curonian Lagoon; Ch. balatonicus is present only in its northern part, from the village of Juodkrante to the city of Klaipeda. In the Vistula Lagoon, Ch. balatonicus is distributed over almost its entire area, while Ch. plumosus is found locally, only near the mouth of the Nogat River. The distribution of the sibling species in the lagoons is determined by the salinity gradient.  相似文献   

20.
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.  相似文献   

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