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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.
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   

4.
~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   

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.
The monopile is the most common foundation to support offshore wind turbines. In the marine environment, local scour due to combined currents and waves is a significant issue that must be considered in the design of wind turbine foundations. In this paper, a full-scale numerical model was developed and validated based on field data from Rudong, China. The scour development around monopiles was investigated, and the effects of waves and the Reynolds number Re were analyzed. Several formulas for p...  相似文献   

9.
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   

10.
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   

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.
In order to clarify the phylogeny and relationships of the most confused hypotrichous ciliates, Holosticha-complex, four closely related holostichids (five populations), Holosticha bradburyae, H. diademata, Anteholosticha sp., and A. manca, were compared and analyzed using ITS2 secondary structures, ITS1-5.8S-ITS2 region and SSrRNA gene sequences. The ITS1-5.8S-ITS2 region sequences of these four species were first sequenced, and they shared sequence identities ranging from 68.0% to 90.1%, while two populations of Anteholosticha sp. differed in three nucleotides (sequence identity 99.8%). There were several minor differences among ITS2 secondary structures of these species, while two populations of Anteholosticha sp. had the identical secondary structure. Phylogenetic trees inferred from the ITS1-5.8S-ITS2 region sequences of stichotrichs using multiple algorithms (Neighbor-Joining, Maximum Parsimony and Bayesian) revealed similar topologies. The results show that:(1) Holosticha bradburyae and H. diademata firmly clustered together with strong bootstrap supports, forming a sister clade with Anteholosticha sp., (2) Anteholosticha appeared to be a paraphyletic assemblage, in which the morphotype A. manca was more closely related to Diaxonella trimarginata than to its congener Anteholosticha sp. Phylogenetic analyses based on the SSrRNA gene and the combined sequences of SSrRNA gene and ITS1-5.8S-ITS2 region revealed the similar relationships between Holosticha and Anteholosticha, nevertheless their positions within the subclass Stichotrichia differed from each other inferred from different genes.  相似文献   

13.
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   

14.
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   

15.
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   

16.
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   

17.
The analysis of the macroalgae distribution along the salinity gradient in the Azov Sea, the Kerch strait, and Taman Bay during the summer allowed finding two macroalgae complexes. The first complex (brackish) is formed by algae belonging to the Enteromorpha, Cladophora, Rhizoclonium, and Chaetomorpha genera in the Taganrog Gulf. The second complex (marine) with dominating algae belonging to the Enteromorpha, Chaetomorpha, Ceramium, and Polysiphonia inhabits the littoral part of the Azov Sea itself, the Kerch Strait, and Taman Bay. The saprobe analysis of the flora showed that the majority of macroalgae species inhabiting the Azov Sea are represented by meso- and polysaprobes and a small number of oligosaprobe species inhabit the Kerch Strait. The biggest species diversity of macroalgae was noted in the southwestern part of the sea; the value of Shannon’s index was 0.65 in the Taganrog Gulf, 1.04 in the Azov Sea, 1.38 in Taman Bay. The leading role in the littoral communities of Taganrog Gulf belongs to aquatic flowering plants with Potamogeton perfoliatus being dominant; as the salinity increases, the share of such species as P. pectinatus, Zostera marina, Z. noltii, Ruppia maritime, and Zannichellia major starts to increase.  相似文献   

18.
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   

19.
The deviations of the marine surface slope spectra (measured using an array of wave gauge sensors) from the theoretical estimates obtained using the linear spectral model of the wave field are analyzed. It has been indicated that the average measured full slope spectra (the sum of the slope component spectra in the orthogonal directions) is higher than the theoretical estimates by 6% at frequencies from the surface wave spectral peak (f m ) to 4.5 f m . The difference between the measured and theoretical estimates of the full slope spectrum rapidly increases at frequencies of f < f m . At f m ≈ 0.75 f m , the average measured full slope spectrum is higher than the theoretical estimate by a factor of more than 5.  相似文献   

20.
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   

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