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Morphological characteristics and DNA barcoding of Pampus echinogaster (Basilewsky, 1855)
Yuan LI, Yan ZHANG, Tianxiang GAO, Zhiqiang HAN, Longshan LIN, Xiumei ZHANG
doi: 10.1007/s13131-017-1124-x
The morphological similarities of Pampus fishes have led to considerable confusion in species-level identification, and no accurate information on neotype or DNA barcoding of Pampus echinogaster is available. Two hundred and seven specimens of P. echinogaster were collected from the coastal waters of Dandong, Dongying, Qingdao, Nantong, Zhoushan, Wenzhou, Changle, Taiwan, and Wakayama (Japan), from June 2010 to April 2013. The diagnostic characteristics of P. echinogaster are as follows: dorsal fin VIII-XI-43–51, anal fin V-VIII-43–49, pectoral fin 22–27, caudal fin 19–22, pelvic fin absent; first gill rakers sparse, slender (pointed), 3–4+12–16=15–20; vertebrae 39–41; transverse occipital canal on top of head moderately small, wavy ridges not reaching upper origin of pectoral fin; ventral branch of lateral line canal spare, shorter than dorsal branch of lateral line canal. By combining congener sequences of the cytochrome oxidase I (COI) gene from GenBank, two absolute groups were detected among all specimens, which further indicated that two valid species were present based on genetic differences in amino acid sequences and the distance between the groups. The sequences of Group 1 can be regarded as DNA barcoding of P. echinogaster. The correct morphological redescription and DNA barcoding of P. echinogaster are presented here to provide a guarantee for efficient and accurate studies, a theoretical basis for classification, and enable appropriate fishery management and conservation strategies for the genus Pampus in the future.
key words: morphological characteristics, DNA barcoding, Pampus echinogaster, genetic differentiation, transverse occipital canal
A morphological evaluation of Chrysaora chinensis of Peninsular Malaysia and distinguishing its populations using geometric morphometrics
Liang Boon Low, Wan Mohd Syazwan, Mohammed Rizman-Idid
doi: 10.1007/s13131-019-1483-6
The morphology of seven specimens of Chrysaora chinensis (Scyphomedusae, Semaestomae) obtained from four sites off the coast of Peninsular Malaysia was examined. Morphological characteristics of C. chinensis that encompasses structures such as the bell, tentacles, oral arms, stomach, manubrium, radial canals and gonads were described in detail. A total of 107 specimens that represented C. chinensis populations of four coastal areas of Peninsular Malaysia (East-Central, East-North, West-Central, and West-North) were also analysed for shape variation using geometric morphometric analysis. Procrustes superimposition, Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA) were applied to the images of gastrovascular pouches of C. chinensis to extract the shape information. Independent contrasts were used for comparisons between shapes. There were no significant differences in shape variation between all the specimens based on the PCA results. However, CVA results showed shape variations between specimens taken from the four areas of Peninsular Malaysia, especially with higher magnitudes of Mahalanobis distances between the east and west coast areas, including between East-Central and East-North, but lower magnitudes were detected between the West-Central and West-North.
key words: geometric morphometrics, Scyphozoa, jellyfish, morphology, Malaysia
Marine green alga Cladophora aokii Yamada and its epiphytes from Yinggehai, Hainan, China: morphological taxonomy, formation and analysis of its environmental adaption
Lanping DING, Yue DAI, Bingxin HUANG, Yongmei LI, Rui LIU, Shaoyang DENG
doi: 10.1007/s13131-018-1299-9
Based on specimens collected in Yinggehai, Hainan, China from 2013 to 2016, a stable epiphytic taxon is found on the surface of the individual of marine green alga Cladophora aokii Yamada. According to the morphological characteristics, the taxonomy of Cl. aokii and its epiphytes is carried out. There are some epiphytes attached on Cl. aokii Yamada including Cl. fascicularis (Mertens ex C. Agardh) Kützing, Chaetomorpha pachynema (Montagne) Kützing, Ceramium camouii Dawson, Licmophora abbreviata Agardh, Lyngbya sp. and Chattonella sp.. The formation of the individual of Cl. aokii is dissected and explained, which can help to analyze the adaption in details among this species, its epiphytes and native marine environment. The results reveal the marine macro-epiphytic taxonomy in Hainan, China, and preliminarily explain the adaptive relationship between macroalgae and environment.
key words: Hainan, Yinggehai, Cladophoraceae, morphological taxonomy, growth pattern, environmental adaption
The morphological and phylogenetic characterization for the dinoflagellate Margalefidinium fulvescens (=Cochlodinium fulvescens) isolated from the Jiaozhou Bay, China
Zhangxi HU, Yunyan DENG, Yuhang LI, Ying Zhong TANG
doi: 10.1007/s13131-018-1295-0
The dinoflagellate genus Margalefidinium has been split from Cochlodinium as a new genus recently and Margalefidinium fulvescens is one of the five Margalefidinium species. Margalefidinium fulvescens is toxic and has been reported from the coastal waters of USA, Canada, Mexico, China, Japan, Indonesia, Korea, Pakistan and Spain. Here we provide the morphological and phylogenetic characterization for an isolate of it from the Jiaozhou Bay, Qingdao, China. Our results showed that the vegetative cells were subspherical to ellipsoidal, 34–60 μm in length, and 19–41 μm in width. Both single cell forms and colonies in chains of 2, 4, or 8 cells were observed in cultures, but chain forms with 2 or 4 cells were observed more often in the field samples. The cingulum was rather deep, encircling the cell approximately twice, but the sulcus was rather narrow, surrounding the cell about one turn. The nucleus was spherical and located at the central epicone. The chloroplasts were granular, brownish, and scattered peripherally. An orange pigmented body also appeared in the epicone. The apical groove appeared vase-like as previously described. Under epi-fluorescence microscopy, a pumpkin-like structure was clearly observed, in which cells were embedded. Cells were observed to exit from the structure, which led us to a hypothesis that the structure may provide cells a shelter to avoid predation or to respond to other stresses. The phylogenetic analyses based on partial LSU rDNA sequences indicated that M. fulvescens from the Jiaozhou Bay was grouped with M. fulvescens populations from other origins and closely related to the clade of M. polykrikoides. Our morphological observations and phylogenetic analyses together confirmed the presence of M. fulvescens in China and our monitoring has also observed the species dominant in the dinoflagellate community of the Jiaozhou Bay in the early autumn of 2015, which alerted us to continually monitor this bloom-forming species in the region.
key words: Margalefidinium fulvescens, morphology, phylogeny, pumpkin-like structure, Jiaozhou Bay, China
Genetic and morphological divergence in the purple sea urchin Paracentrotus lividus (Echinodermata, Echinoidea) across the African Mediterranean coast
Deli Temim, Ben Attia Mohamed Hbib, Zitari-Chatti Rym, Said Khaled, Chatti Noureddine
doi: 10.1007/s13131-017-1090-3
The present investigation focuses on population structure analysis of the purple sea urchin Paracentrotus lividus across the African Mediterranean coast, with the main aim of assessing the influence of the Siculo-Tunisian Strait on gene flow disruption in this highly dispersive echinoid species. For this purpose, patterns of morphological and genetic variation were assessed among its populations from the western and eastern Mediterranean coasts. A total of 302 specimens from seven Tunisian sites were collected and examined for morphometric variability at twelve morphometric traits. Concordant results, inferred from CDA (canonical discriminant analyses), pairwise NPMANOVA (non parametric multivariate analysis of variance) comparisons and MDS (multidimensional scaling) plot, unveiled significant inter-population differences in the measured traits among the studied populations. Furthermore, the combined use of the one way ANOSIM (analysis of similarities) and the Discriminant/Hotelling analysis allowed unravelling two morphologically differentiated groups assigned to both western and eastern Mediterranean basins. The SIMPER (similarity percentages) routine analysis showed that total dry weight, test diameter and spine length were major contributors to the morphometric separation between locations and between groups. Pattern of phenotypic divergence discerned in P. lividus across the Siculo-Tunisian Strait is interestingly in congruence with that inferred from the genetic investigation of the purple sea urchin populations from the same region based on the analysis of the mtDNA COI (cytochrome oxidase I) gene in 314 specimens from nineteen locations covering a wider geographic transect, streching westward to the Algerian coast and eastward to the Libyan littoral. The specific haplotypic composition characterizing each Mediterranean basin, as inferred from the minimum spanning network, confirmed the geographic partioning of genetic variation, as revealed by F-statistics and AMOVA (analysis of molecular variance) analyses, yielding significant genetic differentiation between eastern and western Mediterranean populations. The newly detected phylogeographic patterns, observed for the first time in P. lividus throughout the explored distribution range, suggest the involvement of different biotic and abiotic processes in shaping such variation, and provide evidence that a large and geographically exhaustive dataset is necessary to unveil phylogeographic structure within widespread marine species, previously cathegorized as panmictic in part of their distribution range.
key words: Paracentrotus lividus, Siculo-Tunisian Strait, morphological differentiation, COI, genetic divergence
Derivation of the thermal characteristics of mesoscale eddies
Xuan CHEN, Jing PAN, Chongwei ZHENG, Xi ZHANG, Ming HE
doi: 10.1007/s13131-017-1036-9
This study aims at explaining the relationship between thermodynamic characteristics and direction of rotation of mesoscale eddies (MEs). The geometric characteristics of the MEs are under the following assumptions: the structure of the MEs is symmetrical, and changes of oceanic physical variables are close to linear features in the radial direction in the ME regions. Based on these assumptions, by using primitive equations without friction under a cylindrical coordinate system, the thermodynamic characteristics of the MEs are derived, showing that the conventional relationship of warm anticyclonic eddies with high sea surface height (SSH) and cold cyclonic eddies with low SSH is not consistent with the SSH and sea surface temperature (SST) observations of eddies. The results show that the symmetrical form is an ideal approximation for the geometric characteristics of MEs. In consideration of the above assumptions, there are advantages for derivation of the characteristics of the MEs under a cylindrical coordinate.
key words: mesoscale eddies, thermodynamic characteristics, symmetry
Characteristics analysis for cold water patches off the Jiangsu coast in the last 35 a
Shouxian ZHU, Zhanyuan HE, Wenjing ZHANG, Shijian XIE, Yucheng XU
doi: 10.1007/s13131-018-1293-2
The daily and monthly-mean characteristics of cold water patches (CWPs) off the Jiangsu coast in 35 a of 1982–2016 are examined based on advanced very high resolution radiometer (AVHRR) data. Most of the CWPs are found to occur in the warm and hot months (May–September), with some CWPs in the cool and cold months (October–April). The average radius and intensity of the monthly-mean CWPs are about 81 km and 0.6°C, respectively. The average difference in the sea surface temperature (SST) between the centers of the CWPs and the nearshore is about 2.0°C. The correlation analysis between the CWPs, winds and tides indicates that most of the CWPs occurred during the southerly winds, with some CWPs occurring during the northerly winds. The average intensity of the CWPs during spring tides is slightly stronger than that during neap tides in the warm and hot months, and the difference is very small in the cool and cold months.
key words: Jiangsu coast, cold water patch, characteristic analysis, wind, tide
The Rhines effect on the geographical characteristics of altimeter-observed eddies
Zhiliang LIU, Chongguang PANG
doi: 10.1007/s13131-017-1105-0
The Rhines effect may be regarded as an interaction between Rossby waves and turbulence, in which the Rossby waves may radiate away eddy energy when their frequencies are equal or larger than those of the turbulence, thereby deforming and eventually destroying the existing eddies. Through comparing eddy-scale velocity and long Rossby wave phase speed in the oceans, a generalized form of the Rhines effect is examined on the geographical characteristics of altimeter-observed eddies. The results show that the generalized Rhines effect has a much greater influence on eddy characteristics than its classical form, which only considers the simple beta effect due to the meridional gradient of planetary vorticity. The largest amount of eddies are detected in regions where eddy-scale velocity is larger than the critical Rossby-wave phase speed considering a generalized beta effect. The eddies in those regions can grow via an inverse kinetic energy cascade and have much larger amplitudes and sizes. The " eddy desert” regions outside of the tropical oceans, which have far fewer detected eddies and much weaker eddy amplitudes, lie in areas where the eddy-scale velocity is less than the critical Rossby-wave phase speed. In those regions, the generalized Rhines effect may be a possible mechanism of suppressing eddy growth.
key words: Rhines effect, mesoscale eddy, Rossby wave, energy cascade, eddy desert
The in situ observation of modelled sea ice drift characteristics in the Bohai Sea
Yu YAN, Wei GU, Yingjun XU, Qian LI
doi: 10.1007/s13131-019-1395-5
Sea ice drift is mainly controlled by ocean currents, local wind, and internal ice stress. Information on sea ice motion, especially in situ synchronous observation of an ice velocity, a current velocity, and a wind speed, is of great significance to identify ice drift characteristics. A sea ice substitute, the so-called " modelled ice”, which is made by polypropylene material with a density similar to Bohai Sea ice, is used to complete a free drift experiment in the open sea. The trajectories of isolated modelled ice, currents and wind in the Bohai Sea during non-frozen and frozen periods are obtained. The results show that the currents play a major role while the wind plays a minor role in the free drift of isolated modelled ice when the wind is mild in the Bohai Sea. The modelled ice drift is significantly affected by the ocean current and wind based on the ice–current–wind relationship established by a multiple linear regression. The modelled ice velocity calculated by the multiple linear regression is close to that of the in situ observation, the magnitude of the error between the calculated and observed ice velocities is less than 12.05%, and the velocity direction error is less than 6.21°. Thus, the ice velocity can be estimated based on the observed current velocity and wind speed when the in situ observed ice velocity is missing. And the modelled ice of same thickness with a smaller density is more sensitive to the current velocity and the wind speed changes. In addition, the modelled ice drift characteristics are shown to be close to those of the real sea ice, which indicates that the modelled ice can be used as a good substitute of real ice for in situ observation of the free ice drift in the open sea, which helps solve time availability, safety and logistics problems related to in situ observation on real ice.
key words: Bohai Sea, modelled ice, in situ observation, sea ice drift
Fouling community characteristics in subtropical coastal waters of the southwestern East China Sea
Heshan LIN, Jianjun WANG, Wei LIU, Kun LIU, Shuyi ZHANG, Xuebao HE, Yaqin HUANG, Junhui LIN, Jianfeng MOU, Chengxing ZHENG, Tao YAN
doi: 10.1007/s13131-017-1007-1
A fouling study was conducted in coastal waters southwest of the East China Sea between December 2013 and November 2014. A total of 84 species of fouling organisms belonging to 69 genera, 49 families, and 10 phyla were recorded over the entire year. The community composition was dominated by coastal warm-water species belonging to typical subtropical inner bay communities. The prosperous stage of settlement lasted from April to September, and the adhesion strength of the fouling organisms was the highest in summer. Sessile suspension feeders constituted the main core of settlement for the fouling community. Amphibalanus reticulatus was the most dominant and representative species of fouling organism, and other dominant species included Caprella equilibra, Ectopleura crocea, Anthopleura nigrescens, Stylochus ijimai, Spirobranchus kraussii, Crassostrea angulata, Perna viridis, Jassa falcata, Stenothoe valida, Sphaerozius nitidus, and Biflustra grandicella. The individuals in the fouling community showed a mutual dependence or constraint relationship due to competition for settlement space and food, and they exhibited a particular spatiotemporal distribution in accordance with adaptation to environmental factors. Temperature was the most important environmental factor determining the geographic distribution of fouling organisms. The temperature characteristics of species essentially reflect the differences in the fouling community composition in various climate zones. The species number, settlement stage, and settlement rate of fouling organisms are closely related to water temperature. Local natural environmental conditions (salinity, water currents, light, etc.) as well as human activity (such as aquaculture production) are all important factors affecting the settlement of fouling organisms.
key words: biofouling, coastal waters, East China Sea, community structure

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