2013 Vol. 32, No. 8

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2013, 32(8): .
2013, 32(8): .
2013, 32(8): .
Acta Oceanologica Sinica (AOS) is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.
A comparison of two global ocean-ice coupled models with different horizontal resolutions
SHU Qi, QIAO Fangli, SONG Zhenya, YIN Xunqiang
2013, 32(8): 1-11. doi: 10.1007/s13131-013-0335-z
A global eddy-permitting ocean-ice coupled model with a horizontal resolution of 0.25° by 0.25° is established on the basis of Modular Ocean Model version 4 (MOM4) and Sea Ice Simulator (SIS). Simulation results are compared with those of an intermediate resolution ocean-ice coupled model with a horizontal resolution of about 1° by 1°. The results show that the simulated ocean temperature, ocean current and sea ice concentration from the eddy-permitting model are better than those from the intermediate resolutionmodel. However, both the twomodels have the common problem of ocean general circulation models (OGCMs) that the majority of the simulated summer sea surface temperature (SST) is too warm while the majority of the simulated subsurface summer temperature is too cold. Further numerical experiments show that this problem can be alleviated by incorporating the non-breaking surfacewave-induced vertical mixing into the vertical mixing scheme for both eddy-permitting and intermediate resolution models.
Impact of the slope angle of hummocks on the ride-up of finger ice in the Liaohe Estuary
KONG Xiangpeng, CHEN Naxin
2013, 32(8): 12-15. doi: 10.1007/s13131-013-0336-y
The ride-up and pile-up of sea ice have effects on the ice load of marine structure. The ride-up angle is an important parameter to study the process of ride-up and to determine the possibility of the ride-up to occur. Some conclusions about the ride-up angle are drawn based on field-survey data in this paper. Thirty hummocks with full structure, formed by 0.4-1.6 cm ice layers, were investigated in the Liaohe Estuary of the north of Liaodong Bay. After analyzing the cross-sections of the pile-up body, some conclusions on the ride-up angle are reached. The results indicate that whether the ride-up occurs or not is associated with the slope angle of the hummock. If the slope angle is greater than 10.31° , the ride-up can take place. With the development of riding-up and piling-up, if the slope angle increases to 40.0° , the climbing-up process will stop and the drifting ice begins to accumulate in front of the hummock. The climbing process does not continue until a new slope angle, which is less than 28.0° , is formed. Meanwhile, the forming process of hummocks, which aremade up of 10.0 cmor 22.0 cmice layers, is proved to follow the rule.
Robust LS-SVM regression for ore grade estimation in a seafloor hydrothermal sulphide deposit
ZHANG Xunan, SONG Shiji, LI Jiabiao, WU Cheng
2013, 32(8): 16-25. doi: 10.1007/s13131-013-0337-x
Due to the geological complexities of ore body formation and limited borehole sampling, this paper proposes a robust weighted least square support vectormachine (LS-SVM) regression model to solve the ore grade estimation for a seafloor hydrothermal sulphide deposit in Solwara 1, which consists of a large proportion of incomplete samples without ore types and grade values. The standard LS-SVM classification model is applied to identify the ore type for each in complete sample. Then, a weighted K-nearest neighbor (WKNN) algorithm is proposed to interpolate the missing values. Prior to modeling, the particle swarm optimization (PSO) algorithm is used to obtain an appropriate splitting for the training and test data sets so as to eliminate the large discrepancies caused by randomdivision. Coupled simulated annealing (CSA) and grid search using 10-fold cross validation techniques are adopted to determine the optimal tuning parameters in the LS-SVM models. The effectiveness of the proposed model by comparing with other well-known techniques such as inverse distance weight (IDW), ordinary kriging (OK), and back propagation (BP) neural network is demonstrated. The experimental results show that the robust weighted LS-SVM outperforms the othermethods, and has strong predictive and generalization ability.
Sand wave deposition in the Taiwan Shoal of China
HU Yi, CHEN Jian, XU Jiang, WANG Liming, LI Haidong, LIU Huaishan
2013, 32(8): 26-34. doi: 10.1007/s13131-013-0338-9
The Taiwan Shoal is the convex terrain in the southern Taiwan Strait, the largest strait in China. In 2006 and 2007, 21 samples and more than 200-km sub-bottom data as well as 80-km near shore side-scan sonar data were gotten, which gave an initial image of the boundaries of the Taiwan Shoal and revealed the internal structure of the sand waves in this area. The results showed that the major component of the sediment samples was sand, and sand waves occurred everywhere in this area, which closely followed the range of the Taiwan Shoal as we know. The western boundary of the Taiwan Shoal thus reaches the 30 m isobaths near the shore, and as a result, its area potentially covers approximately 12 800-14 770 km2. The sand waves have different shapes under the complex ocean dynamics, and the height of sand waves in the near shore is usually smaller than that in the Taiwan Shoal. The number of sand waves ranged from 1-5 per kilometer, with more waves in the isobath-intensive area, suggesting the importance of topography for the formation of sand waves. The stratigraphic structure under the seabed has parallel bedding or cross bedding, and large dipping groove bedding can be seen locally in different parts, which may be the result of terrestrial deposition since the Late Pleistocene.
Characterization of the cyp19a1a gene froma BAC sequence in half-smooth tongue sole (Cynoglossus semilaevis) and analysis of its conservation among teleosts
SHAO Changwei, LIU Geng, LIU Shanshan, LIU Changlin, CHEN Songlin
2013, 32(8): 35-43. doi: 10.1007/s13131-013-0339-8
The cyp19a1a gene encodes an aromatase that plays a key role in sex differentiation of the gonad. The first bacterial artificial chromosome (BAC) sequence of half-smooth tongue sole (Cynoglossus semilaevis) containing the intact cyp19a1a gene was reported and the conservation and synteny of the cyp19a1a gene among teleosts were analyzed in the study. The BAC is 107 367 bp in size, with an overall guanine-cytosine (GC) content of 43.44%, and contains 4.38% transposable elements. Nine genes were predicted, including seven functional genes and two hypothetical genes. The cyp19a1a gene of all tested teleosts has nine exons and eight introns, and potential binding sites flanking the transcriptional start site are conserved. The expression pattern among teleosts is also similar during ovarian differentiation. Synteny analysis revealed a conserved gene cluster PKH4B-SL9A5-FHOD3-CEBPG-CEBPA among teleosts. These findings suggest that, among teleosts, cyp19a1a genes not only have similar genomic structures, but also have conserved functions. The genomic environment of cyp19a1a in tongue sole is not universal in teleosts, reflecting the particular evolution of tongue sole cyp19a1a after it diverged from the other teleosts.
Temporal dynamics of shallow subtidal meiobenthos from a beach in Tenerife (Canary Islands, northeast Atlantic Ocean)
Rodrigo Riera, Jorge Núñez, María del Carmen Brito
2013, 32(8): 44-54. doi: 10.1007/s13131-013-0340-2
A shallow subtidal (3 m deep) meiofaunal assemblage in Los Abrigos Bay, Tenerife, Canary Islands was sampled during May 2000-April 2001. Themain aims were to (1) find temporal variations inmeiofaunal assemblage structure and overall abundance, as well as in the most abundant meiofaunal species throughout the study period, and (2) identify environmental variables (sedimentary composition, organic matter content, and total nitrogen) that better explain meiofaunal assemblage structure during the study year. The most abundant species were the nematodes Siphonolaimus sp. 2 and Catanema sp., which represented 46.2% of the overall meiofaunal abundances and varied significantly throughout the study duration. Overall meiofaunal abundance and the most abundant taxonomic groups (nematodes, copepods, and oligochaetes) showed significant temporal variations during the study period. Nematodes overwhelmingly dominated during the study period, ranging from 78% in May to 97.34% in February. Multivariate analyses showed seasonality inmeiofaunal community structure during the study year, with the lowest abundances in May.
Disruption of chemotaxis-related genes affects multiple cellular processes and the virulence of pathogenic Vibrio harveyi
QIN Yingxue, YAN Qingpi, SU Yongquan, LI Haiping, ZOU Wenzheng
2013, 32(8): 55-60. doi: 10.1007/s13131-013-0341-1
Chemotactic motility is involved in the virulence of many pathogenic bacteria. In order to understand the role of chemotactic motility of Vibrio harveyi in cellular processes and virulence, mini-Tn10/Kan transposon-induced mutants with deficient chemotactic motility were constructed, screened, and identified. Sequence analysis revealed that the 465-bp fragment (GenBank accession number HM630274) flanking the transposon insertion site in mutant TS-CM1 had the highest identity (96.9%) with a hypothetical protein gene of V. harveyi ATCC BAA-1116 and the second-highest identity (91.8%) with the pgk gene of V. parahaemolyticus RIMD 2210633. In another mutant, TS-CM2, 356 bp of transposon-flanking sequence (GenBank accession number HM630275) also showed the highest identity (94.6%) with a hypothetical protein gene of V. harveyi ATCC BAA-1116 and the second-highest identity (92.4%) with the flaB gene of V. alginolyticus HY9901. Studies on virulence-related biological characteristics such as growth,motility, adhesion, and infectivity of themutants showed that disruption of either the flagellin gene or energymetabolism gene led to subsequent loss of chemotactic motility and changes in growth, motility, adhesion, and virulence of the pathogenic V. harveyi. Hence, the flagellin gene and crucial energy metabolism gene played an important role in the chemotacticmotility of V. harveyi.
Dynamics of nonstructural carbohydrates in seagrass Thalassia hemprichii and its response to shading
JIANG Zhijian, HUANG Xiaoping, ZHANG Jingping
2013, 32(8): 61-67. doi: 10.1007/s13131-013-0342-0
A field survey was performed to examine nonstructural carbohydrate (NSC) dynamics in seagrass Thalassia hemprichii at the Xincun Bay in southern China. An indoor experiment to investigate the response of NSC in T. hemprichii to shade was conducted. Belowground tissue of T. hemprichii was the dominant site of NSC reserves, and soluble sugar was the primary storage compound. The starch content of belowground tissue was lower in high intertidal areas than in low intertidal areas, indicating that the longer air exposure in high intertidal areas resulted in less NSC synthesis and less accumulation of NSC in T. hemprichii. The lowest level of soluble sugar and its proportion to NSC in belowground tissue were observed near the cage culture area, where the nutrient concentration in water and sediment was the highest;while the highest level of that was observed near the coastal shrimp farm,where salinity was the lowest. Soluble sugar in belowground tissue showed the following trend: summer>spring>winter>autumn. This corresponded to seasonal changes in the intensity of light. Leaf sugar accumulated during the autumn-winter period, providing a carbon and energy source for flower bud formation and seed germination. Short-termshading decreased NSC accumulation. Collectively, these results suggest that nutrient enrichment, freshwater discharge and exposure to air affect NSC dynamics in T. hemprichii. Light intensity, flower bud formation, and seed germination were all found to induce seasonal variations in NSC in T. hemprichii.
Generation and analysis of expressed sequence tags from the salt-tolerant eelgrass species, Zostera marina
KONG Fanna, ZHOU Yang, SUN Peipei, LIU Limin, MAO Yunxiang
2013, 32(8): 68-78. doi: 10.1007/s13131-013-0343-z
Zosteramarina, a monocotyledonous angiosperm, is one of themost important seagrass species. To investigate the salt-tolerancemechanismand discover salt-tolerant genes in Z. marina, a cDNA library was constructed. Single-pass sequencing of the 5' ends of 4 081 clones yielded 4 002 high quality expressed sequence tags (ESTs), which were assembled into 241 contigs and 1 673 singletons, representing 1 914 unigenes. The average length of the ESTs was 582 bp, with sizes ranging from100-1 500 bp. Basic Local Alignment Search Tool (BLASTX) analysis revealed that 1 664 unigenes had significant homology to known genes in the National Center for Biotechnology Information (NCBI) non-redundant (nr) database (E-value≤5-10). Among them, the twomost abundant genes encoded metallothionein (157 ESTs) and chlorophyll a/b-binding protein (38 ESTs), accounting for 7.1% and 1.7% of the total ESTs, respectively. Using Kyoto Encyclopedia of Genes and Genomes (KEGG), 1 462 unigeneswere assigned to 1 161 pathways (E-value≤5-10). A total of 938 unigenes were assigned Gene Ontology (GO) terms based on the GO hierarchy analysis, and InterProScan searches recognized 1 003 InterPro families. Three genes formetallothionein in Z. marina that belonged to Class II was identified. Results of this study will improve understanding of the molecular mechanisms of saline tolerance in Z.marina.
Research Notes
Source diagnostic and weathering indicators of oil spills utilizing bicyclic sesquiterpanes
WANG Chuanyuan, HU Xiaoke, HE Shijie, LIU Xin, ZHAO Mingming
2013, 32(8): 79-84. doi: 10.1007/s13131-013-0344-y
Bicyclic Sesquiterpanes (BSs) are ubiquitous components of crude oils and ancient sediments. BSs in crude oils and diesel oil were identified and characterized, the effects ofmoderate weathering on BS distributions were discussed, and amethodology using diagnostic indices of BSswas developed for oil correlationand differentiation. The results showed that crude oils and oil products had different abundances and distributions of BSs and, consequently, resulted in different diagnostic ratios. The selected diagnostic ratio indices of BSs, such as BS4/BS5 (ratio of 4,4,8,9,9-pentamethyl-decahydronaphthalene to 8β(H)-drimane), BS6/BS5 (ratio of 4,4,9,9,10-pentamethyl-decahydronaphthalene to 8β(H)-drimane), BS8/BS9 (ratio of the second peak to the third peak of C16 sequiterpane), and BS8/BS10 (ratio of C16 sequiterpane to 8β(H)-homodrimane), still maintained better stabilities (%RSD < 5%) after weathering for 30 d. The longer weathering process (150 d) had some effect on such ratios (5% < %RSD < 10%). The facts of the uniqueness, abundance in petroleum, and chemical stability of BSs enable them to be suitable as an effective diagnostic means for identifying spilled oil with moderate weathering, particularly for lighter refined product samples that are difficult to identify by current techniques.
New discovery of seafloor hydrothermal activity on the Indian Ocean Carlsberg Ridge and Southern North Atlantic Ridge—progress during the 26th Chinese COMRA cruise
TAO Chunhui, WU Guanghai, DENG Xianming, QIU Zhongyan, HAN Chenhua, LONG Yanmei
2013, 32(8): 85-88. doi: 10.1007/s13131-013-0345-x
The 26th Chinese COMRA (China Ocean Mineral Resources Research & Development Association) cruise was an important cruise. The Carlsberg Ridge (CR) of the Northwest Indian Ocean and the North Atlantic Ridge (NAR), in which less investigation has been carried out for hydrothermal activities, were investigated and studied during the first two legs of the 26th COMRA cruise. During the first leg, we found one hydrothermal activity field located in the CR at 3.5°-3.8°Non the Northwest Indian Ocean Ridge (NWIR), and sampled seafloor polymetallic sulfide deposits where only abnormalities were found before. During the second leg, we found a new hydrothermal anomaly field located in the NAR at 4°-7°N. The discovery of two hydrothermal and anomaly fields filled in the gap of hydrothermal investigation and study in the corresponding regions for China.