Qingdao Bay Research Articles

Occurrence and distribution of antibiotic pollution and antibiotic resistance genes in seagrass meadow sediments based on metagenomics

Seagrass meadows are one of the most important coastal ecosystems that provide essential ecological and economic services. The contamination levels of antibiotic and antibiotic resistance genes (ARGs) in coastal ecosystems are severely elevated owing to anthropogenic disturbances, such as terrestrial input, aquaculture effluent, and sewage discharge. However, few studies have focused on the occurrence and distribution of antibiotics and their corresponding ARGs in this habitat. Thus, we investigated the antibiotic and ARGs profiles, microbial communities, and ARG-carrying host bacteria in typical seagrass meadow sediments collected from Swan Lake, Caofeidian shoal harbor, Qingdao Bay, and Sishili Bay in the Bohai Sea and northern Yellow Sea. The total concentrations of 30 detected antibiotics ranged from 99.35 to 478.02 μg/kg, tetracyclines were more prevalent than other antibiotics. Metagenomic analyses showed that 342 ARG subtypes associated with 22 ARG types were identified in the seagrass meadow sediments. Multidrug resistance genes and RanA were the most dominant ARG types and subtypes, respectively. Co-occurrence network analysis revealed that Halioglobus, Zeaxanthinibacter, and Aureitalea may be potential hosts at the genus level, and the relative abundances of these bacteria were higher in Sishili Bay than those in other areas. This study provided important insights into the pollution status of antibiotics and ARGs in typical seagrass meadow sediments. Effective management should be performed to control the potential ecological health risks in seagrass meadow ecosystems.

Two new diatom species of the genus Gomphonemopsis (Bacillariophyceae) from the coast of China and two new combinations for the genus.

Two new diatom species belonging to the genus Gomphonemopsis are described, Gomphonemopsisnanasp. nov. and Gomphonemopsisgaoisp. nov. These two species were compared in detail with congeners. Gomphonemopsisnana is distinguished by its high stria density and small size. This species was found so far to be epiphytic only on the eelgrass collected from Qingdao Bay (Yellow Sea). Gomphonemopsisgaoi is characterized by its isopolar valves, simple proximal raphe endings and acutely rounded apices. This taxon was separated from the exoskeleton of marine copepods sampled from the Futian Mangrove Nature Reserve (South China Sea). In addition, two new combinations, Gomphonemopsisoahuensis (Hustedt) Lang Li, Yuhang Li & Changping Chen, comb. nov. and Gomphonemopsisplatypus (Østrup) Lang Li, Yuhang Li & Junxiang Lai, comb. nov. are proposed. This study increases the records and knowledge of Gomphonemopsis along the coast of China.

Service life prediction and time-variant reliability of reinforced concrete structures in harsh marine environment considering multiple factors: A case study for Qingdao Bay Bridge

Chloride attack is the primary cause of performance deterioration and life attenuation of reinforced concrete (RC) structures in marine environments. In an attempt to accurately predict the reliability and service life of RC structures under the co-effects of multiple factors, a comprehensively modified chloride-transport-based model is proposed in this paper. Based on Fick's second law, a multifactor integrated deterministic chloride transport model is developed considering the time dependence, concrete mix proportion, chloride binding capacity, freeze–thaw cycles, sustained load, temperature, humidity and concrete deterioration. Based on extensive literature review combined with the results of multitudinous long-term field exposure tests used in the durability design of Hong Kong-Zhuhai-Macao Bridge and Shenzhen-Zhongshan Bridge, the probability distribution types and parameter values of the governing variables are determined. Taking Qingdao Bay Bridge as an example, the time-variant reliability index, failure probability and reliability-index-based corrosion initiation are determined by using the equivalent normalization method (JC method) and Monte Carlo simulation technique for different environmental zones including atmospheric/splash/tidal/submerged zones. The sensitivity of the reliability index to the control variables and the effects of age index, chloride binding capacity, numbers of freeze–thaw cycles, stress level and concrete deterioration on the reliability index are quantitatively investigated. The results show that the time-variant reliability of different environmental zones is sequenced as: atmospheric zone > submerged zone > tidal zone > splash zone; the sensitivity of reliability to the governing variables sequenced as: concrete cover thickness > surface chloride concentration > chloride diffusion coefficient > critical chloride concentration; the time dependence of the diffusion coefficient has a significant effect on the time to corrosion initiation and cannot be ignored in the predictive model for both the high-performance or ordinary concrete; the number of freeze–thaw cycles and the tensile stress level are relatively insensitive but substantially detrimental to the reliability of corrosion initiation.

Reciprocal Field Transplant Experiment and Comparative Transcriptome Analysis Provide Insights Into Differences in Seed Germination Time of Two Populations From Different Geographic Regions of Zostera marina L.

Seagrasses are the only submerged marine higher plants, which can colonize the sea through sexual (via seeds) reproduction. The transition between seed dormancy and germination is an important ecological trait and a key stage in the life cycle of higher plants. According to our observations, the seeds of Zostera marina L. (eelgrass) in Swan Lake (SL) and Qingdao Bay (QB) in northern China have the same maturation time (summer) but different germination time. To investigate this phenomenon, we further carried out reciprocal transplantation experiment and transcriptome analysis. Results revealed that differences in the seed germination time between the two sites do exist and are determined by internal molecular mechanisms as opposed to environmental factors. Furthermore, we conducted comparative transcriptome analysis of seeds at the mature and early germination stages in both locations. The results that the number of genes related to energy, hormone and cell changes was higher in SL than in QB, could account for that the dormancy depth of seeds in SL was deeper than that in QB; consequently, the seeds in SL needed to mobilize more related genes to break dormancy and start germination. The results could have important practical implications for seagrass meadow restoration via seeds and provide in-depth and comprehensive data for understanding the molecular mechanisms related to seagrass seed germination.

Asphalt Deck Pavement Design for Concrete Bridge under Frost Climate in the North Sea Region

A prefered waterproofing system and bearing course mixtures for asphalt pavement deck were designed to determine a suitable waterproofing system and material/structure combination optimize proposal for Qingdao Bay Bridge, which was built under the frost climate of Shandong province, through a general analysis on the disease type and the damage mechanism of asphalt deck pavement. Based on the laboratory test results, the test section construction and long-term pavement performance observation, a comprehensive comparison and analysis about five types of waterproofing system(Synchronous Seal coat+ Asphalt Sand, Polymer Modified Bituminous Waterproofing Sheets, Priming Coat+Asphalt Rubber Membrance+Protection Board, Polymer Modified Emulsified Asphalt Waterproof coating, Gussasphalt)were made in terms of waterproof effect, workability, quality reliability and long-term performance. Furthermore, the asphalt deck pavement were proposed to be designed on the basis of the layer performance-related concept, and regarded as the system engineering. The construction effect indicates that both the multi-purpose layer (waterproofing high modulus asphalt sand) and the deck pavement structure are adapted to the evidence temperature difference and windy characteristics during the construction. It also shows the excellent workability and quality reliability.

Temporal Dynamics of the Natural and Trimmed Angiosperm Zostera marina L. (Potamogetonales:Zosteraceae), and an Effective Technique for Transplantation of Long Shoots in a Temperate Tidal Zone (Northern China)

In China, the coastal eelgrass Zostera marina has decreased dramatically since the 1980s as a result of human-induced habitat deterioration. From March 2009 to June 2010, we investigated the temporal changes in biometric and biomass features of Z. marina from a declined meadow owing to fisheries mechanical destruction in tidal Qingdao Bay, and we conducted an in situ transplantation experiment to develop an effective technique for transplantation of long shoots. Results showed that shoot height and biomass exhibited strong temporal variation, with a maximum shoot height (128.50 ± 17.63 cm) being recorded in June 2009 and minimum value (29.18 ± 3.89 cm) in January 2010. Shoot density in winter (311 ± 51 shoots m−2) was significantly lower than that in summer (545 ± 113 shoots m−2). N and P contents in the rhizome were significantly lower than those in the leaf and leaf sheath. Low C/P ratios (248.82 ± 81.7, 199.8 ± 87.5 and 289.2 ± 95.1 in leaves, leaf sheaths and rhizomes, respectively) suggested P enrichment of the eelgrass. The field recovery experiment showed that the eelgrass shoots had a high resilience even when most leaves were sheared. Long shoots were not suitable to be directly used for transplantation; however, when they were cut shorter (e.g. 18 cm) with most leaves removed, the transplant survivorship reached a high level (ca. 90%). It is suggested that transplantation may be practiced when seagrass meadows (donor beds) reached high density and biomass, and in this case long shoots should be trimmed short before transplanting as a way to improve early transplant success.

Interactions between Cryptosula and Watersipora (Bryozoa: Cheilostomata) on a ship’s hull in Qingdao Harbour (South Yellow Sea) after five and a half years of immersion

The distributions of two ubiquitous fouling cheilostome bryozoans, Cryptosula pallasiana (Moll, 1803) and Watersipora sp., on a ship moored for almost six years in Qingdao Bay show differences with respect to illumination, Cryptosula being dominant on the side of the ship which was exposed to the sun and Watersipora dominating on the other side which was in shadow for most of the time. Competitive interactions for substrate space were nearly always won by Watersipora, which succeeded in overgrowing the edges of Cryptosula colonies regardless of the side of the ship. Reasons for the superiority of Watersipora in spatial competition with Cryptosula could include faster growth rate and the stronger feeding currents created by the larger lophophores of Watersipora.

Numerical Simulation of Chloride Ion Induced Corrosion of Reinforced Concrete Structures in Marine Environment

A numerical simulation method of chloride ion induced corrosion was proposed. Based on the different corrosion mechanisms of submersion zone, tidal zone, splash zone and atmosphere zone, a series of theoretical equations were built by taking into account the effect of temperature, humidity, concrete age, chloride ion concentration and seawater convection etc. Further,a numerical simulation program was developed to simulate the service status of a bridge pier of Qingdao bay bridge by means of COMSOL coupled with factors such as temperature, humidity and chloride ion transmission etc. The results show that: (1) the numerical method can simulate chloride ion induced corrosion well; (2) the place where depassivation occurred for the reinforced steel bar corresponds to submersion zone, tidal zone, tidal zone and atmosphere zone in turn; (3) for this living example, the first depassivation of reinforced steel bars for a bare reinforced concrete bridge pier may 定稿日期:2014-09-09 基金项目:山东省自然科学基金项目(ZR2012EEL23)资助 作者简介:程旭东,男,1971年生,博士,教授 通讯作者:程旭东,E-mail:chengxd@upc.edu.cn,研究方向为土木工程、油田地面工程结构及LNG储罐 DOI:10.11902/1005.4537.2014.146 2期 程旭东等:沿海钢筋混凝土结构Cl侵蚀数值模拟方法研究 occur in the place about -2.200 m (near to the center of tidal range zone) after in service for 25 a.

Large-scale pilot test study on bearing capacity of sea-crossing bridge main pier pile foundations

Due to the sea-crossing bridge span is generally large and main pier pile foundations are located in deep water and carry large vertical load, sea-crossing bridge main pier pile foundations bearing mechanism and load deformation characteristics are still vague. Authors studied the vertical bearing properties of sea-crossing bridge main pier pile foundations through pilot load tests. Large tonnage load test of Qingdao Bay Bridge main pier pile program is designed by using per-stressed technique to optimize the design of anchor pile reaction beam system. Test results show that the design is feasible and effective. This method can directly test bearing capacity of main pier pile foundations, and analysis bearing behaviors from test results of sensors which embedded in the pile. Through test study the vertical bearing properties of main pier pile foundation and compared with the generally short pile, author summarized the main pier pile foundations vertical bearing capacity and the main problem of design and construction which need to pay attention, and provide a reliable basis and experience for sea-crossing bridge main pier pile foundations design and construction.

Study on Chloride Ion Permeability Resistance Variation of C40 Concrete

The influence of construction seasons and curing condition on chloride ion permeability of entity structure concrete was analyzed, which was based on the monitoring of pier concrete quality constructed seasonal of Qingdao bay bridge. At the same time, durability of entity concrete structure was analyzed combining site construction technology.

Genetic variation in scaly hair-fin anchovy Setipinna tenuifilis (Engraulididae) based on the mitochondrial DNA control region

Scaly hair-fin anchovy (Setipinna tenuifilis) is a small, pelagic and economical species and widely distributed in Chinese coastal water. However, resources of S. tenuifilis have been reduced due to overfishing. For better fishery management, it is necessary to understand the pattern of S. tenuifilis’s biogeography. Genetic analyses were taken place to detect their population genetic variation. A total of 153 individuals from 7 locations (Dongying, Yantai, Qingdao, Nantong, Wenzhou, Xiamen and Beibu Bay) were sequenced at the 5′ end of mtDNA control region. A 39-bp tandem repeated sequence was found at the 5′ end of the segment and a polymorphism of tandem repeated sequence was detected among 7 populations. Both mismatch distribution analysis and neutrality tests showed S. tenuifilis had experienced a recent population expansion. The topology of neighbor-joining tree and Bayesian evolutionary tree showed no significant genealogical branches or clusters of samples corresponding to sampling locality. Hierarchical analysis of molecular variance and conventional pairwise population Fst value at group hierarchical level implied that there might have genetic divergence between southern group (population WZ, XM and BB) and northern group (population DY, YT, QD and NT). We concluded that there might have three different fishery management groups of S. tenuifilis and the late Pleistocene glacial event might have a crucial effect on present-day demography of S. tenuifilis in this region.

Study on Qingdao Bay Bridge Pier Concrete Anti Cl<sup>- </sup>Permeability Change Law and Structural Durability Analysis

Entity structure concrete chloride ion permeability resistance change law were studied, relying on Qingdao Bay Bridge project, using entity structure concrete specimen under the same condition maintenance, using RCM method test diffusion coefficient at the age of 28d,60d,90d,1y and 2y. Different mixture concrete chloride ion permeability resistance change law were Interoperated in essence, combining with cementitious materials hydration mechanism.

Identification by FQ-PCR of AVNV carried by mesoplankton and microplankton at two ocean sites for culturing Chlamys farreri

This paper describes the relationship between transmission routes of AVNV and mesoplankton and mi-croplankton in the ocean for culturing scallops.Plankton samples were collected in Liuqinghe Qingdao and Sang-gou Bay,Rongcheng,from April to November 2009.In August,the AVNV copy number carried by plankton was identified by FQ-PCR.Results showed that plankton samples from both ocean areas carried the virus,and that the virus numbers differed with different particle sizes.Plankton samples with the same particle sizes at the Liuqinghe site carried more AVNV copy numbers than those at the Sanggou Bay site at a given time.Plankton particle sizes smaller than 200 mesh carried the greatest amount of viruses(viral DNA number reached 9.45×106 copy/mg DNA),followed by plankton particle sizes between 60?200 mesh size.Plankton particle sizes larger than 60 mesh carried the least amount viruses.Finally,results suggest that plankton can carry AVNV,and that they may be an important host of AVNV.

Study on High Amount Mineral Admixtures Concrete Performance

Depended on Qingdao Bay Bridge construction, large amount mineral admixture replacing cement has been conducted systematical research aiming at marine concrete, main control index is chloride ion permeability resistance. The main research contents concrete working, mechanical properties and chloride ion permeability resistance at low water binder ratio and large amounts mineral admixture. Measures and adjustment are proposed for marine concrete construction control and cementitious material system that using amount mineral admixtures and low water binder ratio.

Monitoring of Concrete Durability and Application in Qingdao Bay Bridge

The life of concrete structure located in complex environment depends largely on the durability of concrete. The various environmental corrosive effects are the key factor to reduce the durability of concrete structures. The studies on corrosion mechanism and detecting/monitoring technology are carried out in the world, and achieved important results. Since the 90's of last century, corrosion monitoring system for concrete structure has been put into engineering practice in the world, and the technology has been being mature. Qingdao Bay Bridge is located in the special marine environment, so corrosion is the main factor affecting the durability of the bridge. Durability monitoring is one of important aspects of the structure health monitoring and maintenance management system of the Bay Bridge. By corrosion monitoring, the critical data of concrete durability and strength degradation of the structure can be obtained. It is very significant for understanding the evolvement law of the durability, developing anti-corrosion measures, and extending the life of the bridge.

Experimental Study on Durability of Air-Entrained Concrete of Qingdao Bay Bridge

The permeability, frost-resistance and deicer-frost resistance of air-entrained concrete of Qingdao Bay Bridge were studied. The results show that frost-resistance and deicer-frost resistance of concrete can be enhanced by a big margin and impermeability of concrete can be also improved by appropriate air-entrainment. The frost-resistance and deicer-frost resistance of concrete samples gathered from site were inspected and they can meet the design demand for durability of concrete Qingdao Bay Bridge.

Research on Cable Anchorage Systems for Self-Anchored Suspension Bridges with Steel Box Girders

A new type of steel-concrete composite cable anchorage system is conceived and investigated preliminarily for self-anchored suspension bridges with steel box girders to optimize the mechanical behavior of the conventional cable anchorage systems. Model tests and 3D elaborate finite-element analysis (FEA) of the pure steel and steel-concrete composite cable anchorage systems are carried out for the Qingdao Bay Bridge Project, which is under construction in China. For the pure steel anchorage system, a complex stress distribution with obvious stress concentration is observed in the test. The FEA results of the stress distribution correlate well with the experimental measurements. The pure steel anchorage system adopted in the final design of the Qingdao Bay Bridge Project is reliable with a sufficient safety margin. In the contrast test of the composite anchorage system, owing to the composite effect between the steel and concrete, the stress level is reduced significantly and the stress distribution becomes more uniform in comparison with the pure steel anchorage system. The measured stress reduction rate of the composite anchorage averages approximately 40%, which is slightly smaller than the FEA results, and indicates the partial composite effect between the steel and concrete. The proposed composite anchorage system can effectively reduce the thickness and consumption of the steel plates, improve the mechanical behavior of the anchorage system, and simplify the fabrication and construction procedures.

Taxonomy and phylogeny of Tunicothrix (Ciliophora, Stichotrichia), with the description of two novel species, Tunicothrix brachysticha n. sp. and Tunicothrix multinucleata n. sp., and the establishment of Parabirojimidae n. fam.

The morphology and molecular phylogeny of two novel urostylid ciliates, Tunicothrix brachysticha n. sp. and Tunicothrix multinucleata n. sp., were investigated using the techniques of living observation, protargol impregnation and small-subunit rRNA gene sequencing. Both species were found to be frequent in muddy-sand sediment but very rare in sandy sediment of the intertidal zone of Qingdao Bay, China. Tunicothrix brachysticha is about 90 × 30 µm in vivo, with a broadly clavate body shape, and is characterized by a rather short midventral row terminating at 40 % of the body length and a right marginal row 1 terminating at mid-body. Tunicothrix multinucleata is about 190 × 30 µm in vivo, and is characterized by a clavate body shape and the presence of 7-10 macronuclear nodules. Phylogenetic analyses showed that Tunicothrix clustered robustly with Parabirojimia, forming a clade that branches from the Urostylida core clade with high bootstrap values. Based on the morphological and molecular data, we establish a new family, Parabirojimidae n. fam., which comprises Parabirojimia and Tunicothrix and is distinguished by a unique, roughly T-shaped bipartite adoral zone of membranelles, three enlarged frontal cirri and a midventral complex with midventral pairs confined to the buccal field.