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Yan J.,Third Institute of Oceanography | Chen L.,Third Institute of Oceanography | Lin Q.,Third Institute of Oceanography
Powder Technology | Year: 2017

The characteristics of fine particle removal from wet flue gas desulfurization (WFGD) using the simultaneous acoustic agglomeration and supersaturated vapor condensation were investigated experimentally. The impacts of supersaturation degree, residence time and acoustic intensity on the fine particle removal efficiency were demonstrated. High moisture and tiny droplets were contained in the flue gas after WFGD, which benefited the use of coupling external fields in WFGD system. The results showed that the removal of fine particles can be significantly improved in the simultaneous acoustic field and supersaturated vapor condensation. High value of sound pressure level (SPL > 150 dB) was needed to achieve a considerable removal efficiency using acoustic agglomeration only. While low SPL of 130–150 dB can be used to remove fine particle efficiently in WFGD system using simultaneous external fields. Removal efficiency higher than 70% was obtained with S = 1.15 and SPL = 151 dB. The residence time of the simultaneous acoustic agglomeration and condensational growth was determined by the time required by acoustic agglomeration. Particle removal efficiency increased with the residence time, but it tended to be constant as the residence time over 3 s. Multiple horn numbers with low acoustic intensity benefited the improvement of fine particle removal efficiency and the reduction of energy consumption using the simultaneous external fields in WFGD system. © 2017 Elsevier B.V.


News Article | February 27, 2017
Site: www.eurekalert.org

Ocean acidification (OA) is spreading rapidly in the western Arctic Ocean in both area and depth, according to new interdisciplinary research reported in Nature Climate Change by a team of international collaborators, including University of Delaware professor Wei-Jun Cai. The research shows that, between the 1990s and 2010, acidified waters expanded northward approximately 300 nautical miles from the Chukchi slope off the coast of northwestern Alaska to just below the North Pole. Also, the depth of acidified waters was found to have increased, from approximately 325 feet to over 800 feet (or from 100 to 250 meters). "The Arctic Ocean is the first ocean where we see such a rapid and large-scale increase in acidification, at least twice as fast as that observed in the Pacific or Atlantic oceans," said Cai, the U.S. lead principal investigator on the project and Mary A.S. Lighthipe Professor of Earth, Ocean, and Environment at UD. "The rapid spread of ocean acidification in the western Arctic has implications for marine life, particularly clams, mussels and tiny sea snails that may have difficulty building or maintaining their shells in increasingly acidified waters," said Richard Feely, NOAA senior scientist and a co-author of the research. Sea snails called pteropods are part of the Arctic food web and important to the diet of salmon and herring. Their decline could affect the larger marine ecosystem. Among the Arctic species potentially at risk from ocean acidification are subsistence fisheries of shrimp and varieties of salmon and crab. Other collaborators on the international project include Liqi Chen, the Chinese lead principal investigator and scientist with the Third Institute of Oceanography of State Oceanic Administration of China; and scientists at Xiamen University, China and the University of Gothenburg, Sweden, among other institutions. The researchers studied water samples taken during cruises by Chinese ice breaker XueLong (meaning "snow dragon") in summer 2008 and 2010 from the upper ocean of the Arctic's marginal seas to the basins as far north as 88 degrees latitude, just below the North Pole, as well as data from three other cruises. Scientists measured dissolved inorganic carbon and alkalinity which allows them to calculate pH and the saturation state for aragonite, a carbonate mineral that marine organisms need to build their shells. Data collected by ship and model simulations suggest that increased Pacific Winter Water (PWW), driven by circulation patterns and retreating sea ice in the summer season, is primarily responsible for this OA expansion, according to Di Qi, the paper's lead author and a doctoral student of Chen. "This work will help increase our understanding of climate change, carbon cycling, and ocean acidification in the Arctic, particularly as it affects marine and fishery science and technology," said Chen. PWW comes from the Pacific Ocean through the Bering Strait and shelf of the Chukchi Sea and into the Arctic basin. In recent years, melting sea ice has allowed more of the Pacific water to flow through the Bering Strait into the Arctic Ocean. Pacific Ocean water is already high in carbon dioxide and has higher acidity. As the ocean mass moves north, it absorbs additional carbon dioxide from decomposing organic matter in the water and sediments, increasing acidity. The melting and retreating of Arctic sea ice in the summer months also has allowed PWW to move further north than in the past when currents pushed it westward toward the Canadian archipelago. Arctic ocean ice melt in the summer, once found only in shallow waters of depths less than 650 feet or 200 meters, now spreads further into the Arctic Ocean. "It's like a melting pond floating on the Arctic Ocean. It's a thin water mass that exchanges carbon dioxide rapidly with the atmosphere above, causing carbon dioxide and acidity to increase in the meltwater on top of the seawater," said Cai. "When the ice forms in winter, acidified waters below the ice become dense and sink down into the water column, spreading into deeper waters."


Ross A.C.,University of California at San Diego | Xu Y.,Hong Kong University of Science and Technology | Lu L.,Hong Kong University of Science and Technology | Kersten R.D.,University of California at San Diego | And 5 more authors.
Journal of the American Chemical Society | Year: 2013

Thalassospiramides A and B are immunosuppressant cyclic lipopeptides first reported from the marine α-proteobacterium Thalassospira sp. CNJ-328. We describe here the discovery and characterization of an extended family of 14 new analogues from four Tistrella and Thalassospira isolates. These potent calpain 1 protease inhibitors belong to six structure classes in which the length and composition of the acylpeptide side chain varies extensively. Genomic sequence analysis of the thalassospiramide-producing microbes revealed related, genus-specific biosynthetic loci encoding hybrid nonribosomal peptide synthetase/polyketide synthases consistent with thalassospiramide assembly. The bioinformatics analysis of the gene clusters suggests that structural diversity, which ranges from the 803.4 Da thalassospiramide C to the 1291.7 Da thalassospiramide F, results from a complex sequence of reactions involving amino acid substrate channeling and enzymatic multimodule skipping and iteration. Preliminary biochemical analysis of the N-terminal nonribosomal peptide synthetase module from the Thalassospira TtcA megasynthase supports a biosynthetic model in which in cis amino acid activation competes with in trans activation to increase the range of amino acid substrates incorporated at the N terminus. © 2012 American Chemical Society.


Zhang Y.,Third Institute of Oceanography | Zhao J.,Xiamen University | Zeng R.,Third Institute of Oceanography
Extremophiles | Year: 2011

A metagenomic cosmid library was constructed, in which the insert DNA was derived from the coastal sediment near Antarctic China Zhongshan Station. One clone (ACPRO001) expressing protease activity was isolated from the library using milk agar plates. Sequencing of the clone revealed a novel protease gene. The amino acid sequence comparison and phylogenetic analysis indicated that it could be classified as a subtilisin-like serine protease, though the highly conserved residue Asp was replaced by Ala. The ACPRO001 protease gene was expressed in pET-His and purified for characterization. The optimal temperature and pH for the activity of the ACPRO001 protease were 60°C and pH 9. 0, respectively. The enzyme retained about 73% of residual activity after 2 h incubation at 50°C in the presence of Ca 2+. The presence of Ca 2+ increased the thermostability of ACPRO001 protease obviously. The enzymatic activity was inhibited by 1 mM phenylmethyl sulfonylfluoride (PMSF) and hydrochloride 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), indicating that it was a serine protease. © 2010 Springer.


Gu H.,Third Institute of Oceanography | Liu T.,Third Institute of Oceanography | Vale P.,Instituto Portugues do Mar e da Atmosfera IPMA | Luo Z.,Third Institute of Oceanography
Harmful Algae | Year: 2013

Four Gymnodinium species have previously been reported to produce microreticulate cysts. Worldwide, Gymnodinium catenatum strains are conservative in terms of larger subunit (LSU) rDNA and internal transcribed spacer region (ITS) sequences, but only limited information on the molecular sequences of other species is available. In the present study, we explored the diversity of Gymnodinium by incubating microreticulate cysts collected from the Yellow Sea off China. A total of 18 strains of Gymnodinium, from three species, were established. Two of these were identified as Gymnodinium catenatum and Gymnodinium microreticulatum, and the third was described as a new species, Gymnodinium inusitatum. Motile cells of G. inusitatum are similar to those of Gymnodinium trapeziforme, but they only share 82.52% similarity in LSU sequences. Cysts of G. inusitatum are polygonal in shape, with its microreticulate wall composed of approximately 14 concave sections. G. microreticulatum strains differ from each other at 69 positions (88.00% similarity) in terms of ITS sequences, whereas all G. catenatum strains share identical ITS sequences and belonged to the global populations. Phylogenetic analyses, based on LSU sequences, revealed that Gymnodinium species that produce microreticulate cysts are monophyletic. Nevertheless, the genus as a whole appears to be polyphyletic. Paralytic shellfish toxins (PSTs) were found in all G. catenatum strains tested (dominated by 11-hydroxysulfate benzoate analogs and N-sulfocarmaboyl analogs) but not in any of the G. microreticulatum and G. inusitatum strains. Our results support the premise that cyst morphology is taxonomically informative and is a potential feature for subdividing the genus Gymnodinium. © 2013 Elsevier B.V.


Krock B.,Alfred Wegener Institute for Polar and Marine Research | Tillmann U.,Alfred Wegener Institute for Polar and Marine Research | Witt M.,BrukerDaltonik GmbH | Gu H.,Third Institute of Oceanography
Harmful Algae | Year: 2014

Azadinium poporum is a small dinoflagellate from the family Amphidomataceae which is known for the potential production of azaspiracids (AZAs) causative of azaspiracid shellfish poisoning (AZP). A. poporum has been recorded from European and western Pacific waters. Here we report on the high variability of toxin profiles within this species in Chinese coastal waters. Out of 16 analyzed strains of A. poporum from different geographic locations along the Chinese coastline, three strains proved not to contain AZAs, whereas 13 strains contained different combinations of AZA-2, AZA-11, AZA-36, a yet unknown isomer of AZA-1 (named AZA-40) and new AZA with yet unreported molecular mass of 853Da (named AZA-41). The new AZA-40, other than AZA-1 itself, belongs to the recently discovered "348-type" group, which in tandem mass spectrometry displays a group 4 fragment with m/z 348 instead of the group 4 fragment of the classic AZAs with m/z 362, indicating a shift of a methyl group from the C24-C40 part of the molecule (rings F-I) to the C2-C9 part (carboxylic side chain and ring A). AZA-41 apparently is a dehydro variant of AZA-2. In addition, a previously reported AZA with a molecular mass 871DA could be unambiguously assigned to AZA-11, which is known to be a shellfish metabolite of AZA-2. This is the first report of AZA-11 being also de novo synthetized by dinoflagellates. © 2014 Elsevier B.V.


Gu H.,Third Institute of Oceanography | Luo Z.,Third Institute of Oceanography | Krock B.,Alfred Wegener Institute for Polar and Marine Research | Witt M.,Bruker | Tillmann U.,Alfred Wegener Institute for Polar and Marine Research
Harmful Algae | Year: 2013

Azadinium poporum is a small dinoflagellate from the family Amphidomataceae which is known for the production potential of azaspiracid toxins. A. poporum has been recorded from European and Korean waters. Here we present the first report of its occurrence along the coast of China. Morphology of Chinese A. poporum is similar to those from Europe and Korea. Several stalked pyrenoids surrounded by a starch sheath were revealed with light microscopy and confirmed by transmission electron microscopy. Among 25 strains from the China Sea we identified two distinct ribotypes (referred to as ribotypes B and C). ITS sequences of strains within the same ribotype are identical, whereas ribotype B and C differ from each other at 11 positions (98.3% similarity). A. poporum ribotypes B and C type differ from European strains (referred to as ribotype A) at 16 and 15 positions (97.5% and 97.7% similarity). The ITS region pairwise distance within A. poporum ranged from 0.017 to 0.022. Among all three ribotypes, no hemi-compensatory based changes were found within helix III of ITS indicating that they are conspecific. Azaspiracid profiles were analyzed for six strains and turned out to be unexpectedly diverse. Whereas no AZAs could be detected for one strain, another strain was found to contain a m/. z 348 fragment type AZA previously found in a Korean Isolate and traces of two other unknown AZAs of higher masses. A third strain produced a novel AZA with a molecular mass of 871. Da. Three strains were found to contain considerable amounts of toxic AZA-2 as the sole AZA, a finding that might elegantly explain the detection of AZA-2 in sponges in the Sea of Japan and which underline the risk potential of A. poporum blooms with subsequent shellfish intoxication episodes for the Asian Pacific. © 2012 Elsevier B.V.


Gu H.,Third Institute of Oceanography | Liu T.,Third Institute of Oceanography | Mertens K.N.,Ghent University
Phycologia | Year: 2015

The genus Protoperidinium has been divided into several sections based on the shape of the first apical plate, the number/shape of anterior intercalary plates and the presence/absence of antapical horns/spines; however, phylogenetic relationships among these sections have not been fully explored. We examined the cyst-theca relationships of seven Protoperidinium species isolated from sediments along the Chinese coast. Ten partial nuclearencoded large subunit ribosomal DNA (LSU rDNA) sequences were obtained by single-cell polymerase chain reaction (PCR) for seven species belonging to the Conica and Tabulata sections of the genus. New cyst-theca relationships were established for Protoperidinium biconicum and Protoperidinium humile, and the former was restricted to warmer waters. Brigantedinium majusculum was identified as the cyst of Protoperidinium pentagonum; whereas, Trinovantedinium applanatum corresponded to Protoperidinium shanghaiense sp. nov. Phylogenetic analyses based on LSU rDNA sequences were carried out using maximum likelihood and Bayesian inference and revealed that the theca-based section Conica was polyphyletic, and Tabulata was monophyletic. Surprisingly, some cyst-based genera (e.g. Brigantedinium, Selenopemphix) proved to be polyphyletic. © 2015 International Phycological Society.


Jin M.,Zhejiang University | Jin M.,Third Institute of Oceanography | Xu C.,Zhejiang University | Zhang X.,Zhejiang University
Applied Microbiology and Biotechnology | Year: 2015

Small metabolites can participate in the virus-host interactions in eukaryotes. However, little is known about roles of metabolites in the interactions between bacteria and bacteriophages. In this study, the metabolomic profilings of bacteriophage GVE2-infected and virus-free Geobacillus sp. E263, a thermophilic bacterium isolated from a deep-sea hydrothermal vent, were characterized. The results showed that metabolites tryptophol, adenine, and hydroxybenzylalcohol were significantly elevated in Geobacillus sp. E263 in response to the GVE2 infection. Furthermore, our data indicated that tryptophol was involved in the bacteriophage infection. Tryptophol could inhibit the infection/replication of GVE2 by interacting with the host’s Clp protease. Therefore, our study revealed novel aspects of metabolites during the bacteriophage infection in high-temperature environment. © 2015, Springer-Verlag Berlin Heidelberg.


Lai Q.,Third Institute of Oceanography | Liu Y.,Third Institute of Oceanography | Shao Z.,Third Institute of Oceanography
Antonie van Leeuwenhoek, International Journal of General and Molecular Microbiology | Year: 2014

A taxonomic study was carried out on strain HYC-10T, which was isolated from the intestinal tract contents of a flathead mullet, Mugil cephalus, captured from the sea off Xiamen Island, China. The bacterium was observed to be Gram positive, oxidase and catalase positive, rod shaped, and motile by subpolar flagella. The bacterium was found to grow at salinities of 0-12 % and at temperatures of 8-45 C. The isolate was found to hydrolyze aesculin and gelatin, but was unable to reduce nitrate to nitrite. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain HYC-10 T belongs to the genus Bacillus, with highest sequence similarity (99.3 %) to Bacillus aerophilus 28KT, Bacillus stratosphericus 41KF2aT and Bacillus altitudinis DSM 21631T, followed by Bacillus safensis DSM 19292T (99.5 %) and Bacillus pumilus DSM 27T (99.5 %), while the sequence similarities to others were all below 97.6 %. The genomic ANIm values between strain HYC-10T and three type strains (B. altitudinis DSM 21631T, B. safensis DSM 19292T and B. pumilus DSM 27T) were determined to range from 89.11 to 91.53 %. The DNA-DNA hybridization estimate values between strain HYC-10T and the three type strains were from 36.60 to 44.00 %. The principal fatty acids identified were iso-C15:0 (39.1 %), anteiso-C15:0 (22.7 %), iso-C17:0 (13.1 %), C 16:0 (6.1 %), anteiso-C17:0 (5.8 %) and iso-C 16:0 (5.1 %). The G+C content of the chromosomal DNA was determined from the draft genome sequence to be 41.3 mol%. The respiratory quinone was determined to be MK-7 (100 %). Phosphatidylglycerol, diphosphatidylglycerol, aminoglycolipid, two glycolipids and two unknown phospholipids were found to be present. The combined genotypic and phenotypic data show that strain HYC-10 T represents a novel species of the genus Bacillus, for which the name Bacillus xiamenensis sp. Nov. is proposed, with the type strain HYC-10 T (=CGMCC NO.1.12326T = LMG 27143T = MCCC 1A00008T). © 2013 Springer Science+Business Media Dordrecht.

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