Bibliometrics and visualization analysis of EwE model based on CiteSpace.

To explore the historical evolution and current status of the EwE (Ecopath with Ecosim) modelling research, the core dataset and extended dataset were collected by topic retrieval and citation indexing methods from the "Web of Science" from 1984 to 2020. The bibliometric analysis and mapping knowledge were performed by CiteSpace software, focusing on literature distribution, research forces, research theme, and hotspot evolution. The results showed that the annual publications in the EwE model researches were increasing, covering multi-disciplinary fields. Christensen, Walters, and Pauly were representative scholars with an important role in model development and relevant international cooperation. In the early stage, EwE model was usually applied to solve ecosystem problems, including spatial-temporal dynamic of structure and function, and the ecosystem effects of fisheries. Currently, marine resource management, ecosystem modelling, marine protected areas and ecosystem indicators had become the key themes. The research hotspots shifted from model development and food web structure to ecosystem forecasting and resource management, which would provide scientific evidence for ecosystem-based aquatic resource management and the construction of protected area in marine.

Kushneria phosphatilytica sp. nov., a phosphate-solubilizing bacterium isolated from a solar saltern.

A Gram-stain-negative, motile, rod-shaped, non-endospore-forming, aerobic and halophilic bacterium, designated strain YCWA18T, was isolated from the sediment of Jimo-Daqiao saltern in China. This strain was able to grow at NaCl concentrations in the range 0.5-20 % (w/v) with optimum growth at 6 % (w/v) NaCl. Growth occurred at temperatures of 4-40 °C (optimum 28 °C) and pH 4.0-9.0 (optimum 7.0). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain YCWA18T belonged to the genus Kushneria and shared the highest sequence similarity of 98.7 % with Kushneria sinocarnis DSM 23229T. Moreover, the phylogenetic analysis based on the 23S rRNA gene sequence also confirmed the phylogenetic position of this novel strain. The predominant fatty acids were C16 : 0, C17 : 0 cyclo and C12 : 0 3-OH. The major isoprenoid quinone was Q-9 (94.2 %) and the polar lipids were diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), phosphatidylethanolamine (PE), an unidentified aminolipid (AL), an unidentified phospholipids (PL) and two unidentified lipids (L). The complete genome of strain YCWA18T consisted of a single, circular chromosome of 3 624 619 bp, with an average G+C content of 59.1 mol%. A genome-based phylogenetic tree constructed using an up-to-date bacterial core gene set (UBCG) showed that strain YCWA18T formed a clade with K. sinocarnis DSM 23229T. However, the level of the ANI and dDDH values between strain YCWA18T and K. sinocarnis DSM 23229T were 82.3 and 24.6 %, respectively, which were low enough to distinguish strain YCWA18T from K. sinocarnis DSM 23229T. Overall, based on the phenotypic, chemotaxonomic, phylogenetic and genomic analyses, strain YCWA18T represents a novel species of genus Kushneria. The name Kushneria phosphatilytica sp. nov. is proposed, with the type strain YCWA18T (=CGMCC 1.9149T=NCCB 100306T).

Modelling spatiotemporal trends in range shifts of marine commercial fish species driven by climate change surrounding the Antarctic Peninsula.

In recent decades, the relationships between species distributional shifts and climate change have been investigated at various geographic scales, yet there is still a gap in understanding the impacts of climate change on marine commercial fish species surrounding the Antarctic Peninsula. The dynamic bioclimate envelope model (DBEM) is a mechanistic model that encompass species distribution model and population dynamic model approaches to project the spatiotemporal change of marine commercial fish species driven by various climate change scenarios in the Southern Ocean. This paper focuses on the spatiotemporal changes of marine commercial fish species surrounding the Antarctic Peninsula under a high emissions scenario (RCP8.5) and a low emissions scenario (RCP2.6) from 1970 to 2060 following three different Earth System Models (ESMs), namely, the GFDL-ESM 2G, IPSL-CM5A-MR and MPI-ESM-MR. Results reveal that: i) The general latitudinal gradient patterns in species richness shifts poleward associated with a global abundance decrease ii) The Spp. richness in Eastern Antarctic Peninsula (EAP) is higher than in the Western Antarctic Peninsula (WAP) at the same latitude (>65°S latitude). iii) The reasons are that the krill-dependent predators in WAP could face a higher risk of depletion than that in EAP due to ocean warming and anthropogenic activities.

Isolation and Characterization of a Phosphate-Solubilizing Halophilic Bacterium Kushneria sp. YCWA18 from Daqiao Saltern on the Coast of Yellow Sea of China.

Phosphate-solubilizing bacteria (PSB) function in soil phosphorus cycle, increasing the bioavailability of soil phosphorus for plants. Isolation and application of salt-tolerant or halophilic PSB will facilitate the development of saline-alkali soil-based agriculture. A moderately halophilic bacterium was isolated from the sediment of Daqiao saltern on the eastern coast of China, which also performs phosphate-solubilizing ability. The bacterium was assigned to genus Kushneria according to its 16S rRNA gene sequence, and accordingly named as Kushneria sp. YCWA18. The fastest growth was observed when the culturing temperature was 28°C and the concentration of NaCl was 6% (w/v). It was founds that the bacterium can survive at a concentration of NaCl up to 20%. At the optimum condition, the bacterium solubilized 283.16 µg/mL phosphorus in 11 days after being inoculated in 200 mL Ca(3)(PO(4))(2) containing liquid medium, and 47.52 µg/mL phosphorus in 8 days after being inoculated in 200 mL lecithin-containing liquid medium. The growth of the bacterium was concomitant with a significant decrease of acidity of the medium.

Sunxiuqinia elliptica gen. nov., sp. nov., a member of the phylum Bacteroidetes isolated from sediment in a sea cucumber farm.

Three novel aerobic, elliptic bacteria, designated DQHS4(T), DQHS8 and DQHS15, were isolated from sediment of a seashore pond for sea cucumber culture in Jimo, Qingdao, on the east coast of China. Cells were Gram-, oxidase- and catalase-negative. All three strains grew at 15-42 °C, pH 5-9 and NaCl concentrations between 0.5 and 10%. DNA-DNA hybridization experiments revealed high (>85%) relatedness among the three novel isolates and suggested that the strains constitute a single species. Comparative 16S rRNA gene sequence analysis indicated that these bacteria had less than 90% similarity to all described species of the phylum Bacteroidetes; the closest relative of the three isolates was Prolixibacter bellariivorans F2(T), sharing only 89.6% sequence similarity. The major cellular fatty acids were iso-C(17:0) 3-OH (19.8-20.0%), iso-C(15:0) (16.9-17.3%), anteiso-C(17:1) B and/or iso-C(17:1) I (7.4-8.7%), C(17:0) 2-OH (8.4%), anteiso-C(15:0) (8.2-8.6%) and C(17:1)ω6c (5.6-6.0%). The major respiratory quinone was menaquinone-7 (MK-7) and the DNA G+C content was 41.8-43.5 mol%. Based on the distinct phylogenetic position and the combination of genotypic, phenotypic and chemotaxonomic characteristics, these three strains were considered to represent a novel species of a new genus in the phylum Bacteroidetes, for which the name Sunxiuqinia elliptica gen. nov., sp. nov. is proposed. The type strain of Sunxiuqinia elliptica is DQHS4(T) (=CGMCC 1.9156(T) =NCCB 100301(T) =LMG 25367(T)).

Cohaesibacter marisflavi sp. nov., isolated from sediment of a seawater pond used for sea cucumber culture, and emended description of the genus Cohaesibacter.

A Gram-negative, catalase-negative, oxidase-positive, rod-shaped bacterium, strain DQHS21(T), was isolated from sediment of a seawater pond used for sea cucumber culture at Jimo in Qingdao province on the east coast of China. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain DQHS21(T) belonged to the genus Cohaesibacter, sharing the highest sequence similarity (96.1 %) with Cohaesibacter gelatinilyticus CL-GR15(T), while the similarity to other strains was below 93.0 %. The cellular fatty acids consisted mainly of C(18 : 1)ω7c (60.7 %), C(18 : 0) (17.8 %), C(16 : 0) (8.5 %) and summed feature 3 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH; 6.0 %), which together accounted for 93 % of the total fatty acids. Ubiquinone 10 was the major quinone. The G+C content of the chromosomal DNA of strain DQHS21(T) was 55.2 mol%. The combined genotypic and phenotypic data showed that strain DQHS21(T) represents a novel species of the genus Cohaesibacter, for which the name Cohaesibacter marisflavi sp. nov. is proposed, with the type strain DQHS21(T) ( = CGMCC 1.9157(T)  = NCCB 100300(T)).

Halomonas daqiaonensis sp. nov., a moderately halophilic, denitrifying bacterium isolated from a littoral saltern.

Two novel gram-negative, oxidase- and catalase-positive, rod-shaped bacterial strains, designated YCSA28(T) and YCSA39, were isolated from sediment of Daqiao saltern, Jimo, Qingdao, on the east coast of China. The two strains grew optimally at 28-30 °C, at pH 7.5 and in the presence of 7-8 % (w/v) NaCl. They were assigned to the genus Halomonas, class Gammaproteobacteria, based on 16S rRNA gene sequence analysis. The major cellular fatty acids of the two strains were C(18 : 1)ω7c (42.9 %), C(16 : 0) (23.1 %) and C(16 : 1)ω7c/ω6c (18.0 %), and Q-9 was the major ubiquinone. The G+C content of the DNA of strains YCSA28(T) and YCSA39 was 63.7 and 63.9 mol%, respectively. The predominant respiratory lipoquinone, cellular fatty acid profiles and DNA G+C content of strains YCSA28(T) and YCSA39 were consistent with those of recognized species of the genus Halomonas. Levels of DNA-DNA relatedness between strains YCSA28(T) and YCSA39, between YCSA28(T) and Halomonas ventosae Al12(T), and between YCSA39 and H. ventosae Al12(T) were 95, 45 and 50 %, respectively. Together, these data indicated that strains YCSA28(T) and YCSA39 represent a single novel species of the genus Halomonas, for which the name Halomonas daqiaonensis sp. nov. is proposed. The type strain is YCSA28(T) ( = CGMCC 1.9150(T)  = NCCB 100305(T)  = MCCC 1B00920(T)).

Identification of the pathogens associated with skin ulceration and peristome tumescence in cultured sea cucumbers Apostichopus japonicus (Selenka).

The aquaculture of sea cucumbers Apostichopus japonicus (Selenka) has developed rapidly in China in recent years, but is increasingly affected by diseases such as skin ulceration and peristome tumescence. Previous studies on the pathogens causing these diseases focused largely on bacterial causes. In December 2008, we isolated four dominant bacterial species from lesions present in A. japonicus with the aforementioned diseases, from a farm in Yangkou (Qingdao, China). With two of these bacterial species, experimental infection of healthy A. japonicus resulted in the same disease symptoms that occurred in naturally infected A. japonicus. These two species were identified as Pseudoalteromonas sp. and Pseudoalteromonas tetraodonis. The early symptoms of infection for these bacterial species were ulcer spots on the dorsal skin and abdominal parapodia, followed by an increase in the number of ulcer spots or their merging into larger spots. Additionally, we isolated a spherical virus 100-250nm in diameter and with a bilayer capsule, from A. japonicus with another disease from four different farms. By experimental infection with crude extracts of the virus, healthy laboratory-acclimatized A. japonicus developed the same symptoms as in natural infected cases. The early symptoms of viral infection comprised a decrease in tentacle activity, decay of dorsal papillate podia, peristome tumescence and abdominal ulceration. Our study demonstrates that the bacteria and virus were both responsible for skin ulceration and peristome tumescence in A. japonicus, but resulted in different early disease symptoms.