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Chelydra serpentina (Linnaeus, 1758) is native to North America, but has been introduced to numerous nations and is now globally spread. It is extremely adaptive, grow quickly, and its biological population is steadily increasing as a result of the development of aquaculture technology. Given that Chelydra serpentina has already been found alive in the natural ecosystems of China, its proliferation poses a possible threat of invasion. Using the global distribution data of the species in the current environment, a study was carried out to forecast the distribution trend of Chelydra serpentina under future climate circumstances. The study compared the changes in the distribution area under current climatic circumstances and the tendency of proliferation using 19 bioclimatic factors and the ecological niche model Maxent. Using the significance index, the study also examined the size of the appropriate region and the influencing factors to estimate the danger of Chelydra serpentina invasion better quantitatively. In our research, we hypothesized that forthcoming climate change will affect the geographical distribution of Chelydra serpentina. The study results showed that, even in high-intensity environments, the appropriate area for Chelydra serpentina will steadily increase in the future climate. The extent of their suitable habitat might expand (the highly suitable area: 7.42*105 km2 ; 2.13*107 km2 ) in contrast to the distribution area of Chelydra serpentina under the existing climate (highly suitable area: 6.01*105 km2 ; 8.48*106 km2 ). The research findings indicate that the range of the habitat area predicted to proliferate (the highly suitable area of 6.31*105 km2 ; 1.3 *107 km2 ) even in high-intensity environments, albeit at a slower rate than in the low-intensity environment model. The habitat will initially be concentrated in warmer regions before progressively expanding into the colder northern climate. This implies that Chelydra serpentina will be able to more easily adjust to future climates and spread outward over time from its concentrated home. Nonetheless, there is a chance of an invasion due to the rise in Chelydra serpentina populations. Upon establishing a regular reproductive presence in the Chinese waterways they inhabit, these turtles will engage in fierce competition with indigenous species for survival, posing a threat to the environment and potentially resulting in the extinction of some local species.

As one of the biggest ports, the aquatic ecology of Shanghai Port has a significant impact on the health of surrounding residents and aquatic animals. Therefore, this study explored the composition and distribution of bacteria, pathogens, and ARGs at Shanghai Ports by high-throughput sequencing. The results showed that the bacterial community was dominated by the Proteobacteria at the phylum level. With the refinement of classification level, the main composition of bacteria in different samples shows significant differences. In contrast, there was no significant difference in the composition and distribution of pathogens among the samples. It indicates that pathogens and ARGs have steady community composition at Shanghai Port. Pseudomonas aeruginosa and Salmonella enterica could be regarded as candidate indicator pathogens. macB, tetA (58), and evgS were the main ARGs, and they showed a close relationship with Mycobacterium tuberculosis, Magnaporthe oryzae, Streptococcus pneumonia, Xanthomonas oryzae, and Vibrio cholerae in different sites and layers. This may lead to the transfer of ARGs between different pathogens, resulting in more threatening pathogens. The results showed that the pathogens and ARGs present posed a risk of transmission and were potentially harmful to residents in the environment. They can spread to any other ports in the world through the transmission of ballast water, posing a threat to humans and local ecology. In order to keep human health, it is necessary to pay more attention to the water environment of ports and increase the monitoring. Furthermore, it is essential to strengthen the supervision of external source pollution input due to the special features of the port.

Ballast water (BW) poses the risk of introducing species. Therefore, ships install the ballast water management system (BWMS) to reduce the risks caused by BW. To gain a deeper understanding of the treatment effectiveness of the BWMS, in this study we compared the effectiveness of four different treatment processes of BWMSs on seawater phytoplankton, which were electrochlorination treatment, hydroxyl radical oxidation treatment, membrane separation and deoxygenation treatments, and UV irradiation treatment. The results showed that all four BWMSs had a reduction in phytoplankton density of over 99%. In terms of phytoplankton taxa, the effectiveness of the four BWMSs was different. The taxa removal rates of the four BWMSs were 81.25%, 39.58%, 59.31%, and 74.49%, respectively. Electrochlorination treatment and UV irradiation treatment were significantly more effective than hydroxyl radical oxidation treatment and membrane separation and deoxygenation treatments. The residual phytoplankton taxa were mainly dinoflagellate and diatoms, such as Cucumeridinium, Prorocentrum, Navicula, and Skeletonema. Taxa that can tolerate treatment may be more likely to survive and reproduce. There is still a need to continue to strengthen the development and research on the BWMS in the future to promote the development of BW management.

Previous studies have found differences between communities of benthic macroinvertebrates living in constructed tidal flats compared with natural ones. We analyzed the distributional characteristics of benthic macroinvertebrates in a blowing sand reclamation area (Area A), a dike-building silting area (Area B), an out-of-siltation area (Area C), and a natural tidal flat (Area D) in order to characterize the community structure and diversity of benthic macroinvertebrates in a human-disturbed estuarine tidal-flat wetland. A total of 32 benthic macroinvertebrate species were identified (Area A = 7; Area B = 12; Area C = 10; Area D = 27). The diversity index was variable where: Area B 0.05) in the abundance and biomass of Areas A, C, and D. An abundance/biomass curve showed that the habitat in Areas A, B, and C could be categorized as moderately disturbed, whereas Area D was categorized as undisturbed. The results of cluster analysis suggested distinct assemblages in the four sampling areas. Reclamation raised the altitude of tidal flats, weakening the tidal power and changing the physical and chemical parameters of the water, leading to a change in the community structure of benthic macroinvertebrates. Keywords: Reclamation area, Tidal flat, Benthic macroinvertebrates, Community structure

The introduction of species through the release of ballast water has become a major threats to marine biodiversity and ecosystem function worldwide. China is one of the top trading countries, yet little is known about exotic species in the ballast water of ships coming to its ports. Here, we review the biological surveys of ballast water from major Chinese ports. These surveys reveal that 40 species of non-indigenous phytoplankton that, belong to 25 genera and five phyla, have been observed in ballast water. The dominant species are diatoms and dinoflagellates. There were 17 red-tide causing species observed, five of which are noxious algae. Seventeen species of non-indigenous zooplankton have been reported, most of them (11) copepods. There were also 22 species of pathogenic bacteria recorded, including Vibrio alginolyticus, V. carchariae, V. parahaemolyticus, and V. vulnificus. These studies show that species introduction through ballast water potentially a serious threat to the ecology and human health in China. More research, including collaboration with the international community, is urgently needed to address this problem.

Silica/polydopamine/silver (SiO2/PD/Ag) nanoparticles (NPs) with a core-shell-satellite structure were fabricated and the mechanisms of their antibacterial activity were investigated. In this reported work, the results of the reactive oxygen species (ROS) assays, the deoxyribonucleic acid (DNA) damage assays and a cell morphology observation confirmed that Vibrio natriegens, a gram negative bacterium and Bacillus subtilis, a gram positive bacterium could be inhibited by the NPs. Gram negative bacteria exhibited more sensitivity towards the Ag NPs because these NPs were associated with penetration into the cytoplasm, with the subsequent local interaction of Ag with the cell components; thus, causing damages to the cells. SiO2/PD/Ag NPs produced ROS which caused damage to the DNA leading to the suppression of transcription as detected by a reporter gene assay. Furthermore, ROS induced membrane damage was determined by transmission electron microscopy. Thus, the mechanisms of antibacterial activity were interpreted more precisely by using the aforementioned experiments. The results revealed that the production of ROS and damage to the membrane were the two major mechanisms of the bactericidal action of SiO2/PD/Ag NPs; thus, these NPs could be employed as effective antifouling agents. [ABSTRACT FROM AUTHOR]

This paper focuses on the developmental changes that take place inside the eggs of the semi-terrestrial freshwater crab, Sinopotamon yangtsekiense, from Qiantang River in Zhejiang Province, China. The egg consists of two layers, a thick outer membrane and a thin inner membrane that encloses the fluid- filled embryonic sac. Development in this species took up to 77 days, after which the free-living juvenile hatchling crab emerged from the egg. During development the embryo underwent a series of morphological changes that corresponded to the free-living larval stages of marine crabs, and the yolk mass decreased in size and changed color (from creamy pale yellow, to orange, and finally grey). The eggs remained attached to the pleopods in the female's abdominal brood pouch during development and showed a great deal of independence from water. Embryos developed normally whether they were immersed in water or in air. The implications of this adaptation for freshwater crab evolution are discussed. [ABSTRACT FROM AUTHOR]