Уточнить поиск
Результаты 531-540 из 2,513
Effects of salinity on anatomical features and physiology of a semi-mangrove plant Myoporum bontioides Полный текст
2014
Xu, H.M. | Tam, N.F.Y. | Zan, Q.J. | Bai, M. | Shin, P.K.S. | Vrijmoed, L.L.P. | Cheung, S.G. | Liao, W.B.
The effect of different concentrations of NaCl, 0, 100, 200, 300 and 400mM, on the anatomical features and physiology of Myoporum bontioides was investigated. The photosynthetic rates (Pn) were significantly reduced by salt stress, with the lowest values at 400mM NaCl. The content of malondialdehyde (MDA), proline and soluble sugar, as well as the activities of peroxidase (POD) and catalase (CAT) increased at the beginning, but became similar to the control as the experiment proceeded. The NaCl effect on superoxide dismutase (SOD) was different from the other parameters, with a significant reduction at 400mM NaCl at Day 7. Salt glands were found in both upper and lower epidermis, and the ratios of the thickness of palisade to spongy mesophyll tissues increased with NaCl concentrations. The medullary ray was clearly damaged by NaCl at levels of 200 and 300mM. These results demonstrated that M. bontioides could adapt to a relatively low salinity, and was not a halophilous species.
Показать больше [+] Меньше [-]Transcriptomic response to estrogen exposure in the male Zhikong scallop, Chlamys farreri Полный текст
2014
An, Li-hui | Zheng, Bing-hui | Liu, Rui-zhi | Fan, Qiang | Wang, Qing-kui | Luo, Ying-feng
The transcriptomes of Zhikong scallop exposed to 17β-estradiol were determined using the Roche/454. A total of 51,997 unigenes, representing 45,030 contigs and 6967 singlets were obtained. And 14,028, 19,798 and 14,981 of these unigenes were annotated from the non-redundant nucleic acid database, non-redundant protein database and Swiss protein database, respectively. A total of 10,699 unigenes were further annotated to biological processes (9080), molecular functions (8692) and cellular components (7829) using the GO, and 8945 unigenes were mapped to biological pathways including the metabolism (2862) and genetic information processing (2263). Most importantly, 16,692 unigenes and 18,686 unigenes in testis, and 10,492 unigenes and 13,186 unigenes in digestive gland were up-regulated significantly after exposure to 50 and 500ngE2/L; while 10,212 unigenes and 9409 unigenes in testis and 10,629 unigenes and 9463 unigenes in digestive gland were down-regulated. These valuable information provides insights into the mechanisms in invertebrate exposure to EDCs.
Показать больше [+] Меньше [-]Interactive effects of hypoxia and polybrominated diphenyl ethers (PBDEs) on microbial community assembly in surface marine sediments Полный текст
2014
Chan, Yuki | Li, Amy | Gopalakrishnan, Singaram | Shin, Paul K.S. | Wu, Rudolf S.S. | Pointing, Stephen B. | Chiu, Jill M.Y.
Hypoxia alters the oxidation–reduction balance and the biogeochemical processes in sediments, but little is known about its impacts on the microbial community that is responsible for such processes. In this study, we investigated the effects of hypoxia and the ubiquitously dispersed flame-retardant BDE47 on the bacterial communities in marine surface sediments during a 28-days microcosm experiment. Both hypoxia and BDE47 alone significantly altered the bacterial community and reduced the species and genetic diversity. UniFrac analysis revealed that BDE47 selected certain bacterial species and resulted in major community shifts, whereas hypoxia changed the relative abundances of taxa, suggesting slower but nonetheless significant community shifts. These two stressors targeted mostly different taxa, but they both favored Bacteroidetes and suppressed Gammaproteobacteria. Importantly, the impacts of BDE47 on bacterial communities were different under hypoxic and normoxic conditions, highlighting the need to consider risk assessments for BDE47 in a broader context of interaction with hypoxia.
Показать больше [+] Меньше [-]Quality assessment of the blue mussel (Mytilus edulis): Comparison between commercial and wild types Полный текст
2014
De Witte, B. | Devriese, L. | Bekaert, K. | Hoffman, S. | Vandermeersch, G. | Cooreman, K. | Robbens, J.
This study compared species identity, microplastics, chemical and microbial contamination between consumption mussels and wild type mussels, collected at Belgian department stores and Belgian groynes and quaysides, respectively. Species identification based on genetic analysis showed a high number of Mytilus (M.) edulis compared to M. galloprovincialis and M. edulis/galloprovincialis hybrid mussels. The number of total microplastics varied from 2.6 to 5.1fibres/10g of mussel. A higher prevalence of orange fibres at quaysides is related to fisheries activities. Chemical contamination of polycyclic aromatic hydrocarbons and polychlorobiphenyls could be related to industrial activities and water turbidity, with maximum concentrations at the quayside of port Zeebrugge. The inverse was noted for Escherichia coli contamination, which was relatively low at Zeebrugge quayside with a total count of 3.9×102CFU/100g tissue, due to limited agricultural effluents. Results of this complementary analysis stress the importance of integrated monitoring and quality assessment.
Показать больше [+] Меньше [-]Sulfonamide antibiotics in the Northern Yellow Sea are related to resistant bacteria: Implications for antibiotic resistance genes Полный текст
2014
Na, Guangshui | Zhang, Wanru | Zhou, Shiyao | Gao, Hui | Lu, Zihao | Wu, Xian | Li, Ruijing | Qiu, Lina | Cai, Yaqi | Yao, Ziwei
Antibiotic resistance gene (ARG) residues and the mode of transmission in marine environments remain unclear. The sulfonamide (SAs) concentrations, different genes and total bacterial abundance in seawater and sediment of the Northern Yellow Sea were analyzed. Results showed the genes sul I and sul II were present at relatively high concentrations in all samples, whereas the gene sul III was detected fewer. The ARGs concentrations in the sediment were 103 times higher than those in water, which indicated sediment was essential ARG reservoir. Statistical analysis revealed the total antibiotic concentration was positively correlated with the relative abundance of the gene sul I and sul II. The relative abundances of the gene sul I and the gene sul II were also correlated positively with those of the gene int1. This correlation demonstrated that SAs exerted selective pressure on these ARGs, whereas the gene int1 could be implicated in the propagation of the genes sul I and sul II in marine environments.
Показать больше [+] Меньше [-]Could ocean currents be responsible for the west to east spread of aquatic invasive species in Maritime Canadian waters? Полный текст
2014
Brickman, D.
The circulation in the shelf seas of Maritime Canada is predominantly in the northeast–southwest direction. Despite the mean northeast–southwest flow, a number of AIS invasions have been observed to proceed in the opposite direction – from the Gulf of Maine, around Nova Scotia, and into the southern Gulf of St. Lawrence. Flow fields from a numerical circulation model are used to investigate whether these invasions could be due to drift in ocean currents. Particle tracking experiments are performed and probability density functions (PDFs) derived that describe the probability of drifting a given upstream distance in a given drift time. Analysis of these PDFs revealed that for invasions that took 20–40y to occur, propagule drift in ocean currents could be responsible for the upstream spread, while this was not the case for short timescale invasions (<10y). Rafting could be responsible for both short and long timescale invasions.
Показать больше [+] Меньше [-]Sedimentary records of hydroxylated and methoxylated polybrominated diphenyl ethers in the southern Yellow Sea Полный текст
2014
Fan, Ying | Lan, Jing | Zhao, Zongshan | Zhao, Meixun
Although hydroxylated (OH-) and methoxylated (MeO-) polybrominated diphenyl ethers (PBDEs) have caused much concern in recent years, few reports had discussed on their input history. In this study, we measured the contents of nine MeO-BDEs, ten OH-BDEs, and total organic carbon (TOC) of two sediment cores from the southern Yellow Sea. 6-MeO-BDE-47, 2′-MeO-BDE-68, 6-OH-BDE-47, and 2′-OH-BDE-68 were the predominant congeners in HH12, while only 2′-OH-BDE-68 and 6-OH-BDE-47 were frequently detected in core HH11. The records showed that OH-/MeO-BDEs in both cores had increased rapidly since the 1950s. Their existence was detected at the bottom layers (∼1800s) prior to the production of PBDEs (1960s), thus OH-/MeO-BDEs originate from natural origins rather than artificial PBDEs. Comparisons between TOC and OH-/MeO-BDEs indicated that TOC is a potential factor affecting the accumulation of OH-/MeO-BDEs in marine environments. Similar trends and significant correlations between OH-BDEs and MeO-BDEs suggest their common origins or interconversion.
Показать больше [+] Меньше [-]Trace element concentrations in barramundi (Lates calcarifer) collected along the coast of Vietnam Полный текст
2014
Tu, Nguyen Phuc Cam | Ha, Nguyen Ngoc | Haruta, Shinsuke | Takeuchi, Ichirō
We determined concentrations of 23 trace elements (TEs), and stable carbon and nitrogen isotope (δ13C and δ15N) signatures in barramundi (Lates calcarifer) specimens collected along the coast of Vietnam in the Northern (NCZ), Central (CCZ) and Southern (SCZ) zones in the period 2007–2010. A combination of δ13C and δ15N signatures provided insight into ontogenetic shifts in barramundi foraging choices. There were clear zone-dependent differences in Mn, As, Sr and Tl concentrations; levels of Tl were highest in the NCZ, As in the CCZ, and Mn and Sr in the SCZ. Lowest concentrations of Rb occurred in the NCZ, Bi was lowest in the CCZ, and Cd and Cs were lowest in the SCZ. δ15N values significantly increased with increasing Zn, Se, Sn and Cs. Concentrations of TEs in barramundi from Vietnam were below worldwide guidelines for human consumption.
Показать больше [+] Меньше [-]Effects of a coastal power plant thermal discharge on phytoplankton community structure in Zhanjiang Bay, China Полный текст
2014
Li, Xue-Ying | Li, Bin | Sun, Xing-Li
The effects of a thermal discharge from a coastal power plant on phytoplankton were determined in Zhanjiang Bay. Monthly cruises were undertaken at four tide times during April–October 2011. There were significant differences for dominant species among seven sampling months and four sampling tides. Species diversity (H′) and Evenness showed a distinct increasing gradient from the heated water source to the control zone and fluctuated during four tides with no visible patterns. Species richness, cell count and Chl a at mixed and control zones were significantly higher than heated zones, and showed tidal changes with no obvious patterns. The threshold temperature of phytoplankton species can be regarded as that of phytoplankton community at ebb slack. The average threshold temperature over phytoplankton species, cell count and Chl a, and the threshold temperature of cell count can be regarded as that of phytoplankton community at flood slack during spring and neap respectively.
Показать больше [+] Меньше [-]Spatial and temporal characterizations of water quality in Kuwait Bay Полный текст
2014
Al-Mutairi, N. | Abahussain, A. | El-Battay, A.
The spatial and temporal patterns of water quality in Kuwait Bay have been investigated using data from six stations between 2009 and 2011. The results showed that most of water quality parameters such as phosphorus (PO4), nitrate (NO3), dissolved oxygen (DO), and Total Suspended Solids (TSS) fluctuated over time and space. Based on Water Quality Index (WQI) data, six stations were significantly clustered into two main classes using cluster analysis, one group located in western side of the Bay, and other in eastern side. Three principal components are responsible for water quality variations in the Bay. The first component included DO and pH. The second included PO4, TSS and NO3, and the last component contained seawater temperature and turbidity. The spatial and temporal patterns of water quality in Kuwait Bay are mainly controlled by seasonal variations and discharges from point sources of pollution along Kuwait Bay’s coast as well as from Shatt Al-Arab River.
Показать больше [+] Меньше [-]