[Morphological variations and discrimination of medium form of the purple flying squid Sthenoteuthis oualaniensis in the central and southern South China Sea]. / 南海中南部鸢乌贼中型群群体结构.

From 3177 specimens of purple flying squid Sthenoteuthis oualaniensis collected in 2012 and 2013 in the central and southern South China Sea, the morphological indicators including mantle length (ML), arm length-I (AL1), arm length-2 (AL2), arm length-3 (AL3), arm length-4 (AL4), tentacle length (TL), fin length (FL) and fin width (FW) were measured. The morphological variations among the squid species were analyzed using principal component analysis. Results showed that the medium form could be distinguished into cohort I and cohort II which accounted for 69% and 31% of the total, respectively. The percentage of females of the two cohorts decreased first with increasing ML, then increased and reached the ratio of 100% finally. Using Logistic regressing, the MLs at first maturity for females and males of cohort I were estimated to be 164 mm and 112 mm, respectively, and those for females and males of cohort II were 158 mm and 109 mm, respectively. The cohort I concentrated in the waters of Xisha Islands and Nansha Islands, whereas the cohort II was located in the waters of Nansha Islands. Significant differences in all the 8 morphological indicators between either males or females of cohort I and cohort II were found (P＜0.05). Significant differences between cohort I and cohort II in ML, AL1, AL2, AL4, TL and FW were identified in females (P＜0.05), while significant differences between cohort I and cohort II in ML, AL1, AL2, AL3, AL4 and FL were found in males (P＜0.01). The analysis of coefficients of difference indicated that the morphological variations between cohort I and cohort II suggested a clear division within the species.

Changes of the Macrobenthic Faunal Community with Stand Age of a Non-native Mangrove Species in Futian Mangrove National Nature Reserve, Guangdong, China.

Ya-Fang Li, Fei-Yan Du, Yang-Guang Gu, Jia-Jia Ning, and Liang-Gen Wang (2017) Sonneratia apetala, a non-native superior rapidly growing mangrove species with wide environmental tolerance, has been introduced to Futian National Nature Reserve in Shenzhen, Guangdong, China, for mangrove restoration since 1993. However, the community structure of the associated macrobenthic fauna, a vital component of energy ow and nutrient recycling, remains obscure. The present study analyzed the macrobenthic faunal community, associated habitat characteristics and physico-chemical properties of sediment in rehabilitated S. apetala forests at stand ages of 8, 9, 14, 16 and 20 years from November 2014 to May 2015. Habitat complexity and stand structural heterogeneity varied with stand age. Sediment physico-chemical properties were similar for all stands analyzed, although soil organic matter (SOM) content was significantly higher in the 20-year-old stand than in others. Shannon-Weaver (H') and Pielou's evenness (J) indices of macrobenthic fauna were highest in 14- and 16-year- old stands, respectively, and lowest in 8-year-old stands. In contrast, abundance and biomass peaked in 8-year- old stands and were lowest in 16-year-old stands. Multivariate analysis (cluster, ANOSIM and SIMPER) showed that the macrobenthic faunal community in the 20-year-old stand was different from other stand ages because of a greater abundance of small-sized mollusks and opportunistic species. Spearman correlation analysis showed that H' was positively correlated with salinity. The distance-based linear model suggested that SOM was a significant predictor variable correlated with the macrobenthic faunal community. However, SOM was the only significant predictor variable explaining 12.7% of the total variation; this implies that the spatial variation of the macrobenthic faunal community here was mostly independent of the sediment properties measured. Therefore, we conclude that habitat characteristics such as vegetation characteristics can potentially explain the majority of the variation.

Heavy metals in fish tissues/stomach contents in four marine wild commercially valuable fish species from the western continental shelf of South China Sea.

The concentrations of heavy metals (Cd, Pb, Cr, Ni, Cu and Zn) were determined in four commercially valuable fish species (Thunnus obesus, Decapterus lajang, Cubiceps squamiceps and Priacanthus macracanthus), collected in the western continental shelf of the South China Sea. Concentrations of Cd, Pb, Cr, Ni, Cu, and Zn in fish muscles were 0.006-0.050, 0.13-0.68, 0.18-0.85, 0.11-0.25, 0.12-0.77, and 2.41-4.73µg/g, wet weight, respectively. Concentrations of heavy metals in all species were below their acceptable daily upper limit, suggesting human consumption of these wild fish species may be safe, with health risk assessment based on the target hazard quotients (THQ) and total THQ, indicating no significant adverse health effects with consumption. The average concentrations of Zn were higher in gills than in stomach contents, backbones or muscle, while conversely, the other heavy metals had higher concentrations in stomach contents than in other tissues.

Polycyclic aromatic hydrocarbons in surface sediments and marine organisms from the Daya Bay, South China.

Polycyclic aromatic hydrocarbons (PAHs) were investigated in the marine ecosystem of the Daya Bay, South China. The PAH concentrations ranged from 340 to 710 ng/g dry weight in the sediments and from 110 to 520 ng/g wet weight in marine organisms, respectively. The dominant compounds were three- and four-ring PAHs in the sediments (53%-89%) and two- and three-ring PAHs in the marine species (67%-94%), respectively. PAHs mainly originated from both pyrolytic and petrogenic sources. Comparison with the effects-based sediment quality guideline values suggested that the ecological risk caused by the total PAHs was relatively low (less than 25% incidence of adverse effects) in the sedimentary environment. The median cancer risk level via seafood consumption (1.6 × 10(-5) for urban residents and 1.2 × 10(-5) for rural residents, respectively) was slightly higher than the maximum admissible level (10(-5)) set by US EPA, but lower than the priority risk level (10(-4)).

Fuzzy comprehensive assessment of heavy metals and Pb isotopic signature in surface sediments from a bay under serious anthropogenic influences: Daya Bay, China.

The fuzzy comprehensive assessment was undertaken to evaluate the marine sediment quality in Daya Bay, China based on the monitoring data of 2015 and China National Standard for Marine Sediment Quality (GB 18668-2002). The results demonstrated that the average metal concentrations (mg/kg) were 0.08 (Cd), 51.30 (Pb), 91.30 (Cr), 29.63 (Cu), 143.42 (Zn), 0.03 (Hg), and 7.31 (As), which were clearly higher with respect to their corresponding background values. Cr was the major pollutant based weight matrices calculated. Taken as whole, the membership degree of class I was a range from 0.65 to 1, suggesting that the marine sediment quality in Daya Bay belongs to class I. Pb stable isotopic analysis coupled with geographic information system (GIS) approach showed the sedimentary Pb mainly originated from petrochemical industry at northwest coast of Daya Bay.

Heavy metal concentrations in wild fishes captured from the South China Sea and associated health risks.

Heavy metal concentrations were measured in 29 marine wild fish species from the South China Sea. Concentrations (wet weight) were 0.51-115.81 ng/g (Cd), 0.54-27.31 ng/g (Pb), 0.02-1.26 µg/g (Cr), 8.32-57.48 ng/g (Ni), 0.12-1.13 µg/g (Cu), 2.34-6.88 µg/g (Zn), 2.51-22.99 µg/g (Fe), and 0.04-0.81 µg/g (Mn), respectively. Iron concentrations in all and Mn in some fish species were higher than the acceptable daily upper limit, suggesting human consumption of these wild fish species may pose a health risk. Human health risk assessment, however, indicated no significant adverse health effects with consumption.

Complete mitochondrial genome of the sixbar grouper Epinephelus sexfasciatus (Perciformes: Epinephelidae).

In this study, we presented the complete mitogenome for the sixbar grouper Epinephelus sexfasciatus. The complete mitogenome of E. sexfasciatus is 16,786 bp in length with the typical mitochondrial gene order and composition in vertebrates. Overall base composition was 28.40% A, 27.93% C, 27.21% T and 16.45% G. The COI gene used GTG and the ATP6 gene used CTG as the start codon. The tRNA-Ser2 lost the dihydrouridine arm and replaced with a simple loop. Both the maximum likelihood (ML) and Bayesian inference (BI) methods yielded the same tree topology using available mitogenomes of the genus Epinephelus. Epinephelus sexfasciatus was nested to E. akaara. E. awoara and E. fasciatomaculosus, and then combined with E. stictus formed a clade.

Complete mitochondrial genome of the black-dotted grouper Epinephelus stictus.

The complete mitochondrial genome of the black-dotted grouper Epinephelus stictus was first determined in this study. It is 16,524 bp in length, including 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes and one control region, with the typical gene arrangement in vertebrates. There are some variations in the initiate and terminal codons among 13 protein-coding genes. The 12S rRNA and 16S rRNA genes are 952 and 1705 bp, respectively. The tRNA-Ser2 gene lacked DHC arm and could not fold into a typical clover-leaf secondary structure. The base composition is different between each portion of mitochondrial genome.

Complete mitochondrial genome of the threespot grouper Epinephelus trimaculatus.

We present the complete mitochondrial genome of the three-spot grouper Epinephelus trimaculatus (16,761 bp) in this study. The gene order and orientation in E. trimaculatus were the same as the typical vertebrates. The COI and ND4 genes started with the GTG codon and the ATP6 gene started with the CTG codon, the remaining protein-coding genes started with the ATG codon. All protein-coding genes used the TAA or incomplete T as the stop codon. A 41 bp sequence was identified as the origin of L-strand replication (OL) between tRNA-Asn and tRNA-Cys genes. The tRNA-Ser2 lost the dihydrouridine (DHU) arm and formed one loop. A tandem repeat motif (5'-AAATACATAATATGCTTT-3') and three conserved sequence blocks (CSB1-3) were found in the control region.

[Residues and risk assessment of polycyclic aromatic hydrocarbons in the surface sediments and marine organisms from Dapeng Bay, Shenzhen].

In order to assess contamination by polycyclic aromatic hydrocarbons (PAHs), surface sediments and marine organism samples of fish, shrimp and shellfish were collected from the Dapeng Bay, Shenzhen in October 2011. Concentrations fof sixteen priority PAHs were determined by gas chromatography and mass spectrometry (GC-MS). The total concentrations of PAHs (Sigma PAHs ) ranged from 216. 56 ng.g-1 to 1 314. 92 ng.g-1 dry weight in sediment samples and from 70. 88 ng.g-1 to 251.90 ng.g-1 wet weight in biological samples, respectively. The mean concentration was the highest in fish (171.52 ng.g-1 ), followed by mussel (134.75 ng.g-1) and shrimp (123.35 ng.g-1) in the studied marine organisms. Compared with those in other water bodies around the world, PAHs pollution in the studied area was at medium level. The dominant fraction in the surface sediments was the 4-ring PAHs. Identification of PAH sources suggested that PAHs in Dapeng Bay were likely originated from both pyrolytic and petrogenic sources. The most abundant PAHs were 3-ring PAHs in the tissues of organisms, which may be governed by their feeding behaviors, habitats, and bioavailability of PAHs. Ecological risk assessment indicated that PAHs in surface sediments might have adverse impacts on local ecosystem. Health risk analysis revealed that the potency equivalent concentrations of BaP to the total PAHs in marine organisms from Dapeng Bay were relatively high and may cause some concerns on human health by consumption.

Levels, composition profiles and sources of polycyclic aromatic hydrocarbons in surface sediments from Nan'ao Island, a representative mariculture base in South China.

Levels, composition profiles and sources of 16 polycyclic aromatic hydrocarbons (PAHs) in surface sediments from Nan'ao Island, one of the largest mariculture bases in South China were investigated. The total PAHs concentrations ranged from 265.49 to 951.27 ng/g (dry weight) with a mean of 515.90 ng/g, and seven possible carcinogenic PAHs accounted for 76.94% of total PAHs. Among various mariculture sections, the highest PAHs level was found in the large seaweed culture; while the lowest concentration was detected in the abandoned culture. The composition of PAHs was characterized by low molecular weight PAHs, and Phe Ant and Pyr were the dominant constituent. PAHs may be mainly originated from petroleum and combustion of biomass and coal. Risk assessments suggested that the probability of adverse effect was lower than 25% and PAHs exposure was moderately carcinogenic.

[Effects of PM2.5 exposure on Klebsiella pneumoniae clearance in the lungs of rats].

OBJECTIVE: To investigate the effects of PM2.5 exposure on susceptibility to Klebsiella infection and bacterial clearance, and to discuss its possible mechanisms. METHODS: Eighty-six healthy male SD rats were randomly divided into 4 groups: a control group, a Klebsiella pneumoniae infection group(infection group), a PM2.5 group and a PM2.5+ Klebsiella pneumoniae infection group (combined group) .We developed a rat model in which the animals were given Klebsiella pneumoniae, PM2.5 exposure and PM2.5 exposure followed by infection with Klebsiella pneumoniae respectively. The clinical scores were evaluated. The total mortality of each group was assessed. Bacterial load in the BALF was quantified and the infection rate of each group was assessed.Lung histopathological changes were detected by HE staining. The concentrations of IL-6 and TNF-α in serum were detected by ELISA. Cells in the BALF were counted for each group by microscopy. The changes of tracheal membrane epithelial cells were observed by scanning electron microscope. RESULTS: The total mortality in the combined group (n = 14) was higher than that in the control group (n = 0), infection group(n = 4) and PM2.5 group(n = 4). The infected cases in the combined infection group (n = 13) was higher than that in the infection group (n = 6). The total number of WBC in BALF in the combined group on the first day[(11.96 ± 0.56)×10(5)/L] and seventh day [(15.68 ± 0.81)×10(5)/L] was higher than that in the control group, the infection group and the PM2.5 group. The neutrophil number in BALF in the combined group on the first day[(5.76 ± 0.44)×10(5)/L] and seventh day [(9.41 ± 0.64)×10(5)/L] was higher than that in the control group, the infection group and the PM2.5 group. The lung pathological changes were much more severe in the combined group as compared to those in the control, the infection and the PM2.5 groups. Concentrations of TNF-α in serum in the combined group on the first day [(829 ± 90) ng/L] and the seventh day [(1055 ± 91) ng/L] were higher than those in the control group and the PM2.5 group. Concentrations of IL-6 in serum in the combined group on the first day [(1.26 ± 0.16) ng/L] and seventh day [(1.95 ± 0.18) ng/L] was higher than those in the control, the infection and the PM2.5 groups. Tracheal cilia in the PM2.5 group showed signs of disorderly arrangement, adhesion and ecclasis. CONCLUSIONS: PM2.5 exposure increased the susceptibility of the rats to Klebsiella pneumoniae infection and decreased bacterial clearance.Its mechanism may be related to impairment of the bronchial mucociliary system and interaction of cytokines.

[Variation characteristics of macrobenthos productivity in Daya Bay of South China Sea].

Based on the 7 cruises survey data collected from 63 research stations in the Daya Bay of South China Sea in January and July 1988 and in March, May, September and December 2004, the variation characteristics of the abundance, biomass, productivity, and P/B value of macrobenthos in the two years were analyzed by using Brey's empirical formula. The results showed that in 2004, the mean productivity and P/B value of macrobenthos in study area were 10.22 g AFDM x m(-2) x a(-1) and 0.85 x a(-1), respectively, being at the medium-high level among the sea areas in China and higher than those in 1988 (7.25 g AFDM x m(-2) x a(-1) and 0.76 x a(-1), respectively), which corroborated the conclusion that the high output system of Daya Bay relied on the fast turnover to maintain its high productivity. The variation characteristics of the productivity and P/B value varied among the four main groups of macrobenthos, and the horizontal distribution of macrobenthos productivity also had a greater variation. The regional differences of the productivity and P/B value were closed related to human activities, and the areas in which the productivity varied significantly were intensively affected by human activities.