Institutional Repository of South China Sea Institute of Oceanology, CAS
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Steroid bioaccumulation profiles in typical freshwater aquaculture environments of South China and their human health risks via fish consumption
No full textMore attention was previously paid to adverse effects of steroids on aquatic organisms and their ecological risks to the aquatic environment. So far, little information has been reported on the bio-accumulative characteristics of different classes of steroids in cultured fish tissues. The present study for the first time provided a comprehensive analysis of the occurrence, bioaccumulation, and global consumers' health risks via fish consumption of androgens, glucocorticoids and progestanges in typical freshwater cultured farms in South China. The numbers and total concentrations of steroids detected in the tissues of five common species of the cultured fish were in the order of plasma > bile > liver > muscle and plasma > bile, muscle > liver, respectively. The field bioaccumulation factors for the detected synthetic steroids ranged from 450 to 97,000 in bile, 450 to 65,000 in plasma, 2900 to 16,000 in liver, and 42 to 2600 in muscle of fish, respectively. This data suggests that steroids are bioaccumulative in fish tissues. Mostly important, 4-androstene-3,17-dione (AED) and cortisone (CRN) were found to be reliable chemical indicators to predict the levels of steroids in plasma and muscle of the inter-species cultured fish, respectively. Furthermore, the maximum hazard quotients (HQs) of testosterone and progesterone were 5.8 x 10(-4) and 9.9 x 10(-5), suggesting that human health risks were negligible via ingestion of the steroids-contaminated fish. (C) 2017 Elsevier Ltd. All rights reserved
Comparison of metals levels in two mangrove species (Rhizophora stylosa and Sonneratia hainanensis) from Hainan Island, South China
No full textTrace metals in mangrove tissues (leaf, branch and root) of two species (Rhizophora stylosa and Sonneratia hainanensis) from Dongzhai Harbor and Sanya Bay of Hainan Island were studied. The total average concentrations of Cu, Pb, Zn, Cd, Cr, Hg and As in the two mamgrove species were 2.4 +/- 1.3, 1.1 +/- 0.7, 7.8 +/- 8.0, 0.03 +/- 0.05, 1.4 +/- 1.6, 0.03 +/- 0.01 and 0.2 +/- 0.2 mu g g(-1) dw, respectively. Metals concentrations among different tissues of mangroves showed different pattern. In general, Zn, Cd and Hg were slightly enriched in leaf, Cu, Pb and As was enriched in root, and Cr were enriched in branch. Metals levels in R. stylosa and S. hainanensis from both Dongzhai Harbor and Sanya Bay were compared, which suggested that different mangrove species have their unique mechanism to bioaccumulate metals and TOC in the mangrove sediment could be one of the important factors for regulating metals in mangrove tissues. The biota-sediment accumulation factors (BSAF) of metals in mangrove tissues were calculated. The distribution of metals concentrations in mangrove tissues against metals levels in sediment demonstrated that mangrove leaves could be employed as a bio-indicator for some metals (Cu, Zn, Cd and Hg) with temporal monitoring
Bioconcentration of polybrominated diphenyl ethers and organochlorine pesticides in algae is an important contaminant route to higher trophic levels
No full textPersistent organic pollutants (POPs) present in water may be bioconcentrated in phytoplankton and further transferred into higher trophic levels. In the present study, seawater, sediment, phytoplankton and macroalgae (Ulva lactuca L.) samples were collected from two estuarine bays in South China and analyzed for 24 polybrominated diphenyl ethers (PBDEs) and 22 organochlorine pesticides (OCPs). The concentrations of PBDE congeners except BDE-209 were low in both phytoplankton and Ulva. BDE-209 was the predominant congener in phytoplankton and Ulva, accounting for 89.5% and 86.6% of the total average concentrations of PBDEs (48.5 and 4.1 ng g(-1) dw), respectively. The average concentrations of DDTs, HCHs and 1-chloro-2,2-bis(4-chlorophenyl) ethane (p,p'-DDMU) in phytoplankton were 398, 241 and 11.3 ng g(-1) dw, respectively, while those of DDTs and HCHs in Ulva were 8.4 and 33.1 ng g(-1) dw. The levels of both PBDEs and OCPs were an order of magnitude higher in phytoplankton than in Ulva, indicating that phytoplankton with larger surface areas have higher uptake efficiency for POPs than Ulva. Bioconcentration factors (BCFs) of DDT and PBDE in phytoplankton from the two bays were in the range of 10(5)-10(6), suggesting that bioconcentration may be one of the key sources of POPs and algae can be an important route for POPs to move toward higher trophic levels. (C) 2016 Elsevier B.V. All rights reserved
Adaptation and evolution of deep-sea scale worms (Annelida: Polynoidae): insights from transcriptome comparison with a shallow-water species
No full textPolynoid scale worms (Polynoidae, Annelida) invaded deep-sea chemosynthesis-based ecosystems approximately 60 million years ago, but little is known about their genetic adaptation to the extreme deep-sea environment. In this study, we reported the first two transcriptomes of deep-sea polynoids (Branchipolynoe pettiboneae, Lepidonotopodium sp.) and compared them with the transcriptome of a shallow-water polynoid (Harmothoe imbricata). We determined codon and amino acid usage, positive selected genes, highly expressed genes and putative duplicated genes. Transcriptome assembly produced 98,806 to 225,709 contigs in the three species. There were more positively charged amino acids (i.e., histidine and arginine) and less negatively charged amino acids (i.e., aspartic acid and glutamic acid) in the deep-sea species. There were 120 genes showing clear evidence of positive selection. Among the 10% most highly expressed genes, there were more hemoglobin genes with high expression levels in both deep-sea species. The duplicated genes related to DNA recombination and metabolism, and gene expression were only enriched in deep-sea species. Deep-sea scale worms adopted two strategies of adaptation to hypoxia in the chemosynthesis-based habitats (i.e., rapid evolution of tetra-domain hemoglobin in Branchipolynoe or high expression of single-domain hemoglobin in Lepidonotopodium sp.)
Relocation of two earthquakes in the Southwest Indian Ridge area combining land seismic stations' with OBSs' data
No full textTwo earthquakes were recorded by 20 ocean bottom seismometers (OBS) deployed in the Southwest Indian Ridge (SWIR) area during a three-dimensional seismic survey in 2010. Their magnitudes (both M (b) = 4.4) and hypocenters have been determined by National Earthquake Information Center (NEIC) only using land seismic stations onset times. After the frequency analysis and the band-pass filtering of the OBSs' data, 7 and 13 P-phase onset times from OBSs were successfully picked for these two events, respectively. Then these two events were relocated by HYPOSAT program with onset times together from OBSs and land seismic stations using different velocity models. These relocation experiments confirm both the importance of adding OBSs' onset data and the need to apply a local oceanic velocity model for the location of these two events happened on the SWIR. This research has accumulated a wealth of experience for earthquakes observation and research using OBSs in the ocean
南海北缘珠三坳陷新生代构造沉降特征
No full text盆地的构造沉降史是盆地基底垂向升降的历史记录,不仅可以反映盆地形成演化历史,而且可能记录了深部地质过程的信息。近年来,越来越多的地球物理证据显示,雷琼地区深部存在延伸到下地幔的柱状低速异常体。为了揭示该深部异常体的活动信息,利用地震资料和钻孔资料,采用回剥和应变速率反演技术,计算了珠三坳陷各构造单元的构造沉降曲线和理论构造沉降曲线。结果显示,珠三坳陷新生代构造沉降可划分为5个阶段:初始张裂慢速沉降(65~49.5 Ma),张裂期快速沉降(49.5~30 Ma),裂后慢速热沉降阶段Ⅰ(30~23.03 Ma),裂后加速沉降(23.03~16.5 Ma),裂后慢速热沉降阶段Ⅱ(16.5~0 Ma)。珠三坳陷在裂陷期存在沉降亏损现象,裂后期存在300~800m异常沉降可能是对前期沉降不足的补偿,可能与裂陷期软流圈热物质上涌和消退有关。研究结果还表明23.03~10.5 Ma珠三坳陷构造沉降中心发生北东向的迁移,是否与深部异常体活动有关或受区域应力场影响,还需进一步研究
全球俯冲带大洋钻探进展与启示
No full text俯冲带是地球最重要的板块边界之一,对研究地球内部的物质与化学成分循环、岛弧与陆壳的形成以及地震与海啸机制至关重要。大洋钻探对于研究俯冲带过程具有不可替代的作用。回顾了全球俯冲带过程的大洋钻探研究,简述近年来取得的重要进展、科学目标以及对我国大洋钻探发展规划的启示
马尼拉海沟俯冲带北段天然地震研究进展
No full text南海东部为俯冲型大陆边缘。南海海盆沿马尼拉海沟向东俯冲,自西向东形成了南海海盆、马尼拉海沟、增生楔、弧前盆地(北吕宋海槽和西吕宋海槽)和火山弧(吕宋岛弧)构造组合(李家彪等,2004)。马尼拉海沟俯冲带是南海惟一的俯冲汇聚边界,代表着南海从陆缘张裂、洋脊扩张、
沉积盆地盐构造热效应及其油气地质意义
No full text海相沉积盆地广为发育盐岩,盆内油气藏多与盐岩有关.塔里木盆地是中国最大的海相沉积盆地,该区以往的盐构造研究主要集中于其作为良好盖层的封堵性能和作为构造圈闭的盐相关构造.实测表明,盐岩热导率远大于普通沉积岩(约2~3倍),盐岩这一强烈的热物性差异必然会对盆地地层温度分布及烃源岩热演化产生显著影响,但该问题尚未引起重视.本文基于系列理论模型和库车前陆盆地盐构造地震解释剖面,采用二维有限元数值模拟实验,定量探讨了盐构造的热效应及其对烃源岩热演化的影响.研究表明,盐体会造成盐上地层显著增温(3%~13%)和盐下地层降温(11%~35%),进而分别加速盐上烃源岩和抑制盐下烃源岩的热演化过程.盐体的热导率、几何形态、厚度和埋深是控制地热异常幅度的主要因素.异常范围与盐体尺寸有关,横向上可达盐体宽度的2倍、垂向上为盐体厚度的2~3倍.盐构造使得库车前陆盆地盐下地层温度显著降低,造成盐下侏罗系烃源岩镜质体反射率(Ro)降低约18%,从而有利于盐下深层油气的保存.库车前陆盆地东、西部的盐构造在埋深、厚度、成分和构造变形样式等方面均存差异,这可能是造成该区中生界烃源岩有机质成熟度时空差异分布的原因.上述盐构造的热效应对中国海相沉积盆地深层油气资源潜力评价与勘探具有重要意义
南海北部陆缘热流变化特征及其影响因素分析
No full text热流调查和构造热演化数值模拟是油气地热研究不可或缺的重要内容。沉积盆地在其演化过程中往往叠加了特殊构造事件。通过热流调查和构造热演化数值计算可以更好地约束这些特殊过程,重建更为真实的构造热演化历史。该文通过对南海北部琼东南盆地和珠江口盆地中段热流变化特征分析和构造热演化数值模拟,探讨了影响其热流变化的主要因素。结果表明,琼东南盆地可分3个热流分区:北部陆架与上陆坡区(50~70mW/m~2)、中央坳陷带深水区(70~85mW/m~2)和盆地东部深水区高热流带(>85mW/m~2);珠江口盆地中段从陆架往海盆方向热流呈阶梯式抬高,西江凹陷平均热流为55mW/m~2,番禺低隆起为58mW/m~2,白云凹陷为70mW/m~2,下陆坡区为85mW/m~2;陆坡区高热流不仅与岩石圈强烈减薄相关,而且还受到岩石圈破裂时引起的深部热物质上涌的影响,后者对现今陆坡区还有约20mW/m~2的热流贡献;琼东南盆地东部高热流值则主要受到晚中新世以来的岩体侵位热事件的影响,岩体侵入热事件对现今热流值贡献可达10~25mW/m~2。分析表明,在南海深水盆地开展构造热演化数值计算时,需要考虑沉积过程、海底扩张以及岩浆活动等影响因素