川东北板东地区长兴组生物礁型储层研究

四川盆地东北部板东地区长兴组地层主要由含生物(屑)灰岩-生物(屑)灰岩、礁灰岩、泥-粉晶白云岩和细-中晶白云岩构成,其中以细-中晶白云岩的储集性能最好。以礁顶部测井曲线变化特征为依据,认为该礁至少是由3个旋回叠加而成。成岩作用中对储层影响最大主要是胶结充填作用、白云石化作用、溶蚀作用。经镜下观察认为胶结充填作用分3期,充填了大部分的原生孔隙;混合水云化作用使生物屑灰岩演变成具或不具生物(屑)残余结构的细—中晶白云岩;溶蚀作用形成的晶间溶孔、不规则溶孔、溶洞构成了生物礁主要储集空间。     

鞍钢钢渣矿渣制备人工鱼礁混凝土复合胶凝材料

以81.5％的矿渣、5％的钢渣、12.5％的脱硫石膏以及1％的水泥熟料,制备出了28 d抗压强度为56.75 MPa的低碱度胶凝材料,该胶凝材料可用于制备低碱度人工鱼礁混凝土.通过改变钢渣和脱硫石膏的掺量,研究了其掺量变化与试件强度的影响关系.实验结果表明:在该体系中,当钢渣掺量小于5％时,胶砂试块的强度随着钢渣的增加而提高;当钢渣掺量大于5％时,胶砂试块的强度随着钢渣掺量的增加而降低,并在钢渣掺基大于20％时快速下降.脱硫石膏的掺量对胶砂试块的强度影响更为显著;当脱硫石膏掺量达到12.5％时,与不含脱硫石膏的试样相比,抗压强度和抗折强度分别提高了168％和176％.利用XRD和SEM分析净浆的水化过程,结果表明,体系在早期水化主要生成AFt相和C-S-H凝胶,并对强度的增长起了主要作用.     

川东北宣汉盘龙洞长兴组生物礁剖面沉积相分析

结合区域构造、地层概况、岩相古地理等方面的背景资料,对宣汉盘龙洞上二叠统长兴组生物礁地层剖面进行了观测描述.通过室内镜下岩石薄片鉴定分析,识别出主要岩石类型为礁灰岩、礁云岩、生屑灰岩、颗粒灰岩及晶粒白云岩.根据露头观察和室内镜下岩石薄片鉴定分析,结合岩石学、古生物等沉积相标志的研究,认为该剖面发育开阔台地、台地边缘生物...     

吕泗渔场人工鱼礁群流场效应及稳定性研究

随着海洋渔业资源的衰退和海洋生态环境的破坏,人工鱼礁技术得到迅速发展,成为海洋牧场建设的重要组成部分。采用CJK3D-WEM建立了吕泗渔场组合型人工鱼礁群二维潮流数学模型,模拟了礁群实施后周边海域水动力的变化,并通过分析海床泥沙活动性探讨了礁群的稳定性。研究结果表明:礁体的阻挡作用会在礁体后方形成了一个梭状的缓流区域,离礁体越近流速越小;多礁体之间形成了流速渐次变化的生物和鱼类栖息带,流场效应较好;礁群的实施对海床泥沙活动影响相对较小,短期内人工鱼礁下沉或掩埋的风险较小。     

川东北长兴组典型剖面台地边缘礁沉积微相精细刻画

为了精细刻画川东北地区生物礁的微相特征,基于薄片鉴定等分析,对四川盆地东北部地区盘龙洞、羊鼓洞生物礁微相特征进行了精细刻画。结果显示,川东北盘龙洞和羊鼓洞台缘礁均发育多个礁滩旋回,但盘龙洞生物礁比羊鼓洞礁发育完整。盘龙洞生物礁骨架岩和粘结岩发育,白云石化作用发育,海绵骨架和骨架间填隙成分均见白云石化;羊鼓洞生物礁以障积礁和粘结礁为主,灰泥含量高,白云石化作用不发育。同一台地边缘的生物礁,其发育特征及物质组成具有明显差异,这种差异性直接影响了后期成岩作用的改造及礁滩储层储集性能的差异。     

Predictive mapping of reef fish species richness, diversity and biomass in Zanzibar using IKONOS imagery and machine-learning techniques

During the last three decades, the large spatial coverage of remote sensing data has been used in coral reef research to map dominant substrate types, geomorphologic zones, and bathymetry. During the same period, field studies have documented statistical relationships between variables quantifying aspects of the reef habitat and its fish community. Although the results of these studies are ambiguous, some habitat variables have frequently been found to correlate with one or more aspects of the fish community. Several of these habitat variables, including depth, the structural complexity of the substrate, and live coral cover, are possible to estimate with remote sensing data. In this study, we combine a set of statistical and machine-learning models with habitat variables derived from IKONOS data to produce spatially explicit predictions of the species richness, biomass, and diversity of the fish community around two reefs in Zanzibar. In the process, we assess the ability of IKONOS imagery to estimate live coral cover, structural complexity and habitat diversity, and we explore the importance of habitat variables, at a range of spatial scales, in the predictive models using a permutation-based technique. Our findings indicate that structural complexity at a fine spatial scale (∼ 5 to 10 m) is the most important habitat variable in predictive models of fish species richness and diversity, whereas other variables such as depth, habitat diversity, and structural complexity at coarser spatial scales contribute to predictions of biomass. In addition, our results demonstrate that complex model types such as tree-based ensemble techniques provide superior predictive performance compared to the more frequently used linear models, achieving a reduction of the cross-validated root-mean-squared prediction error of 3-11%. Although aerial photographs and airborne lidar instruments have recently been used to produce spatially explicit predictions of reef fish community variables, our study illustrates the possibility of doing so with satellite data. The ability to use satellite data may bring the cost of creating such maps within the reach of both spatial ecology researchers and the wide range of organizations involved in marine spatial planning.     

顶帽变换在川北长兴组生物礁分布预测中的应用

四川盆地北部长兴组碳酸盐岩地层中生物礁发育,是该区油气勘探的主要目的层之一。礁体的分布预测是该区油气勘探面临的现实课题。为此,根据生物礁沉积厚度较同期非礁相地层大的沉积地质学原理,利用地震解释获得的含生物礁地层的时间厚度数据,应用顶帽变换方法开展礁体的平面分布预测,取得满意效果。与人工地震相分析方法相比,该方法具有准确、快速高效和定量化的优点。进行顶帽变换时需要注意的是,结构元素大小的选择应与实际地质体的尺度相符,结构元素过大或过小,均可能导致预测结果的偏差。此外,断层发育等因素可能导致地层厚度出现异常,亦可能对顶帽变换结果造成影响,对此需予以区分。所采用的方法适用于构造变形程度相对较弱的碳酸盐岩地层中礁体的分布预测。     

Isolation of new brominated sesquiterpene feeding deterrents from tropical green algaNeomeris annulata (Dasycladaceae: Chlorophyta)

We investigated the natural products chemistry and feeding deterrent effects of brominated sesquiterpenes produced by Pacific collections of the calcareous tropical green algaNeomeris annulata. Assays conducted with whole algae showed thatN. annulata was not susceptible to grazing by natural populations of herbivorous fishes on Guam. Crude extracts and column chromatography fractions containing the brominated sesquiterpenes deterred feeding by herbivorous fishes at natural concentrations in field assays on Guam. Two majorN. annulata sesquiterpenes isolated from Guam collections and three related sesquiterpenes previously reported from Bermuda all deterred fish feeding at the high end of their natural concentration ranges, with the exception of one metabolite from Bermuda collections of the alga that differed structurally from the other compounds. The results support our hypothesis that the compounds produced byNeomeris function as chemical defenses against herbivores. The alga produces both structural defenses (CaCO₃ in the form of aragonite) and secondary metabolites that defend against herbivory by reef fishes.     

地震沉积学在生物礁滩预测中的应用——以川东褶皱带建南-龙驹坝地区为例

为减少常规方法预测生物礁滩的多解性,以地震沉积学理论为主体思路,在分析建南-龙驹坝地区生物礁滩岩相模式与地球物理响应特征的基础上,将地震相控非线性随机反演引入地震沉积学,利用反演结果,并结合地震解释成果进行地震沉积学解释。依据生物礁滩的岩相模式,利用典型井生物礁滩的地震相与反演剖面特征建立生物礁滩识别模式,进行生物礁滩全区追踪预测。钻井资料证实,预测结果较可靠。     

Nanomaterials in sunscreens: Potential human and ecological health implications

Inorganic nanomaterials such as TiO₂ and ZnO provide significant benefits in terms of UV protection, and their use generally has increased in commercial sunscreens. However, more recently there have been concerns about their potential human and ecological health implications, mostly driven by perception rather than by formal assessments. The large and increasing body of literature on these nanomaterials indicates that in most circumstances their risk are minimal. Penetration of the human epidermis is minimal for these nanomaterials, significantly reducing the potential effects that these nanomaterials may pose to internal organs. The excess Zn ion dose is very small compared to normal dietary consumption of Zn, which is a necessary element. The levels of residual nanomaterials or released ions in public swimming pools is also low, with minimal effect in case this water is ingested during swimming or bathing. In natural environments with significant water flow due to wind and water currents, the concentrations of nanomaterials and released ions are generally well below levels that would cause effects in aquatic organisms. However, sensitive habitats with slow currents, such as coral reefs, may accumulate these nanomaterials. The number of studies of the levels and effects of nanomaterials in these sensitive habitats is very small; more research is needed to determine if there is an elevated risk to these ecosystems from the use of sunscreens with these nanomaterials.