Antimony, Arsenic and Thallium Bioaccumulation in Asiatic Clam (Corbicula fluminea) Transplanted along the Manadas Creek, Laredo, Texas

Manadas Creek is an urban tributary of the Rio Grande that flows past a decommissioned antimony smelter and processing plant. This antimony plant is associated with heavy metal contamination in the creek and still poses a threat to the surrounding aquatic environment. Corbicula fluminea was used to determine bioaccumulation from the water column and sediments in Manadas Creek. The metals arsenic (As), antimony (Sb) and thallium (Tl) were analyzed in the water, sediments, gills, mantle, foot, digestive (DI) tract, gonads and shell of clams being monitored at eight sites between March and August 2013. Sediment, water, and dissected Corbicula fluminea samples from different sites in the Creek were acid-digested and analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy. High levels of antimony (25.88 ug/L;75.96 mg/kg) and arsenic (8.26 ug/L;6.41 mg/kg) in the water and sediments were observed at the site downstream from the smelter. There were no detectable concentrations of arsenic, antimony, or thallium in the shell of C. fluminea. Arsenic and antimony were detected in the tissues of C. fluminea but thallium was not detected. Based on the results, the organotropism for arsenic is DI tract > gills > gonads > foot > mantle > shell and the organotropism for antimony is gills > DI tract > gonads > mantle > foot > shell. This study shows that the Asiatic clam (Corbicula fluminea) is a useful bio-monitor to provide data on the status of metal pollution in Manadas Creek, Laredo, Texas.

Examining the evolution of tidal creeks in the Huanghe River delta using multi-temporal Landsat images

Coastal tidal creeks are important channels for exchanges of material and energy between sea and land,and play an important role in the ecological protection of tidal flats.Although tidal creeks have evolved differently in various regions,the evolutionary process of tidal creeks in the Huanghe(Yellow)River delta of China,one of the most active deltas worldwide,is not entirely clear.Therefore,the evolution of tidal creeks in the delta from 1981 to 2021 was investigated by quantitatively analysing the tidal creeks and developing a standard for dividing their evolution periods.Visual interpretation and supervised classification methods were applied to the Landsat images to extract the tidal creek network,and 17 groups of tidal creek systems were selected.Results indicate that Creek S 1 was the most developed creek for having 113 tidal creeks totaling 65.8 km in length,while Creek E 3 had the fastest growth rate for having average annual increase of 1.9 km.Meanwhile,the level of tidal creeks increased,the average and median lengths of tidal creeks increased,and the number of tidal creeks decreased since 1981.The evolution of the tidal creek system could be divided into four stages,namely,rising,developing,stabilizing,and degrading.Analyses of a representative tidal creek show that there was no degenerated tidal creek during the rising period,with an increase in the number of 50 and a length increase of 57.9 km between 1981 and 1989.The proportion of new tidal creeks in the developing period was more than 50%and the new tidal creeks in the stabilizing period were equal to the degraded tidal creeks.Extinct tidal creeks were greater than 50%during the degrading period.There was no fixed order of tidal creek evolution in each period,and there may be a skip in evolution.Our findings provided a reference for studying the evolution of tidal creeks.

Evaluation of Growth Rate of Invasive Aquatic Macrophytes and Contribution to Its Use in Organic Fertilizer Production: A Case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon)

From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.

Diel,seasonal,and annual variations of fish assemblages in intertidal creeks of the Changjiang River estuary

The use patterns of salt marsh habitats by fish assemblages were investigated in two welldeveloped intertidal creeks in the Changjiang(Yangtze)River estuary on spatial and temporal scales.Samples were collected using fyke nets at two sites during day and night in each season throughout four years.Notable changes in fish assemblages were detected over seasonal and interannual cycles,with many more marine species present in winter assemblages,whereas freshwater and estuarine species characterized the other seasonal samplings.The appearance of catadromous species in intertidal creeks mainly depended upon their specific physiological requirements,such as spawning migration.No significant diel shifts were observed in fish assemblages.This diel pattern may be a combined consequence of avian predation pressure and other drivers(i.e.,inherent living behaviors,food availability,and predation by piscivorous fishes).The spatial difference in fish community was insignificant even though the two intertidal creeks were different in size.Intertidal creeks with different size could possess similar ecological value for fish fauna.Redundancy analysis(RDA)showed that biological factors exerted greater effects on fish assemblages than physical variables.Temporal variations were strongly facilitated by food availability,but negatively impacted by avian predation.Salinity,water temperature,and river runoff had weak influence on temporal variations of fish communities.The lengthfrequency distribution showed that the fish collected in these two sites mainly consisted of young-of-year and juvenile fish,which confirmed that the creeks provided important nursery and forage roles in the process of fish ontogenetic development.Further,we proposed that salt marsh conservation management should be equally applied to all well-developed intertidal creeks regardless of creek size.

地震综合解释技术在尼日尔三角洲盆地STUBB CREEK区块中的应用

通过对尼日尔三角洲盆地STUBB CREEK区块复杂断块油藏的研究,以新采集的三维地震资料为基础,探讨了复杂断块油藏的研究思路及研究方法,利用相干数据体、时间切片研究断层平面展布规律,借助三维可视化解释技术查看断层面空间展布形态,综合地震资料综合解释的成熟技术,探索出一套适合复杂断块油藏研究的思路,形成了一套有效的综合解释的技术流程。在研究的基础上部署了两口井,取得了油气突破。

生物膜对潮滩动力地貌演变影响的数值模拟研究

河口海岸潮滩湿地是一个复杂的生态系统,其地貌的形成和演变是水动力、泥沙输移和生物过程等多种因子相互作用的结果,特别是,探究潮滩生物过程并阐明其生物-物理效应是当前海洋科学领域研究的热点和难点。本文聚焦微生物生物膜,构建了耦合生物膜与水动力、沉积物输移、地貌演变的二维生物动力地貌模型,探究了生物膜在潮滩泥沙输移和地貌演变中发挥的作用。利用文献数据验证生物动力地貌模型,模型结果与文献数据吻合较好,表明所构建的模型可以较好地模拟出生物膜的增长规律及年际变化情况。结果表明,当水动力较弱时,在有生物膜作用的潮滩上,潮沟向陆侧延伸更充分,呈现出树杈状分布,潮间带区域的潮沟两侧分布有生物膜。通过对潮沟形态进行定量分析,发现生物膜的存在促进了潮沟数量增加,并向纵深方向发展,同时限制了其宽度的增加。相较于没有生物膜影响的潮滩,潮沟的平均深度增加,总面积减小,总长度增加,平均宽度减小,总体积增加。研究结果有助于加深对生物膜在潮滩地貌塑造中的作用机制认识,为海岸带保护与生态修复工程提供科学依据。

海南文昌清澜湾红树林潮沟地下水溶解碳通量的潮汐动态

海底地下水排泄(SGD)是陆地溶解碳向海洋输送的一个重要途径。以清澜湾潮沟为研究对象,以盐度为保守参数计算淡水SGD的占比为2.5%~22.7%,平均为13.0%;SGD净流量为0.86×10^(5) m^(3)/d。基于地下水溶解碳浓度,计算出该潮沟输出的溶解无机碳(DIC)和溶解有机碳(DOC)通量分别为5.78×10^(5)和0.10×10^(5) mol/d。其中,DIC是潮沟溶解碳输送的主要形式,占总溶解碳的98.3%。低潮时,DOC的49%来源于红树林植物碎屑,51%来源于SGD;DIC的78%来源于SGD,22%来源于红树林沉积物有机质。高潮时,DOC的44%来源于被污染的海水,56%来源于红树林植物碎屑;DIC的65%来源于海水,35%来源于孔隙水交换。红树林潮沟SGD向清澜湾输送了大量的溶解碳,其对近海水体碳酸盐平衡体系的影响需要进一步研究。

黄河三角洲典型潮沟发育演变过程分析

以黄河三角洲东部、侧弯丁坝北部为研究区域,基于1997—2021年内共8期Landsat系列遥感影像,采用目视解译的方法提取潮沟网络,通过分析不同时期潮沟数量、长度、密度等特征,揭示了潮沟阶段性演变规律。结果表明:潮沟的全生命周期可划分为幼年期、青年期、成熟期和退化期4个阶段,其中幼年期潮沟数量和长度增长率最大,是青年期的3倍以上;青年期潮沟数量和长度继续增加,但增长率明显降低,潮沟网络系统逐渐趋于稳定;成熟期潮沟系统发育基本完成,潮沟长度、数量、曲率等形态特征无明显变化;退化期部分潮沟萎缩、消亡、废弃,2005—2007年Ⅰ组潮沟每年消亡10.8%。

储层横向预测技术在尼日利亚Stubb Creek油田的应用

Stubb Creek油田研究工区面积42 km2,研究层位是阿格巴达组的C3、C7、C9、D1、D3、D5、D8小层。根据已钻探的4口井和现有的认识成果,进行了测井曲线标准化、井震标定、体系域的层序划分,进行了岩石物理和岩相物理的研究,通过多种地震相结合单井相,刻画出了上述7层的有利相带。用支持向量机技术,进行了泥质含量的分频反演,通过砂岩的泥质含量门槛值计算了上述7层的砂体厚度,筛选了C9、D3两个有利相带。在有利相带控制下雕刻了过井砂体的顶面构造图和砂体厚度等值线图,并进行了综合评价。

Sustainable Wetland Management Using the Kunming-Montreal Global Biodiversity Framework as a Guide in the Sierra Leone Case

The Sustainable Wetland Management adopted for this study depicts that, the identification of drivers and impacts is needed first, in other to get a clearer roadmap, after which the Kunming-Montreal Global Biodiversity Framework would come into play to serve as a pathway for Sustainability. The study evaluates how Sierra Leone might implement the Framework’s proposed strategies in National Wetland Management. As a result, the research tried to thoroughly examine the factors that contribute to wetland degradation as well as the effects they have on the people who live nearby. The purposive sampling method was used to administer 385 structured questionnaires to inhabitants. The data was then processed in an Excel spreadsheet. Microsoft Publisher was used to draw the framework and a descriptive analysis was done. Results indicated that;the majority of the inhabitants of Aberdeen Creek are traders/self-employed, furthermore, the majority chose the place because it’s less expensive and nearer to the workplace, settlement expansion and pollution are the two most common degrading activities, while flooding and health-related issues are some of the consequences, and the Kunming-Montreal Global Biodiversity Framework is regarded to be a perfect tool for wetland management. It was concluded that to accomplish the objectives in the framework, it is necessary to have both political and social will. Satellite data and water quality research are further needed to validate the report.

Numerical three-dimensional modeling of earthen dam piping failure

A physically-based numerical three-dimensional earthen dam piping failure model is developed for homogeneous and zoned soil dams.This model is an erosion model,coupled with force/moment equilibrium analyses.Orifice flow and two-dimensional(2D)shallow water equations(SWE)are solved to simulate dam break flows at different breaching stages.Erosion rates of different soils with different construction compaction efforts are calculated using corresponding erosion formulae.The dam's real shape,soil properties,and surrounding area are programmed.Large outer 2D-SWE grids are used to control upstream and downstream hydraulic conditions and control the boundary conditions of orifice flow,and inner 2D-SWE flow is used to scour soil and perform force/moment equilibrium analyses.This model is validated using the European Commission IMPACT(Investigation of Extreme Flood Processes and Uncertainty)Test#5 in Norway,Teton Dam failure in Idaho,USA,and Quail Creek Dike failure in Utah,USA.All calculated peak outflows are within 10%errors of observed values.Simulation results show that,for a V-shaped dam like Teton Dam,a piping breach location at the abutment tends to result in a smaller peak breach outflow than the piping breach location at the dam's center;and if Teton Dam had broken from its center for internal erosion,a peak outflow of 117851 m'/s,which is 81%larger than the peak outflow of 65120 m3/s released from its right abutment,would have been released from Teton Dam.A lower piping inlet elevation tends to cause a faster/earlier piping breach than a higher piping inlet elevation.

Jackson Creek中学的“戏趣”教育模式探略

Jackson Creek中学是美国印第安纳州的一所五星级初中。该校的"戏趣"教育模式颇受瞩目,诸如形同"剧场"的流动课堂、人人"有戏"的团队合作、情境"入戏"的填字训练、现场"看戏"的调研实践、情状"戏谑"的教师言行,等等,其生发的"趣味"易激发学生的积极性、参与度,吸引学生的注意力,有利于教学活动的开展和学生个性的培养,从而能形成良性的课堂教学和教育模式。其"戏趣"教育模式值得我们借鉴,将能促进和优化已有的教育模式和教学形态。

习近平生态文明思想的价值逻辑与生动实践——以木兰溪治理为例

从习近平生态文明思想的价值意蕴出发,介绍其蕴含的深刻内涵、理论意义和实践价值。基于人与自然和谐共生共享的生态逻辑、绿水青山就是无价之宝的绿色发展理念、“变害为利、造福人民”的治理要求和美丽中国建设的整体逻辑,指出人与自然、社会与生态之间的辩证关系,阐述木兰溪生态治理的现实逻辑。进而从观点基础、生态建设、实现载体和路径选择4个方面探讨习近平生态文明思想在木兰溪治理中的生动实践。

龙涧溪地表水体浮游生物群落调查与水质评估研究

国家非常重视长江水体的保护,党的“十八大”提出“筑牢长江上游重要生态屏障”,以长江上游重要支流——沱江下游末端支流龙涧溪河段为研究对象,于2023年7-12月分别在上中下游选取3个断面,对其水生浮游生物种类、数量、群落组成等指标进行调查检测,并根据浮游生物组成和数量变化情况对龙涧溪水质进行了评估。结果表明:(1)龙涧溪水体中包括浮游植物8门,浮游动物3门。浮游植物包括蓝细菌门(Cyanobacteria)、隐藻门(Cryptophyta)、金藻门(Chrysophyta)、甲藻门(Pyrrophyta)、黄藻门(Xanthophyta)、裸藻门(Euglenophyta)、硅藻门(Bacillariophyta)及绿藻门(Chlorophyta),优势种以硅藻门为主、占11.98%,其次是隐藻门、蓝细菌门;浮游动物有3门,分别为原生动物门(Protozoa)、轮虫(Rotifer)、枝角类(Cladocera),占比分别为34.7%、8.8%、1.7%,优势种为原生动物门。(2)浮游生物平均密度为1.444×10^(7)cell/L。(3)统计计算出Shannon-Weiner多样性指数(H′)平均值为1.282、Pielou均匀度指数(J)平均值为0.500、Margalef丰富度指数(d)平均值为1.160,经综合评估可知调查河段物种丰富度较低、群落结构较简单,总体表现为中度污染、一般级别水质。建议加强对龙涧溪沿线排污口的排查和管理,加强农村污水管网和处理设施的建设,继续加大环保宣传力度,增强群众的生态环境保护意识。

江南地区泾浜体系地域风景的再生设计实践——以江阴青阳镇滨水景观带设计为例

伴随着愈发快速的城镇化发展,近些年我国城乡风景面貌的差异性、多样性不断降低,尤其是特色鲜明的传统地域风景正不断消失。江阴青阳镇拥有太湖流域典型的江南水网平原特质,其独具特色的泾浜系统却在城镇的变迁发展中难以为继。在此背景下进行了青阳镇滨水带景观设计,文章思考泾浜体系在现代城镇发展语境中的功能与角色转变,探讨如何运用景观设计手法延续地域风景特征,提升城镇环境活力,为当下快速发展的城镇人居环境更新建设提供思路。

航空磁法在澳大利亚北领地Tennant Creek金矿田勘探中的应用

Tennant Creek金矿田矿床类型属铁氧化物型铜金矿(IOCG),含矿部位均呈现高的航磁异常。本区矿体地表露头以褐铁矿为主,深部以磁铁矿为主,高品位的金通常位于铁矿体底部,呈细脉-浸染状产出。为了进一步寻找IOCG型矿床,在Tennant Creek金矿田内28 904区块开展了大比例尺航空磁法工作,综合分析航磁-地层特征,圈出航磁异常17处。其中2处异常经地表查证,发现了大型褐铁矿化带,并有Au异常显示。下一步若对其它异常进行钻探验证,证明其深部存在IOGC型金矿,则说明大比例尺航空磁法测量在Tennant Creek金矿田是有效的找矿方法。

A Siltation Simulation and Desiltation Measurement Study Downstream of the Suzhou Creek Sluice, China

The Suzhou Creek Sluice is currently the largest underwater plain gate in the world, with a single span of 100 m. It is located in a tidal estuary at the junction of the Huangpu River and Suzhou Creek in Shanghai, China. In this study, physical and 2D vertical mathematical models were used to investigate and distinguish the mechanism of siltation downstream of an underwater plain gate from that of other gates types. According to quantitative data obtained by site investigation and the application of the physical hydrodynamic models, it was found that the characteristics of the tidal estuary as well as the fact that the sluice span is equal to the creek width are the major reasons contributing to siltation. A possible desiltation treatment system is proposed for the underwater plain gate. The system includes selection of a suitable location that allows the determination of a reasonable top elevation of the sluice floor, reserving sufficient space under the gate to accommodate siltation, setting up a mechanical desiltation system, and flushing silt along with overflow over the top of the gate. Furthermore, on-site hydraulic silt flushing experiments and a topography survey were conducted. These results showed that the measurement system is effective, and by maintaining this scheduled operation once a month, the downstream riverbed has been maintained in a good condition.

Preliminary Study on Nitrogen and Phosphorus Releases from Creek Sediments in Shanghai Suburbs

A laboratory study was conducted to observe the release ofnitrogen and phosphorus from the sediments under both anaerobic andaerobic conditions. The samples used were five creek sediments and afish-pond sediment (as a comparison) obtained from suburban Shanghai.High loads of nitrogen and phosphorus were found in the creeksediments. Total nitrogen of the sediments ranged form 1.17 to 5.95 gkg^-1; total phosphorus from 608.63 to 2 033.95 mg kg^-1. Making upmore than 90/100 of the total nitrogen, organic nitrogen was thedominant nitrogen fraction in the sediments; whereas inorganicphosphorus was the dominant phosphorus fraction, which made up morethan 85 percent of the total phosphorus. Ca-bound phosphorus fractiondominated inorganic phosphorus, which occupied more than 50/100 ofthe total.

Level study on fractal characteristics of tidal creeks and information of seashell habitats in the Gaizhou Beach based on high-resolution satellite images

The fractal characteristics of tidal creeks in the Gaizhou Beach are analyzed based on high-resolution images fusionof Landsat TM and ERS2, and then the graphic models and characteristics of converse information tree of tidalcreeks in the Gaizhou Beach are established. A calculation model is established based on the above results, and at thesame time, quantitative calculation of the evolution characteristics and the diversity between the northern and thesouthern parts of the Gaizhou Beach is carried out. By the supervised classification of these images, distribution andareas of high tidal flats, middle tidal flats and low tidal flats in the Gaizhou Beach are studied quantitatively, and imagecharactistics of seashell habitats in the Gaizhou Beach and the correlation between mudflat distribution and seashellhabitats are studied. At last, the engineering problems in the Gaizhou Beach are discussed.

美国俄亥俄州Sugar Creek流域的病原微生物来源分析

为了解美国俄亥俄州Sugar Creek流域的病原微生物污染程度和污染源,为决策层制定行之有效的治污办法提供数据支持,利用拟杆菌分子溯源技术跟踪测定了上游水域21个取样点微生物污染状况,并调查了水域内土地利用及化粪池系统情况。结果表明:Sugar Creek流域受到微生物严重污染,除社区居民饮用水源外,其余20个取样点均超过州环保部娱乐用水安全标准(235个/100mL),20个样点(95.2%)均受到人粪便污染,其中有4个样点受动物粪便污染。不适合的污水处理系统、化粪池污水直排和化粪池泄漏是污染的主要原因。