三江平原小叶章湿地生态系统硫的生物地球化学循环

以三江平原小叶章湿地生态系统为研究对象,应用分室模型研究了硫在大气-土壤-植物系统各分室中的分布及循环过程。结果表明,在植物-土壤系统内,土壤是主要的贮存库和流通介质,有97.78%的硫贮存在土壤中,且主要以有机硫的形态存在,2.22%的硫贮存在植物中。在植物亚系统中,根是主要的贮库,79.60%的硫贮存在根中。湿地植物地上部分吸收的总S量为0.75gS/m^2;向地下再转移的总S量为0.24gS/m^2,向枯落物S库转移的总S量为0.51gS/m^2;根吸收的总S量为3.76gS/m^2;根向土壤S库转移的总S量为3.07gS/m^2;现存枯落物中的总S量为0.75gS/m^2;枯落物向土壤S库的转移量最低为0.52gS/m^2·a。输入和输出过程的研究表明,小叶章湿地生态系统在生长季（5-9月份）向大气排放H2S的量为1.42mgS/m^2,从大气吸收COS的量为1.83mgS/m^2;通过大气降水输入到生态系统中的硫为4.85mgS/m^2,其差值为5.26mgS/m^2,这表明硫在小叶章湿地生态系统中处于累积状态,湿地存在潜在的酸化趋势。     

国内外湿地生态系统研究进展

湿地生态系统具有重要的生态功能和社会经济价值。由于诸多因素的影响,目前全球范围内相当一部分湿地生态系统已经丧失或正在遭受不同程度的威胁,湿地生态系统已经成为近年来相关领域研究的热点之一。近年来,国内外湿地生态系统的研究主要集中在湿地生态系统生物多样性本底资料的调查、湿地生态系统的动态以及湿地生态系统胁迫因子研究、退化湿地生态系统的重建和管理,以及恢复湿地有效性的评估体系等4个方面。一些新方法、新技术也不断应用于湿地生态系统研究中。除了自然湿地外,人工湿地的构建和评价体系的建立也成为该领域研究的热点方向。影响湿地生态系统的因素涉及到自然、社会经济、文化等多个方面,加之湿地类型多样性,因此开展更为广泛的湿地生态系统结构、功能和动态的研究是十分必要的。同时,对特定区域内的湿地生态系统修复过程中的关键技术(包括物种的选择等)的研究、新方法和新手段的应用研究也应该在湿地生态系统研究中给予特别关注。     

黄淮海湿地生态系统服务与生物多样性保护格局的耦合性

研究生物多样性格局与生态系统服务格局之间的空间耦合效应,探讨以生物多样性保育为核心目标的自然保护体系同时能多大程度满足对生态系统服务功能的维护和支撑,已成为自然保护领域新的热点关注问题。目前研究多限于陆域生态系统,其方法难以适用于湿地生态系统。以黄淮海湿地——这一高强度人类活动的区域为研究区,基于湿地生态系统的横向连接度、纵向连接度(2D)以及结合地下水的垂向连接度(3D),对黄淮海地区湿地具有的生态系统服务功能进行了空间评估和分析,识别出具有重要意义的生态系统服务功能区域,结合现有保护区分布情况进行空间分析,评价现有保护区对生态系统服务功能的支持程度,即生物多样性保护与生态系统服务功能重点区域的空间耦合性。研究结果表明:目前湿地保护区并未有效覆盖湿地生态系统关键区域,湿地生态系统服务关键格局也存在大量明显的保护空缺。同时,随着2D到3D延伸,保护区对生态系统服务功能的支持程度也稍有提高,这与系统保护规划中选择不同保护目标后保护规划格局发生变化的情况类似,而生态系统服务功能的"热点地区"(重要区域)与保护生物学中所指的物种保护的热点地区类似,这表明生态系统服务功能的规划和保护也可以借鉴保护生物学中系统保护规划的理论和方法,为后续研究提供参照。     

滨海湿地 生物量最大的生态系统

全球近海海洋生态系统的服务功能的价值大约每年12.6万亿美元,与陆地生态系统服务功能的价值相当,但近海的面积仅为陆地的1/5。而海岸带水域的服务功能价值又要高出滨外海域的15-20倍。……不但支持了沿海居民,而且支持了陆地上的全部生命。例如湿地的功能就包括支撑生物多样性、调节物质循环、保持水动力平衡、涵养水源、防止土壤侵蚀、缓冲风暴潮对陆地的影响等。     

东太湖地区湿地水质与浮游细菌群落结构关联性研究北大核心

[目的]考察东太湖地区湿地水质与浮游细菌群落结构之间的关联,探索对湿地水质具有指示作用的微生物。[方法]应用高通量测序研究浮游细菌群落结构;通过相关性分析考察了浮游细菌群落多样性与水质的关联,并运用LEf Se分析定位不同水质水样的标志微生物。[结果]东太湖湿地浮游细菌主要分布于放线菌门(相对丰度34.78%)、变形菌门(26.30%)及蓝细菌门(19.28%)等7个门;水质指标综合得分与浮游细菌群落香农-威纳指数和辛普森指数分别显著相关(r=-0.597,p<0.05;r=0.694,p<0.01);蓝细菌门与伯克氏菌科的相对丰度在不同水质水样中差异最为显著(LDA得分>4.0)。[结论]东太湖地区,较高的浮游细菌多样性表征较好的湿地水质;蓝细菌相对丰度较高(27.80%)指示湿地水质较差,而伯克氏菌相对丰度较高(5.48%)指示湿地水质相对较好。     

三江自然保护区自然和干扰湿地节肢动物群落组成和生态指示

节肢动物是湿地生物多样性的重要组分,在维持湿地生态功能,指示湿地环境变化中发挥重要作用。在2020年7月对黑龙江三江国家级自然保护区沼泽湿地的23个采样点进行节肢动物样品采集,运用统计方法分析人类活动干扰对湿地节肢动物数量、群落组成、多样性的影响以及节肢动物对人类活动干扰的指示作用。共采集到节肢动物10目47科1825只,主要以双翅目和半翅目昆虫为主。自然湿地节肢动物的多度是干扰湿地的4.27倍;生物多样性指数在不同湿地类型之间存在一定差异,节肢动物的物种丰富度在自然湿地显著高于干扰湿地(P<0.05),而Pielou均匀度指数在干扰湿地显著高于自然湿地(P<0.05)。人类活动干扰对湿地节肢动物群落组成影响显著,聚类和非度量多纬尺度排序(NMDS)显示,两种湿地类型节肢动物群落结构相似性较低。指示值法分析显示,自然湿地的指示类群为叶甲科、蚁形甲科、叶蝉科、蚜科、盲蝽科、摇蚊科以及姬蜂总科,干扰湿地未发现指示类群。综上所述,湿地节肢动物对人类活动干扰响应十分敏感,可以作为指示湿地健康状况的关键生物类群。     

黄河三角洲湿地生态系统的形成及其保护

通过对黄河三角洲新生湿地的野外调查,利用TM陆地卫星影像图的判读,结合黄河尾闾变动的历史资料分析,结果表明,黄河三角洲新生湿地是多泥沙的黄河淤积和海岸蚀退所形成.受区域气候、地貌、地质沉积、土壤、植被的相互作用和互相影响,形成4.5×105hm2的湿地,其中有6.84×104hm2的人工湿地.湿地生态类型随着黄河尾闾摆动和海退陆进程度而变化,自海洋向陆地依次为潮下带水生生态系统潮间带湿地生态系统潮上带盐生生态系统芦苇獐茅湿地生态系统草甸湿地生态系统陆上农田生态系统.该系统资源丰富,共有野生动物1524种,鸟类300种,鱼类1040种.石油开发和近年来黄河断流对湿地产生一定影响,应在开发利用中加强管理和保护     

土壤线虫对环境污染的指示作用

线虫作为土壤中型动物区系的一部分,在土壤生态系统中发挥着重要的作用,因其所特有的生物特性,使其广泛地应用于土壤健康状况的指示研究中．根据国内外的研究现状,分别对典型线虫在土壤污染指示与诊断中的应用和线虫群落的各种指数指标法(如成熟指数、多样性指数、相似度指数、关键种法、N／C比值和生理指标法)及其特点进行概述,论述了土壤动物线虫及其对污染环境的生物指示作用。提出土壤线虫作为一种有效的生态毒理诊断指标具有良好的发展前景．     

重金属污染土壤的湿地生物修复技术

生物修复技术是近年来发展起来的一种有前途的污染治理技术,重金属的湿地植物稳定技术和植物萃取技术等植物修复技术是一研究热点;同时,针对微生物对重金属的生物积累、生物转化及生物修复作一分析,重金属的生物修复生理机制及其提高富集效率的条件作一综述,以期推动国内这一国际热点领域的研究。     

湿地农田生态系统的特点及其调节

所谓湿地,系一个笼统的名称,直到目前并没有确切的定义。通常认为凡受地下水与地表水影响的土地均可称为湿地。它又可区分为两大类,即自然湿地与人工湿地,区别在于受不受人为活动干扰及其干扰程度。湿地包括沼泽型土壤、草甸型土壤与稻田土壤,稻田土壤在我国早期的土壤分类系统中也归为湿地族。近年来,国外对湿地研究十分活跃,从已有文献看其概念也欠确切,且因目的不同而有一定出入。例如在W.Z.Mitsh所著《湿地》一书中就引用了如下几种概念: 1.湿地系为浅水或间歇浅水层所淹没的低地,包括有植被着生的浅水湖区。2.水位接近或高于地表的土地,或者由于长期水分饱和形成的湿地,或者是具有水成土过程的土地,包括水成土以及适于水生植物     

无锡鼋头渚夜鹭体内重金属残留与分布特征

分析了太湖鼋头渚夜鹭幼鸟各组织样品中Cd、Pb、Cr、Hg、Se等重金属的残留水平,发现Cr与Se在各组织中的残留量相对较高,而Cd的残留量最低,从几种重金属在各组织中的分布特征来看,Pb和Cd在羽毛中残留水平最高,Se,Hg,Cr在肝脏中残留量最高,研究证实羽毛和肝脏是重金属富集的主要目标器官,而且Hg和Cd等重金属残留水平与Se含量有一定的相关性,同其它类似研究结果相比,该地区夜鹭体内的重金属污染水平尚未达到明显的致害浓度。     

New high-resolution mass spectrometric approach for the measurement of polychlorinated biphenyls and organochlorine pesticides in human serum

To increase our analytical throughput for measuring polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticides without sacrificing data quality, we have developed and validated a combined PCB/OC pesticide gas chromatography-high-resolution mass spectrometry (GC-HRMS) analysis. In a single GC-HRMS analysis, both selected PCBs and OC pesticides are detected and quantified. Previously, this has been difficult, if not impossible, because of the major difference in masses of the most abundant electron-impact ions. However, we have identified slightly less abundant ions to monitor that allow us to successfully combine these analytes into a single analysis without sacrificing any analytical sensitivity or instrument reliability. Consequently, we have been able to double our analytical throughput by modification of mass spectrometric parameters alone. Our new methodology has been validated against our current GC-HRMS method, which entails using two separate injections, one for PCB analysis and one for OC pesticide analysis. The two methods differ by less than 4% overall, with no systematic bias. We used this method to analyze approximately 350 serum samples over a period of several months. We found that our new method was as reliable in automated, overnight runs as our current method.     

Serum organochlorine pesticides residues and risk of cancer: A case-control study

Organochlorine pesticides (OCPs) are frequently used worldwide as insecticides, fungicides, herbicides and termiticides and have been associated with a variety of cancers in animal and human studies. In the present study, we examined residues of fourteen OCPs in the serum samples of diagnosed cancer patients and healthy residents of Karachi, Pakistan. A random collection of fasting blood samples was carried out from the donors with informed consent. Serum was separated within 2?h of blood collection and was then subjected to extraction with organic solvents followed by purification with florisil column. The final organic extract of each serum sample was processed with Gas Chromatograph coupled with Electron Capture Detector (GC-ECD). OCPs were detected in 97.59% of the cancer cases and 93.75% of the healthy subjects. Mean concentrations of total OCPs (ΣOCPs) was found elevated in the cancer group (0.606?mg/kg) compared with the control group (0.322?mg/kg). Endosulfan was the highest prevalent OCP with a mean concentration of 0.214?mg/kg in the cancer group and 0.166?mg/kg in the control group. The second most prevalent OCP was 4,4-DDE with a mean concentration of 0.131?mg/kg in the cancer group and 0.019?mg/kg in the control group. Highest level of ΣOCPs was detected in the breast cancer cases (20.411?mg/kg) with a mean level of (2.041?mg/kg). In light of the obtained results and available literature on the subject, it has been concluded that OCPs are positively associated with the risk of various cancers in humans.     

Improved sample preparation method for selected persistent organochlorine pollutants in human serum using solid-phase disk extraction with gas chromatographic analysis

An improved solid-phase extraction (SPE) method was developed to isolate and concentrate trace levels of selected POPs (persistent organochlorine pollutants) in human serum prior to GC–MS in SIM mode or GC–ECD quantitation. The extraction involves denaturation of serum proteins with formic acid, SPE using C₁₈ Empore™ disk cartridges, followed by elimination of lipid interferences using a sulfuric acid wash of the eluate. Use of the SPE disk improved assay throughput and gave a cleaner analytical matrix compared with previously reported solid-phase and liquid–liquid extraction techniques. The extraction method provided consistent recoveries at three fortification levels using ¹³C₁₂ PCB 149 as internal standard. Recoveries ranged from 48 to 140% for organochlorine pesticides (6.25, 12.5 and 25 ng/ml) and 71 to 126% for polychlorinated biphenyls (0.625, 1.25 and 2.5 ng/ml).     

Persistent organochlorine pesticides detected in blood and tissue samples of vultures from different localities in South Africa

Gaschromatography was used to establish the presence of quantifiable residues of 14 persistent chlorinated hydrocarbon pollutants in whole blood, clotted blood, heart, kidney, liver and muscle samples obtained from individual African whitebacked (Pseudogyps africanus), Cape griffon (Gyps coprotheres) and Lappetfaced (Torgos tracheliotos) vultures from different localities in South Africa. The levels of pesticides measured in whole blood samples of live specimens were compared between nestlings from two natural breeding colonies, adults from a wildlife area and birds held in captivity. Statistically significant (P<0.05) differences between populations were detected in geometric means calculated for γ-BHC (lindane), α(cis)-chlordane and α-endosulfan. Five of the organochlorine contaminants displayed significant variations between concentrations detected in the clotted blood, organs and muscles excised from vulture carcasses. This includes residues of γ-BHC, α-chlordane, dieldrin, β-endosulfan and heptachlor epoxide. Values of the respective biocides measured in vulture samples were generally low in comparison to results documented for a number of avian species. Although no threat is posed by any of the organochloride pesticides, continual monitoring of especially breeding colonies is recommended. Furthermore, the suitability of African whitebacked vulture nestlings as basic bioindicators is highly advocated.     

Historical deposition behaviors of organochlorine pesticides (OCPs) in the sediments of a shallow eutrophic lake in Eastern China: Roles of the sources and sedimentological conditions

Organochlorine pesticides (OCPs) were quantified in sediments from Lake Chaohu, a shallow eutrophic lake in Eastern China, to investigate their historical deposition behaviors and to reconstruct their use history. The OCP concentrations ranged from 2.17 to 18.61 ng g⁻¹ in the surface sediments in the lake region and from .28 to 86.27 ng g⁻¹ in the inflowing river. The highest values of the aforementioned variables were attributed to urban-industrial pollution sources in the west lake region and decreased with distance from the river inlets. Historically, OCP contamination displayed three stages in Lake Chaohu: an initial increase before the 1930s, a sharp increase until the 1980s, and a decrease due the implementation of policies banning their use in the 1980s. During the second stage, the OCP concentrations increased rapidly from .69, .58, 1.95 and .02 ng g⁻¹ in the C4, C5, C6 and C10 samples in the 1930s to 8.68, 61.89, 24.14 and 3.53 ng g⁻¹, respectively, in the early 1980s. This temporal trend of OCP concentrations corresponded with historically intense anthropogenic activities, indicating that contamination by OCPs was accompanied by industrialization and civilization prior to their prohibition. In addition, dichlorodiphenyltrichloroethane (DDT) contamination was derived from the historical use of technical DDTs, whereas hexachlorocyclohexane (BHC) contamination was attributed to the historical use of technical BHCs with Lindane and new inputs of illegal DDTs. Strong positive relationships between the OCP concentrations and the total organic carbon (TOC) concentrations, sediment grain sizes (<4 μm), nutrient contents and heavy metal contents indicated that the sedimentary conditions and human activities affected the depositional characteristics of the OCPs. The DDT residues and their metabolites, particularly those in the inlet rivers, should be of concern because they result in an ecotoxicological risk in the catchment of Lake Chaohu.     

长江下游地区夜鹭种群微卫星变异及遗传多样性

利用微卫星位点对长江下游地区夜鹭3个地方种群的遗传多样性及其种群结构进行了分析。研究结果表明:除了Ah526位点外,其他7个位点在夜鹭种群中均为高度多态。在3个地方种群中,6个微卫星位点中经Bonferroni校正后南京大校场种群和芜湖四褐山种群中分别有2个及3个位点显示杂合不足,显著偏离了哈迪-温伯平衡,这可能与夜鹭繁殖后个体的扩散能力较强及长江下游地区夜鹭存在着替代型迁徙现象有关。突变-漂移平衡分析表明,长江下游地区夜鹭种群显著具有杂合过剩的位点,这表明长江下游地区夜鹭种群已偏离了突变-漂移平衡,近期可能经历了瓶颈效应,种群数量曾经下降。地方种群间Fst分析表明,长江下游地区夜鹭地方种群间遗传分化程度较低,并没有形成显著的遗传结构,在保护与管理上可以作为同一个保护单元(或管理)单元     

巢湖表层水体中有机氯农药的分布及其组成

以固相萃取-气相色谱法/电子捕获检测器(SPE-GC/ECD)作为检测手段,对巢湖表层水体中有机氯农药(OCPs)的分布及组成特征进行分析.结果表明:研究区13个采样点中共检出包括六六六(HCHs)、滴滴涕(DDTs)、β-硫丹(β-Endosulfan)、艾氏剂(Aldrin)、六氯苯(hexachlorobenzene)和七氯(Heptachlor)在内的16种有机氯农药,其总含量范围为0.54～64.01ng.L-1;16种有机氯农药中以HCHs和DDTs为主,其平均质量浓度分别为5.56ng.L-1和16.57ng.L-1,约占其总量的84.75%;研究区的有机氯农药污染除了主要源于历史上农田中有机氯农药的残留外,近期可能还有新的农药污染源进入水环境;研究区所检出的各类有机氯农药均未超过国家地表水环境质量标准,巢湖表层水体中有机氯农药含量及潜在风险均属于中等偏低水平.     

Aquatic biota as potential biological indicators of the contamination,bioaccumulation and health risks caused by organochlorine pesticides in a large,shallow Chinese lake (Lake Chaohu)

Aquatic biota have long been recognized as bioindicators of the contamination caused by hydrophobic organic contaminants (HOCs) in aquatic environments. The primary purpose of the present study is to identify which species of aquatic biota are the most sensitive to organochlorine pesticides (OCPs) in Lake Chaohu and can therefore serve as indicators of the lake's health and assist in the assessment of OCPs risks to human health. OCP levels in eight species of aquatic biota were measured using GC–MS, and the relationships between the biota and OCP levels in the water and suspended solids were studied. DDTs pose potential human health risks and were the predominant OCP components found in the aquatic biota. DDT had the highest mean bioaccumulation factor (BAF) and biota suspended solids accumulation factor (BSSAF) of all of the studied OCP components. The food web magnification factors (FWMF) for p, p′-DDT were greater than 1, implying that biomagnification occurred. This finding indicates that DDTs still pose a serious threat to the ecosystem and human health in Lake Chaohu, even though the agricultural application of DDT powder has been officially banned since 1983. There were significant positive relationships between OCPs levels in Culter erythropterus and those in both water and suspended solids, as well as between OCPs levels in Protosalanx hyalocranius and those in suspended solids. This finding suggests that C. erythropterus and P. hyalocranius are the most sensitive aquatic biota to OCPs and may serve as the most effective bioindicators for monitoring OCP contamination in the water and suspended solids of Lake Chaohu. Megalobrama amblycephala, which contained the highest wet weight mean OCP concentration, is the most sensitive OCP indicator and can be used to assess the human carcinogenic risk of OCPs in Lake Chaohu.