海洋初级生产力的卫星遥感估算模型

海洋初级生产力估算在渔业资源管理、碳循环和全球变化研究中具有重要意义,准确的海洋初级生产力估算模型可直接为渔业生产和海洋管理提供决策支持,卫星遥感技术能够及时提供地表大尺度、动态的生态环境参数,因而在海洋初级生产力估算方面得到了广泛的应用.首先介绍了遥感估算海洋初级生产力的原理,对不同遥感模犁包括经验模型和基于生物机理的BPM模型、LPCM模型和VGPM模型等生理过程模型进行了比较分析.以渤黄海海域为研究区,利用MODIS/AQIJA卫星数据产品中的海表温度SST、离水辐射率Lw、海水漫射衰减系数.Kd490和海洋光合有效辐射PAR,计算出水柱的最大碳固定速率、真光层深度、遥感叶绿素浓度.选择全遥感数据驱动的生理过程模型VGPM,对渤黄海的初级生产力进行了估算和分析.结果表明:通过MODIS卫星数据基于VGPM模型估算的渤黄海海域的海洋初级生产力很好地揭示了海洋初级生产力在不同海区的分布和变化.整个渤黄海海区初级生产力的总体分布为从近海向外逐渐降低,其中渤海要较高一些,和前人调查比较一致.     

基于本土物种的3种典型化合物急性生态效应阈值研究

预测无效应浓度(PNEC)是进行风险污染物水生态安全管理的重要依据。本研究进行了3种典型化合物五氯酚、硝基苯和氯化镉对10种我国不同营养级水生生物的24 h、48 h和96 h的急性毒性测试,根据实验结果计算了相应的急性PNEC,同时与根据美国环境保护局毒性数据库里的毒性数据计算获得的急性PNEC值,以及综合本实验结果与毒性数据库里的数据计算得到的急性PNEC值进行对比,发现通过3种数据来源获得的急性PNEC值中,硝基苯的PNEC值差异较大,由本次实验结果获得的急性PNEC值最小;其他2种化合物差异较小。这可能是由于本次实验所选的本土生物中华田螺和麦穗鱼对硝基苯比较敏感,并且数据库中硝基苯的急性致死数据较少、毒性值较大且变化范围较窄,而其他2种化合物数据量较为丰富,变化范围较宽,包括了较敏感物种的毒性数据。这表明为给我国水生生物提供一个安全可靠的保护,对于数据量较为丰富并且毒性值变化较宽的化合物(如五氯酚和氯化镉)可以直接根据数据库里的毒性数据进行PNEC值的计算;而对于毒性数据量较少、毒性值偏大且变化较窄的化合物(如硝基苯)需要进行本土敏感物种的毒性测试。     

不同理论方程模拟华南桉树人工林蒸散量的比较

森林生态系统蒸散作为生态系统中的重要生态过程,联系着生态系统的水分平衡和能量平衡,并与养分循环密切相关.以雷州半岛桉树人工林纪家、河头林场为研究样地,在样地调查的基础上,对林地有关气象因子、土壤水文生态因子作了近4 a的定位观测.选取TURC公式、Penman-Monteith方程(PM)和周国逸公式作为代表,三者分别以温度为指标、以辐射与能量转换为驱动因子和以物理过程为主导的蒸散量理论计算方法.并将理论计算结果同水量平衡法估算结果进行比较.结果表明,尽管各种计算方法的结果均存在一定的波动性,但是其波动的原因是不一样的.对于PM方程而言,结果对所选参数有一定的依赖性.对于周国逸公式来说,在计算较小时间尺度(≤1 a)蒸散量时可能会出现一定的波动,波动的原因可能在于参数的时间尺度匹配问题.对于TURC公式,计算结果波动的根本原因在于其公式的经验局限性.理论计算值同水量平衡估算结果比较说明,三者均可以在一定程度上反映系统的年蒸散量.比较而言,周国逸公式计算结果的波动性范围较小,较适用于热带、亚热带森林生态系统蒸散量的计算.     

取代苯酚对人体外周血淋巴细胞的遗传毒性及定量结构关系

应用人体外周血淋巴细胞微核试验测定了29种取代苯酚类化合物的遗传毒性(72h-lgMN20),并对此类化合物的遗传毒性大小进行了分析比较,同时构建了遗传毒性与分子结构参数之间的QSAR 模型.结果表明,29种取代苯酚类化合物都显著地导致了微核的产生,具有明显的遗传毒性;遗传毒性大小与取代官能团及官能团位置存在一定的规律;遗传毒性的大小与分子结构参数溶剂连接性指数(X2SOL)、自由基信息参数(ICR)、零阶平均分子连接性指数(X0A)及修正指数(LOP)之间存在良好的结构-活性相关关系,所建模型的相关系数r2= 0.816,可以用于定量评估其它取代苯酚类化合物的遗传毒性.     

Vero细胞对2,4,6-三氯苯酚的毒性响应特征和敏感性分析

以2,4,6-三氯苯酚(2,4,6-trichlorophenol,TCP)为例,采用MTT比色实验和ANNEXIN V-FITC/PI双染色-流式细胞技术研究了Vero细胞对有机化学污染物的毒性响应特征和敏感性,以期发现一种灵敏、可靠的表征微量化学物质综合毒性的方法.研究结果表明:1)TCP浓度对Vero细胞的毒性响应特征有决定作用.低浓度TCP(≤0.5mg·L-1)即可使部分细胞从原有的刚性不规则三角形结构变为圆形或椭圆形,但细胞的生长未受明显抑制.TCP浓度在1~5mg·L-1时,细胞生长开始受到抑制,表现为细胞增殖受到抑制及部分细胞凋亡或死亡,但增殖抑制率和TCP浓度之间的关系不明显.当TCP浓度大于5mg·L-1时,细胞增殖明显受到抑制,且随TCP浓度的增加,细胞增殖抑制率逐渐升高.2)TCP作用时间对Vero细胞的毒性响应特征有显著影响.ANNEXIN V-FITC/PI双染色-流式细胞仪检测结果表明,TCP作用24h内Vero细胞毒性表现为以细胞膜的完整性受到损伤为主,凋亡或坏死细胞比例较小;而48h后,凋亡细胞的比例明显增加.细胞复壮实验结果进一步证实24h内形态发生变化的细胞并未完全坏死或凋亡.以上结果表明细胞形态变化和细胞膜损伤均为细胞毒性的早期表现特征,两者之间可能存在某种相关性,以此表征化学污染物的生物毒性具有较高的灵敏度,值得进一步研究.     

基于物种敏感性分布的保护海水水生生物的石油烃急性毒性基准研究

溢油污染对水生生物的危害以及分散剂使用对原油毒性的影响一直是溢油应急响应及危害评估时关注的焦点。本研究收集筛选了基于标准测试方法的90组急性毒性数据(LC50/EC50),其中37组毒性数据来自15种油品的水容纳组分(water accommodated fraction,WAF),53组来自11种化学分散剂与15种油品的分散液(chemically dispersed water accommodated fraction,CEWAF),应用物种敏感性分布(species sensitivity distribution,SSD)方法推导了基于水生生物保护的石油烃总量(total petroleum hydrocarbon,TPH)的急性毒性基准值,同时还分析了分散剂和不同暴露方式对原油毒性的影响。结果显示,以名义浓度(nominal concentrations)所表示的毒性结果可能高估分散剂对原油毒性的影响,基于CEWAF和WAF的LC50/EC50所推导的有害浓度(HC5s)差异较小,计算出的保护水生生物TPH急性毒性基准值为0.38 mg·L-1(TPH);鱼类对原油污染的响应明显敏感于甲壳类;同时证明了SSD方法在溢油毒性评估及风险阈值推导中具有可行性和合理性。     

MTBE与雌二醇对螺旋鱼腥藻的联合毒性

以螺旋鱼腥藻(Anabaena spiroides)为实验材料,采用每天测定数据,连续跟踪10d的方法,研究了甲基叔丁基醚(Methyl tert-buty1 ether,MTBE)与雌二醇对螺旋鱼腥藻的单一毒性以及在不同毒性单位配比下的联合毒性,选用毒性单位(TU)、相加指数(AI)、混合毒性指数(MTI)和毒性增大指数(TEI)进行联合毒性评价.结果表明,MTBE与雌二醇共存时,在实验周期(10d)内,其联合作用方式基本表现为协同作用.此外,MTBE和雌二醇的单一毒性和联合毒性数据随着培养时间的变化而产生剧烈变化,毒性数据在培养时间3～7d比较平稳,在4～5d最佳.     

有机磷农药对蛋白核小球藻的毒性相互作用研究

水体中农药复合污染产生的毒性效应具有潜在风险。为系统考察有机磷农药(OPs)混合物对淡水生态系统中绿藻的联合毒性效应,以马拉硫磷(MIT)、敌敌畏(DDVP)、敌百虫(TRC)、乐果(DIT)和氧乐果(OMT)等5种OPs作为混合物组分,运用直接均分射线法设计9组二元混合物体系共45条混合物射线。利用96孔微板测定5种OPs及其二元混合物对蛋白核小球藻(C. pyrenoidosa)的生长抑制毒性,通过基于置信区间的组合指数法分析混合物的联合毒性及毒性相互作用。结果表明,以p EC50为毒性指标,5种OPs对C. pyrenoidosa的毒性大小顺序为:TRCMITDDVPOMTDIT,OPs对C. pyrenoidosa的毒性大小受其中心磷原子的电正性影响;因混合组分的不同,部分OPs混合物对C. pyrenoidosa的联合毒性依赖于组分浓度比; OPs混合物对C. pyrenoidosa的毒性相互作用以加和为主,部分发生拮抗作用,发生拮抗作用的混合体系具有低效应区域呈加和作用,高效应区域呈拮抗作用的规律;与MIT混合的体系均有发生拮抗作用,且依赖于MIT浓度,MIT浓度比例越高,拮抗作用越强,OPs混合物的毒性相互作用与组分浓度比相关; OPs混合物的毒性相互作用组分浓度比依赖性与其联合毒性的组分浓度比依赖性规律不相关。     

生物炭早期植物毒性评估培养方法研究

为更加科学地评估生物炭潜在植物毒性,采用生物炭(B)、生物炭+土壤(B+S)、生物炭水浸提液+土壤(AE+S)、生物炭+石英砂(B+Q)、生物炭水浸提液+石英砂(AE+Q)5种不同的培养方法进行早期植物毒性效应实验。比较分析不同培养方法中西红柿种子发芽率、根长、芽长对生物炭的响应。结果表明:在5种培养方法中,随生物炭剂量增加,西红柿种子发芽率、根长、芽长呈现先增后降的变化趋势。虽在低剂量生物炭处理下(10.0 g·kg~(-1)),种子萌发表现出促进作用。但随剂量增加,除B+S和AE+S外,均表现出一定的抑制作用,且当剂量为160.0 g·kg~(-1)时,抑制作用达到最大。对比有土和无土培养方法中种子萌发情况发现,在高剂量下,无土培养方法中种子发芽率,根、芽生长所受抑制作用显著高于有土培养方法。无土方法中,尤其AE+Q方法中,高剂量生物炭对种子发芽率、根长、芽长表现出最大的抑制作用,其中发芽率抑制率为91.1%,根长抑制率为77.7%,芽长抑制率为93.7%。综合比较分析,生物炭水浸提液+石英砂(AE+Q)的培养方法干扰因子少,可提高毒性响应灵敏度。因此,在生物炭早期植物毒性效应评估中,该法可作为推荐的培养方法。     

三氯生对青海弧菌Q67和人乳腺癌细胞MCF-7的时间毒性

三氯生(triclosan,TCS)是一种广谱性抗菌剂,2005年欧盟水框架指令将TCS列为一种新型污染物。目前对TCS的研究局限于急性毒性实验,关于TCS毒性随时间的变化以及不同溶解状态下TCS的毒性差异的研究却鲜有报道。应用以96孔微板为暴露反应载体的微板毒性分析法,添加氢氧化钠(NaOH)或使用二甲亚砜(DMSO)作为助溶剂溶解TCS,分别测定其对青海弧菌Q67的相对发光抑制毒性(15min急性毒性和时间毒性)和对人乳腺癌细胞MCF-7在不同暴露时间(24、48和72h)内的细胞增殖抑制毒性。Q67的急性毒性实验结果表明,碱性条件下TCS的毒性(EC50=3.97(10-8mol.L-1)大于DMSO作为助溶剂时的毒性(EC50=1.68(10-4mol.L-1)。无论碱性条件还是DMSO助溶,TCS在不同暴露时间内对Q67的时间毒性没有明显差异。在不同暴露时间下MCF-7增殖抑制率实验中,DMSO作为助溶剂时,TCS的最高实验浓度为1.46(10-3mol.L-1,随着暴露时间的延长,抑制率在24、48和72h时分别为27.8%、44.2%和62.4%;碱性环境时TCS的最高实验浓度为1.39(10-6mol.L-1,随着暴露时间的延长,抑制率在24、48和72h时分别为20.2%、55.8%和73.9%。研究表明,在DMSO和NaOH作为助溶剂的条件下,TCS对MCF-7均存在时间毒性差异,并且NaOH碱性溶液中TCS对MCF-7的毒性远大于DMSO作为助溶剂时的毒性。     

5%阿维菌素乳油对台湾乳白蚁毒力测定的SPSS分析

台湾乳白蚁(Copotermes formosanus)是海南省危害房屋建筑最为严重的白蚁之一,为此研究防治药剂对台湾乳白蚁的毒力,减轻其对房屋建筑的危害将有重要意义。通过药膜法和毒土穿透法测定了5%阿维菌素乳油对台湾乳白蚁的毒力,用45%毒死蜱乳油做药剂对照,应用SPSS软件中的Probit模块,统计分析了5%阿维菌素乳油对台湾乳白蚁的毒力测定数据,从而得出毒力回归方程,LC_(50)、LC_(95)以及95%置信区间,对数单位与概率单位的关系图。结果表明:5%阿维菌素乳油防治台湾乳白蚁的最低有效浓度为15.625 mg·kg~(-1),与对照药剂45%毒死蜱乳油相近,其LC_(50)、LC_(95)分别为11.58和135.66 mg·kg~(-1)。由于阿维菌素对环境污染小,很可能会取代毒死蜱成为防治台湾乳白蚁的主要灭治药剂。     

An EM algorithm for capture-recapture estimation

Analysis of capture—recapture data often involves maximizing a complex likelihood function with many unknown parameters. Statistical inference based on selection of a proper model depends on successful attainment of this maximum. An EM algorithm is developed for obtaining maximum likelihood estimates of capture and survival probabilities conditional on first capture from standard capture—recapture data. The algorithm does not require the use of numerical derivatives which may improve precision and stability relative to other estimation schemes. The asymptotic covariance matrix of the estimated parameters can be obtained using the supplemented EM algorithm. The EM algorithm is compared to a more traditional Newton-Raphson algorithm with both a simulated and a real dataset. The two algorithms result in the same parameter estimates, but Newton-Raphson variance estimates depend on a numerically estimated Hessian matrix that is sensitive to step size choice.     

5种取代酚化合物对淡水发光菌的联合毒性

以新型淡水发光菌——青海弧菌Q67(Vibrio-qinghaiensissp.—Q67)为检验生物,以VeritasTM微孔板光度计为发光强度测试设备,分别测定了3,5-二羟基甲苯、2,3-二甲基苯酚、对氯苯酚、邻氯苯酚、2,4-二氯苯酚对淡水发光菌的发光抑制毒性及其混合物的联合毒性.结果表明,5种取代酚的剂量-效应关系都可用Weibull模型有效描述,从这些模型估算的半数效应浓度负对数值(-logEC50)分别为2.69、3.08、3.43、2.81和3.66,可知其对发光菌的毒性大小顺序为:2,4-二氯苯酚>对氯苯酚>2,3-二甲基苯酚>邻氯苯酚>3,5-二羟基甲苯.分别设计浓度等于各自之EC50和EC10的2个等效应浓度比混合物以及3个不同效应浓度比混合物进行联合毒性实验,结果发现,在所实验的浓度范围内各个混合物的剂量加和(DA)模型与独立作用(IA)模型具有相似的作用规律,其联合毒性既可用DA模型也可用IA模型进行预测.     

天津市温室气体排放匡算

以2008年天津市主要领域碳排放情况为基数,采用IPCC指南中的计算方法,选取IPCC指南明确的五大领域中,对天津市而言具有代表性的部分内容,对2008年天津市全市碳排放量进行匡算.匡算结果表明,能源活动(化石燃料燃烧)为天津市主要温室气体排放源,且其比例占据了主导地位.在能源活动中工业和发电行业排放的温室气体较大,分...     

Variances and variance estimators of the improved ratio estimators under adaptive cluster sampling

Although not design-unbiased, the ratio estimator is recognized as more efficient when a certain degree of correlation exists between the variable of primary interest and the auxiliary variable. Meanwhile, the Rao–Blackwell method is another commonly used procedure to improve estimation efficiency. Various improved ratio estimators under adaptive cluster sampling (ACS) that make use of the auxiliary information together with the Rao–Blackwellized univariate estimators have been proposed in past research studies. In this article, the variances and the associated variance estimators of these improved ratio estimators are proposed for a thorough framework of statistical inference under ACS. Performance of the proposed variance estimators is evaluated in terms of the absolute relative percentage bias and the empirical mean-squared error. As expected, results show that both the absolute relative percentage bias and the empirical mean-squared error decrease as the initial sample size increases for all the variance estimators. To evaluate the confidence intervals based on these variance estimators and the finite-population Central Limit Theorem, the coverage rate and the interval width are used. These confidence intervals suffer a disadvantage similar to that of the conventional ratio estimator. Hence, alternative confidence intervals based on a certain type of adjusted variance estimators are constructed and assessed in this article.     

Cu对我国17种典型土壤硝化速率的影响

硝化作用是对土壤重金属生物毒性最敏感的微生物过程之一.采用室内模拟的方法,研究了Cu对我国17种典型土壤潜在硝化速率(PNR)的影响.结果表明:随着添加Cu浓度的升高,17种土壤的PNR均呈阶梯状降低,Cu可显著抑制土壤硝化作用;17种土壤EC50值(使PNR降低至对照一半所需Cu浓度)在73.4~2164.4mg·kg-1之间;土壤EC50分别与土壤pH、Mg和Ca含量呈显著正相关关系(p<0.05,p<0.01);PNR(0原始土样的硝化速率)与土壤粘度(<2μm)、Al含量呈显著负相关关系(p<0.01),与pH呈显著正相关关系(p<0.01);EC50、PNR0与阳离子交换量、土壤Cu背景值相关性不大.     

Biomonitoring insecticide pollution using non-target soil microarthropods

The scope of biomonitoring insecticide pollution in soil is discussed with the help of field and laboratory findings on the density, prey-predator ratio and fecundity of non-target microarthropod fauna. Field experiments were conducted in small plots with mustard, wheat and lady's finger crops and insecticides namely heptachlor 20EC (3.25 kg ai/ha = 16.25 lit/ha) and endosulfan 35EC (0.875 kg ai/ha = 2.5 lit/ha) applied at the seedling stages. Soil microarthropod population estimated at fortnightly intervals in the treated and untreated control plots revealed a general trend of adverse effect of the insecticides, prominently on the density and relative abundance of major prey groups like Collembola and Acari leading to notable decline in prey-predator ratio. Comparison of the percentage reductions of major taxonomic and trophic groups between pre-treatment and post-treatment intervals also demonstrated the ill effect of both heptachlor and endosulfan, notably on Collembola and the prey category. In the laboratory the survival success and fecundity of Cyphoderus javanus (Collembola) and Archegozetes longisetosus (Acari) were compared by exposing freshly emerged adults to sub-lethal concentrations of heptachlor and endosulfan for varying durations. The untreated control sets recorded high fecundity for both C. javanus and A. longisetosus, but chronic toxicity of the insecticides on adults confined to the treated soil resulted into very low fecundity. Even short duration exposure to heptachlor and endosulfan treated soil for 24 or 72 hours only was found to delay the egg-laying and decrease the fecundity of both the species. It is concluded that population responses and reproductive sensitivity in non-target soil microarthropods are potential eco-toxicological parameters for detecting pesticide pollution in soil and for ecological health assessment since the results are based on the bioactivity of toxicants.     

Use made in marine ecology of methods for estimating demographic parameters from size/frequency data

Macdonald and Pitcher's method of decomposing a sizefrequency histogram into cohorts (mathematical optimization of the fit of the distribution function to the histogram) has been used to estimate the composition of random samples drawn from populations with known cohort structure. The large-sample behaviour of the method is in accordance with the results of asymptotic theory. With sample sizes typical of those used in many ecological studies, good estimates often could not be obtained without imposing constraints upon the estimation procedure, even when the number of age classes in the population was known. If the number of age classes was not known, it was frequently difficult to determine from small samples. When unconstrained solutions were obtainable, confidence limits about estimates were often very wide. Our results and information in the theoretical literature indicate that if the Petersen method (whereby several modes on a size-frequency histogram are taken to represent single age classes and all age classes to be present) does not work, accurate estimates of demographic parameters are unlikely to be obtainable using more rigorous methods. In view of these difficulties, we recommend that an iptimization method, such as that described by Macdonald and Pitcher, be used to estimate demographic parameters. Standard errors of estimates should be reported. Optimization methods give an indication when the data is inadequate to obtain accurate parameter estimates, either by failing to converge or by placing large standard errors about the estimates. Graphical methods do not give a clear warning of this, and should be avoided except where the modes on the size-frequency histogram are very well separated and sample sizes are large. Often, assumptions must be made about population parameters to enable their estimation. This may involve constraining some parameters to particular values, assuming a fixed relationship between cohort mean sizes and their standard deviations, or by assuming that individuals grow according to a von Bertalanffy curve. Any such assumptions need detailed justification in each case.     

Estimation of algal growth parameters from vertical primary production profiles

Phytoplankton maximum growth rate and the saturation light intensity, I_s, can be estimated from vertical profiles of primary production by non-linear least-squares estimation. Solution through the normal equations leads to formulae which are relatively simple and easy to implement. The computation of confidence contours is demonstrated, and the results are contrasted to the confidence limits on the parameters individually. These can be quite misleading due to model non-linearity and correlation between parameter estimation.The procedure has been applied to primary production data from Lake Balaton, a shallow lake in Hungary. The growth rate-temperature relation is analysed by separating the parameters into two groups characteristic for “warm” and “cold” water phytoplankton, respectively. A bell-shaped curve is found for “cold” water communities, with an optimum at about 7–9°C, whereas the “warm” water phytoplankton exhibits a strong exponential dependency in the temperature range of interest (up to 25°C). I_s also appears to be related to temperature except for the “cold” water group, where I_s is essentially constant. However, a roughly linear relation with considerably less scatter is obtained when I_s is plotted directly versus day-averaged solar radiation. This apparent fast adaptation is attributed to the extremely short turnover time in Lake Balaton. Maximum growth rates of 10–20 d^?1 have been found for temperatures between 20 and 25°C. These results and a critical appraisal of available literature suggest that the common notion of maximum growth rates being in the order of 1–3 d^?1 needs revision, at least for lakes with relatively high summer temperatures.     

有机锡化合物对水生无脊椎动物的毒性研究

通过不同层次水生无脊椎动物的毒理学研究，能更好地反映有机化合物的生态效应，以氯化三丁基锡（ＴＢＴＣｌ）为例，结果表明，ＴＢＴＣｌ对原生动物等５种水生无脊椎动物的半致死浓度（ＬＣ５０）为２５．６５－３５５．６３ｐｐｂ，有明显的种特异性，ＴＢＴＣｌ对河口轮虫种群净生殖率ＥＣ５０为１０ｐｐｂ，影响平均寿命ＥＣ５０为２２ｐｐｂ，根据浓度Ｃ及原生动物平衡种类数Ｓｅｑ进行回归，得方程Ｓｅｑ＝１１．８７－１．８