基于凤眼莲(Eichhirnia crassipes)原位修复的养殖水体水质变化特征及氮磷平衡估算

为研究凤眼莲(Eichhirnia crassipes)原位修复养殖水体的效能,在苏州市金庭镇大成现代农业园区选择了3个0.54 hm2的池塘开展现场试验,设置3个处理,分别是0(对照)、5％和10％的植物覆盖度.4月初投放鱼种,5月初投放凤眼莲种苗.4-11月每月采集水样并监测水中总氮(TN)、氨氮(NH4+-N)、...     

DDT对太湖大银鱼种群危害的生态风险

DDT作为难降解、高脂溶性的污染物,对湖泊水生生态有重要影响。该研究选择太湖大银鱼(Protosalanx hylocranius(Abbott))种群为研究对象,通过分析大银鱼在整个生命周期富集DDT的过程,结合相关的毒理学研究成果,分析DDT富集对大银鱼各生长阶段种群存活率的影响;并在此基础上,应用Lesile矩阵模型分析DDT富集对大银鱼种群规模的影响,研究结果表明,当太湖水体DDT浓度为9.3μg.L-1时,随着DDT在大银鱼体内的富集以及由此导致的毒性效应的影响,大银鱼种群规模在一个生命周期内减少6.39%,其影响较为显著。虽然具体的定量过程受到一些不确定性因素,如水体污染物浓度、剂量-反应关系等的影响,模拟准确度有待进一步提高,但本研究同样也为湖泊水生生态风险的细化提供了有益的尝试。     

流速对太湖铜绿微囊藻生长的影响

通过室内模拟试验研究了不同流速条件对太湖水中铜绿微囊藻生长的影响.结果表明:在温度为25 ℃、[光]照度为3 300 lx、光暗比为10 h: 14 h的条件下,流速在0～75 cm·s-1范围内,适合藻类生长的最佳流速条件为u=30 cm·s-1,当流速u＜30 cm·s-1或u＞30 cm·s-1时,藻类生长均受到不同程度的影响.尤其当流速u≥50 cm·s-1时,藻类生长受到明显限制,数量无明显增加.     

构建限制性条件下微生物群体生长模型时的问题

Logistic生长模型在表征营养限制性生长条件下微生物群体生长时,遇到了种种困难．该模型未能明确给出微生物群体生长的“延迟期”和“代时”两个重要生长动力学参数,也忽视了方程中参数“r”应为平均生长速率,且不具有内禀生长率性质等诸多生物学特点．采用E．coli ATCC31343,37℃液体摇瓶培养下获得的实验数据,证实了Logistic模型存在的上述局限性．通过对E．coli以葡萄糖和山梨醇共作碳源时,表现出的“二峰生长”曲线与用Logistic方程拟合结果的比较,表明适合度分析（goodness—fit test）不能作为模型是否适合的唯一判据．并对构建微生物群体生长模型的策略进行了讨论．图5参31     

青蒿毛状根分支生长的动力学模型

近年来，用m质粒转化药用植物诱导毛状根生产有用代谢产物的研究日益增多，转化产生的毛状根不仅生长迅速，分支多，而且遗传性和生理、生化特性稳定，具有较强的次生代谢合成能力，因此可望应用于大规模生产有用的次级代谢产物［‘－’］．青蒿毛状根可产生大量的次生代谢产物     

基于遥感技术的松辽平原盐渍化动态研究

运用.RS、GIS手段,以航天遥感MSS/TM/ETM为主要信息源,运用参数构造法、空间叠加分析法和网格等值线追踪法.对松辽平原盐渍化进行多时相遥感动态监测.研究结果表明.近30年来松辽平原盐渍化面积持续增加.强度持续增强.盐渍化面积变化总动态度为-1.03%,其中,1975-1989年为-1.67%,1989-2003年为-0.31%.盐渍化强度中心位于大安与乾安之间,1975-1989年,强度中心向北东方向移动22.81 km;1989-2003年,强度中心向西南方向移动16.50 km.松辽平原盐渍化是自然因素和不合理人类活动共同作用造成的.     

太湖围湖利用及网围养殖的遥感调查与分析

利用多期LandsatTM、LandsatETM 和航片从时间、空间和利用类型3个方面分析了太湖围湖利用、网围养殖的时空变化。结果表明:1984—2003年间太湖围湖利用面积为4.45km2,与20世纪50年代至70年代中期相比,围湖利用规模较小、速度较慢,围湖利用的主要类型是鱼塘养殖,主要分布在苏州市;太湖网围养殖增长迅速,尤其是1995年以后,1990年太湖网围养殖面积13.17km2,1995年为25.95km2,2003年为107.72km2,1995—2003年间网围养殖年增长速率是1990—1995年间年增长速率的4倍,太湖网围养殖主要分布在东太湖。     

太湖有色可溶性有机物4种光谱模型的对比

利用指数函数、幂函数等4种模型对太湖2006-2007年50个站点250个样本的有色可溶性有机物(CDOM)光谱吸收系数进行拟合,发现其他3种模型都比传统的取自然对数进行线性回归的模型拟合效果好.统计检验显示,幂函数模型的光谱拟合效果最好,平均决定系数为0.999 0,大于其他3种模型,而平均相对误差、均方根误差则小于其他3种模型.利用幂函数模型计算得到,在280～500 nm光谱范围内,CDOM吸收光谱斜率均值为(6.66±0.40) nm-1,变异系数6.08%,其频率基本上遵循正态分布.对于太湖CDOM吸收光谱斜率值,在空间分布上,梅梁湾显著小于大太湖开阔水域(P< 0.001);时间分布上,最大值出现在春季,最小值在秋季,夏季值小于冬季值.CDOM吸收光谱斜率与吸收系数呈显著负相关,相关性随波长增加而增强.     

基于遥感技术的生态保护红线保护成效评估——以肇庆市为例

对生态保护红线的保护成效进行动态评估是生态保护红线监管的一项重要基础工作.以肇庆市为例,利用遥感技术计算生态保护红线2000—2020年生态系统质量指数,通过分析生态系统质量指数的时空动态变化规律,对生态保护红线的保护成效进行科学评估.结果表明:1)利用遥感技术可便捷地对生态保护红线的生态系统质量进行科学、动态、定量的...     

A vertical-compressed three-dimensional ecological model in Lake Taihu, China

A three-dimensional ecological model on the basis of the analyses of environmental characteristics is set up for Lake Taihu, one of the largest shallow lakes in China. The hydrodynamic processes, nutrient cycling, chemical processes and biological processes are integrated in the model. Model state variables include: water current, surface displacement, nutrients of nitrogen and phosphorus, as well as their different forms such as ammonia nitrogen, nitrate nitrogen, phosphate phosphorus, etc., biomasses of macroplankton, phytoplankton, zooplankton and fish, and also the nutrient levels of macroplankton and phytoplankton. A nutrient budget and sediment transformation are also coupled in the model. The data from January 17, 1997 to January 18, 1998 are use to calibrate the model. The model results have shown good agreement with the observations. It implies that the model could be used for the lake environmental management and research for examining the processes and determining the water quality. The reasons of deviations between the modelled results and the observed values are also discussed. There are six factors that explain the deviations of the modelled results from the observed values and they can be grouped into two sets. One set of problems is associated with the standard deviation introduced by sampling and analyses. The second set of problems can be solved by introduction of processes lacking in the present model (resuspension, phytoplankton transportation mode under the wind with low speed, shifts in species composition and varied size of phytoplankton and zooplankton). The latter two processes should be included in the model at a later stage by integration of a structurally dynamic approach into the three-dimensional model.     

从上海市凤眼莲的生活史特征与繁殖策略探讨其控制对策

凤眼莲是上海地区水体中危害最严重的外来人侵种之一。通过对上海地区凤眼莲种群的连续监测，探究其生活史特征及其繁殖策略，结果表明，1）每年3～5月为凤眼莲的萌芽阶段，7月下旬为凤眼莲爆发起始时期，8～12月为凤眼莲爆发的高峰期，12月下旬凤眼莲开始枯萎死亡。但其腋芽能够存活越冬，是来年凤眼莲爆发的种源。2）上海地区凤眼莲主要以无性繁殖为主。导致该结果的内因是凤眼莲具有高的克隆生长潜力，外因是上海市水体富营养化严重。3）河道内其它水生植物的广泛分布是凤眼莲固着生长的主要机制，这些植物主要为：喜旱莲子草、菰、芦苇、牛筋草和千金子等。有鉴于此，根据上海市凤眼莲的生活史特征和繁殖策略，提出其综合防治对策为：1）最佳的打捞时期为12月至翌年6月，以去处种源为目标；2）清理河道内及堤岸上的水生杂草；3）开展生物防治的研究；4）加强与周边省份的协调合作。     

应用物种敏感性分布法分析太湖及天目湖水体的生态风险

采用物种敏感性分布法(SSDs法),应用水生生物急性和慢性毒性数据计算了31种污染物在水中和其中疏水物质在沉积物中的预测无效应浓度(PNECwater和PNECsed),通过收集以往报道的16种污染物在太湖和天目湖的环境浓度,用商值法求得物质的风险商并进行排序.结果发现:蒽、菲、萘、荧蒽、阿特拉津和马拉硫磷在太湖的梅梁湾和五里湖具有很大的生态风险;毒死蜱、三丁基锡氧化物和环己锡虽无环境浓度报道但很有可能具有风险.     

不同水力负荷下凤眼莲去除氮、磷效果比较

采用人工模拟方法,研究了不同水力负荷(0.14、0.20、0.33和1.00m3.m-2.d-1)对凤眼莲去除富营养化水体氮、磷效果的影响,试验期间进水TN、NH4+-N、NO3-N、TP平均质量浓度分别为4.85、1.33、2.92和0.50mg.L-1。结果表明,凤眼莲净化系统对富营养化水体具有较好的去除效果,低水力负荷(0.14、0.20m3.m-2.d-1)下,出水TN、NH4+-N和TP均达到了GB3838—2002《地表水环境质量标准》的Ⅳ类水质标准;当水力负荷提高到1.00m3.m-2.d-1后,出水TN、NH4+-N、NO3-N和TP质量浓度明显上升。4种水力负荷下,凤眼莲净化系统对TN和TP去除率分别为84.95%和80.65%、73.87%和73.04%、51.60%和64.05%、30.77%和47.79%,即随水力负荷的提高而降低;相应的TN、TP去除负荷分别为0.58和0.06、0.72和0.07、0.83和0.11、1.47和0.23g.m-2.d-1,即随水力负荷的提高而增加。综合考虑净化效果和污水处理能力,本试验条件下凤眼莲系统的水力负荷宜控制在0.33m3.m-2.d-1。     

太湖水体中5种有机磷农药混合物生态风险评价

有机磷农药是一类广泛分布于我国水环境中的污染物,即使在水体中的污染水平处于规定“安全标准”之下,其联合暴露产生的风险仍有可能威胁水生生态安全。采用基于浓度加和模型与生物敏感度分布曲线的混合物风险商法,评价了太湖水体中敌敌畏、对硫磷、甲基对硫磷、马拉硫磷和乐果5种有机磷农药混合物产生的生态风险。结果表明：2003～2004年期间3个不同时期太湖水体中5种有机磷农药的混合物生态风险商(RQ_m )均大于1,有机磷农药混合物在2003～2004年期间对太湖水生生物构成了一定威胁。     

普萘洛尔在太湖沉积物上的吸附特征

主要研究了pH、离子强度、腐殖酸和沉积物有机质对普萘洛尔在太湖沉积物上吸附行为的影响.结果表明,沉积物对普萘洛尔具有一定的吸附能力.在强酸环境下,由于H+与带正电荷的普萘洛尔之间的竞争作用使得普萘洛尔的吸附量较小,随着pH的增大,吸附量逐渐增大至基本稳定,但当pH＞9时,吸附量明显下降.K+、Na+和Ca2+的存在会减...     

Assessment of heavy metals in water,sediment, Anabas testudineus and Eichhornia crassipes in a former mining pond in Perak,Malaysia

The concentrations of Al, As, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Sn and Zn were analysed in water, sediment, muscle of climbing perch fish (Anabas testudineus), and tissue of water hyacinth plants (Eichhornia crassipes) collected from a former tin-mining pond in Perak, Malaysia. The monitoring was performed during the minimum and maximum rainfall periods. The concentrations of As, Cr, Fe, Ni, Pb and Zn in water exceeded the permissible limits set by the Interim National Water Quality Standards for Malaysia (INWQS). The risk index (RI) values determined for As, Cd, Cr, Cu, Hg, Pb and Zn in sediment presented a low degree of ecological risk. The order of the top three heavy metals measured in fish muscle was Zn?>?Fe?>?Al. The estimated daily intake (EDI) of As and Cr exceeded the allowable limits in both rainfall periods. The bioconcentration factor (BCF) and translocation factor (TF) values of Zn in water hyacinth were 24.865 and 3.214, respectively. The concentrations of Cu and Zn in the plant tissue were significantly correlated (p?<?.05) with the concentrations of heavy metals in water. Overall, climbing perch and water hyacinth are excellent bioindicators of environmental impacts on water bodies.     

A model on the carbon cycling in Lake Taihu, China

A model of the carbon cycling in Lake Taihu was developed based on the previous developed model EcoTaihu Model, which couples the hydrology, the nutrient cycling and a number of biological processes. The carbon cycling model (abbreviated CCM) has in addition to the states variables of the EcoTaihu Model, the carbon in phytoplankton, zooplankton, fish, macroplant, hydrogen carbonate carbon, carbonate carbon, dissolved carbon, abiotic organic carbon in water, organic carbon in sediment, soluble organic carbon in pore water, inorganic carbon in sediments, soluble inorganic carbon in pore water and pH. The calibration and validation of the CCM showed that the model results are in good accordance with the observations (from the period February17 to December. 5, 2003). It implies that the model can be used to assess the variation of the carbon dioxide flux at the water-air interface, and to find the pH value of the lake water as function of time. According to the model, the carbon dioxide flux at the water-air interface has clear, diurnal variations. Eutrophied water is a sink for the atmospheric carbon dioxide due to the phytosynthesis during the summer. Due to the terrestrial input of carbon to the lake, Lake Taihu is, however, a source of atmospheric carbon dioxide. The total annual flux is almost equal to the terrestrial input of carbon to the lake.