Iron speciation of sediments from Kuhai Lake in China by Mössbauer spectroscopy

The vertical distribution of iron species in the sediments collected from Kuhai Lake was investigated in this study. Their Mössbauer spectra were composed of one sextet and four doublets ascribable to one paramagnetic high-spin Fe³⁺, two paramagnetic high-spin Fe²⁺ with different quadrupole splittings, and one diamagnetic low-spin Fe²⁺ that corresponds to pyrite (FeS₂). The distribution of pyrite was considered to reflect the climatic change during the past 2,000 years. Mössbauer spectroscopy was successfully applied to the analysis of the Kuhai Lake sediments so as to reconstruct the history of the past climate.     

基于突变级数法的千岛湖流域生态安全评价

针对千岛湖流域生态系统退化、生态安全受到威胁的现状,对千岛湖流域生态安全进行了综合评价,以识别影响流域生态安全的主要因素.研究引入了基于突变理论的多准则评价方法--突变级数法,基于压力 状态 响应(PSR)模型构建了由15个相关指标组成的评价指标体系,对千岛湖流域2008~2011年间的生态安全进行了全面评估.评估结果表明,2008~2011年间,千岛湖流域生态安全2010年达到较安全级别,其他年份均处于基本安全的级别.相对而言,压力系统的安全度最低,状态系统安全度最佳.研究结果表明,虽然目前千岛湖流域生态安全状况较好,但总体状况、压力和响应指标都显示出下降的趋势,说明千岛湖面临着较大的安全压力.      

太湖水面多角度遥感反射率光谱测量与方向特性分析

水体光场不是各向同性的,其方向性分布规律的研究对于水质参数遥感反演建模具有十分重要的意义。大洋水体光场的二向性研究已经相对比较成熟,而内陆水体光场的二向性分布规律研究仍存在许多问题。水面原位多角度光谱测量数据是分析水体光场二向性的重要依据,但是目前国际上还缺少相关测量设备。设计并制作了一种能够在野外原位测量水面光场二向性的多角度水面光谱测量杆,它可以配合光谱仪测量多个角度的水面遥感反射率光谱。利用该设备在太湖开展了一次水面多角度光谱测量实验,利用该实验获取的数据分析了太湖水面遥感反射率光谱的方向性分布规律, 进而给出了能够降低方向性影响的水质参数遥感反演建模策略。     

千岛湖次生林优势种幼苗光合特性及其对群落演替的指示意义

利用LCA-4型便携式全自动光合测定仪,于2009年8月下旬晴朗天气,对千岛湖次生林优势种马尾松（Pinus massoniana）、苦槠（Castanopsis sclerophylla）、石栎（Lithocarpus glabra）、青冈（Cyclobalanopsis glauca）幼苗在林窗、林下2种生境中的光合生理生态特性进行了研究.结果表明：（1）在林窗中马尾松光合日进程为＂单峰＂曲线,其他3种均为＂双峰＂曲线,有明显光合＂午休＂现象.在林下这4种幼苗的光合日进程均为＂单峰＂曲线,但曲线平缓,峰值不明显.在林窗中青冈的日均Pn显著低于其他3物种,而在林下马尾松的日均Pn显著低于其余3物种.4个优势种的日均Pn在2种生境中均差异显著.（2）LCP、LSP、Amax、Rd均是马尾松最高,苦槠次之,青冈、石栎较低;青冈、石栎的AQY显著高于马尾松和苦槠,苦槠的AQY也显著高于马尾松.（3）在林窗中,青冈Fm最高,与其他3种均差异显著;Fv/Fm为马尾松最高,显著高于其他3物种.这说明马尾松属强阳性树种,苦槠为阳性树种,青冈和石栎具有较强的耐荫性,随着进展演替,群落郁闭度的增大,马尾松、苦槠将逐渐退出群落,而青冈和石栎将成为群落演替顶极阶段的优势种.     

鄱阳湖流域沉积物中有机氯农药的残留特征及风险评估

采用GC/ECD分析了鄱阳湖流域沉积物中有机氯农药的残留特征及生态风险,结果表明:所测样品中有机氯农药浓度范围为1.22～32.19 ng/g,其中,六六六(HCHs)、滴滴涕(DDTs)、六氯苯(HCB)在几乎所有采样点都有检出,含量分别是未检出～12.95 ng/g、0.75～12.57ng/g、未检出～10.8.所测样品中大部分W_(DDT)/(W_(DDE)+W_(DDD))>1,表明有新的DDT输入,HCHs主要为长时间降解后的农药残留.鄱阳湖流域沉积物中DDT、DDD和DDE含量绝大部分小于风险评估中值(ERM),但接近一半介于风险评估低值(ERL)和ERM之间,而且有一个点大于ERM,表明其生态风险大多介于10%～50%,但有一个点的生态风险大于50%.     

鄱阳湖黄鳝体内鳗鲡独孤吸虫季节动态与种群分布

通过对鄱阳湖黄鳝体内鳗鲡独孤吸虫感染情况的调查,结果发现在799尾黄鳝中,有101尾黄鳝的消化道中发现有吸虫感染,感染率为12.64%,丰盛度为3.33±1.71。不同月份之间黄鳝体内鳗鲡孤独吸虫的感染率存在显著的差异(G=144.968>x02.005=18.548,df=6,P<0.005);其中5月份的感染率与丰     

基于定量遥感反演的内陆水体藻类监测

叶绿素作为衡量湖泊富营养化的重要指标,利用遥感技术对其进行实时动态监测具有重要意义。以太湖为例,通过对水体实测光谱和水质采样数据的分析,建立了光谱反射率比值与叶绿素a浓度的回归模型。结果显示,700 nm附近波段与625 nm附近波段所构建的比值模型R2最高,710 nm以后波段与其他可见光波段所构建的比值模型的R2会随可见光波长的增大而逐渐下降。在高光谱遥感估算模型的基础上,应用同步MODIS卫星遥感数据进行了太湖叶绿素a浓度的空间分布反演,并基于MODIS绿度指数建立了太湖藻华水体信息提取模型,从叶绿素a浓度估算和藻华信息提取两个方面实现了太湖藻类空间分布特征的定量反演,为太湖等大型内陆水体藻类的实时定量遥感监测提供了新的研究思路。     

鄱阳湖生态经济区生猪绿色供应链利益分配

基于低碳经济的视角,建立鄱阳湖生态经济区生猪绿色供应链;基于供应链物流与价值流分析,构建生猪供应链各节点利益分配模型;通过对鄱阳湖生态经济区内38个县市区生猪市场、饲料市场及猪肉市场的实地调研和跟踪调查,分析鄱阳湖生态经济区生猪市场的现状以及存在问题;结合构建的     

金华仙源湖水利旅游区的主题确立和景观设计

鉴于金华仙源湖水利旅游区区内自然山水旅游资源的局限,在开发中我们转面以更广大的区域为背景,寻找山水自然风光与深邃文化意蕴密切结合的途径,大胆引入新的文化因素,确立了以中国古典文学样式的代表之一“词文化”为主线的高品位文化主题;再围绕这一主题进行景观设计,赋自然山水以词情画意,取得了较好效果。     

Effects of freeze-drying on partitioning patterns of major elements and trace metals in lake sediments

The effect of freeze-drying on elemental partitioning pattern in four lake sediments was evaluated using the sequential extraction method developed under the auspices of Community Bureau of Reference (BCR) of the Commission of European Communities. Redox-sensitive elements like iron, manganese, phosphorus, and sulfur were analyzed simultaneously with several trace metals. This allows a qualitative determination of which trace metal-scavenging phases commonly found in freshwater sediments that are most susceptible to freeze-drying.The comparison of a surface layer and a deeper more reduced layer collected from four sediment cores ranging from sub-oxic to anoxic condition indicate the changes in partitioning pattern due to freeze-drying. Two of the lakes exhibiting clearly reduced environments are most affected by freeze-drying in terms of change in partitioning patterns. However, this effect is element specific and varies with sediment depth along the redox gradient. Elements commonly associated with a sulfide phase (S, Fe, Cu, Zn, and Pb) and extracted in BCR step 3 are the most affected elements, but at the same time also dependent on the organic matter content in the sediment. Si and Al that are often considered as conservative elements show a shift from step 3 to step 2, and it is interpreted as a release of Si and Al from organic matter and the subsequent formation of oxides during freeze-drying. Calcium and manganese, elements that are often associated with a carbonate phase, do not seem to be severely affected by this kind of treatment. Carbonate-associated iron (operationally defined), however does show a clear tendency to oxidize during the freeze-drying process. In fact, the shift in iron (carbonate to oxide fraction) corresponds to 3-4% (w/w) of the total sediment in some cases. Surprisingly, a significant fraction of iron originally extracted in step 1 (as “carbonate”) seems to be immobilized during freeze-drying.These results clearly show that freeze-drying does not preserve the speciation pattern of major elements, trace metals, phosphorus, and sulfur in anoxic lake sediment core sections during storage prior to BCR sequential extraction procedures.