山东烟台市土壤中有机氯农药的残留及来源研究

烟台市表层土壤中DDTs(滴滴涕)、HCHs(六六六)有不同程度的检出,DDTs检出率34.59%,p,p′-DDE是主要残留物;HCHs检出率2%,δ-HCH含量最高。总体而言,HCHs残留量低于其它一些国家或地区,而DDTs残留量偏高。通过对α-HCH/γ-HCH、p,p′-DDD/p,p′-DDE和(p,p′-DDE+p,p′-DDD)/p,p′-DDT比值变化特征的研究,表明烟台市土地利用较多处于好氧环境中,大部分地段HCHs、DDTs农药使用时间较长,但局部土壤可能存在DDTs新的污染源,并对土壤质量产生较大影响,个别采样点有林丹被使用的可能性。分析认为,烟台市土壤中HCHs风险较低,但局部土壤DDTs仍有一定风险。     

1990—2009年中国大陆主汛期降水的变化特征及其可能原因

利用我国160个台站1951—2010年逐月降水观测资料,分析了我国1990—2009年夏季（6—8月）降水的变化特征,对其代表性雨型进行了分类,重点分析了1990年代和2000年代主要多雨带的变化特征。此外还分析了1990年代和2000年代的北半球500 hPa大尺度环流背景和气温及海温背景的差异,从而探讨了夏季降水...     

西北中等城市热岛效应变化特征——以天水市为例

为探索西北部中等城市的城市热岛效应规律,利用2004—2010年天水市城、郊自动气象站资料,对天水市城、郊温度差异进行了系统分析。结果表明:天水市城区热岛效应比较显著;冬季是热岛现象最强的季节,夏季是热岛现象最弱的季节;城区热岛现象持续时间为18:00—10:00,占全天的2/3,最大强度达1.5℃;城区凉岛持续时间为11:00—17:00,占全天的1/3,最大强度为0.3℃;地面温度城、郊差比气温更大,40cm以下城区地温全年大于郊区;降雪日及连阴雨天气的中后期,城区基本上维持凉岛;强降温天气下,城、郊气温变化基本一致,差别不大。     

象山港海域N、P和CODMn的变化趋势及其与富营养化的关系

根据近20多年来(1984～2005)象山港海域海洋环境监测的基础资料,建立象山港海域CODMn、DIN和PO4-P的时间序列,用平均差值法、最小二乘法和自回归滑动平均法3种趋势分析方法,统计检验了该海域CODMn、DIN和的PO4-P的长期变化趋势。并用相关分析和影响因子分析方法,分析了CODMn、DIN和的PO4-P年际波动与富营养化的关系。结果表明:近20多年来象山港海域DIN和PO4-P的年平均浓度长期以来均呈增加的趋势,而CODMn呈降低的趋势;象山港海域富营养状态指数E长期以来一直呈降低的趋势,这与CODMn相同,与DIN和PO4-P的变化趋势相反。CODMn的变化与富营养状态指数E呈显著的正相关,DIN和PO4-P的变化与富营养化状态指数E呈弱的正相关;CODMn,DIN和PO4-P对富营养装态指数E的影响因子分别为6.9822,2.2449和3.3836,CODMn对富营养状态指数E年际变化的贡献程度远大于DIN和PO4-P。当CODMn含量变化幅度较大的时候,海水营养状态指数E的变化不能真实反映海域营养盐的含量变化特征,富营养状态指数E在表征海水富营养化程度时存在一定的局限性,这也揭示了中国第Ⅰ代海水富营养化评价体系存在的问题。     

流域地表水体污染过程的时空差异及其影响机制分析:以温榆河中上游地区为例

以温榆河流域中上游地区作为研究区,通过2009年6～8月的地表水质监测,分析了水质的季节变化特征和空间差异.结果表明,温榆河上游与中游山前平原区的地表水体污染表现出明显不同的时空差异:①在温愉河上游山区,总氮、硝酸盐、氨氨及总有机碳在6～8月总体表现为先上升后下降的趋势,溶解氧及化学需氧量呈先下降后上升趋势;②在温榆河...     

Host intra-clutch variation,cuckoo egg matching and egg rejection by great reed warblers

Prevailing theory predicts that lower levels of intra-clutch variation in host eggs facilitate the detection of brood parasitism. We assessed egg matching using both human vision and UV-VIS spectrophotometry and then followed the nest fate of great reed warblers naturally parasitised by European cuckoos. Rejection was predicted by the following three variables: matching between cuckoo and host eggs on the main chromatic variable defined by principal components analysis of the egg spectra (which has a strong loading in the UV); the number of host eggs in the nest; and human estimates of intra-clutch variation. The first variable is not correlated to human estimates of matching, which do not predict rejection. In line with another recent study, rejection rates were predicted by higher levels of intra-clutch variation in the host eggs, suggesting that higher rather than lower levels of intra-clutch variation can facilitate the discrimination of cuckoo eggs by hosts. We suggest that the importance of intra-clutch variation is context dependent, with intra-clutch variation being important when there is good matching between the host and the cuckoo eggs. Our results also suggest that both spectrometric and human visual assessments of egg matching and intra-clutch variation are prudent: the former provide the best method of estimating reflectance variation, whereas the latter include some assessment of patterns of maculation.     

The attractiveness fragment—AFLP analysis of local adaptation and sexual selection in a caeliferan grasshopper, <Emphasis Type="Italic">Chorthippus biguttulus</Emphasis>

Genetic variability among males is a necessary precondition for the evolution of female choice based on indirect genetic benefits. In addition to mutations and host–parasite cycles, migration of locally adapted individuals offers an explanation for the maintenance of genetic variability. In a previous study, conducting a reciprocal transplant experiment on a grasshopper, Chorthippus biguttulus, we found that environmental conditions significantly influenced not only body condition but also an important trait of male calling song, the amplitude of song. Although not significant, all other analysed physical and courtship song traits and attractiveness were superior in native than in transferred males. Thus, we concluded that local adaptation has a slight but consistent influence on a range of traits in our study populations, including male acoustic attractiveness. In our present study, we scanned male grasshoppers from the same two populations for amplification fragment length polymorphism (AFLP) loci connected with acoustic attractiveness to conspecific females. We found greater differences in allele frequencies between the two populations, for some loci, than are expected from a balance between drift and gene flow. These loci are potentially connected with locally adapted traits. We examined whether these alleles show the proposed genotype environment interaction by having different associations with attractiveness in the two populations. One locus was significantly related to sexual attractiveness; however, this was independent of the males’ population affiliation. Future research on the evolution of female choice will benefit from knowledge of the underlying genetic architecture of male traits under intraspecific sexual selection, and the ‘population genomics’ approach can be a powerful tool for revealing this structure.     

Spatial and temporal variation of nitrogen exported by runo from sandy agricultural soils

The eutrophication problem has drawn attention to nutrient leaching from agricultural soils, and an understanding of spatial and temporal variability is needed to develop decision-making tools. Thus, eleven sites were selected to monitor, over a two-year period, spatial and temporal variation of runoff discharge and various forms of N in surface runoff in sandy agricultural soils. Factors influencing the variation of runoff discharge and various forms of N in surface runoff were analyzed. Variation of annual rainfall was small among 11 sites, especially between 2001 and 2002. However, variation of annual discharge was significant among the sites. The results suggest that rainfall patterns and land use had significant effect on discharge. The concentrations of total N, total kjeldahl N （TKN）, organic matter-associated N （OM-N）, NO3- -N, and NHn＋-N in the runoff ranged widely from 0.25 to 54.1, 0.15 to 20.3, 0.00 to 14.6, 0.00 to 45.3, and 0.00 to 19.7 mg/L, respectively. Spatial and temporal variations in the N concentration and runoff discharge were noted among the different sites. Annual loads of N in the runoff varied widely among monitoring sites and depend mainly on runoff discharge. High loads of total N, OM-N, NO3--N, and NHn＋-N in the runoff either in citrus groves or on vegetable farms occurred from June to October for each year, which coincided with the rainy season in the region. This study found that N in surface runoff was related to rainfall intensity, soil N level, and fertilizer use.     

三峡水库蓄水后不同水位期干流氮、磷时空分异特征

研究三峡水库蓄水前后营养盐的变化,对于探讨水库运行对其的影响并提出合理的管理建议具有重要意义.依据2008年3月～2009年2月对长江干流三峡区段朱沱、寸滩、扇沱、清溪场、晒网坝、培石,共6个断面和其中1个垂直断面逐月水文、水质监测,按照三峡水库运行的水位特点,将数据样本分成高水位(10～2月)和低水位(3～9月)2个...     

基于GIS的中国碳排放时空分布规律研究

利用美国橡树岭国家实验室二氧化碳信息分析中心公布的我国碳排放数据和各省的化石能源消费及水泥产量数据,对1980-2011年我国碳排放时空分布规律进行了研究.结果表明:全国及各省碳排放量呈现明显的阶段分布特征;各省碳排放量的区域差异呈现“高—低—高—低”的变化趋势;地均碳排放强度存在以低值集聚为主的正的空间自相关性,集聚趋势不断变化且在2006年后逐渐稳定;在0.05的显著性水平下,地均碳排放强度最终呈现北京、江苏和浙江的显著性“高—高”区,甘肃、青海、四川、新疆、宁夏和云南的显著性“低—低”区及大量不显著区稳定分布的特点.