Long-term change of the marine environment and plankton in the Xiamen Sea under the influence of climate change and human sewage

ABSTRACT

Long-term observations of the Xiamen Sea in Fujian Province were used to analyze variations in sea temperature, salinity, inorganic nitrogen (N), activated phosphate (P), and phytoplankton, as well as the features of red tides. Results showed that in recent decades, sea temperature and concentrations of N and P nutrients increased while salinity decreased attributed to climate warming, rainfall, and human sewage. In addition, reduction in the number of phytoplankton species and rising abundance of phytoplankton indicated that the structure of phytoplankton community presented a simplified and minimized trend which magnified the dominance of dominant phytoplankton species. Since 2000, red tides have occurred more frequently, and the eutrophic-type diatom species, Skeletonema costatum appears to be the predominant species. Data suggested that variations of N and P nutrients exert a potent and rapid influence on phytoplankton than sea temperature and ocean salinity.     

The predictive value of cytogenetic diagnosis after CVS based on 4860 cases with both direct and culture methods

Cytogenetic analysis was performed in 4860 chorionic villus samples by means of both direct preparation and long-term culture. The results of the analysis were compared with a classification including all theoretical types of combinations between the chromosomal constitution of the cytotrophoblast, extraembryonal mesoderm, and fetus, with the aim of evaluating the cytogenetic variability along the trophoblast—embryo axis. Eighteen of 29 possible combinations were found demonstrating a considerable heterogeneity. A mosaic conceptus was found in 1·5 per cent of cases, with generalized mosaicisms and confined mosaicisms in 0·2 and 1·3 per cent, respectively. Cytogenetic variability along the trophoblast—embryo axis was found in 1·42 per cent of cases. Results possibly leading to diagnostic errors (false-positive and false-negative results) were found in only 1·38 per cent. False-positive results of direct preparation were the most commonly observed discrepancy (0·8 per cent), while the incidence of false-positive results of the culture method and of both methods was 0·31 and 0·16 per cent respectively. The incidence of false-negative results was 0·1 per cent, with false-negative results of direct preparation 0·08 per cent and false-negative results of both methods 0·02 per cent. False-negative results of the culture method were not found. Our data confirm the high diagnostic accuracy of chorionic villus sampling and the utility of the combined use of the two methods in minimizing diagnostic errors and in reducing the need for follow-up amniocentesis.     

珠穆朗玛峰地区近200年冰芯草酸根记录及其环境意义

 1997年5月中美联合珠峰地区绒布冰川考察期间，在远东绒布冰川海拔6500m北支冰流粒雪盆内钻取到一支41m长冰芯.该冰芯定年至1814年．远东绒布冰芯中近200年来草酸根浓度变化与Ca²⁺和NH₄浓度变化一致性较差，表明草酸根的来源有别于大气尘埃和生物来源．草酸根浓度与冰芯中气温指标δ¹⁸O的变化具有一致性,说明气温是影响大气中草酸根浓度变化的因素之一，但非主导因素.远东绒布冰芯记录的20世纪以来草酸根浓度的迅速升高反映了人类工业活动对大气环境的污染．20世纪50～80年代，大气中受人类工业活动污染的草酸根浓度约为19世纪自然本底值的3倍，其中60年代人类活动排放的草酸盐类对大气的污染最为严重.     

The preserving of chorionic villi before establishing long-term cell cultures for cytogenetic analysis

The possibility of preserving intact chorionic villi in culture medium for up to 7 days before establishing long-term cultures for prenatal chromosome analysis is demonstrated. The preserving itself had no negative effect on the growth capacity of the mesenchymal cells.     

长期定位施肥对土壤微量元素含量的影响

在25年长期定位试验研究基础上,分析了无肥、N、NP、NPK、N 有机肥和N 秸秆6个不同施肥处理的0～20cm土壤微量元素B、Fe、Mn、Cu和Zn的质量分数变化。结果表明:不同施肥处理的土壤有效B和有效Zn均为增加,分别是试验基础数值的2.9倍～4.7倍和1.0倍～4.7倍。N 有机肥处理质量分数最高,无肥处理最低。有效Fe、Mn、Cu的质量分数除N 有机肥处理的Fe和Cu增加了0.95mg·kg-1和0.43mg·kg-1以外,都呈现出下降的趋势。各处理的土壤全量Fe呈减少趋势,全量Mn、Cu和Zn除无肥处理和Cu除单施N肥处理稍有减少以外,都呈现增加的趋势。全量Cu和Zn以N 有机肥处理质量分数最高,N 秸秆和施用P肥处理次之。施用以垃圾、畜禽废弃物为原料的有机肥以及施用P肥等可以增加土壤微量元素,施肥是影响土壤微量元素质量分数变化的重要因素。     

填埋场环境下HDPE膜老化特性及其对周边地下水污染风险的影响

为研究危险废物填埋场环境下防渗系统HDPE膜（高密度聚乙烯膜）材料老化规律及其对渗滤液产生、渗漏和区域地下水环境的影响,通过HDPE膜缺陷现场检测及室内老化性能测试,获取了HDPE膜初始缺陷特征参数（漏洞密度）和缺陷演化特征参数（老化起始时间和半衰期）,并以上述参数作为输入,综合运用HELP模型（填埋场水文过程评估模型）与Landsim模型（填埋场地下水污染风险模拟模型）对HDPE膜老化条件下的渗滤液产生、渗漏和地下水污染过程进行模拟预测.结果表明:①现场条件下HDPE膜在第2年开始老化,第8年达到半衰期.②HDPE膜老化导致漏洞数量和渗透系数增加,进而导致渗滤液渗漏量增加,地下水污染风险逐渐增加.短期（0~5 a）内,地下水超标概率为0,污染风险较小;中期（5~10 a）内,距离填埋场200 m内污染超标概率污染≥ 80%,污染风险较大,但400 m外的污染概率为0,污染风险较小;就长期（>10 a）而言,距离填埋场1 000 m处,污染超标概率达100%,地下水污染风险极大.填埋场现场条件下,防渗材料劣化及老化过程较实验室条件更为迅速,导致渗滤液长期渗漏、地下水污染风险加剧,因此建议加强填埋场设计和运行中HDPE膜抗老化研究,保障危险废物填埋场长期安全运行.      

不同施肥处理对棕壤N2O排放量的影响

采用田间试验研究不同施肥处理对棕壤N2O排放量的影响。结果表明,N2O释放量随着耕层土壤硝态氮含量增加而上升。不同施肥处理对N2O排放量影响不同,低氮处理(N1)排放量(整个玉米生育期按185d计算)为1.18kg·hm-2,高氮处理(N2)为2.39kg·hm-2。随着施氮量的增加,反硝化作用加强,N2O排放量上升,以N2O形式损失加剧。相同施氮水平条件下,随着有机肥施入量的增加土壤N2O排放量上升,其中以高氮高有机肥处理(M2N2)N2O排放量最高,达到了7.05kg·hm-2,占所投入氮肥的2.34%。相同氮素供应水平条件下增施磷、钾肥,也会增加N2O排放量。整个玉米生育时期通过N2O排放损失的肥料占投入氮肥比例为0.99%～2.46%。     

Long-Term Ecosystem Dynamics in the Serengeti: Lessons for Conservation

Abstract:  Data from long-term ecological studies further understanding of ecosystem dynamics and can guide evidence-based management. In a quasi-natural experiment we examined long-term monitoring data on different components of the Serengeti-Mara Ecosystem to trace the effects of disturbances and thus to elucidate cause-and-effect connections between them. The long-term data illustrated the role of food limitation in population regulation in mammals, particularly in migratory wildebeest and nonmigratory buffalo. Predation limited populations of smaller resident ungulates and small carnivores. Abiotic events, such as droughts and floods, created disturbances that affected survivorship of ungulates and birds. Such disturbances showed feedbacks between biotic and abiotic realms. Interactions between elephants and their food allowed savanna and grassland communities to co-occur. With increased woodland vegetation, predators' capture of prey increased. Anthropogenic disturbances had direct (hunting) and indirect (transfer of disease to wildlife) effects. Slow and rapid changes and multiple ecosystem states became apparent only over several decades and involved events at different spatial scales. Conservation efforts should accommodate both infrequent and unpredictable events and long-term trends. Management should plan on the time scale of those events and should not aim to maintain the status quo. Systems can be self-regulating through food availability and predator-prey interactions; thus, culling may not be required. Ecosystems can occur in multiple states; thus, there may be no a priori need to maintain one natural state. Finally, conservation efforts outside protected areas must distinguish between natural change and direct human-induced change. Protected areas can act as ecological baselines in which human-induced change is kept to a minimum     

Time Series Analysis to Monitor and Assess Water Resources: A Moving Average Approach

An understanding of the behavior of the groundwater body and its long-term trends are essential for making any management decision in a given watershed. Geostatistical methods can effectively be used to derive the long-term trends of the groundwater body. Here an attempt has been made to find out the long-term trends of the water table fluctuations of a river basin through a time series approach. The method was found to be useful for demarcating the zones of discharge and of recharge of an aquifer. The recharge of the aquifer is attributed to the return flow from applied irrigation. In the study area, farmers mainly depend on borewells for water and water is pumped from the deep aquifer indiscriminately. The recharge of the shallow aquifer implies excessive pumping of the deep aquifer. Necessary steps have to be taken immediately at appropriate levels to control the irrational pumping of deep aquifer groundwater, which is needed as a future water source. The study emphasizes the use of geostatistics for the better management of water resources and sustainable development of the area.