麻多高寒湿地冻结过程中土壤热通量变化特征分析

准确量化高寒湿地下垫面冻结过程中土壤热通量的变化特征,对认识高寒湿地—大气间水热交换过程有重要的科学意义。本文利用中国科学院麻多气候与环境综合观测站2014年5月至2015年5月的观测资料,分析了下垫面冻结过程中土壤热通量变化特征,探讨了冻结潜热对土壤热通量的贡献。基于温度积分计算土壤热通量的算法,指出在计算冻结过程中的土壤热通量时,需要同时考虑土壤热通量板以上的土壤热贮存及热通量板以上的冻结潜热。研究表明:（1）冻结锋面形成后,锋面所在深度土壤体积含水量迅速降低,锋面以下土壤热通量接近于零,土壤液态水开始冻结,冻结潜热向上穿过热通量板所在土壤层;降水下渗土壤后冻结所释放的潜热能使次日凌晨5 cm深度土壤热通量接近于零。（2）季节性冻结期,凌晨气温较高时穿过5 cm土壤层的向上土壤热通量很小,可能是由表层土壤发生了日冻融循环所致。土壤水释放的冻结潜热使土壤温度波动减弱并维持在冰点附近。高寒湿地下垫面仅在很浅的表层发生日冻融循环,无法通过5 cm土壤温度资料判断下垫面循环出现日期。（3）加入冻结潜热项,土壤热通量的计算值与实测值之间的均方根误差将会从11.5 W m-2下降到6.2 W m-2。以上研究结果对认识寒区陆面过程有重要的贡献。     

Geochemical Characteristics of Amino Acids in Sediments of Lake Taihu, A Large, Shallow, Eutrophic Freshwater Lake of China

To examine the biogeochemistry of amino acids (AAs) in the sediment of Lake Taihu, surface sediments (0–3 cm) and deeper sediments (18–21 cm) were collected at 21 sites from different ecotype zones of the lake. AAs were extracted from the sediments, and the total hydrolyzable amino acids (THAA) were determined by high-performance liquid chromatography instrument. The THAA contents in Taihu sediment were much lower than that in marine sediments, ranging from 6.84 to 38.24 μmol g⁻¹ in surface sediments and from 2.91 to 18.75 μmol g⁻¹ in deeper sediments in Taihu, respectively. AAs were a major fraction of the organic matter (OM) and organic nitrogen in Taihu sediments. The AAs on average contributed 8.2% of organic carbon (OC) and 25.0% of total nitrogen (TN) from surface sediments, and 5.9% of OC and 20.5% of TN in deeper sediments, respectively. AA composition provided very useful information about the degradation of OM. Glycine (Gly) and lysine (Lys) were the predominant forms of AAs in the sediments, irrespective of lake regions, followed by alanine, glutamic acid, serine (Ser), and aspartic acid (Asp). The high concentrations of Gly, Lys, and Ser suggested that these forms of AAs were relatively refractory during OM degradation in sediments. The relationship between the Asp/Gly ratio and Ser + Thr [mol%] indicated that OM in surface sediment was relatively fresher than that in deeper sediments. The AAs-based degradation index (DI) gave a similar conclusion. The composition and DI of AAs in surface sediments are markedly different across different zones in Taihu. The percentages of AAs to organic carbon (AA-C%) and total nitrogen (AA-N%) were higher in phytoplankton-dominated zones than those in macrophyte-dominated zones. These results suggest that DI could provide useful information about the degradation of OM in shallow lakes such as Taihu.     

Does a Kuznets curve apply to flood fatality? A holistic study for China and Japan

A Kuznets curve is the graphical representation of Simon Kuznets’ hypothesis that as a country develops, there is a natural cycle of economic inequality driven by market forces, which at first increase inequality and then decrease it after a certain average income is attained. The concept has been applied to environmental studies hypothesizing that the relationship between per capita income and the use of natural resources and/or the emission of wastes has an inverted-U shape. This paper presents a holistic study aimed at validating the applicability of the Kuznets curve to flood disaster. The focus is China and Japan. Both countries are prone to flooding and have experienced great economic growth. Data analysis detected the turning points of annual flood fatality in both countries, and the change in annual flood fatality with economic growth in both countries was found to match the Kuznets curve. However, the variation pattern of annual flood-caused economic loss was different between China and Japan. The difference may be partially attributed to the difference in residential characteristics between the two countries. Besides, it was found that climate change affected the flood-caused economic loss in Japan over recent decades. Furthermore, the variations in annual flood fatality and economic loss in the largest city of China were also analyzed.     

The research on division and correlation of stratigraphic sequence based on the “three instantaneous” attribute features of logging data

The stratigraphic division and correlation has important guiding significance to oil and gas field. This paper presents the application of Hilbert-Huang Transform to extract the “three instantaneous” attribute features of logging data (GR,AC) to perform the division and correlation of stratigraphic sequence, that is, the three properties of "instantaneous frequency", "instantaneous amplitude", "instantaneous phase" are extracted from logging data, which revealed the frequency characteristics of each depth of logging data and clearly reflected the structural characteristics of the frequency change. According to the oscillation anomalies of different attributes, we scale sequence boundaries, and use the variation characteristics of oscillation period of different frequency components attributes to scale the periodic characteristics of different scale sequence cycle, then use the “three instantaneous” attribute information for stratigraphic correlation, and for describing the internal features of formation. These attributes anomalies can be used to clearly find the different class interface of stratigraphic sequence, to achieve the sequence division at all levels, and under the control of sequence stratigraphic framework at all levels, we can do the isochronous stratigraphic correlation at all levels. The “three instantaneous” attribute extraction of logging data provides a new approach and idea for high resolution sequence stratigraphy analysis, and it has important significance for promoting the development of high-resolution sequence stratigraphy.     

�����ƴ��ˮ׼����Ϸ����������Է���

?????θ???????????С??GPS/?????????????????????????????????????????????????????????????????????????????????????????????澫???????????Ч????     

川西花岗- 伟晶岩型锂矿科学钻探：科学问题和科学意义

松潘-甘孜造山带是一条锂-铍-钽稀有元素超常富集的地带。针对锂矿资源上游勘探开发的瓶颈,实施川西锂矿3000m科学钻探,穿过变质岩、伟晶岩和花岗岩,建立多学科地壳锂柱。围绕"花岗-伟晶岩型锂矿的构造成因"、"与锂矿有关的花岗岩属性和成因类型"、"花岗岩与伟晶岩的关系及分异作用"、"稀有金属的"源-运-储-剥"过程"、"变形-变质-岩浆-成矿的造山过程:从热量耗损到锂的富集",以及"含稀有元素极端条件下微生物的特异性、多样性及与深度关系"等关键科学问题,实现为锂矿的找矿突破提供构造背景、制约要素、参考数据和科学依据,为找矿远景预测靶区提供科学标志,并力图建立创新性锂矿成因理论,具有重要的科学意义和应用价值。     

太湖蓝藻水华的年度情势预测方法探讨

在太湖、巢湖、滇池、洱海、三峡水库等我国重要湖泊和水库,蓝藻水华时常发生但年际之间藻情往往有较大差异,给蓝藻水华的防控物资及人员投入、湖库水源地水质安全保障带来较大的挑战,亟待探索周年尺度的蓝藻水华强度预测方法.本文收集了太湖连续15年的蓝藻水华情势观测数据和同步的气象、水文数据用于构建蓝藻水华预测模型,提出了利用遥感反演的蓝藻水华面积(A_(BL))及人工观测的水体浮游植物叶绿素α浓度([Chl.a]_(LB))共同表征的蓝藻水华强度指标(BI).分析了太湖年尺度的BI值与环境条件的关系,提出了基于年初能够掌握的气象、水文、营养盐等综合环境指标进行年度BI预测的统计模型.结果表明,太湖年度BI值与冬季及初春(12-3月)日均水温(WT_(12-3))、冬春季有效积温(AT_(12-3))、前一年降雨总量(RF_(YB))等环境因子呈显著正相关,与冬季及初春的水体总氮(TN_(12-3))、溶解性总氮(DTN_(12-3))、总磷(TP_(12-3))及溶解性总磷(DTP_(12-3))不存在统计上的显著相关关系.此外,本研究开展了基于上述因子(BI为因变量,其余环境因子为自变量)的多元(或一元)回归分析,并遴选出最优模型.总体而言,最优模型的模拟计算结果与实测浓度具有较高的一致性,因此本研究得出的模型对太湖蓝藻水华年际强度预测具有较高精度.本研究对太湖等富营养化湖库蓝藻水华的中长期预测具有指导意义.     

太湖水体磷浓度与赋存量长期变化(2005-2018年)及其对未来磷控制目标管理的启示

为揭示大型浅水湖泊水体磷浓度对湖泊外源负荷削减和生态系统变化的响应规律,指导富营养化湖泊水生态修复和管理实践,利用太湖湖泊生态系统研究站20052018年连续14年的太湖水体各形态磷浓度的月、季度调查数据,估算了太湖湖体各形态磷赋存量的季度变化,分析了太湖水体磷浓度受湖泊水位、水量、蓝藻水华态势(蓝藻总生物量及水华出现面积)等环境条件变化的影响特征.结果表明,在连续10年的全流域高投入污染治理背景下,太湖水体总磷浓度仍未发生显著下降,水体各形态磷浓度在年际、月际及空间上的变幅大,不同季节和不同湖区总磷浓度的时空差异性大于14年来总磷浓度年均值的差异性;全湖32个监测点上、中、下3层混合样水体总磷平均值为0.113 mg/L(n=1788),其中颗粒态磷浓度平均值为0.077 mg/L,是水体总磷的主要赋存形式,溶解性总磷浓度平均值为0.036 mg/L,其中反应性活性磷浓度平均值为0.015 mg/L,占总磷浓度的13%;太湖水体总磷的赋存量介于410~1098 t之间,56个季度的平均值为688 t,其中冬季(122月)、春季(35月)、夏季(68月)、秋季(911月)平均值分别为683、604、792和673 t,夏季湖体磷赋存量明显高于其他季节.统计分析表明,蓝藻水华态势和水情要素(水位)对水相总磷、颗粒态磷等主要形态磷的赋存量影响显著,蓝藻水华态势的影响可能大于水量变化的影响.本研究表明,在水体营养盐浓度仍然充分满足蓝藻水华发生的背景下,气象水文波动所造成的湖泊水华面积及生物量的变化及大型水生植被消长带来的内源交换变化能引起水体总磷浓度剧烈变化,太湖水体磷浓度的稳定控制也依赖于蓝藻水华态势的稳定控制,由于太湖当前的蓝藻水华态势受气象水文条件变化影响甚大,短期内太湖水相总磷浓度稳定控制到0.05 mg/L的水质治理目标较难实现.治理策略上,若要实现太湖水体磷浓度的进一步明显下降,一方面需要大幅度削减外源磷负荷,另一方面需要大面积恢复沉水植被等.管理策略上,由于湖体磷浓度变化包括了较大的非人为因素影响,应将太湖总磷治理目标考核重点放在流域磷减排强度、入湖负荷等方面,科学看待气候波动等非人为因素影响下的水相磷浓度波动.     

天目湖沙河水库水质对流域开发与保护的响应

利用长期水质监测资料,对苏南地区天目湖沙河水库十多年来的开发与保护工作的水库水质影响情况进行了分析.结果发现:大规模放养鳙鱼等不合理的渔业开发对水库硅藻、蓝藻等浮游植物异常增殖有较大的促进作用;在营养盐处于中富营养水平下,利用不同食性鱼类的组合调控,能够较快地抑制浮游植物的异常增殖,但当浮游植物生物量下降到一定程度以后,其控制能力下降,营养盐和气候因子的影响变得更为重要;流域的旅游开发和农业开发都对水库营养盐、透明度等水质指标产生较大影响,特别是坡地大规模茶叶种植等农业开发对水库氮的影响十分明显;春季少雨等气候变化因子对水库氮等营养盐浓度影响较大,但影响是短时段的.研究表明,合理调控水库渔业养殖,控制流域农业、旅游等开发活动强度,减少农业化肥施用量,恢复和扩大湿地等流域营养盐削减途径,是沙河水库水质保护的关键,也对同类水库水质保护具有示范价值.     

The nutrient forms, cycling and exchange flux in the sediment and overlying water system in lakes from the middle and lower reaches of Yangtze River

This paper is a review of research works concerning the nutrient transportation, transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and aluminium are rich in sediment because of the adsorption and flocculation. This means that the lakes have capability of eliminating the nutrient loadings. Investigations for the lakes from middle and down stream of Yangtze River have suggested that most lakes have the self-cleaning capability. Dredging the control of the internal loading, therefore, is only applicable to the small lakes or undisturbed bays which normally are situated nearby the city or town and rich in organic materials in the sediment. In addition, the strong reduction condition and weak aeration of these lakes and bays make these small lakes and bays release much more bio-available nutrient and without much self-eliminating capability. Moreover, eutrophication induced algal bloom in these lakes will change the pH of water, which further induces the increase in the nutrient release. In turn, the increase in nutrient release promotes the growth of phytoplankton and results in severe algal bloom. For the heavily polluted water, research suggests that the biomass of bacteria and alkaline phosphatase activity will be higher corresponding to the higher concentration of nutrients, which accelerates the nutrient recycling between water, sediment and biota. Quick recycling of nutrient, in turn, promotes the production and biomass growth of microorganism and leads to more severe eutrophication. Further research work should focus on the nutrient transformation mechanism and the effects of microbial loop on the eutrophication.