云南省泸沽湖、洱海现代沉积物中210Pb,137Cs的垂直分布及其计年

云南省泸沽湖,洱海＾２１０Ｐｂｅｘ的垂直分布受Ｆｅ,Ｍｎ循环下＾２１０Ｐ;ｏ和＾２１０Ｐｂ沉积后再迁移的影响,分别表现为三种不同的剖面分布特征,＾２１０Ｐｂｅｘ计年的没积物堆积速率分别为０．０５０－０．０５１ｇ．ｃｍ＾－２ａ＾－１和０．０４４－０．０４６ｇ．ｃｍ＾－２ａ＾－１,反映百年时间尺度上的堆积结果,泸沽湖,洱海＾１３７Ｃｓ的垂直剖面分布虽然受分子扩散作用的影响,并没有改变其峰值位置。     

武汉后湖湖球蚬的周年生产量

采用体长频率法和瞬时生长率法对后湖湖球蚬Sphaerium lacustre的周年生产量进行了测算. 结果表明两种方法得到的生产量较为吻合.生产量的带壳湿重和去壳干重分别是体长频率法1.048 g/(m2a) 0.0599 g/(m2a); 瞬时生长率法1.178 g/(m2a), 0.0673 g/(m2a).对应的P/B系数为3.23.4.     

丽江7.0级地震前后滇西实验场的重力异常变化特征

１９９６年２月３日，在云南省西北部的丽江县境内发生了一次Ｍｓ７．０级强烈地震。此次地震前后滇西实验场重力网共进行２７期流动重力观测，其重力变化的总体特征为：１．震中附近地区的丽江－剑川－洱源－带震前为下降变化，下降变化的幅值平均约３０×１０＾－８ｍｓ＾－２左右，震后重力变化继续下降；２．距震中稍远一点的渡口附近地区震前为持续上升变大，累计上升变化的最大幅值达１２３×＾－８ｍｓ＾－２，震后重力变化下     

断层崖形成年代的数学模拟计算

本文在对物质扩散方程进一步推导基础上，分别用数学方程模型Ⅰ、Ⅱ、Ⅲ对发育在昌马断裂带中，东段的单一型地震断层崖和复合型地震断层崖剖面进行了拟合计算，并用最大坡值－断距（ｔｇθｓ－２ａ）图分析了阿尔金断裂带和昌马断裂带上分布的离散型断层崖。结果求得：昌马断裂带断层崖的物质扩散系统数Ｋ值为２．１～３．４Ｍ＾２／１０＾３ａ阿尔金断裂带上发育有４组距今年龄分别为０．６Ｋａ，２－２．７Ｋａ，４Ｋａ和６－６６     

武汉后湖长角涵螺的周年生产量

采用两种方法对后湖长角涵螺(Alocinma longicornis)的周年生产量进行了测算,结果表明,两种方法得到的生产量较为吻合.生产量的带壳湿重和去壳干重分别是:体长频率法,2.22 g/(m2·a),0.111 g/(m2·a);瞬时生长率法,2.177 g/(m2·a),0.109 g/(m2·a).对应的P/B系数为4.0,5.4.     

百草枯和H2O2预处理提高盐泽螺旋藻对铅的耐受性

用１０μｍｏｌ．Ｌ＾－１的百草枯（Ｐａｒａｑｕａｔ）和２ｍｍｏｌ．Ｌ＾－１的Ｈ２Ｏ２对盐泽螺旋藻（Ｓｐｉｒｕｌｉｎａ ｓｕｂｓａｌｓａ）作预处理,以诱导提高藻细胞内超氧物歧化酶（ＳＯＤ）,过氧化氢酶（ＣＡＴ）和过氧化物酶（ＰＯＤ）的活性,随后用４０ｍｇ．Ｌ＾－１的Ｐｂ＾２＋进行肋迫试验,实验结果表明,预处理组的藻细胞生长量和光合速率的下降幅度明显较未预处理组小;预处理组的ＳＯＤ、ＣＡＴ活性虽有衰减     

岩溶系统土壤吸释CO2作用及其环境意义——以桂林丫吉村岩溶？…

野外监测土壤ＣＯ２释放结果表明,土壤ＣＯ２释放量晴天高于雨天,洼地,垭口土壤ＣＯ２释放量高于坡地土壤ＣＯ２释放量,试验场土壤ＣＯ２年释放量在１０５７．８ｔ（１．７６３ｋｇｍ＾－２）与５５２．６ｔ（０．９２１ｋｇｍ＾－２）之间,估算值为８１０．０ｔ（１．３５ｋｇｍ＾－２）。野外溶蚀试验结果表明,试验场岩土作用过程年吸收ＣＯ２量为１３．０８ｔ,岩溶系统年吸收ＣＯ２量为６１．７３ｔ。土壤温室气体（ＣＯ２     

不同培养条件下多刺裸腹溞的生殖和种群增长参数

于 １９９６年在实验室对多刺探腹溞（Ｍｂｉｎａ　ｍａｃｒｏｃｏｐａ）种群的增长率及相关生态学参数进行了研究．结果表明,３个温度梯度（２４、２８和３２℃）和３个面包酵母（Ｓａｃｃｈａｒｏｍｙｃｅｓ　ｃｅｒｅｖｉｓｉ－ａｅ）密度（０．２５、２ ５和２５ ｘ １０_６ｃｅｌｌ．ｍＬ~（－１）下,以２８℃时内禀增长力（ｒ_ｍ）最高;２８℃时,面包酵母的投喂密度为２５×１０_６ｃｅｌｌ．ｍＬ_（－１）时,其ｒ_ｍ最大．温度２８℃,面包酵母密度为２５×１０_６ｃｅｌｌ．ｍＬ~（－１）时,该溞的繁殖前期最短,繁殖期和寿命均最长,并且怀卵量（每窝产仔数）最大．该溞的种群密度和瞬时增长率分别在接种后第７ｄ和第３－４ｄ达高峰．该搔批量培养时采收时间以第５ｄ为宜．     

江西红山隐爆角砾岩—斑岩型铜矿床的成因

红山铜矿成矿流体δＤ在－５２．７‰－－８７．８‰,‰δ＾１８ＯＨ２ｏ在＋１‰－＋６‰,δ＾３４ＳＨ２Ｓ在０－２．５‰之间。矿石铜同位素表明铅主要来自岩浆岩,两阶段模式计算出第一阶段比值为４．２１,第二阶为３．８２±０．１１。     

太湖水体中碱性磷酸酶的作用阈值

对不同ＰＯ＾３－４－Ｐ浓度下,不同粒级组分中碱性磷酸酶活性的分布及其变动规律的研究表明：（１）随着水体中ＰＯ＾３－４－Ｐ浓度的增加,水体中总碱性磷酸酶活性（ＴＡＰＡ）相应的减少（ｒ＝－０．５８６,ｎ＝５５）,水体中的ＴＡＰＡ增值,在ＰＯ＾３－４－Ｐ浓度范围为０－０．０１０ｍｇ．Ｌ＾－１,无显著差异;而当ＰＯ＾ ３－４－Ｐ浓度〉０．０１０ｍｇ．Ｌ＾－１时,差异极显著（Ｐ〈０．０１）,（２）水体中的碱     

Soil respiration in tropical seasonal rain forest in Xishuangbanna, SW China

With the static opaque chamber and gas chromatography technique, from January 2003 to January 2004 soil respiration was investigated in a tropical seasonal rain forest in Xishuangbanna, SW China. In this study three treatments were applied, each with three replicates: A (bare soil), B (soil+litter), and C (soil+litter+seedling). The results showed that soil respiration varied seasonally, low from December 2003 to February 2004, and high from June to July 2004. The annual average values of CO2 efflux from soil respiration differed among the treatments at 1% level, with the rank of C (14642 mgCO2· m-2. h-1)＞B (12807 mgCO2· m-2. h-1)＞A (9532 mgCO2· m-2. h-1). Diurnal variation in soil respiration was not apparent due to little diurnal temperate change in Xishuangbanna. There was a parabola relationship between soil respiration and soil moisture at 1% level. Soil respiration rates were higher when soil moisture ranged from 35% to 45%. There was an exponential relationship between soil respiration and soil temperature (at a depth of 5cm in mineral soil) at 1% level. The calculated Q1o values in this study,ranging from 2.03 to 2.36, were very near to those of tropical soil reported. The CO2 efflux in 2003was 5.34 kgCO2· m-2. a-1 from soil plus litter plus seedling, of them 3.48 kgCO2· m-2. a-1 from soil (accounting for 62.5%), 1.19 kgCO2· m-2. a-1 from litter (22.3%) and 0.67 kgCO2·m-2. a-1 from seedling (12.5%).     

Soil organic carbon storage and soil CO_2 flux in the alpine meadow ecosystem

High-resolution sampling,measurements of organic carbon contents and 14C signatures of selected four soil profiles in the Haibei Station situated on the northeast Tibetan Plateau,and application of 14C tracing technology were conducted in an attempt to investigate the turnover times of soil organic car-bon and the soil-CO2 flux in the alpine meadow ecosystem. The results show that the organic carbon stored in the soils varies from 22.12×104 kg C hm-2 to 30.75×104 kg C hm-2 in the alpine meadow eco-systems,with an average of 26.86×104 kg C hm-2. Turnover times of organic carbon pools increase with depth from 45 a to 73 a in the surface soil horizon to hundreds of years or millennia or even longer at the deep soil horizons in the alpine meadow ecosystems. The soil-CO2 flux ranges from 103.24 g C m-2 a-1 to 254.93 gC m-2 a-1,with an average of 191.23 g C m-2 a-1. The CO2 efflux produced from microbial decomposition of organic matter varies from 73.3 g C m-2 a-1 to 181 g C m-2 a-1. More than 30% of total soil organic carbon resides in the active carbon pool and 72.8%―81.23% of total CO2 emitted from or-ganic matter decomposition results from the topsoil horizon (from 0 cm to 10 cm) for the Kobresia meadow. Responding to global warming,the storage,volume of flow and fate of the soil organic carbon in the alpine meadow ecosystem of the Tibetan Plateau will be changed,which needs further research.     

Effects of different gap filling methods and land surface energy balance closure on annual net ecosystem exchange in a semiarid area of China

Based on eddy covariance measurements over two kinds of land surfaces(a degraded grassland and a maize cropland)in a semiarid area of China in 2005 and 2008,the effects of different gap filling methods,energy balance closure and friction velocity threshold(u*)on annual net ecosystem exchange(NEE)were analyzed.Six gap filling methods,including mean diurnal variation(MDV),marginal distribution sampling(MDS),and nonlinear regressions method,were investigated by generating secondary datasets with four different artificial gap lengths(ranging in length from single half-hours to 12 consecutive days).The MDS generally showed a good overall performance especially for long gaps,with an annual sum bias error less than 5 g C m-2 yr-1.There was a large positive annual sum bias error for nonlinear regressions,indicating an overestimate on net ecosystem respiration.The offset in the annual sum NEE for four nonlinear regressions was from 8.0 to 30.8 g C m-2 yr-1.As soil water content was a limiting factor in the semiarid area,the nonlinear regressions considering both soil temperature and soil water content as controlling variables had a better performance than others.The performance of MDV was better in daytime than in nighttime,with an annual sum bias error falling between-2.6 and-13.4 g C m-2 yr-1.Overall,the accuracy of the gap filling method was dependent on the type of the land surface,gap length,and the time of day when the data gap occurred.The energy balance ratio for the two ecosystems was nearly 80%.Turbulent intensity had a large impact on energy balance ratio.Low energy balance ratio was observed under low friction velocity during the night.When there was a large fetch distance in a wind direction,a low energy balance ratio was caused by mismatch of the footprints between the available energy and turbulent fluxes.The effect of energy balance correction on CO2 flux was evaluated by assuming the imbalance caused by the underestimation of sensible heat flux and latent heat flux.The results showed an average increase of 10 g C m-2 yr-1 for annual NEE in both ecosystems with an energy balance correction.On the other hand,the u*threshold also have a large impact on annual sum NEE.Net carbon emission increased 37.5 g C m-2 yr-1 as u*threshold increased from 0.1 to 0.2 m s-1,indicating a large impact of imposing u*threshold on net ecosystem carbon exchange.     

Interannual variations of bomb radiocarbon during 1977—1998 recorded in coral from Daya Bay, South China Sea

Radioactive isotope tracers such as 14C, 3H, 222Rn and 226Ra are extensively applied in oceanological research, simply because these radioactive isotopes can be indicative of some ex-tremely slow processes occurring in sea water, which may include the off…     

Application of ~(137)Cs fingerprinting technique to interpreting sediment production records from reservoir deposits in a small catchment of the Hilly Loess Plateau, China

According to variations of 137Cs and clay contents, 44 flood couplets were identified in a profile of res- ervoir deposit with a vertical length of 28.12 m in the Yuntaishan Gully. Couplet 27 at the middle of the profile had the highest average 137Cs content of 12.65 Bq·kg?1, which indicated the 1963s' deposits, then 137Cs content decreased both downward and upward in the profile. The second top and bottom couplets had average 137Cs contents of 2.15 Bq·kg?1 and 0.92 Bq·kg?1, respectively. By integrated analysis of reservoir construction and management history, variations of 137Cs contents over the profile, sediment yields of flood couplets and rainfall data during the period of 1958-1970, individual storms related to the flood couplets were identified. 44 floods with a total sediment yield of 2.36×104 m3 occurred and flood events in a year varied between 1 and 10 times during the period of 1960-1970. 7-10 flood events occurred during the wet period of 1961-1964 with very wet autumn, while only 1-2 events during the dry period of 1965-1969. Average annual specific sediment yield was 1.29×104 t·km?2·a?1 for the Yuntaishan Gully during the period of 1960-1970, which was slightly higher than 1.11 ×104 t·km?2·a?1 for the Upper Yanhe River Basin above the Ganguyi Hydrological Station and slightly lower than 1.40 ×104 t·km?2·a?1 for the nearby Zhifang Gully during the same period. Annual specific sediment yields for the Yuntaishan Gully were correlated to the wet season's rainfalls well.     

Contamination and potential biodegradation of polycyclic aromatic hydrocarbons in mangrove sediments of Xiamen, China

Five stations were established in the Fenglin mangrove area of Xiamen, China to determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and the numbers of PAH-degrading bacteria in surface sediments. Assessing the biodegradation potential of indigenous microorganisms and isolating the high molecule weight (HMW)-PAH degrading bacteria was also one of the aims of this work. The results showed that the total PAH concentration of sediments was 222.59 ng g(-1) dry weight, whereas the HMW-PAH benzo(a)pyrene (BaP) had the highest concentration among 16 individual PAH compounds. The variation in the numbers of PAH-degrading bacteria was 2.62 x 10(2)-5.67 x 10(4)CFU g(-1) dry weight. The addition of PAHs showed a great influence in increasing the microbial activity in mangrove sediments. A bacterial consortium, which could utilize BaP as the sole source of carbon and energy, and which was isolated from mangrove sediments and enriched in liquid medium for nearly one year degraded 32.8% of BaP after 63 days incubation.     

Seasonal patterns and environmental control of ecosystem respiration in subtropical and temperate forests in China

Continuous measurement of carbon dioxide exchange using the eddy covariance (EC) technique was made at two ChinaFLUX forest sites including the young subtropical Pinus plantation (Qianyanzhou) and old temperate broad-leaved Korean pine mixed forest (Changbai Mountains) as part of the ChinaFLUX network. Seasonal patterns and environmental control of ecosystem respiration in the subtropical and temperate forests were evaluated by the often-used multiplicative model and Q10 model as a function of temperature and soil water content. The resuits suggested that ( i ) temperature was found to be a dominant factor in the ecosystem respiration, and most of the temporal variability of ecosystem respiration was explained by temperature. However, in the drought-stressed ecosystem, soil water content controlled the temporal variability of ecosystem respiration other than temperature effects, and soil water content became a dominat factor when severe drought affected the ecosystem respiration; (ii) the regression models analysis revealed that in the drier soil, ecosystem respiration was more sensitive to soil moisture than was expressed by the often-used multiplicative model. It was possible to accurately estimate the seasonal variation of ecosystem respiration based on the Q10 model; and (iii)annual ecosystem respiration derived from the often-used multiplicative model was 1209 g C m-2and 1303 g C m-2, and was consistently a little higher than the Q10 model estimates of 1197 g C m-2 and 1268 g C m-2 for Qianyanzhou and Changbai Mountains, respectively.     

Growth of Mytilus edulis in net bags transferred to different localities in a eutrophicated Danish fjord

The growth rate has been measured in Mytilus edulis transferred in net bags to seven localities in the brackish Danish fjord, Limfjorden, in which certain areas are heavily eutrophicated. The increase in shell length, shell weight and flesh body weight was measured after growth periods of 14–18 days. The increase in, e.g., flesh dry weight ranged from twice the start weight to a four-fold increase of the start weight. The net growth efficiencies were estimated to be between 54 and 73%. Algal concentration was in no case the limiting growth factor, but low growth rates were observed in areas with seasonal oxygen depletion and release of toxic H₂S from the sediments. It is suggested that measurements of actual growth in M. edulis can be a useful technique in the study of biological effects in marine recipients.