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为研究南美洲鳗鲡(Anguillarostrata)的耗氧率及其对水温、低溶氧、非离子氨和亚硝酸盐耐受性,本研究采用自制的鱼类呼吸装置测定其耗氧率和窒息点,以黑仔鳗为试验材料,探索其对水温、非离子氨、亚硝酸盐耐受性。结果表明,南美洲鳗鲡耗氧率存在昼夜变化,其昼间耗氧率为(86.46±37.77)mg/(kgh),夜间耗氧率为(123.58±22.56)mg/(kgh),二者存在显著性差异(P0.05);在15—30°C范围内,耗氧率随温度升高逐渐增大,耗氧率和水温的回归方程y=–0.1316x2+9.4507x–13.712(R2=0.9993);南美洲鳗鲡的耗氧率随体质量增大而降低,耗氧量随体质量增加而增大,耗氧量和体重的回归方程为y=0.2321x0.8334(R2=0.9979);在水温25°C时其窒息点随鱼体质量的增大而降低,均重10g、40g和160g的鳗鲡窒息点溶解氧浓度分别为(0.98±0.25)、(0.46±0.06)和(0.32±0.02)mg/L;13—29°C为南美洲鳗鲡的适温范围,25—29°C为其生长适宜水温,在一定范围内的短时低水温或高水温环境对其损伤是可逆的;水中非离子氨对南美洲鳗鲡的LC50和SC分别为12.22mg/L和1.22mg/L,亚硝酸盐氮对南美洲鳗鲡的LC50和SC分别为61.68mg/L和6.17mg/L。 相似文献
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三门湾沉积记录中长链烯酮不饱和指数-海表温度和浮游动物群落对厄尔尼诺/拉尼娜的响应 总被引:2,自引:1,他引:1
应用沉积地层记录中长链烯酮不饱和指数(U3K7)估算1916—2003年三门湾表层海水温度(SST)与变化。SST波动范围为15.97~18.00℃,年平均为17.03℃。该值比当年实测海水全年平均温度低3.52℃,同时应用长链烯醇不饱和指数与SST的关系重建历史上的厄尔尼诺现象。研究显示三门湾的厄尔尼诺气候事件在大尺度上与东太平洋一样均受制于气候影响,在变化尺度上又受到地理位置和地方性气候(季风)的影响,厄尔尼诺事件在形式和年代上相互对应,但是其涛动幅度不如东太平洋的强烈。通过比较厄尔尼诺期间(2003/2002年)和非厄尔尼诺期间(2006/2005年)的浮游动物群落结构变动信号、生物量、密度以及物种多样性等,在厄尔尼诺时期浮游动物种类数、生物量和丰度呈现偏高的趋势,三门湾的暖水性浮游动物类群、数量变化与台湾暖流活动过程中携带的浮游性动物有密切的联系。 相似文献
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C. LOUMAGNE M. NORMAND M. RIFFARD A. WEISSE A. QUESNEY S. LE HÉGARAT-MASCLE 《水文科学杂志》2013,58(1):89-102
Abstract The purpose of this paper is to present the methodology set up to derive catchment soil moisture from Earth Observation (EO) data using microwave spaceborne Synthetic Aperture Radar (SAR) images from ERS satellites and to study the improvements brought about by an assimilation of this information into hydrological models. The methodology used to derive EO data is based on the appropriate selection of land cover types for which the radar signal is mainly sensitive to soil moisture variations. Then a hydrological model is chosen, which can take advantage of the new information brought by remote sensing. The assimilation of soil moisture deduced from EO data into hydrological models is based principally on model parameter updating. The main assumption of this method is that the better the model simulates the current hydrological system, the better the following forecast will be. Another methodology used is a sequential one based on Kalman filtering. These methods have been put forward for use in the European AIMWATER project on the Seine catchment upstream of Paris (France) where dams are operated to alleviate floods in the Paris area. 相似文献
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The 1984 PROTEA expedition, leg 5, to the central SouthwestIndian Ridge recovered basaltic lavas from fracture zones andridge segments between 25?E and 48?E. In terms of petrographyand major element variations the samples are unremarkable forocean ridge basalts and range from aphyric to highly plagioclasephyric and from primitive (mg-number = 70) to moderately evolved(mg-number = 40) in composition. Multiply saturated (i.e., olivine,plagioclase, and clinopyroxene) basalts are common within thisregion. There is no systematic difference in compositional characteristicsbetween basalts dredged from fracture zone walls and those dredgedfrom ridge segments, and fractional crystallization has playedan important role in controlling the overall range in lava compositionin both tectonic environments. Incompatible element abundance ratios in the basalts are morenotable and distinguish between geochemically depleted (N-type)MORB with high Zr/Nb (1668) and Y/Nb (4?723) ratios and low(La/Sm)m, ratios (0-?761?00), and geochemically enriched(E-type) MORB with low Zr/Nb (3?415?8) and Y/Nb (0?58?8)and high (La/Sm). ratios (1?073?8). N-type MORB appearsto be absent in the immediate vicinity of Marion Island, butoccurs further along the ridge to the northeast and southwest.Geochemically enriched MORB occurs at scattered localities alongthe ridge but is particularly abundant along the section ofthe ridge closest to the Marion hotspot. In detail, two distinct varieties of E-type MORB can be recognized.The one type has incompatible element and isotopic ratios similarto, although slightly less enriched than, those characteristicof the Marion hotspot (Zr/Nb=5?88?6; Y/Nb=0?50?8;Ba/Nb=5?19?0). The second type can be distinguished byhaving high Ba/Nb ratios (922), unlike any lavas directlyassociated with the Marion hotspot, but similar to those characteristicof DUPAL ocean island basalts (OIB). A single sample from thisgroup for which there are isotopic data indicates derivationfrom an isotopically anomalous source region. A model is proposed whereby the sub-oceanic mantle below thisportion of the southwest Indian Ocean has experienced at leasttwo distinct enrichment events. The one is associated with theupwelling of the Marion mantle plume (geochemically characterizedby having low Ba/Nb ratios and normal OIB isotopic ratios).The other is associated with upwelling from a DUPAL source (characterizedby having high Ba/Nb ratio and unusual isotopic ratios) whichhas been proposed to exist beneath this portion of the southwestIndian Ocean (Hart, 1984). On the basis of Ba/Nb and Nb/U ratios,recycled oceanic lithosphere is favoured as a source for theMarion hotspot, while recycled oceanic lithosphere plus ancientpelagic sediment appears to be the most likely source for theDUPAL anomaly and the DUPAL E-type MORB in this region. 相似文献
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链烷烃的热力学性质与分子拓扑指数的关系 总被引:1,自引:0,他引:1
定义了一种新的连接性指数^1Y=Σk1/m^2 n^2,研究了链烷烃的标准生成焓、标准熵、标准生成吉布斯自由能等三个热力学性质与碳原子个数N,^1Y之间的定量关系,相关系数为优,其计算值与实验值较为接近,对未参与回归的正癸烷的60个异构体的三个热力学性质进行了计算,计算值与实验值较一致。 相似文献
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