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751.
Distributions and taxonomy of phyllosoma larvae were examined in Taiwanese waters, based on ichthyoplankton samples collected from May 1990 to July 1995. Phyllosoma larvae belonged to the two families Scyllaridae and Palinuridae representing 6 genera and 13 species. Of the collected phyllosoma larvae, those of Scyllarus and Panulirus species were most abundant, forming 90% of total numbers. Early stage Scyllarus and Panulirus phyllosoma larvae were abundant in Taiwanese waters. Middle to late stages (except the final stage) of Panulirus phyllosoma larvae were absent from the waters throughout the year, while those of Scyllarus phyllosoma larvae were collected in the waters. This suggests that all stages of Scyllarus phyllosoma larvae may be retained in the northern part of the waters around northern Taiwan while middle to late stages of Panulirus phyllosoma larvae may be flushed out from the waters, the sub-final and final stages then possibly returning to the waters. An anticlockwise eddy existed in the waters off northeastern Taiwan, which may be closely related to flushing out and returning of Panulirus phyllosoma larvae through a much longer planktonic period. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
752.
长江口以南我国沿岸海域经济贝类中的重金属   总被引:11,自引:0,他引:11  
本文报道了长江口以南我国沿岸海域经济贝类中各重金属的含量及其分布趋势。结果表明,各种贝类体内Zn的含量总是最高,Hg的含量总是最低。各重金属平均含量一般呈Zn>Cu>As≈Cd>Cr≈Pb>Hg的排列顺序。该海域牡蛎的Hg、Pb、Cr、As的含量低,区域分布较均匀;Cu、Zn、Cd的含量相差悬殊,以珠海海区牡蛎的Cu、Zn、Cd含量最高,分别为431×10-6~474×106,864×10-6~1044×10-6,7.02×10-6~8.25×10-6(m/m),其主要原因可能是工业排污造成的。本调查牡蛎分布较广,对Cu、Zn、Cd有较强的积累能力,推荐它为我国局部海域海洋污染监测Cu、Zn、Cd的指示生物。  相似文献   
753.
南沙群岛海区有机碳沉积作用与古生产力估算   总被引:1,自引:0,他引:1  
根据南沙群岛海区5个沉积柱样和大量表层样的分析资料讨论了有机碳的沉积作用。深海有机碳含量一般为0.2%-1.3%。水柱深度对其分布的控制作用不明显。分析结果发现冰期、间冰期,尤其是本次冰期有机碳含量变化明显,4个柱样晚第四纪的质量堆积速率在末次冰期时最大。有机碳保存的主要控制因素是溶解氧浓度、粘土矿物含量、水柱深度和底栖混合强度,其中溶解氧浓度是最重要因素。底栖有孔虫的相对丰度,如Uvigerina和Bulimi-na,可用来指示溶解氧和有机碳含量。有机碳含量与海洋生产力关系极为密切,它可用来重建海洋古生产力的长期变化。采用Mller和Suess方程以及Sarnthein方程的计算结果与目前生产力值结果比较表明,后一种方法因充分考虑了溶解氧浓度和水柱深度而更接近现代值。  相似文献   
754.
采用大型抽水试验法分析评价了新密市豫鑫煤矿突水矿井的供水能力,揭示了矿井水来源和矿井水水质特征及变化趋势,评价结果可作为矿井水资源评价和开发利用的依据.  相似文献   
755.
Quantitative inference models for water-chemistry variables are derived from epiphytic diatom assemblages in 186 lentic and mostly shallow freshwaters in lower Belgium (Flanders). When the complete pH range is considered (pH 3.4–9.3), robust transfer functions are obtained for median pH (jack-knifed r 2 = 0.88, RMSEP = 0.38 pH units or 6.4% of the observed range) and dissolved inorganic carbon concentration (jack-knifed r 2 = 0.86, RMSEP = 0.194 log10 mg DIC l−1 or 10.2% of the observed range) by means of weighted-averaging partial least squares regression (WA-PLS). For these variables, the calibration models are as reliable as those based on sedimentary diatom assemblages. Inferences of pH may be improved by combining estimates from epiphytic and sediment assemblages. In circumneutral and alkaline conditions, WA-PLS calibration of maximum or median total phosphorus is possible (log-transformed; jack-knifed r 2 = 0.64 or 0.66 and RMSEP = 14% or 12.3% of the observed range, respectively). It makes little difference if taxa showing no response to TP are taken into consideration or not. These models considerably expand the prospects of using historical herbarium materials to hindcast environmental conditions and also allow more accurate interpretation of current compositional changes in epiphytic communities. Compared to littoral sediment assemblages, fewer water-column variables can be inferred reliably from epiphyton. This probably results from differences between the effective gradients in both habitats, together with lower in situ species diversity and less effective spatial integration (i.e. lower recruitment of phytoplankton) in the epiphyton. A comparison of the HOF response-model types and WA-optima of diatom taxa for epiphytic and sediment assemblages shows that the relationship to individual variables, and in particular to those related to trophic status, may differ with habitat. Thus, the combination of samples from both habitat types in the same calibration model is not recommended. Electronic Supplementary Material Supplementary material is available and is accessible for authorised users in the online version of this article at  相似文献   
756.
Axel Kley  Gerhard Maier   《Limnologica》2006,36(2):79-90
The gammarid composition at 25 sites in the rivers Danube, Main and the southern reaches of the Rhine were studied during the years 2002–2004. Dikerogammarus villosus and Echinogammarus ischnus were the most frequent species prevailing at 17 sites. Sympatric occurrence of D. villosus and E. ischnus was observed at 12 sites. Dikerogammarus haemobaphes was recorded at 7 sites; this species prevailed in the Danube, west of the Weltenburger Enge and in the Isar mouth where it co-existed with native species (Gammarus pulex and/or G. roeseli) at 6 sites. Dikerogammarus bispinosus and E. berilloni were found at only 1 site, where they co-existed with D. villosus and E. ischnus, and with D. villosus and native species, respectively. Investigation of reproductive characteristics at 3 sites showed that females of D. villosus and D. haemobaphes produced the biggest clutches with more than 100 eggs. Females of E. ischnus produced much smaller clutches (10–35 eggs on an average), but very big eggs. Clutch sizes and egg volumes of D. bispinosus and E. berilloni resembled those of native species. Our results suggest that the most successful invaders (D. villosus, D. haemobaphes and E. ischnus) display reproductive traits that facilitate their success. Both Dikerogammarus sp. allocate energy into production of many but small eggs, thus maximizing offspring number, while E. ischnus allocates its energy into production of fewer but large eggs which could be beneficial at sites where food is scarce.  相似文献   
757.
The quality of the river Chienti (eastern‐central Apennines, Italy) has been evaluated according to the Water Framework Directive 2000/60/EC, taking into consideration both biotic (animal and vegetable) and chemical parameters. In studying the biotic component, two indices were used: the E.B.I, Extended Biotic Index (version adapted to the Italian rivers), based on macroinvertebrates, and the EPI‐D, the Eutrophication and/or Pollution Index, based on diatoms. For both macroinvertebrates and diatoms, two samplings were conducted, one in June and the other in October 2003. Instead, according to the Italian Law 152/99 the chemical and bacteriological analyses were conducted monthly for the entire year. The results of biomonitoring and chemical‐bacteriological analyses unanimously demonstrated a good ecological situation for the upper section of the Chienti, though the situation tends to worsen as the river continues its descent and undergoes increased anthropogenic pressure. Data obtained were correlated with Spearman's coefficients and principal component analysis. Both statistical calculations showed clear, direct correlation between the two biotic indices and an inverse correlation between these and the chemical and bacteriological parameters. However, a few differences of judgement that emerged among the various indices highlight the importance of using them simultaneously in order to obtain a more accurate diagnosis of the ecological status of the watercourses.  相似文献   
758.
大连市近岸海域水环境质量及影响因素分析   总被引:5,自引:0,他引:5       下载免费PDF全文
盖美  王本德 《水科学进展》2003,14(4):454-458
大连是中国北方沿海重要的中心城市和旅游城市,近年来,由于经济的发展,废水排放量的增加,近岸海域水质恶化已成为大连市主要的生态环境问题.采用模糊模式识别模型对大连市近岸海域进行水质评价,研究近岸海域水环境动态变化及影响因素分析,提出了水环境改善措施.  相似文献   
759.
水分胁迫下棉花冠层叶片氮素状况的高光谱估测研究   总被引:4,自引:3,他引:4  
在不同灌水量条件下,对棉花单叶叶绿素含量和单叶全氮含量做相关分析,并采用地物光谱仪。获取北疆棉花冠层关键生育时期的高光谱数据。应用一阶微分光谱,衍生出基于光谱位置变量的分析方法。以红边积分面积(SDr)为白变量,冠层全氮(TN)含量为因变量,做相关分析。结果表明:叶绿素含量与TN含量呈显著的正相关(R=0.8723^**。n=39),叶绿素含量能有效的估计棉花单叶TN含量;红边积分面积变量与冠层TN含量呈显著的相关性,相关系数是0.7394^**(n=40),利用构建的相关模型可以较为精确地估测新陆早6号、8号冠层叶片的全氮含量,RMSE分别为0.3859和0.4272。研究认为红边积分面积变量具有预测棉花冠层全氮含量的应用潜力。  相似文献   
760.
Precipitation anomalies in the first raining season of southern China were analyzed, with the suggestion that there are obvious interannual variation of peak values. In the raining season, the general tendency of precipitation is not obvious and the anomalous oscillation is multi-scale. Corresponding to years of more or less precipitation in the raining season, there are sharply opposite distribution across the nation in the simultaneous periods. In addition, by studying the distribution of correlation between anomalous precipitation in southern China in the first raining season and SSTA over offshore waters of China in the preceding period (June ~ August of the previous year), a sensitive zone of waters has been found that has steady effect on the precipitation of southern China in the season. Discussions are also made of the sensitive period, its simultaneous SSTA and subsequent anomalous circulation field in relation to precipitation anomalies and simultaneous circulation field in the first raining season of southern China. In the last part of the work, relationship between the SSTA in the sensitive zone and global SSTA is analyzed. A possible mechanism by which SSTA in offshore Chinese waters affects the precipitation anomalies in the first raining season of southern China is put forward.  相似文献   
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