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排序方式： 共有321条查询结果，搜索用时 218 毫秒
31.
黄河三角洲海参养殖池塘微型浮游植物多样性研究 总被引：2，自引：1，他引：1
采用相关性分析方法研究了温度、盐度、营养盐等环境因子对黄河三角洲海参养殖池塘微型浮游植物多样性的影响。结果表明,群落多样性指数H′值主要受营养盐特别是PO43-P、NH4+-N限制,温度、盐度对H′值影响不显著。丰富度指数d值受营养盐影响不显著。温度、盐度是d值的主要影响因素,在温度15—30℃、盐度22—32范围之内,d值随温度、盐度升高而降低。均匀度指数J值受营养盐影响不显著,但受温度、盐度影响作用较为明显,在温度15—30℃、盐度22—32范围之内,J值随着温度、盐度升高而升高。由于池塘内温度、盐度、营养盐波动较大,浮游植物群落并不稳定,多样性一直处于受干扰状态。 相似文献
32.
V. E. Neall 《新西兰海洋与淡水研究杂志》2013,47(2):117-125
Neothyris lecticularis (Deshayes, 1839) live mainly south o'f 44°S in waters 90–180 m (extremes 18–384 m) deep where bottom temperatures are always >7°c. Fossil N. “avails” (Hutton, 1886) in the early Pleistocene limestone at Castlepoint (41 °S) are associated with an assemblage of animals generioally the same as the living N. lenticularis assemblage of Foveaux Strait. The granular substrate occupied by the living animals is similar to the matrix of the Castlepoint limestone. Thus the early Pleistocene marine climate in 90–180 m at 43°S may have been about 5°c cooler than it is today; the possible use is mentioned of the presence of the fossil assemblage in studies of palaeoelimates. Population analysis of living and fossil stocks show a constant bias toward the older age‐groups; this finding is discussed. Various ecological observations are recorded. 相似文献
33.
The seaweed Sargassum hemiphyllum is widely distributed throughout the coastal waters of Asia and has high commercial value.In recent years,its natural biomass has declined due to over-exploitation and environmental pollution.To seek for a feasible way to culture this seaweed efficiently,we designed a simple long-line system in a shrimp pond for the culture during winter,and the growth and nutritional composition of the seaweed were examined.Results show that the culture system was durable and flexible allowing S.hemiphyllum to grow vertically off the muddy bottom of the pond.Although the length of pondcultured S.hemiphyllum was inhibited by water depth,the weight-specific growth rate((1.65±0.17)%/d) was nearly three times higher than that of wild plants((0.62±0.19)%/d).The crude protein(6.92%±0.88%) and ash content(21.52%±0.07%) of the pond-cultured seaweed were significantly lower than those of the wild plants(9.38%±0.43% and 26.93%±0.07%,respectively);however,crude fat(1.01%±0.04%) was significantly higher than that of the wild plants(0.87%±0.02%).In addition,the nutritional composition of both pond-cultured and wild S.hemiphyllum was comparable to or even higher than those of other common seaweeds being used as food and/or aquaculture fodder.Future studies shall be focused on the impact of environmental parameters on its growth and nutritional composition. 相似文献
34.
Dongyan Liu John K. Keesing Zhijun Dong Baoping Di Peter Fearns 《Marine pollution bulletin》2010,60(9):1423-1432
In the summer of 2008, the world’s largest green-tide occurred in the Yellow Sea, China. The hypothesized cause was the expansion of Porphyra yezoensis aquaculture along the Jiangsu coastline and the re-occurrence of a green-tide in 2009 was predicted. In this study, satellite and field images showed the formation of the June 2009 green-tide which again originated from the Jiangsu coast. The responsible species, its source and biomass accumulation were studied to support the previous hypothesis. Morphological and phylogenetic analysis demonstrated the homology of Ulva prolifera in the 2008 green-tide with the U. prolifera from P. yezoensis aquaculture rafts. About 91-505 kg/ha of U. prolifera was attached to the P. yezoensis aquaculture rafts and a total biomass of 4956 tonnes was estimated during the harvesting of P. yezoensis. This is sufficient to seed a bloom when they are dislodged from the rafts as a result of harvesting practices. 相似文献
35.
36.
湛江流沙湾马氏珠母贝的养殖容量 总被引：3，自引：0，他引：3
2008年3月—2009年1月调查分析流沙湾浮游动植物的生物量、叶绿素a含量、初级生产力、马氏珠母贝Pinctada martensii含壳重与鲜组织重的比值、养殖贝类和野生滤食性动物的滤水率、潮间带和潮下带底栖贝类及吊养区附着滤食性动物现存量等,应用营养动态模型和贝类养殖容量估算模型估算滤食性动物的总容量,扣除野生滤食性动物现存量,最终确定马氏珠母贝的养殖容量。结果显示,2种模型估算马氏珠母贝的养殖容量分别为19637.5t和20126.4t,平均养殖容量19881.95t。依据流沙湾马氏珠母贝的通常养殖密度(1.05×105个.hm-2)和平均商品规格(41g.个-1)计算,流沙湾马氏珠母贝的适养面积为461.83hm2。 相似文献
37.
乐清湾水环境特征及富营养化成因分析 总被引：8，自引：0，他引：8
根据2002-2003年乐清湾海域春、夏、秋、冬4个航次的调查资料,分析了乐清湾海域水化学要素在不同季节的分布和变化特征,探讨了陆源污水、海水养殖自身污染与富营养化的关系.结果表明,乐清湾水域DIN和DIP浓度全年平均分别为0.630mg/dm^3和0.039mg/dm^3秋、冬季几乎100%测站属劣四类水质,春、夏季近90%超过四类水质标准.水体营养状态指数（E）值各季平均在4～9,呈严重富营养化状态.研究指出沿岸工农业废水、生活污水的排放及水产养殖业的无序、无度发展是造成该水域严重富营养化的三个主要原因.认为目前乐清湾水质已不能满足该海域功能区划提出的要求,必须进行综合整治. 相似文献
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39.
本实验旨在探究维生素E对半滑舌鳎垂体组织中生长激素基因表达的影响。作者在每千克等氮等能的基础饲料中分别添加0、400和1 600mg的DL-α-生育酚乙酸酯(维生素E)投喂半滑舌鳎(Cynoglossus semilaevis)成鱼(464±2.6) g,进行为期8周的养殖实验;另外,在L-15培养基中添加0、18和54μmol/L的维生素E,对半滑舌鳎成鱼(464±2.6) g的垂体细胞进行为期3 d的体外原代培养实验。分别取垂体组织和原代细胞,通过荧光实时定量PCR分析其gh mRNA的相对表达量。实验结果表明:垂体组织中gh mRNA的相对表达量随着饲料中维生素E含量的增加而呈现先升高后下降的变化趋势,在400 mg/kg组时显著高于其他各组(P0.05);随着细胞培养液中维生素E浓度的升高, gh mRNA的相对表达量显著增加(P0.05)。由此可见,适宜浓度的维生素E能够促进半滑舌鳎垂体组织中生长激素基因的表达。 相似文献
40.
