排序方式: 共有22条查询结果,搜索用时 437 毫秒
1.
根据1986~1987年逐月调查和1987年以来结合教学实习采集的朱家尖海滨底栖无脊椎动物资料,并参考前人对该岛的调查,叙述了朱家尖岛海滨底栖无脊椎动物10门257种,分析了生活潮区、栖息底质等,提出了该岛潮间带生物资源保护的建议。 相似文献
2.
B. Streit 《Cellular and molecular life sciences : CMLS》1995,51(5):425-436
The goal of this article is twofold: 1) It aims at providing an overview on some major results obtained from energy flow studies in individuals, populations, and communities, and 2) it will also focus on major mechanisms explaining community structures. The basis for any biological community to survive and establish a certain population density is on the one hand energy fixation by primary producers together with adequate nutrient supply and the transfer of energy between trophic levels (bottom-up effect). On the other hand, predator pressures may strongly control prey population densities one or more trophic levels below (top-down effect). Other interpopulation effects include competition, chemical interactions and evolutionary genetic processes, which further interact and result in the specific structuring of any community with respect to species composition and population sizes. 相似文献
3.
Lily Campbell Sarah E. Dudas Francis Juanes Travis G. Gerwing 《Journal of Natural History》2020,54(15-16):919-945
ABSTRACT The Skeena River estuary supports commercial and culturally important salmon fisheries. However, considerable development has occurred in the area, and more has been proposed. If anthropogenic development degrades this critical habitat, the Skeena salmon run, that every year contributes $110 million to local economies, may be negatively impacted. Benthic invertebrates are common indicator species, as they often respond to disturbances before commercial species, warning of potential impacts. Unfortunately, invertebrates in the Skeena estuary have not been extensively studied, and we lack the detailed understanding of their community structure and dynamics for them to serve as indicator species in this region. Therefore, present conditions of the Skeena estuary are established here (invertebrate community, sediment conditions and food availability), in order to provide the data required both to anticipate changes associated with potential anthropogenic disturbances and to detect changes in this system if development occurs. 相似文献
4.
The one-to-four rule and paralogues of sex-determining genes 总被引:5,自引:0,他引:5
S. Ohno 《Cellular and molecular life sciences : CMLS》1999,55(6-7):824-830
5.
海洋浮游单胞藻在海产动物育苗中生产性培养新方法的试验研究 总被引:1,自引:0,他引:1
本文提出了一种在中继培养以后.以1∶1接种不施肥培养的新方法.此法能在两天内培养出育苗生产所要求的高浓度饵料液,饵料液的氨氮含量及三态氮总量较常规培养分别降低约70倍及10倍.可节省营养盐用量50%.此法适用于目前北方常用的几种海洋浮游单胞藻。 相似文献
6.
《Journal of Natural History》2012,46(43-44):2645-2659
Abundance and species richness of terrestrial cave invertebrates are not well known but are thought to be constrained by nutrient (food) supplies. A standard sampling procedure for collecting cave invertebrates does not exist. The majority of cave systems in the southeastern USA (e.g. Alabama and Georgia) have not been extensively sampled for invertebrates. We tested a baited ramp-pitfall trap for collecting terrestrial invertebrates from caves and investigated whether macroinvertebrate abundance and species richness follow total organic matter (TOM) levels from cave soils. In 14-day sampling periods, we captured 21,204 invertebrates from 14 orders comprising at least 44 species from five caves in north Alabama and Georgia. Diptera was the most frequently captured order, comprising 18 species and over 91% of our captures. Overall, our traps were successful at sampling terrestrial invertebrates from caves; however, species richness and abundance did not always correlate with TOM concentration. 相似文献
7.
8.
《Journal of Natural History》2012,46(47-48):2917-2928
A quantitative survey of the aquatic invertebrate community at a salar on the Chilean Altiplano is described. To establish the taxonomic composition and abundance we monitored inter-annual changes in community structure for four consecutive years covering different conditions. The community was composed of 21 taxa, representing 16 families, and was mainly dominated by arthropods. We found a high number of endemic species compared to other freshwater systems despite the low abundances detected. There were statistically significant inter-annual differences in diversity. A canonical correlation indicated that species richness was mainly affected by temperature. We studied this unique system by taking advantage of the “natural laboratory” that it offers. We found a combination of eutrophic conditions with low species diversity at the consumer level. This system invites further research on the community dynamics and microevolutionary aspects of invertebrate populations. 相似文献
9.
《Journal of Natural History》2012,46(37):3321-3342
Twenty‐one lakes, ten pools, seven coastal pools, three streams, two seal wallows, a penguin wallow, and three flooded moss carpets on South Georgia were sampled for aquatic invertebrates. More than 100 invertebrate species were found comprising 59 species of Rotifera, 29 Arthropoda (including five Anomopoda, three Calanoida, two Harpacticoida, three Ostracoda, 12 Acarina and four Insecta) and at least 22 other invertebrate species (including four Platyhelminthes, three Gastrotricha, six Tardigrada, six Nematoda, and two species of Annelida). The fauna of South Georgia, although similar to that of the other Scotia Arc Islands, particularly Signy Island, is much richer by virtue of its lower latitude and milder climate. 相似文献
10.
海葵等四种动物粘多糖碱提取的比较研究 总被引:1,自引:0,他引:1
采用碱提取法从绿疣海葵等4种海洋无脊椎动物中提取酸性粘多糖,其粗品产率分别为:绿疣海葵9.9%。绒毛近方蟹4.9%,毛肤石鳖4.3%,平背蜞3.6%.用蒽酮比色法和酚一硫酸法测定产品糖含量。考马斯亮蓝法测定蛋白质含量.醋酸纤维素薄膜电泳显示粘多糖的电泳迁移率相似,海葵粘多糖与甲苯胺蓝染色呈蓝色,绒毛近方蟹、平背蜞粘多糖呈紫色. 相似文献