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1.
洞庭湖轮虫生态分布的研究 总被引：5，自引：0，他引：5
1985～1986年,对洞庭湖水体进行了8次轮虫样品的采集和分析。两年观察到轮虫108种,其中终年出现的种类有10种。轮虫总数O—512.8ind./L,全湖平均75.1ind./L。本文从湖区自然生态环境对轮虫种类、数量的影响进行研究,探讨了大型开放湖泊轮虫分布与若干生态因子的关系。认为泥沙含量、流速、营养盐多寡以及入湖水体轮虫种群状况是影响洞庭湖轮虫分布的主要因素。 相似文献
2.
Winfried Lampert 《新西兰海洋与淡水研究杂志》2013,47(3):483-490
Laboratory studies on cyanobacteria‐zooplankton interactions have largely focused on the inadequacy of cyanobacteria as a food source. Some features of cyanobacteria can be regarded as anti‐herbivore defences. Large colonies of Aphanizomenon, Anabaena and Microcystis cannot be handled by zooplankton, but do not interfere seriously with the filtering process. Small colonies and filaments, however, may cause severe inhibition of the feeding process by mechanical interference. This reduces zooplankton growth, reproduction, and survival. Copepods, rotifers, and Bosmina are less affected by mechanical disturbance than cladocerans. If ingested, some cyanobacteria may be poorly digested or may not provide essential nutrients. Some cyanobacteria are reported to be toxic to zooplankton. Several strains of Microcystis produce an endotoxin, but the amount of toxin produced differs among strains and with the condition of Microcystis. Zooplankton encountering toxic cells cease feeding. Some evidence of an extra‐cellular herbivore deterrent was found for Anabaena. Thus, cyanobacteria may either be individually protected or may create an environment that is unfavourable for efficient grazers (e.g., Daphnia). 相似文献
3.
Data on the seasonal variability of the quality and quantity of zooplankton are presented for the shallow eutrophic Darss-Zingst estuary. These data are the result of a monitoring programm from 1969–1995. Copepods and rotifers were the main components of the biomass. They showed a pattern of seasonal fluctuation which remained unchanged during the whole period of investigation. Copeods were dominant in spring and autumn and had their maximum in summer. Considerable biomass peaks of cladocerans were observed only in some years in connection with low salinities and high temperatures. A peak of meroplanktic larvae of polychates was observed in late autumn since 1989. Copepods were inversily correlated with the pH-value. An inverse correlation was also found between rotifers and water temperature. 相似文献
4.
作为轮虫动物门的主体,单巢类轮虫是淡水浮游动物的重要组成部分.它们通常作为一类主要的初级消费者在淡水生态系统中起着重要作用,因而深入了解它们在自然水体中的种群动态及其决定机制对淡水生态系统理论与应用研究都有重要意义.作为一类具有典型周期性孤雌生殖生活史的动物,有性生殖的发生和进化策略对其种群动态和进化都有重要影响,因而单巢类轮虫有性生殖的机理和进化研究一直是轮虫学研究领域的一个核心内容.本文就当前单巢类轮虫有性生殖的主要研究进展,包括其发生机理、信息素、理论模型、影响因素和相关实证研究等进行了系统综述;特别就单巢类轮虫有性生殖策略的三个理论模型:"bang-bang"模型、中等有性生殖比率模型和非延迟的有性生殖模型进行了详细论述.此外,本文还对影响单巢类有性生殖的内外源因素进行了总结,主要的外源因素包括食物的浓度及种类、温度、盐度和特殊的细菌等,而主要的内源性因素则包括母体年龄、食物浓度诱导的跨代母系效应、延迟的有性生殖和其他一些潜在的母系效应因素等.其中,因为延迟的有性生殖现象广泛存在且可能是轮虫物种共存或克隆共存现象的一种潜在解释,所以就此现象的理论模型、机理和实证研究等方面进行了深入讨论.另外,本文还简要讨论性比率资源分配与单巢类轮虫有性生殖的关系.最后,对未来几个可能的热点方向简单评述,以期为国内轮虫学和相关方面的研究提供帮助. 相似文献
5.
Distribution patterns and trophic contributions of rotifers from freshwater through polyhaline estuarine waters were examined in the southern Chesapeake Bay and its major tributaries for a two-year period. Trichocerca marina and Synchaeta spp. were the major taxa in abundance, followed by Polyarthra vulgaris, Keratella cochlearis and Brachionus spp. There was a significant negative correlation between salinity and rotifer density, biomass, and number of species. Rotifers were a component of the microzooplankton biomass during specific periods and at particular sites, dominating summer assemblages in tidal freshwater and river–estuary transition sites, plus the winter communities in estuarine waters. This observation indicates that rotifers may play an important trophic role by seasonally replacing metazoan nauplii as a biomass source in both tidal freshwater and estuarine ecosystems. The annual contribution of rotifers to the total microzooplankton biomass exclusive of heterotrophic dinoflagellates was brief but intensive, achieving over 50% of annual biomass during a 2–3 month period. Despite the small annual mean contribution of rotifers to the total microzooplankton biomass, rotifers may have a limited, but significant impact on the trophic dynamics of the zooplankton community in Chesapeake Bay and its major tidal tributaries. 相似文献
6.
本文为高州水库轮虫调查(1988)的第三部分。各水层轮虫数量的季节变化是:上层(5米以上水层),春季占82.5％,夏季占67％,冬季占65.2％,秋季由于轮虫种群向中层(10至15米)迁移,只占46.5％;下层(20至30米)各季节轮虫数量一般少于8％。除7、8月份外,它们的最大密度都在2-4米水层。轮虫垂直变化的特点主要是由占轮虫总量83％的8种优势轮虫所形成。文中还讨论了水温、水深、风和其他因素对轮虫垂直分布的巨大影响。 相似文献
7.
青山水库轮虫群落结构特征的时空差异对水质变化的影响 总被引：2，自引：1，他引：1
为研究青山水库轮虫群落结构特征的时空差异对水质变化的影响,对其进行了四个季度的采样调查。结果共发现轮虫物种30种,分属于9个科,其中优势种为长肢多肢轮虫和针簇多肢轮虫,后者是一种污染指示种,表明水质处于中度污染状态。轮虫平均密度为171 ind./L,平均生物量为0.0158 mg/L。通过对水库理化因子与轮虫群落生物指数进行相关性分析,初步确定水温和溶解氧是青山水库轮虫群落演替的主要影响因子。根据轮虫群落结构聚类分析表明,青山水库分为四大区域。另外,主成分分析结果表明水质的下降可能与营养盐的的增加有关,特别是氮的输入。综合理化指标、营养状态指数、轮虫多样性指数以及优势种指示种等多种评价方法,结果表明2012—2013年青山水库水质属于中度—重度污染之间,营养程度为中度富营养状态,青山水库水环境污染严重。依据理化指标和轮虫群落结构特征来评价水质状况,得到的结果基本一致,因此轮虫可以作为青山水库一个较为理想的检测指标。 相似文献
8.
高密度轮虫对点带石斑鱼早期仔鱼培育影响的研究 总被引：4，自引：1，他引：4
本试验在水体为1000dm^3、仔鱼密度为15ind．／dm^3条件下，研究不同轮虫密度(10、25、40、70、100ind．／cm^3)对点带石斑鱼早期仔鱼摄食和生长的影响．至仔鱼12日龄的培育试验结果表明，在点带石斑鱼早期仔鱼的培育过程中，投放轮虫对水质有影响，特别是在2～6日龄间，DO值和pH值都有一降低过程，但随后即回升并相对稳定；轮虫密度越高则pH值越低，pH值最低出现在4～6日龄，4日龄时10ind．／cm^3组的pH值比100ind．／cm^3组高0．32．在10～100ind．／cm^3的轮虫密度范围内，较低的轮虫密度对仔鱼的生长有利，12日龄10ind．／cm。组仔鱼的全长比100ind．／cm^3组高31．83％，但100ind．／cm^3组仔鱼的成活率比10ind．／cm^3组的高出近一倍；不同轮虫密度下仔鱼摄食轮虫数量的差异并不明显；但9日龄以后，过高的轮虫密度100ind．／cm^3下仔鱼生长速度显著降低． 相似文献
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10.
Eutrophication in Lake Geneva (= Lake Léman) appears primarily as changes in chemical characteristics and plankton populations, inducing quantitative changes in the rotifer assemblages and species combinations.In the course of eutrophication, an increase of the rotifer abundance was found, together with settlement of new species and increase of eutrophication tolerant species, and despite the decrease or disappearance of eutrophication sensitive species.The new equilibrium in the trophic state of Lake Geneva related with the decreasing inputs of nutrients, induces a new structure and less abundance of the total pelagic rotatorian community. 相似文献