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一座季节性休渔湖泊——洱海轮虫的季节动态特征 总被引：1，自引：1，他引：0
于2009年2-11月对洱海轮虫进行月际采样,分析洱海轮虫的多样性及其群落结构季节动态特征.洱海作为一个高原湖泊,其轮虫种类组成仍然呈现出热带-亚热带的主要特征.本研究共鉴定轮虫68种,多数种类为广布性或暖水性种类,隶属17科25属,异尾轮属、腔轮属和臂尾轮属是种类最多的三个属,占鉴定轮虫种类的37%.Lecane arcuata和Tricho-cera inermis为我国新纪录种.轮虫生物量的季节分布呈"双峰型",并分别出现在休渔期的中期和捕鱼期前期.在休渔期中期,轮虫主要以前节晶囊轮虫为优势种;在捕鱼期前期,轮虫先以螺形龟甲轮虫和广生多肢轮虫为优势,后以前节晶囊轮虫为优势.季节性休渔不仅使鱼类对轮虫的捕食压力出现季节性变化,而且还通过影响枝角类的群落结构改变枝角类对轮虫的竞争压力.在捕食和竞争的双重作用下,轮虫主要以大型杂食性种类———前节晶囊轮虫为优势种类,并呈现"双峰型"的季节分布模式. 相似文献
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Lake morphometry and wind exposure may shape the plankton community structure in acidic mining lakes
Acidic mining lakes (pH <3) are specific habitats exhibiting particular chemical and biological characteristics. The species richness is low and mixotrophy and omnivory are common features of the plankton food web in such lakes. The plankton community structure of mining lakes of different morphometry and mixing type but similar chemical characteristics (Lake 130, Germany and Lake Langau, Austria) was investigated. The focus was laid on the species composition, the trophic relationship between the phago-mixotrophic flagellate Ochromonas sp. and bacteria and the formation of a deep chlorophyll maximum along a vertical pH-gradient. The shallow wind-exposed Lake 130 exhibited a higher species richness than Lake Langau. This increase in species richness was made up mainly by mero-planktic species, suggesting a strong benthic/littoral - pelagic coupling. Based on the field data from both lakes, a nonlinear, negative relation between bacteria and Ochromonas biomass was found, suggesting that at an Ochromonas biomass below 50 μg C L−1, the grazing pressure on bacteria is low and with increasing Ochromonas biomass bacteria decline. Furthermore, in Lake Langau, a prominent deep chlorophyll maximum was found with chlorophyll concentrations ca. 50 times higher than in the epilimnion which was build up by the euglenophyte Lepocinclis sp. We conclude that lake morphometry, and specific abiotic characteristics such as mixing behaviour influence the community structure in these mining lakes. 相似文献
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Nicole Lair Hassan Taleb Patricia Reyes-Marchant 《Aquatic Sciences - Research Across Boundaries》1996,58(3):253-268
We investigated the causes of the shift which occurs in the horizontal distribution of planktonic rotifers of Lake Aydat. A normalised PCA was used to analyse the spatio-temporal distribution of 18 rotifer species. They are more numerous in the littoral zone, but seasonal changes remain higher than spatial changes. Results illustrate the capability of rotifers to take efficiently advantage of available space and food. The digestive tracts of fry and juvenile roach was also analysed and the index of Ivlev was used to determine prey selection. Fish predation occurs in the nearshore zone and the interactions between invertebrate predators and their prey are illustrated by the quantitative changes in community dynamics. Among the complex cascade of events varying in the course of the year, and despite of resource partitioning, predator-prey interactions as well as the exploitative competition between rotifers and crustaceans produce gradients exhibited in the horizontal distribution of rotifers in Lake Aydat. 相似文献
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洱海是位于我国西南亚热带高原地区的重要淡水生态系统，在高强度的人类活动与气候变化的影响下出现了较为严重的水质退化与富营养化现象，其中北部湖区的问题最为突出。本文以北部湖区为对象，设置了喜洲等5个样点，于2020年3、6、9和12月对该湖北部的轮虫群落及环境因子进行了季节性调查，分析了轮虫群落的季节演替特征及主要影响因子。本次调查共检出26属48种轮虫，多数种类为广布种或暖水种，其中无柄轮属、晶囊轮属、胶鞘轮属、须足轮属、龟甲轮属、多肢轮属在4个季节均出现。异尾轮属的种类数最多，共计9种。螺形龟甲轮虫、长肢多肢轮虫和前节晶囊轮虫是主要的优势种类。其中，螺形龟甲轮虫在4个季节均为丰度优势种，而前节晶囊轮虫在4个季节均为生物量优势种。非度量多维尺度分析表明，洱海北部湖区轮虫群落结构存在显著的季节差异。这种季节差异主要反映了水温的直接与间接影响，后者主要表现为鱼类捕食压力与食物资源的季节性。冗余分析表明，透明度、温度和浮游植物丰度为解释轮虫群落结构变化的重要变量。群落的物种组成与季节变化反映了主要轮虫优势种类对水温和水质变化的敏感性。 相似文献
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