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1.
A benthological survey in a deep caldera, Lake Ikeda, southern Kyushu, Japan, in 1998 revealed that no zoobenthos were found
in the deep profundal, although two tubificid oligochaetes, Tubifex tubifex and Limnodrilus hoffmeisteri, and a chironomid, Procladius sp., were distributed in the upper profundal zone. This is the first record of oligochaete composition in the lake. Lake
Ikeda had been typically oligotrophic until the 1940s, and zoobenthic assemblages were recorded throughout the profundal bottom
in the 1920s and 1970s. Recent disappearance of the deep profundal zoobenthos could be caused by the stagnation of anoxic
waters in the hypolimnion, in connection with eutrophication triggered by nutrient loading, as well as change in the thermal
circulation system presumably caused by global warming. 相似文献
2.
放养河蟹对黑龙江东湖水库底栖动物和水生维管束植物的影响 总被引:3,自引:0,他引:3
在面积为2700hm2的东湖水库,以散养的方式养殖河蟹。在放养密度不同的情况下,研究放养河蟹对水库中底栖动物和水生植物的影响。2001年规格为220只/kg河蟹放养量为1500kg、密度为122只/hm2时,对摇蚊幼虫和寡毛类影响显著,而对其他软体动物和水生植物无显著影响。2002年同样规格的河蟹放养量增加至3500kg、密度为285只/hm2时,对底栖动物和部分沉水植物影响显著。本文对河蟹养殖容量作了讨论,认为东湖水库散养河蟹的放养量不应超过1500kg。
相似文献
3.
Modelling production and biomasses of zoobenthos in lakes 总被引:5,自引:0,他引:5
This work presents a dynamic model to predict zoobenthos in lakes. The model has been developed within the framework of a more comprehensive lake ecosystem model, LakeWeb, which also accounts for the following functional groups of organisms, phytoplankton, bacterioplankton, two types of zooplankton (herbivorous and predatory), macrophytes, prey fish and predatory fish. This work also presents a new data-base for zoobenthos in lakes. Many of the lakes included in this study are situated in the former Soviet Union. They were investigated during the Soviet period and those results have been largely unknown in the West. Using this data-base, this work also presents new empirical models for zoobenthos. The new dynamic model gives seasonal variations (the calculation time, dt, is 1 week using Euler's method and enough iterations to get stable solutions). The basic aim of the dynamic model is that it should capture general functional and structural patterns in lakes. We have demonstrated by several model tests along limnological gradients (total phosphorus concentrations, pH, lake colour, latitude and lake size) that the dynamic model gives predictions that agree well with the values given by the empirical regressions, and also expected and requested divergences from these regressions when they do not provide sufficient resolution. It would have been very difficult indeed to carry out such tests regarding ecosystem responses using traditional methods with extensive field studies in a few lakes. We have given algorithms for (1) production of zoobenthos from eating macrophytes, benthic algae and sediments, (2) elimination (related to the turnover time of zooplankton), and (3) zoobenthos consumption by prey fish, and the factors influencing these processes/rates. The model is driven by data easily accessed from standard monitoring programs or maps a prerequisite for practical utility in contexts of lake management. 相似文献
4.
Primary production of phytoplankton and secondary production of a daphnid and a chaoborid were studied in a small eutrophic
pond. The gross primary production of phytoplankton was 290 gC m−2 per 9 months during April–December. Regression analysis showed that the gross primary production was related to the incident
solar radiation and the chlorophylla concentration and not to either total phosphorus or total inorganic nitrogen concentration. The mean chlorophylla concentration (14.2 mg m−3), however, was about half the expected value upon phosphorus loading of this pond. The mean zooplankton biomass was 1.60
g dry weight m−2, of whichDaphnia rosea and cyclopoid copepods amounted to 0.69 g dry weight m−2 and 0.61 g dry weight m−2, respectively. The production ofD. rosea was high during May–July and October and the level for the whole 9 months was 22.6 g dry weight m−2.Chaoborus flavicans produced 10 complete and one incomplete cohorts per year. Two consecutive cohorts overlapped during the growing season. The
maximum density, the mean biomass, and the production were 19,100 m−2, 0.81 g dry weight m−2, and 11.7 g dry weight m−2yr−1, respectively. As no fish was present in this pond, the emerging biomass amounted to 69% of larval production. The production
ofC. flavicans larvae was high in comparison with zooplankton production during August–September, when the larvae possibly fed not only
on zooplankton but also algae. 相似文献
5.
杭州西湖底栖动物群落的研究 总被引:4,自引:0,他引:4
对杭州西湖的底栖动物,在25个布点,四季采样,共获54种。其中寡毛类22种,摇蚊幼虫18种,其它各类动物14种。如果不包括三潭内湖,则西湖中只采到21种。底栖动物的加权年平均密度为443.9个/m~2,生物量为1.473g/m~2;摇蚊幼虫的数量居次。软体动物相当贫乏,与该湖富营养化程度较重,底泥松软,水生植被缺乏有关。在苏堤以西3个湖区,底栖动物的数量明显高于东面两个湖区,反映了环境条件的差异。西湖底栖动物的优势种如霍甫水丝蚓等,Ig数值表明它们均呈聚集分布。然而在水草繁茂的三潭内湖,底栖动物多达48种,优势种组成也有较大差异。文中对底栖动物数量的季节变动作了分析,并对底栖动物的鱼产潜力进行了初步估算。 相似文献
6.
Changes in the biota of Chany Lake along a salinity gradient 总被引:1,自引:0,他引:1
Laura M. Kipriyanova Nadezhda I. Yermolaeva Dmitry M. Bezmaternykh Serafima Ya. Dvurechenskaya Elena Yu. Mitrofanova 《Hydrobiologia》2007,576(1):83-93
Relationships among salinity and diversity, abundance, biomass of major biological components of Chany Lake (western Siberia,
Russia) are examined across a salinity gradient. As salinity increased from 0.8 to 6.4 g l−1, the species richness of aquatic vascular plants decreased from 16 to 2 species, of phytoplankton from 98 to 52 species,
and of zooplankton from 61 to 16 species, but changes in species diversity of zoobenthos were negligible.
Guest Editor: John M. Melack
Saline Waters and their Biota 相似文献
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8.
Summary The relationship between relative body condition (deviation from expected mean body weight) and burying depth was investigated
in five macro-zoo benthic species living in a marine intertidal habitat. Body weight increased with depth when animals of
the same size were compared. The increase amounted to 50% in the clamScrobicularia plana, ca. 40% in the wormNereis diversicolor, 25% in the clamMacoma balthica and 20% in the cockleCerastoderma edule and the clamMya arenaria. Only a part of the prey was within reach of some feeding wader species. Therefore prey value may be overestimated if one
does not take into account the fact that shallow and accessible prey often have a relatively poor body condition. 相似文献
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10.
Marie Nordström Erik Bonsdorff Sonja Salovius 《Journal of experimental marine biology and ecology》2006,333(1):58-70
Mass occurrence of macroalgae is a phenomenon attributed to eutrophication, and can lead to drastic changes in the benthic communities on soft bottoms. While the negative effects of macroalgal blooms on the macrozoobenthos have been studied extensively, the effects of the infauna on the macroalgal material have not previously been studied in the northern Baltic Sea. The impact of the infaunal species Nereis diversicolor and Saduria entomon on the burial and biomass of Enteromorpha spp., Cladophora glomerata and Fucus vesiculosus, was assessed through a series of microcosm experiments. Results show that S. entomon did not significantly affect the biomass of the algae, nor actively relocate them. N. diversicolor redistributed the filamentous green algae into the sediment, down to 4 cm at most, and decreased the biomass of the filamentous algae by 140-360%. Furthermore, the loss of biomass promoted in presence of polychaetes proved to be a density dependent process. The effect on the perennial macroalgal species, F. vesiculosus, was less clear, as no redistribution or significant change in macroalgal biomass was observed. Our findings show that infauna can contribute to a loss in macroalgal biomass through feeding and burrowing activities leading to the redistribution and incorporation of the detritus into bioturbated sediment. 相似文献