Structure and dynamics of zooplankton communities maintained in closed systems, with special reference to the algal food supply |
| |
Authors: | Ferguson AJD; Thompson JM; Reynolds CS |
| |
Institution: | Freshwater Biological Association The Ferry House, Ambleside, Cumbria, UK |
| |
Abstract: | Seasonal changes in the structure of the zooplankton communitiesof two large (18 500 m3) experimental enclosures (LundTubes) are reviewed. The diets of the two most prominentcrustaceans, Daphnia hyalina and Diaptomus gracilis, were investigatedby direct analyses of gut contents and in a series of shortterm experimental manipulations of communities isolated in 6m3 bags, placed in one of the enclosures. The relative abundanceof Daphnia hyalina generally coincided with warmer water temperaturesbetween late spring and late summer, but its numbers fluctuatedwithin that period, apparently in response to the availabilityof smaller algae (<104 µm3 unit volume: chiefly cryptomonads,chlorellids and Ankyra). Daphnia numbers declined steadily throughthe summer in the enclosure overwhelmingly dominated by Microcystis,although it did feed on smaller colonies (< 105 µm3in volume). Diaptomus gracilis and most rotifers were also prominentin the first half of the year, but peak abundances of Keratellaquadrata followed the presence of large populations of small(<103 µm3) algae. Under conditions of limiting foodavailability, mortality was greatest amongst the smaller speciesand the juvenile instars of the large Crustacea.
1Present address: Anglian Water Authority, North Street, Oundle,Peterborough, UK |
| |
Keywords: | |
本文献已被 Oxford 等数据库收录! |
|