Toxic and inhibitory effects of the blue-green alga Microcystis aeruginosa on herbivorous zooplankton

Experimental studies on the effects of toxic Microcystis aeruginosa PCC7820 on the survival and reproduction of two freshwater rotifers Brachionus calyciflorus and Brachionus rubens

“…indicated that by providing some nutrition, even toxic cells could prolong survival when compared to starvation. Similar to our results, Fulton and Paerl (1987) observed that B. calyciflorus were able to resist M. aeruginosa toxins and to utilize M. aeruginosa at least as a supplementary nutritional source. Our previous study also testified this result (Geng and Xie 2006).…”

“…The possible reason may be the inadequate nutrition of Microcystis, which have been testified in some other studies (Arnold 1971;Fulton and Paerl 1987;Smith and Gilbert 1995;Ferräo-filho et al 2000). In our population growth experiment, we found that animals cultured with S. obliquus survived and reproduced much better than those fed Microcystis alone, indicating the lower food quality in Microcystis comparing to green alga S. obliquus.…”

“…The comparison of r m suppression in four zooplankton species suggests that the inhibition of two Daphnia species was greater than that of two Brachionus rotifers in the presence of M. aeruginosa. Previous laboratory investigations have also shown that large cladocerans are more inhibited by toxic cyanobacteria than smaller cladocerans and rotifers (Fulton and Paerl 1987;Fulton 1988;Gilbert 1990;Smith and Gilbert 1995). In field, such differential inhibition by toxic cyanobacteria could be much more pronounced.…”

“…Although numerous studies have examined the effects of M. aeruginosa on zooplankton, most investigations have focused on cladocerans, especially the genus Daphnia (Nizan et al 1986;Lampert 1987;Reinikainen et al 1994;Hietala et al 1995;DeMott 1999;Rohrlack 1999;Ferräo-Filho et al 2000;Chen and Xie 2003). Few studies are known about the rotifers (Fulton and Paerl 1987;Rothhaupt 1991;Smith and Gilbert 1995;Nandini and Rao 1998;Nandini 2000). Moreover, the results of above-mentioned studies on rotifers are most often limited to temperate climate, lacking information from subtropical waters.…”

Benefits and costs of the grazer-induced colony formation inMicrocystis aeruginosa

“…A previous study in our laboratory showed that filtered lake water with abundant zooplankton could induce colony formation in M. aeruginosa, whereas M. aeruginosa populations in the control and the treatment of filtered lake water with few zooplankton were still strongly dominated by unicellular and paired cells and no colony was formed (Yang et al, 2005). Microcystis aeruginosa would release microcystin to resist the grazing pressure from cladocerans (Jungmann, 1992;Jang et al, 2003;Lu¨rling, 2003), so the colony formation in M. aeruginosa could not be induced by cladocerans (Fulton and Paerl, 1987;Hessen and van Donk, 1993). Correspondingly, we observed colonies when M. aeruginosa was cultivated with the flagellate Ochromonas sp.…”