Encystment of Peridinium gatunense: occurrence, favourable environmental conditions and its role in the dinoflagellate life cycle in a subtropical lake

Abstract

1. The abundance of cysts of the bloom-forming dinoflagellate Peridinium gatunense in the sediments of Lake Kinneret and the effects of environmental conditions on encystment were studied in relation to bloom dynamics. Peak cyst formation coincided with the highest growth rate of the population, prior to bloom peak. 2. Peridinium cysts were counted in water and sediment corer samples from 2000 to 2003 and in archived sediment trap samples collected during 1993-94. The cyst data were examined in relation to ambient temperature and nutrient records, and revealed no direct correlation. 3. In laboratory encystment experiments with Peridinium cells collected from the lake, 0.2-3% of the vegetative cells encysted. Temperature, light and cell density had no significant effect on the percentage of encystment. 4. Cysts were always present in the lake sediments but their abundance in 'non Peridinium' years was much lower than after a massive bloom. Vegetative cells were always present in the water column after the collapse of the annual dinoflagellate bloom, potentially serving as the inoculum for the next bloom. We propose that the hardy cysts serve as an emergency 'gene bank' to initiate population build up following catastrophic die outs.

Eco-fingerprinting of the dinoflagellate Borghiella dodgei: experimental evidence of a specific environmental niche

“…This was in line with similar low growth rates reported for dinoflagellates (e.g. Tang, 1996;Jensen & Moestrup, 1997;Alster et al, 2006). Moreover, nutrient addition did not change cell volume, but P-depleted medium led to a dramatic increase in volume.…”

“…Little work has been done on the effects of low temperature (\10°C) on dinoflagellate encystment. However, for temperatures [15°C, encystment can increase (Sgrosso et al, 2001;Grigorszky et al, 2006) or remain unaffected (Chapman & Pfiester, 1995;Alster et al, 2006). For Borghiella, age of the culture ([10 weeks) was an additional factor inducing cyst formation.…”

“…Cyst formation is a common feature in many planktonic species, and dinoflagellate resting cysts are formed from vegetative cells producing gametes, that in turn fuse to form a planozygote. This diploid stage matures into a hypnozygote or resting cyst that after a period of quiescence germinates under favourable conditions (Alster et al, 2006;Figueroa et al, 2006). Resting cysts of dinoflagellates are characterised by thick walls and orange/red inclusion bodies (Olli & Anderson, 2002;Figueroa et al, 2006).…”

Temperature‐induced changes in lipid biomarkers and mycosporine‐like amino acids in the psychrophilic dinoflagellate Peridinium aciculiferum

“…In P. aciculiferum, the growth rate of vegetative cells was low for all temperature treatments (≤5.6°C) and similar to other dinoflagellates (Tang, 1996;Alster, Dubinsky & Zohary, 2006). In P. aciculiferum, the growth rate of vegetative cells was low for all temperature treatments (≤5.6°C) and similar to other dinoflagellates (Tang, 1996;Alster, Dubinsky & Zohary, 2006).…”

Dinoflagellates of the Trentino Province, Italy

“…Pollingher 1987, as P. cinctum f. westii). Its growth characteristics have been studied in details by Lindström (1984Lindström ( , 1991 and Alster et al (2006). Highest growth rates were obtained at relatively high conductivity, pH 7-8 and a temperature about 23°C…”