Avtor/Urednik		Simčič, Tatjana; Brancelj, Anton
Naslov		Seasonal dynamics of metabolic activity of the Daphnia community in Lake Bled (Slovenia)
Tip		članek
Vir		Hydrobiologia
Vol. in št.		Letnik 442
Leto izdaje		2001
Obseg		str. 319-28
Jezik		eng
Abstrakt		Seasonal changes of the community composition, oxygen consumption (R) and respiratory electron transportsystem (ETS)-activity of the Daphnia community living in Lake Bled (Slovenia) were studied between January and December 1998. The ETS activity of ovigerous Daphnia females at in situ temperature ranged from 3.27 ul O2 mg dw-1 h-1 in February to 20.91 ul O2 mg dw-1 h-1 in July. Respiration rates at in situ temperature varied from 4.04 ul O2 mg dw-1h-1 in December to 18.68 ul O2 mg dw-1 h-1 in July. The influence of four factors (temperature, body size, fecundity, genetic differences) on the matabolism were investigated. Both ETS activity and respiration rate correlated with temperature. The proportion of hybrid D. cucullata x galeata in Daphnia community correlated significantly with respiration rate at in situ temperature and ETS activity at standard temperature also. ETS activity and respiration rate showed no significant correlation with body size and the fecundity of Daphnia, whereas ETS activity in D. hyalina x galeata and D. cucullata x galeata separately correlated with body size. ETS activity of D. hyalina x galeata also was correlated with fecundity. Hybrid D. hyalina x galeata had up to one third lower ETS activity than D. cucullata x galeata. The mean ETS/R ratio in the Daphnia community was 1.16 +-0.28 (N=12). The ETS/R ratio did not correlate significantly with temperature, body size, fecundity or the proportion of D. cucullata x galeata in the Daphnia community. Laboratory experiments showed that both hybrids had similar ETS/R ratios.
Deskriptorji		FRESH WATER ECOSYSTEM DAPHNIA POPULATION DENSITY OXYGEN CONSUMPTION SEASONS ELECTRON TRANSPORT TEMPERATURE BODY HEIGHT BIOMASS ZOOPLANKTON HYBRIDIZATION