ISSN:
1573-5117
Keywords:
tropical zooplankton
;
diel migration
;
thermocline
;
cladocerans
;
vertical distribution
;
summer
;
winter
;
tropical lake
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Six genera of Clad ocera (Diaphanosoma, Daphnia, Ceriodaphnia, Moina, Bosmina, Bosminopsis), each of them usually with only one species were found in Lake D. Helvecio, a natural valley lake located in the eastern part of Brazil. Diurnal migratory movements of the organisms observed in this lake showed a different pattern in different species. Closely related species, which explore the same food source, live in different layers, thus avoiding interspecific competition. The migratory behaviour of the species was studied mainly in relation to temperature and oxygen distribution in the lake. Thus, analyses were made in the summer (January, 1978) when a strong stratification occurs with the establishment of a thermocline and an oxycline. Comparisons were made also with the data obtained in winter (July, 1978), when a complete mixing of water occurs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00026616
