Revista Chilena de Historia Natural 77 (1): 29-41, 2004
RESEARCH ARTICLE
Diel vertical migration patterns of three zooplankton populations in a Chilean
lake
In this work we analyzed the depth-distribution, at noon and midnight, of three zooplankton
populations which are common inhabitants of lakes from central Chile and coexist in lake El Plateado. The species were
Tumeodiaptomus diabolicus, Diaphanosoma chilense and Bosmina longirostris. Also, we
analyzed the association between the depth-specific abundances of the groups and the depth-specific temperature and oxygen values
during the sampling period. Our results show that: (1) the three population exhibited diel vertical migration during part of the year; (2)
T. diabolicus and D. chilense exhibited the normal pattern of vertical migration, and B. longirostris
presented both the normal and the reverse pattern; (3) for all species and most dates, zooplankters experience significant
decreases in oxygen exposure as a consequence of downward migration. Temperature costs are less important but present in
T. diabolicus and D. chilense during part of the year.
Key words:
depth-selection,
Cladocera, Copepoda, reverse vertical migration, Chile
