Comunidade dormente e ativa de Cladocera (Crustacea: Branchiopoda) no lagoTupé, Manaus-Am

Abstract

Some cladocerans produce eggs resistance to persist in the environment when conditions become adverse. They are produced at different times of year by different species sinking in lake sediment, forming an egg bank. These eggs form the dormant community, which periodically or continuously hatch. It also facilitates the maintenance of the organisms in the environment, it grows the genetic diversity, allow the spread of species, It has an influence in the structure of the community and also they help with diversity studies, evolution and environmental changes. In Brazil, most of the dormant forms studies have been carried in the northeast, southeast and south regions. In Western Amazon there is not dormant forms studies of microinvertebrates. As well, this study verified the feasibility existence as dormancy of cladocerans and its distribution on sediments of Tupe lake, the density of dormant forms was calculated, and it was possible to identify which species of the active community of cladocerans produce these forms of dormancy. Besides being analyzed and compared the relationship between the two communities. This study showed that Ilyocryptus spinifer, Ephemeroporus barroisi, Diaphanosoma sp., Holopedium amazonicum, Ceriodaphnia cornuta, Moina minuta, Bosmina longirostris and Bosminopsis deitersi produce dormant forms that were found on the sediment of the lake. The species had more number of individuals hatched foi I. spinifer and together with E. barroisi were the only species benthic that came out in this study. The others are of habit planktonic. These forms dormant are distributed in a heterogeneously. They were found in greater amounts in the margins, especially where they drain the two main streams of the lake. It was possible to observe that it seems the species to alternate in the active community, some disappearing for a few months and dominating others and vice-versa. Species that were in this study represent only 8% of the active species in the lake.