Zooplankton resting egg banks in permanent and temporary tropical aquatic systems

Abstract

Aim: We evaluated zooplankton resting egg banks and active communities in five coastal lagoons and in five temporary pools, aiming to compare the active and the dormant communities in such environments. As they differ in hydroperiod, we expected that pools present richer resting egg banks in comparison to those found in lagoons. Methods: Zooplankton community was sampled twice in 2006 (lagoons) and in 2010 (pools) and resting egg banks were sampled once in December 2007 (lagoons) and in May 2010 (pools). Resting eggs were isolated from the sediment by applying the sugar flotation method. Results: In opposition to our expectation, species richness in the resting egg banks of pools did not differ from those of lagoons. Additionally, no difference was found between the active and the dormant zooplankton communities in each water body for both temporary and permanent environments. However, similarity between active and dormant communities was greater in permanent environments than it was in temporary environments. Conclusions: It seems that the diapause strategy observed in certain tropical zooplankton populations cannot be predicted based on the awareness of the environment type (permanent or temporary), since hatching cues may be species-specific.

Current knowledge of South American cladoceran diapause: A brief review

“…The first study for the region that used this second approach was conducted by Maia-Barbosa et al (2003) in Pampulha Reservoir (Brazil) and reported a low hatching success. This approach was used later in a single study in a mountain system (Coronel et al, 2009) as well as simultaneously in temporary and permanent systems (Ara ujo et al, 2013). Moreover, in Maia-Barbosa et al (2003), in Coronel et al (2009) andGerhard et al (2016), detailed descriptions and photographs of each isolated resting egg were presented, which constituted the first attempts to present local identification material.…”

“…In contradiction with previous results, Araújo et al () found a lower species richness in the egg banks than in active water samples of most permanent and temporary systems evaluated. Nevertheless, as only the hatchlings were compared to the active community, it is possible that some species were present in the egg bank, but did not hatch in the experiments.…”

Composition of cladoceran dormant stages in intermittent ponds with different hydroperiod lengths

“…On the other hand, Santangelo et al (2011) and Arau´jo et al (2013) reported hatchings of five and nine cladoceran species, respectively, in coastal lagoons of southeastern Brazil. Such variations in richness might have been yielded by differences in the experimental conditions, as the timing of emergence of cladoceran species varied among studies.…”

“…Thus, hydroperiod length influences the community structure of invertebrates that produce dormant stages (Williams 2006). Some studies show that richness of zooplankton dormant stages is lower in ponds with predictable flooding periods or long hydroperiod (Ebert and Balko 1987;Frisch et al 2006;Palazzo et al 2008), while others report similar richness between temporary and permanent ponds (Arau´jo et al 2013).…”

Description of the male of Coronatella paulinae (Crustacea, Branchiopoda, Chydoridae) with an identification key for the genus based on the male morphology

“…This alternation between asexual and sexual reproductive cycles has an important role in the dispersion, colonization and increase of genetic variability in the novel aquatic system due to the production of resting eggs by ephipial females. Resting eggs may persist in the environment for many years and initiate new populations once stable conditions return (Grebelnyi, 1996;Cáceres and Soluk, 2002;Brock et al, 2003;Santangelo, 2009;Araújo et al, 2013).…”