“In vitro” evaluation of the bacterivore potential of three Cladoceran species occurring in tropical and subtropical regions

Abstract

Cladocerans occupy an important position among the bacterial consumers in freshwater food webs, being relatively non-selective filter feeders that can exert a strong impact on microbial populations. We evaluated the bacterivory potential of three cladocerans species of subtropical and tropical occurrence (Ceriodaphnia silvestrii, Daphnia gessneri and Ceriodaphnia cornuta) at different life stages, by scanning electron microscopy (SEM) and by the quantification of their bacterial consumption rates using fluorescently labeled bacteria (FLB). All species showed filter mesh sizes sufficiently narrow to retain bacteria. The largest distance between setules was found in primiparous C. cornuta, and the smallest in neonate D. gessneri. The lowest ingestion (IR) and removal (RR) rates were observed in primiparous C. silvestrii and the highest values were observed in adults of D. gessneri. We conclude that bacteria may be considered an important food supplement, particularly for neonates who presented smaller intersetular distances and higher filtration rates than the other life stages. Keywords

Egg production and life history of Alona guttata Sars, 1862 (Cladocera, Chydoridae): implications for colonization of temporary ponds

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Most cladocerans may be bacterivorous, herbivorous or detritivorous, feeding upon a wide spectrum of items including organic detritus, bacteria and algae (Rocha et al, 2011;Hayashi-Martins et al, 2017). In addition to their high species diversity, this high functional diversity makes cladocerans a key group shaping food webs and community structure in shallow lakes (Lampert, 1997;Simões et al, 2009).

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Avaliação dos efeitos tóxicos do tratamento de efluente doméstico por reator de leito fluidificado enriquecido com o anti-inflamatório diclofenaco em invertebrados aquáticos

“…As Cladoceras, embora sensíveis a contaminação amoniacal presente no esgoto (NØRGAARD; ROSLEV, 2017), são encontradas em ambientes impactados por efluentes (VARSHNEY et al, 2014;KIRAN, 2016), o que indica uma certa tolerância a poluição a esgotos. Sua principal rota de contato com agentes tóxicos é através do processo de filtração não seletiva do meio aquoso (AGASILD; NÕGES, 2005;SCHERER et al, 2017;HAYASHI-MARTINS et al, 2017), por isso esses organismos estão menos sujeitos às partículas sedimentadas.…”