Grazing impacts of the invasive bivalve Limnoperna fortunei (Dunker, 1857) on single-celled, colonial and filamentous cyanobacteria

Brazilian Journal of Biology

V Gazulha²  Mcd Mansur¹  Lf Cybis²  Smfo Azevedo¹ 

[1] ,Universidade Federal do Rio Grande do Sul Instituto de Pesquisas Hidráulicas Porto Alegre RS ,Brazil

关键词: golden mussel;    Microcystis;    Planktothrix;    filtration rates;    exotic species;    Mexilhão dourado;    Microcystis;    Planktothrix;    taxas de filtração;    espécies exóticas;   

DOI  :  10.1590/S1519-69842012000100004

来源: SciELO

【 摘 要 】

Feeding behavior of the invasive bivalve Limnoperna fortunei in the presence of single-celled, colonial, and filamentous cyanobacteria was tested in laboratory experiments to evaluate the effects of size and shape on mussel feeding. The first hypothesis holds that golden mussel filters more efficiently smaller particles, such as single cells of Microcystis, which could be more easily assimilated by its filtering apparatus. The second hypothesis sustains that L. fortunei filters more efficiently rounded colonies, such as Microcystis, which would be more easily ingested than lengthy filamentous, such as Planktothrix. Filtration rates of golden mussel in the presence of single-celled, colonial and filamentous cyanobacteria were similar. Nevertheless, there was a great difference in the ingestion and pseudofeces production rates. Single cells were widely accepted as food, while filamentous and colonial cyanobacteria were massively expelled as pseudofeces. The results confirmed the first hypothesis that golden mussel prefers to ingest smaller particles. The second hypothesis was rejected since filamentous were preferentially ingested than colonial cyanobacteria. Golden mussel has the potential to remove toxic cells (Microcystis), however this potential would be reduced in cyanobacteria blooms, where colonial forms which are preferentially rejected by L. fortunei, are predominant. In this case, the presence of this invasive bivalve could also enhance the occurrence of blooms by rejecting colonial and filamentous cyanobacteria in pseudofeces.

【 授权许可】

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