Abstract

LEMOS, Vanessa Oliveira; COSTA, Rauquírio Marinho da  and  PEREIRA, Luci Cajueiro Carneiro. Filtration and ingestion rates of Thalassiosira Weissflogii (Bacillariophyta) by Euterpina acutifrons Dana (Copepoda). Bol. Mus. Para. Emilio Goeldi Cienc. Nat. [online]. 2006, vol.1, n.3, pp.121-127. ISSN 1981-8114.

Short-term experiments were carried out to study the feeding performances of the copepod Euterpina acutifrons fed on Thalassiosira weissiogii. Four adult females of this species were sorted and transferred to 15 ml glass bottles filled with different dilutions of the diatom cultures to obtain cell concentrations of 7.5, 10.0, 12.5, 15.0, 17.5, 20.0, 22.5 and 25.0 x 10³ cell.ml^-1 (8 treatments, 3 replicates, 4 copepods/replicate). Initial and final cell concentrations of control and experimental bottles were determined using a Neubauer Chamber. Filtration and ingestion rates were measured thought 1 hour grazing trials performed under controlled laboratory conditions. Filtration rates of  Euterpina acutifrons  oscillated from 0.81 to 2.92 ml. copepod^-1 .h^-1 and they significantly higher (p<0.05) on 7.5 x 10³ cell.ml^-1 concentration. Ingestion rates varied between 1.8 and 8.13 x 10³ cell.copepod^-1.h^-1, showing significative differences (p<0.05) between treatments with low (7.5 x 10³ cell.ml^-1) and high (22.0 x 10³ cell.ml^-1) number of cells. The feeding rates of  Euterpina acutifrons  fed on Thalassiosira weissüogii revealed the important hole of this species of copepod on the aquatic food web of coastal ecosystems of the Amazonian region, especially on the northeast of Pará where it is commonly found.

Keywords : Feeding rates; Copepods; Diatoms.

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