AB - Vol. 18 No. 3 - Feature article

Daphnia magna egg with remnants of sediment. Photo: Elizabeta Briski

Briski E, Bailey SA, MacIsaac HJ

 

Separation strategies for invertebrate dormant stages contained in sediment

 

Assessment of invertebrate community composition requires the consideration of both active and dormant life stages. Recent studies on the invasion risk associated with ships’ ballast tanks have used two different methods to separate dormant stages from ballast tank sediment: the colloidal silica sol Ludox HS 40 and sugar flotation. It has been assumed that the former provides more accurate density counts, while the latter results in higher viability of dormant stages in hatching studies. Briski and co-workers demonstrate that there is no difference between the methods. The financial cost of sugar flotation is lower than that of Ludox HS 40, and costs can be further reduced by using only one method.

 

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