Separation strategies for invertebrate dormant stages contained in sediment

E Briski,Hj Macisaac,Sa Bailey

doi:10.3354/ab00509

Abstract

Invertebrates and their dormant stages are an essential component of most freshwater and marine ecosystems (Caceres 1997). As the active invertebrate community has a very variable distribution, both in time and space (Arnott et al. 1999, Folt & Burns 1999), reliable assessment of community diversity consequently requires repeated sampling across multiple locations for a prolonged period of time. Various invertebrate taxa produce dormant stages such as dormant eggs (also called diapausing eggs or resting eggs), cysts, or statoblasts that often sink and accumulate in sediments, forming ‘egg banks’ (Brendonck & De Meester 2003). Dormant stages provide a mechanism for invertebrates to endure inhospitable environments and to undertake natural long-distance dispersal (Caceres 1997). Sediment egg banks integrate spatial, seasonal and annual variation in the abundance and distribution of invertebrates (Brendonck & De Meester 2003, Jeppesen et al. 2003). To accurately assess community composition for purposes of taxonomy, ecological biogeography, paleolimnology, nature conservation, and evolutionary, community, population and invasion ecology, both active and dor mant stages of taxa should be considered (Brendonck & De Meester 2003). FEATURE ARTICLE

Highlights

Invertebrates and their dormant stages are an essential component of most freshwater and marine ecosystems (Cáceres 1997)
Our study showed that both methods, the colloidal silica sol Ludox HS 40 and sugar flotation, are suitable for separation of dormant stages from sediment to assess abundance and viability, as well as to conduct genetic studies
As both separation methods rely on differences in density between minerals, separation solution and organic matter to effect separation (Hairston & Van Brunt 1994, Hairston et al 1995, Burgess 2001), the efficacy of dormant stage separation may be maximized by continually confirming the specific gravity of the colloidal silica sol or sucrose solution

Summary

Introduction

Invertebrates and their dormant stages are an essential component of most freshwater and marine ecosystems (Cáceres 1997). As the active invertebrate community has a very variable distribution, both in time and space (Arnott et al 1999, Folt & Burns 1999), Daphnia magna dormant stage with remnants of sediment Photo: Elizabeta Briski reliable assessment of community diversity requires repeated sampling across multiple locations for a prolonged period of time. Dormant stages provide a mechanism for invertebrates to endure inhospitable environments and to undertake natural long-distance dispersal (Cáceres 1997). To accurately assess community composition for purposes of taxonomy, ecological biogeography, paleolimnology, nature conservation, and evolutionary, community, population and invasion ecology, both active and dormant stages of taxa should be considered (Brendonck & De Meester 2003)

Methods

Results

Conclusion