Freshwater-saltwater interface and estuarine sediment in situ assays based on post-exposure feeding of chironomids and polychaetes

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Soares, S (Author) Other; Moreira, S (Author) Other; Andrade, S (Author) Other; Guilhermino, L. (Author) ICBAS; Ribeiro, R (Author) Other

Journal

Title: Estuaries

Vol. 28

Pages: 314-319

ISSN: 0160-8347

Publisher: ESTUARINE RESEARCH FEDERATION

Indexing

ISI Web of Knowledge - 10 Citations

Scopus - 9 Citations

Other information

Authenticus ID: P-000-3ZA

DOI: 10.1007/bf02732864

Abstract (EN): An integrated approach for ecological and ecotoxicological sediment assessments along the freshwater-saltwater interface (FSl) and estuarine areas in general was developed, through the adaptation of recently proposed methods for the midge larva Chironomus riparius (an in situ assay based on post-exposure feeding for sediment toxicity assessments in freshwater systems) and the development of new techniques for the polychaete Hediste (Nereis) diversicolor (an in situ post-exposure feeding assay). Based on the previously proposed methods, improvements were made to the feeding quantification of C. riparius fourth instar larvae. A method to quantify the post-exposure feeding of H. diversicolor was developed and optimized under laboratory conditions using newly hatched Artemia franciscana nauplii as a food source. Assay chambers and procedures from C. riparius assays were easily adapted for H. diversicolor in situ exposures. Sediment assays using this integrated approach were successfully performed at an uncontaminated river-estuarine system. They consisted of a 48-h exposure followed by a 1-h post-exposure feeding for chironomids and a 2-h post-exposure feeding for polychaetes. Good recovery rates were obtained after the 48-h field exposure. Fluctuations in various physicochemical variables at the FSI, due to the tidal regime, did not significantly influence C. riparius larval post-exposure feeding rates, suggesting that uncontaminated freshwater sites located upstream of FSI areas can be used as reference sites for C. riparius in situ evaluations in estuaries. Adapted assay chambers and procedures were suitable for H. diversicolor in situ exposures.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6