PARENT SESSION
22 - Biochemical, Cellular and Molecular Background of Biomarkers
8:00 AM to 6:30 PM, Monday, 13 May 2002
Exhibition Area

(22-52) Cellular aggregation as a biomarker of exposure in marine sponges.

Brown, Rebecca^*,1, Lowe, David², Jones, Malcolm¹, Galloway, Tamara¹, Depledge, Michael¹, ¹ Plymouth Environmental Research Centre, Plymouth, D² Plymouth Marine Laboratory, Plymouth, Devon

ABSTRACT- The application of marine sponges as bioindicators of contaminant body burdens is well established due to their simple body structure, filter feeding life style and widespread abundance. Sponges are unique among marine invertebrates in that they possess no internal organs being specifically designed for filtering large volumes of water (between 100 and 1200 ml h^-1 g^-1 sponge). The aim of this study was to exploit the specialised and undifferentiated bodyform of the sponge phyla in the development of an ecologically relevant biomarker of general condition. The sponge aggregation assay looks at the ability of sponge cells to recognise self and re-aggregate in the presence of calcium. This assay has been optimised for the sponge Halichondria panicea which is widespread and abundant along the shores of the Northeast Atlantic coast. Calcium chloride at a final concentration of 24 mM and calcium magnesium-free seawater of pH 7 provide optimal conditions for re-aggregation in this sponge. Halichondria panicea was exposed separately to three reference toxicants [copper (Cu), nonylphenol (NP) and fluoranthene (FL)] for 48h at sub-acute concentrations. Sponge aggregation was significantly inhibited compared with the controls at 100 g Cu l^-1 and at 50 g l^-1 NP and FL. As sponge aggregation was affected by contaminants in the laboratory a field validation study was carried out to compare sites contaminated with PAHs and metals with designated non contaminated sites. Sponge aggregation was significantly inhibited at the contaminated sites compared with two reference sites. This bioassay could be used as a cheap and simple screen for contaminant exposure in sponges and as an indicator of water quality.

Key words: Halichondria panicea, biomarker, toxicity, aggregation