Fouling assemblage development on copper-chromium-arsenic-treated timber submerged in European waters
IRG/WP 02-50181
C Brown, R J Eaton, S M Cragg, P Goulletquer, A Nicolaidou, M J Bebianno, J Icely, G F Daniel, T Nilsson, A J Pitman, G Sawyer
The effect of the anti-marine-borer timber preservative CCA on community development of non-target marine fouling animals was investigated. Panels of Scots pine treated to target retentions of 12, 24 and 48 kg CCA per m3 of wood, plus untreated controls were submerged at seven coastal sites (Portsmouth, UK; La Tremblade (2 sites), France; Ria Formosa, Portugal; Sagres, Portugal; Kristineberg, Sweden; Athens, Greece). Inspections were made after 6, 12 and 18 months exposure and the fouling community on the surface of the panels was assessed both qualitatively and quantitatively. Multivariate statistical methods were used to compare community structure between panel treatments. Results showed that panels treated to the three CCA loadings supported very similar fouling assemblages which, in most cases, had higher numbers of taxa and individuals compared to assemblages on untreated panels. There were no detectable detrimental effects on epibiota community development caused by the presence of CCA preservatives within the matrix of the wood at any of the treatment levels. Similar trends were found at all seven exposure sites. This indicates that the range of environmental conditions at the sites had no bearing on preservative impact on fouling biota. Differences in community structure between CCA-treated and untreated panels may be due to enhanced larval settlement on CCA-treated timber by some species as a result of modifications to the surface properties of the timber by the CCA preservative. Possible reasons for the higher numbers of certain species on the surface of CCA-treated panels are discussed.