CHANGES IN THE FEEDING ECOLOGY OF POLYCHAETES DURING RECOVERY OF A FORMER FLY-ASH DUMPSITE
Herrando-Pérez, S. & Frid, C. L. J.
Dove Marine Laboratory, Newcastle University, Cullercoats, Tyne & Wear NE30 4PZ, UK
Approximately 14 million tonnes of fly ash from the Blyth Power Station were disposed of at a dumpsite 6 km off the Northumberland coast, from 1956 to December 1992. The recovery of the sediment and the macrofauna at the impacted areas was assessed against a control site during the 26 months following cessation of dumping. Three sediment surveys (August 1993, March & October 1994) and three faunal surveys (January 1994, September 1993 & 1994) were undertaken from the R.V. Bernicia, using a 0.1 m² van Veen grab. An area of 27 km² was covered comprising 32 sediment sites and 3 faunal stations. The fauna was dominated by polychaetes and signs of recovery were observed throughout the whole study period. Disturbance triggered the success of certain species-specific life histories, and was accompanied by dramatic increases in diversity. The most dramatic change was in the degree of subsurface detritivorism. This occurred between the winter and summer of 1994 as a response to a 80% decrease in the fly-ash waste content of the sediments Macrobenthic recolonisation patterns involved the reproductive co-success of 1) taxa behaving opportunistically, 2) ambient dominants, and 3) species experiencing regional population expansion.