The infl uence of estuarine water quality on cover of barnacles and Enteromorpha spp. Environmental Monitoring and Assessment

1 This is the accepted version of the manuscript that was published in Environmental Monitoring and Assessment 175:685-697 (2011). Abstract. The influence of ambient water quality on the settlement of barnacles and the green alga Enteromorpha spp. to an artificial substratum in the estuaries of Sydney, Australia, was investigated to test the efficacy of both groups of organisms as indicators of changes in water quality due to urban stormwater runoff and/or sewage overflows. Wooden settlement panels were immersed for four months on 17 occasions between 1996 and 2005 at 11 locations known to vary in water quality parameters (conductivity, total uncombined ammonia, oxidised nitrogen, total nitrogen, filterable phosphorus, total phosphorus, faecal coliforms and chlorophyll-a) and ambient meteorological conditions (total rainfall, maximum rainfall). Water quality data were collected during the time that the settlement panels were deployed. Cover of barnacles was highly variable among locations (range 1.2 -55.2%). Hierarchical partitioning found that chlorophylla, total phosphorus and total nitrogen had significant independent positive effects on barnacle cover. Together, these variables explained 26% of the variation in barnacle cover. Mean cover of Enteromorpha spp., however, did not vary significantly among locations suggesting that other potentially more important factors are influencing its settlement and growth. The results of this study suggest that barnacle cover is likely to be a useful indicator of some components of water quality

The influence of estuarine water quality on cover of barnacles and Enteromorpha spp

The influence of ambient water quality on the settlement of barnacles and the green alga Enteromorpha spp. to an artificial substratum in the estuaries of Sydney, Australia, was investigated to test the efficacy of both groups of organisms as indicators of changes in water quality due to urban stormwater runoff and/or sewage overflows. Wooden settlement panels were immersed for 4 months on 17 occasions between 1996 and 2005 at 11 locations known to vary in water-quality parameters (conductivity, total uncombined ammonia, oxidised nitrogen, total nitrogen, filterable phosphorus, total phosphorus, faecal coliforms and chlorophyll-α) and ambient meteorological conditions (total rainfall, maximum rainfall). Water-quality data were collected during the time that the settlement panels were deployed. Cover of barnacles was highly variable among locations (range 1.2–55.2%). Hierarchical partitioning found that chlorophyll-α, total phosphorus and total nitrogen had significant independent positive effects on barnacle cover. Together, these variables explained 26% of the variation in barnacle cover. Mean cover of Enteromorpha spp., however, did not vary significantly among locations suggesting that other potentially more important factors are influencing its settlement and growth. The results of this study suggest that barnacle cover is likely to be a useful indicator of some components of water quality