title: What does impacted look like? High diversity and abundance of epibiota in modified estuaries.
abstract: Ecosystems modified by human activities are generally predicted to be biologically impoverished. However, much pollution impact theory stems from laboratory or small-scale field studies, and few studies replicate at the level of estuary. Furthermore, assessments are often based on sediment contamination and infauna, and impacts to epibiota (sessile invertebrates and algae) are seldom considered. We surveyed epibiota in six estuaries in south-east Australia. Half the estuaries were relatively pristine, and half were subject to internationally high levels of contamination, urbanisation, and industrialisation. Contrary to predictions, epibiota in modified estuaries had greater coverage and were similarly diverse as those in unmodified estuaries. Change in epibiota community structure was linearly correlated with sediment-bound copper, and the tubeworm Hydroides elegans showed a strong positive correlation with sediment metals. Stressors such as metal contamination can reduce biodiversity and productivity, but others such as nutrient enrichment and resource provision may obscure signals of impact.
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: g.clark@unsw.edu.au.
authors.forename: Graeme F
authors.initials: GF
authors.lastname: Clark
authors.affiliation: National Marine Science Centre & Centre for Coastal Biogeochemistry Research, School of Environment, Science and Engineering, Southern Cross University, Coffs Harbour, NSW 2450, Australia.
authors.forename: Brendan P
authors.initials: BP
authors.lastname: Kelaher
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Dafforn
authors.affiliation: New South Wales Fisheries, Department of Primary Industries, Coffs Harbour, NSW 2450, Australia.
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Coleman
authors.affiliation: NSW Department of Primary Industries, Jervis Bay Marine Park, Huskisson, NSW 2540, Australia.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Knott
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Ezequiel M
authors.initials: EM
authors.lastname: Marzinelli
authors.affiliation: School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia.
authors.forename: Emma L
authors.initials: EL
authors.lastname: Johnston
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000145:classification* / Q000254:growth & development; D044822:Biodiversity; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004784:Environmental Monitoring; D063366:Estuaries; D019015:Geologic Sediments / Q000737:chemistry; D006802:Human Activities; D007448:Invertebrates / Q000145:classification / Q000254:growth & development; D008670:Metals / Q000032:analysis; D011077:Polychaeta; D013021:South Australia; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D008670:Metals; D014874:Water Pollutants, Chemical
keywords: Biodiversity; Bioindicators; Introduced species; Metals; Nutrients; Pollution