Weak and habitat-dependent effects of nutrient pollution on macrofaunal communities of southeast Australian estuaries

PLoS One. 2013 Jun 17;8(6):e65706. doi: 10.1371/journal.pone.0065706. Print 2013.

Abstract

Among the impacts of coastal settlements to estuaries, nutrient pollution is often singled out as a leading cause of modification to the ecological communities of soft sediments. Through sampling of 48 sites, distributed among 16 estuaries of New South Wales, Australia, we tested the hypotheses that (1) anthropogenic nutrient loads would be a better predictor of macrofaunal communities than estuarine geomorphology or local sediment characteristics; and (2) local environmental context, as determined largely by sediment characteristics, would modify the relationship between nutrient loading and community composition. Contrary to the hypothesis, multivariate multiple regression analyses revealed that sediment grain size was the best predictor of macrofaunal assemblage composition. When samples were stratified according to median grain size, relationships between faunal communities and nitrogen loading and latitude emerged, but only among estuaries with sandier sediments. In these estuaries, capitellid and nereid polychaetes and chironomid larvae were the taxa that showed the strongest correlations with nutrient loading. Overall, this study failed to provide evidence of a differential relationship between diffuse nutrient enrichment and benthic macrofauna across a gradient of 7° of latitude and 4°C temperature. Nevertheless, as human population growth continues to place increasing pressure on southeast Australian estuaries, manipulative field studies examining when and where nutrient loading will lead to significant changes in estuarine community structure are needed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Australia
  • Biodiversity
  • Ecosystem*
  • Estuaries*
  • Marine Biology*
  • Water Pollutants / analysis
  • Water Pollutants / toxicity*

Substances

  • Water Pollutants

Grants and funding

The research was funded by the Macquarie University Higher Degree Research Fund (to A. Nicastro) and an Australian Research Council Discovery Grant DP1093444 (to Melanie Bishop). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.