Exploring the relationships between abiotic variables and benthic community structure in a polluted estuarine system

• Published in: Water research (Oxford) Vol. 32; no. 12; pp. 3799 - 3807
• Main Authors: González-Oreja, José Antonio, Saiz-Salinas, José Ignacio
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 1998; Elsevier Science
• Subjects: Animal, plant and microbial ecology; Applied ecology; Applied sciences; Bilbao Estuary; Biological and medical sciences; Earth sciences; Earth, ocean, space; Ecotoxicology, biological effects of pollution; Engineering and environment geology. Geothermics; estuarine fauna; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; hydrographic variables; Marine and brackish environment; Natural water pollution; organic enrichment; oxygen depletion; Pollution; Pollution, environment geology; Seawaters, estuaries; Water treatment and pollution; Bilbao Estuary; estuarine fauna; hydrographic variables; organic enrichment; oxygen depletion; Brackish water environment; Fauna; Estuaries; Data processing; Zoobenthos; Sediments; Oxygen content; Hydrography; Eutrophication; Mud flats; Macrofauna; Intertidal environment; Water pollution; Pollutant effect; Principal component analysis
• ISSN: 0043-1354; 1879-2448
• DOI: 10.1016/S0043-1354(98)00167-5

Assessed was the effect of a man-induced interference in an estuarine system by monitoring a set of hydrographic and sedimentary variables together with a faunal survey of intertidal mudflats. A reference site was established in a nearby unpolluted estuary. A principal components analysis (PCA) reduced the original environmental data to a few more manageable factors. PCA factor I, defined by changes in salinity at the surface of the water column and dissolved oxygen at the bottom, explained 40% of the total variance. Pair-wise correlations between different structural metrics and PCA factor I explained up to 70% of the variability observed in the community metrics. Macrobenthic communities were simpler (with minor values of abundance, diversity, evenness and a much lower value of biomass) where dissolved oxygen at the bottom of the water column was minimum. An afaunal stage developed along intertidal mudflats where anoxic conditions prevailed. There was a large “weight-of-evidence” that a depletion of dissolved oxygen was causing a severe stress to the estuarine biota.