Towards a classification of organic enrichment in marine sediments based on biogeochemical indicators

• Published in: Marine pollution bulletin Vol. 56; no. 5; pp. 810 - 824
• Main Authors: Hargrave, B.T., Holmer, M., Newcombe, C.P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2008; Elsevier
• Subjects: Aerobiosis; Anaerobiosis; Animal and plant ecology; Animal, plant and microbial ecology; Animals; Applied ecology; Biodiversity; Biological and medical sciences; Carbonates; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; Geologic Sediments; Macrofauna; Marine; Marine and brackish environment; Sea water ecosystems; Sulfate reduction; Sulfides; Sulfur Compounds - analysis; Sulfur Compounds - toxicity; Synecology; Toxicity; Sulfate reduction; Sulfides; Biodiversity; Toxicity; Macrofauna; Organic matter; Marine sediments; Ecotoxicology; Fauna; Environmental factor; Sulfates; Indicator; Marine environment; Aquatic environment; Medium enrichment; Biogeochemistry; Classification; Water pollution
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2008.02.006

A nomogram is developed to show that pH, redox potentials (Eh NHE) and measures of dissolved sulfides (H 2S + HS − + S 2−)(total free S 2−) can be used to classify organic enrichment impacts in marine sediments. The biogeochemical cycle of sulfur in marine sediments is described to show that changes in macrobenthic infauna community structure associated with high levels of organic matter supply result from stress due to oxygen deficiency (hypoxia and anoxia) and toxic effects of S 2−. The changes reflect enhancement of microbial sulfate reduction under conditions of high organic matter sedimentation and the progressive formation of hypoxic–anoxic conditions measured by decreased Eh NHE and increased concentrations of S 2−. The nomogram provides a basis for classification of the oxic status of marine sediments based on changes in inter-related biological and biogeochemical variables along an organic enrichment gradient.