Influence of Chironomus riparius (Diptera, Chironomidae) and Tubifex tubifex (Annelida, Oligochaeta) on oxygen uptake by sediments. Consequences of uranium contamination

• Published in: Environmental pollution (1987) 2009-04, Vol.157 (4), p.1234-1242
• Main Authors: Lagauzère, S., Pischedda, L., Cuny, P., Gilbert, F., Stora, G., Bonzom, J.-M.
• Format: Article
• Language: English
• Subjects: Animal, plant and microbial ecology; Animals; Annelida; Applied ecology; aquatic invertebrates; benthic organisms; Biological and medical sciences; Bioturbation; Chemical Sciences; Chironomidae; Chironomidae - physiology; Chironomus riparius; Diffusive oxygen uptake; Diptera; Ecology - methods; Ecology, environment; Ecotoxicology, biological effects of pollution; Fresh Water; Freshwater macroinvertebrates; Fundamental and applied biological sciences. Psychology; General aspects; Geologic Sediments - chemistry; Heavy metals; Insecta; Invertebrates; Life Sciences; Oligochaeta; Oligochaeta - physiology; Organic chemistry; Oxygen - analysis; oxygen consumption; sediment contamination; sediment-water interface; Sediments; Tubifex; Tubifex tubifex; uranium; Uranium - analysis; Uranium - toxicity; Water Pollutants, Radioactive - analysis; Water Pollutants, Radioactive - toxicity
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2008.12.004

The diffusive oxygen uptake (DOU) of sediments inhabited by Chironomus riparius and Tubifex tubifex was investigated using a planar oxygen optode device, and complemented by measurements of bioturbation activity. Additional experiments were performed within contaminated sediments to assess the impact of uranium on these processes. After 72 h, the two invertebrate species significantly increased the DOU of sediments (13–14%), and no temporal variation occurred afterwards. Within contaminated sediments, it was already 24% higher before the introduction of the organisms, suggesting that uranium modified the sediment biogeochemistry. Although the two species firstly reacted by avoidance of contaminated sediment, they finally colonized it. Their bioturbation activity was reduced but, for T. tubifex, it remained sufficient to induce a release of uranium to the water column and an increase of the DOU (53%). These results highlight the necessity of further investigations to take into account the interactions between bioturbation, microbial metabolism and pollutants. This study highlights the ecological importance of bioturbation in metal-contaminated sediments.