The influence of bioturbation and water column oxygenation on nutrient recycling in reservoir sediments

• Published in: Hydrobiologia Vol. 847; no. 4; pp. 1027 - 1040
• Main Authors: Gautreau, Edwige, Volatier, Laurence, Nogaro, Géraldine, Gouze, Emma, Mermillod-Blondin, Florian
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.02.2020; Springer; Springer Nature B.V
• Subjects: Aerobic treatment; Anaerobic conditions; Anaerobic treatment; Anoxia; Anoxic conditions; Anoxic sediments; Biodiversity and Ecology; Biomedical and Life Sciences; Biotic factors; Bioturbation; Ecology; Ecosystem components; Environmental Sciences; Eutrophication; Fauna; Fluxes; Freshwater & Marine Ecology; Lake sediments; Lakes; Larvae; Life Sciences; Mineral nutrients; Nutrient dynamics; Nutrient sources; Nutrients; Oxygenation; Primary Research Paper; Reservoirs; Sediment; Sediments; Sediments (Geology); Variation; Water circulation; Water column; Zoology; Chironomid larvae; Water–sediment interface; Phosphorus; Nitrogen; Tubificid worms; Aerobic/anaerobic conditions; Fauna activity; Aerobic; anaerobic conditions; Water-sediment interface
• ISSN: 0018-8158; 1573-5117
• DOI: 10.1007/s10750-019-04166-0

Sediments are sinks of nutrients in reservoirs, but may also act as temporary nutrient sources to the water column, leading to eutrophication during the warm season. Several abiotic and biotic factors at the water–sediment interface are known to influence the role of sediments as temporary nutrient sources. This study aimed at quantifying the effects of two factors (i.e., oxygenation and bioturbation) on fluxes of nutrients from the water–sediment interface of the reservoir. An experimental approach was developed in the laboratory to test three fauna conditions (no fauna, presence of tubificid worms, and chironomids larvae) and three conditions of water column oxygenation (aerobic, fluctuating, and anaerobic conditions). Chironomid larvae significantly increased concentrations of N (NH 4 +  + NO 3 − ) and PO 4 3− released from sediments by 3.7-fold and by 17-fold, whereas tubificid worms had a lesser effect (twofold for N and threefold for PO 4 3− ). Anaerobic conditions increased N by 56-fold and PO 4 3− by 102-fold compared to the aerobic treatment. Thus, anaerobic conditions produced greater N and P fluxes than fauna. Nevertheless, fauna and anoxic conditions at the water–sediment interface should not be neglected when quantifying the role of sediments on nutrient dynamics in lakes and reservoirs.