The North American oligochaete Sparganophilus tamesis is widespread in European freshwaters. Its ecological effects on benthic nitrogen (N) biogeochemistry were studied in two contrasting environments: the organic-rich muddy sediments of the eutrophic Mincio River (Italy) and the organic-poor sandy sediments of the oligotrophic Cazaux-Sanguinet Lake (France). Oxygen and inorganic N fluxes and denitrification rates (IPT) were measured by dark incubation of intact cores with different worm biomass. Sediment oxygen demand and denitrification were higher in muddy than in sandy sediments; however, at the two sites, bioturbation by the oligochaetes stimulated differing microbial O-2 and NO3- respiration and NH4+ production. In particular, the relative effect of S. tamesis on sediment metabolism was greater in Cazaux-Sanguinet Lake than in the Mincio River. As a result, S. tamesis favored net N loss in the Mincio River, whereas it increased NH4+ recycling and lowered denitrification efficiency in the Cazaux-Sanguinet Lake. Our results suggest that the effects of S. tamesis on N biogeochemistry might differ depending on local trophic settings. These results have implications for the conservation of isoetids in the French Lake, whose persistence can be menaced by oligochaete-induced nutrient mobilization.

Contrasting effects of an alienworm on benthic n cycling in muddy and sandy sediments / Benelli, S.; Bartoli, M.; Ribaudo, C.; Fano, E. A.. - In: WATER. - ISSN 2073-4441. - 11:3(2019), p. 465. [10.3390/w11030465]

Contrasting effects of an alienworm on benthic n cycling in muddy and sandy sediments

Benelli S.;Bartoli M.;Ribaudo C.;Fano E. A.
2019-01-01

Abstract

The North American oligochaete Sparganophilus tamesis is widespread in European freshwaters. Its ecological effects on benthic nitrogen (N) biogeochemistry were studied in two contrasting environments: the organic-rich muddy sediments of the eutrophic Mincio River (Italy) and the organic-poor sandy sediments of the oligotrophic Cazaux-Sanguinet Lake (France). Oxygen and inorganic N fluxes and denitrification rates (IPT) were measured by dark incubation of intact cores with different worm biomass. Sediment oxygen demand and denitrification were higher in muddy than in sandy sediments; however, at the two sites, bioturbation by the oligochaetes stimulated differing microbial O-2 and NO3- respiration and NH4+ production. In particular, the relative effect of S. tamesis on sediment metabolism was greater in Cazaux-Sanguinet Lake than in the Mincio River. As a result, S. tamesis favored net N loss in the Mincio River, whereas it increased NH4+ recycling and lowered denitrification efficiency in the Cazaux-Sanguinet Lake. Our results suggest that the effects of S. tamesis on N biogeochemistry might differ depending on local trophic settings. These results have implications for the conservation of isoetids in the French Lake, whose persistence can be menaced by oligochaete-induced nutrient mobilization.
2019
Contrasting effects of an alienworm on benthic n cycling in muddy and sandy sediments / Benelli, S.; Bartoli, M.; Ribaudo, C.; Fano, E. A.. - In: WATER. - ISSN 2073-4441. - 11:3(2019), p. 465. [10.3390/w11030465]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11381/2867113
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