CALLIER, M.D., M. RICHARD, C.W. McKINDSEY, 2009. Responses of benthic macrofauna and biogeochemical fluxes to various levels of mussel biodeposition : an in situ "benthocosm" experiment. Mar. Pollut. Bull., 58(10): 1544-1553.

[Résumé disponible seulement en anglais]
An in situ experiment was done to evaluate the dose-dependent response of mussel biodeposition on benthic communities and biogeochemical fluxes. Natural benthic communities were exposed to 7 different levels of mussel biodeposition (equivalent to that produced by 0–764 mussels m^-2) over 50 days. Benthic communities responded as predicted from the Pearson, T.H., Rosenberg, R., 1978. Macrobenthic succession in relation to organic enrichment and pollution of the marine environment. Oceanogr. Mar. Biol. Annu. Rev. 16, 229–311 model of organic enrichment. Total abundance and species richness decreased with increasing biodeposition. The abundance and biomass of opportunistic species (Capitella spp.) increased in the mesocosms subject to the greatest biodeposition. Sensitive species Tellina agilis and Pherusa plumosa tended to decrease in abundance and biomass with increasing biodeposition. The biotic index M-AMBI responded clearly to increased biodeposition and may be a useful tool for assessing the effect of mussel biodeposition on the benthic environment. These results are important for the construction of predictive models for determining environmental carrying capacity for bivalve aquaculture. Crown Copyright ©2009 Published by Elsevier Ltd.

RICHARD, M., P. ARCHAMBAULT, G. THOUZEAU, C.W. McKINDSEY, G. DESROSIERS, 2007. Influence of suspended scallop cages and mussel lines on pelagic and benthic biogeochemical fluxes in Havre-aux-Maisons Lagoon, I^les-de-la- Madeleine (Quebec, Canada). Can. J. Fish. Aquat. Sci., 64: 1491-1505.

Une série d’expériences in situ a été réalisée en juillet 2004 afin de tester et de comparer l’influence de cultures de bivalves en suspension (moules (Mytilus edulis) de 1 an et de 2 ans et pétoncles (Placopecten magellanicus)) sur les flux biogéochimiques dans la colonne d’eau et à l’interface eau-sédiment dans la lagune du Havre-aux-Maisons (Québec, Canada). Les structures aquacoles augmentent la biomasse de la macrofaune pélagique (PMB) et agissent comme un puits d’oxygène et une source de nutriments dans la colonne d’eau en condition d’obscurité. Bien que la PMB soit plus faible au niveau de la pectiniculture, l’influence des paniers de pétoncles sur les flux pélagiques est similaire, voire supérieure (nitrates et nitrites), à celle des filières de moules. Au contraire de la pectiniculture, les cultures de moules enrichissent le sédiment en matière organique et diminuent l’abondance des organismes benthiques par comparaison aux zones témoins. Cependant, la demande benthique en oxygène ne varie pas entre les différentes zones de culture et les zones témoins. Les flux benthiques de sels nutritifs atteignent un maximum sous les structures aquacoles. L’interface benthique et l’interface pélagique modifient potentiellement les stocks d’oxygène et de sels nutritifs dans les zones de cultures de la lagune du la lagune du Havre-aux-Maisons. La contribution des structures aquacoles aux stocks d’oxygène, d’ammonium et de phosphates pourrait dépendre de la PMB et du type des bivalves en culture. Alors que les structures aquacoles jouent un rôle important dans le cycle des nitrates et des nitrites, le cycle du silicium est régi principalement par la minéralisation benthique des biodépôts.©2007 NRC Canada

RICHARD, M., P. ARCHAMBAULT, G. THOUZEAU, G. DESROSIERS, 2007. Summer influence of 1 and 2 yr old mussel cultures on benthic fluxes in Grande-Entre´e lagoon, Îles-de-la-Madeleine (Que´bec, Canada). Mar. Ecol. Prog. Ser., 338: 131-143 .

[Résumé disponible seulement en anglais]
The summer influence of 1 and 2 yr old suspended mussel lines on benthic fluxes (oxygen, silicates, ammonium, phosphates, nitrates and nitrites) was studied in Grande-Entrée lagoon (GEL), Îles-de-la-Madeleine, Québec, Canada. This influence and its temporal variation were examined in relation to bottom water, sediment and macrofauna characteristics. In situ mensurative experiments using benthic chambers and sediment cores were carried out at 2 mussel sites (M1 and M2) and 2 control sites (C1 and C2) in July, August and September 2003. In contrast to 1 yr old mussel lines (M1), 2 yr old lines (M2) enriched the sediment in organic matter and increased silicate, ammonium, phosphate and nitrite fluxes at the water-sediment interface. Silicate, ammonium and phosphate fluxes were highest in August, when temperature was highest. The main nutrient releases observed at the water-sediment interface in M2 could reduce nitrogen and silica limitation in the water column. Mussel lines did not influence benthic macrofauna biomass, but favoured the recruitment of many small-sized organisms. No influence of mussel lines was observed on oxygen consumption at the water-sediment interface. Macrofauna biomass and oxygen consumption increased in parallel during the summer, but the respiration of the low biomass alone cannot explain the greater overall benthic oxygen demand. The latter was probably also driven by the oxidation of reduced compounds such as sulfides. The reduced nature of the sediment could be natural in GEL, but the continuous accumulation of mussel biodeposits since 1985 has probably contributed to the degradation of the benthic environment in the mussel farm. ©2007 Inter-Research