Respiration, calcification, and excretion of the invasive slipper limpet, Crepidula fornicata L.:: Implications for carbon, carbonate, and nitrogen fluxes in affected areas

We measured in situ respiration, calcification, and excretion of the slipper limpet, Crepidula fornicata L., and considered both seasonal variations and individual size, to estimate the effects of this exotic species on annual budgets of carbon, carbonate, and nitrogen in the Bay of Brest (France). Respiration, calcification, and excretion rates changed significantly with size and season. Oxygen consumption varied from 6 to 63 mu mol O-2 g(-1) ash-free dry weight (AF dry wt) h(-1), which corresponded to a carbon dioxide release that ranged from 2 to 44 mu mol CO2 g(-1) AF dry wt h(-1). Maximum respiration rates were observed in summer, and minimum rates were observed in winter. CaCO3 production ranged from -4 to 44 mu mol CaCO3 g(-1) AF dry wt h(-1) from winter to summer, respectively. Ammonium release varied from 0.7 to 3.1 mu mol NH4+ g(-1) AF dry wt h(-1), with the highest excretion rate in spring. Total carbon release by C fornicata in highly colonized zones in the Bay of Brest averaged 290 g C m(-2) yr(-1), carbonate production was similar to 515 g CaCO3 m(-2) yr(-1), and nitrogen production by ammonium excretion was similar to 25 g N m(-2) yr(-1). C fornicata respiration and excretion account for 55% and 85% of the benthic community respiration and excretion, respectively. These results illustrate the importance of this invasive species to carbon and nitrogen cycles, including biogenic carbonate production, in coastal ecosystems.