Benthic metabolism over the emersion - Immersion alternation in sands colonized by the invasive Manila clam Ruditapes philippinarum

Type Article
Date 2018-01
Language English
Author(s) Migne Aline1, Trigui Rima Jihane2, Davoult Dominique1, Desroy Nicolas2
Affiliation(s) 1 : Sorbonne Univ, UPMC Univ Paris 06, CNRS, UMR AD2M 7144,Stn Biol, F-29680 Roscoff, France.
2 : IFREMER, Lab Environm Ressources Bretagne Nord, Stn Dinard, F-35800 Dinard, France.
Source Estuarine Coastal And Shelf Science (0272-7714) (Academic Press Ltd- Elsevier Science Ltd), 2018-01 , Vol. 200 , P. 371-379
DOI 10.1016/j.ecss.2017.11.030
WOS© Times Cited 2
Keyword(s) Benthic fluxes, Benthos, Inorganic carbon, Nutrients, Suspension-feeding bivalve, Tidal flats, France, Western English Channel
Abstract

The effect of an invasive infaunal suspension-feeding bivalve, the Manila clam Ruditapes philippinarum, on benthic inorganic carbon and nutrient fluxes was examined through in situ incubations. Measurements were performed in spring and summer on a tidal sandflat of the Rance estuary (south part of the Western English Channel) colonized by the Manila clam after its deliberate introduction in the 1990's. Benthic inorganic carbon fluxes were measured using light and dark benthic chambers both at emersion and immersion. Benthic nutrient fluxes were measured using dark benthic chambers at immersion. Inorganic carbon (IC) and ammonium sediment release under darkness at immersion reached 5.60 mmol m−2 h−1 and 441 μmol m−2 h−1 respectively for a clam density of 291 ind m−2. The sediment IC-release under darkness was lower during emersion than during immersion, probably due to the reduced activity of infauna at low tide. Under ambient light, a sediment IC-uptake was systematically measured at emersion, indicating a net autotrophy under the condition of measurements (125 < surface PAR < 1670 μmol m−2 s−1), while either sediment IC-uptake or release was measured at immersion according to light variation (20 < underwater PAR < 990 μmol m−2 s−1). The highest gross community primary production, calculated from highest IC-fluxes at light (i.e. net community production) and highest IC-fluxes at dark (i.e. community respiration), was similar at emersion and immersion and reached 6.2 mmolC m−2 h−1. These results suggest that the metabolic activity of the invasive Manila clam Ruditapes philippinarum contributes to increase inorganic C and ammonium sediment release. These regenerated nutrients may support microphytobenthic production which appeared particularly high on this intertidal sand flat

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