Contrasted impact of two macrofaunal species (Hediste diversicolor and Scrobicularia plana) on microphytobenthos spatial distribution and photosynthetic activity at microscale

Microphytobenthos is most often the primary source of carbon for coastal soft-sediment communities, especially in intertidal and shallow subtidal environments. The influence benthic macrofaunal organisms on microphytobenthic biomass, spatial distribution photosynthetic capacities not only resulting from their feeding intensity but also indirectly bioturbation activity, which regulates nutrient fluxes sediment mixing. This study compares impact two species (Hediste diversicolor Scrobicularia plana) that dominate communities estuarine mudflats biomass activity. Imaging-PAM fluorescence was used to non-invasively map development assess its extent. Our results showed that, due intense deposit feeding, plana quickly limited microphytobenthos growth even at low density (<250 ind m?2). In contrast, negative Hediste direct consumption very low. Thereby, stimulation sediment-water interface bioirrigation seems enhance photosynthesis.