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

微型底栖动物通常是沿海软沉积群落碳的主要来源，尤其是在潮间带和浅潮带下环境中。底栖大型真菌生物对微底栖生物量，空间分布和光合能力的影响，不仅是由于它们的摄食强度，而且还间接地由于它们的生物扰动活性，从而调节了养分通量和沉积物的混合。这项研究比较了两种物种（Hediste diversicolor和Scrobicularia Plana）的影响。）在河口潮间带滩涂中的大型动物群落中，对藻类底栖生物量和光合活性具有重要作用。成像PAM荧光用于无创地绘制微底栖生物量的发展并评估其空间范围。我们的结果表明，由于强烈的沉积物喂养，即使在低密度（<250 ind m ^-2）下，平面链霉菌也迅速限制了微底栖藻的生长和光合活性。相比之下，由于直接食用，多种花色对微藻底栖动物发育的负面影响非常低。因此，生物灌溉引起的沉积物-水界面养分通量的刺激似乎增强了微底栖动物的生长和光合作用。