Abstract
The slipper limpet Crepidula fornicata is an emblematic invasive species along the northeast Atlantic coast. This gregarious gastropod lives in stacks of several individuals and forms extended beds in shallow subtidal areas. The effects of this engineer species on the colonized habitat can be physical (e.g., presence of hard-shell substrates with uneven topography) or biological (e.g., nutrient enrichment by direct excretion or via biodeposition). We hypothesized that through biological activity, nutrient fluxes at the sediment-water interface are enhanced, leading to stimulated primary productivity by microphytobenthos (MPB) associated with Crepidula beds. To test this fertilization hypothesis, we conducted a 10-day mesocosm experiment using C. fornicata (live and dead) placed on top of sieved and homogenized sediment collected in situ. We used hyperspectral imaging to non-invasively map the development of MPB biomass, and to assess the potential influence of C. fornicata and its spatial extent. Our results showed that live C. fornicata significantly promote MPB growth through both physical and biological effects, with the biological effect dominating over the pure physical one. The highest stimulation was observed on the shells, suggesting that dissolved metabolic products excreted by C. fornicata were likely the main factor stimulating MPB growth in our short-term experiment. Our findings provide first direct evidence that stimulation of MPB growth by the biological activity of larger benthic epifauna occurs not only in intertidal but also in shallow subtidal habitats. More research is needed to assess the contribution of this fertilization effect to the trophic functioning of subtidal benthic systems.
Highlights
Microphytobenthos (MPB) refers to a complex assemblage of benthic unicellular eukaryotic algae and cyanobacteria living at the sediment-water interface (MacIntyre et al, 1996)
We aim to explore this phenomenon in subtidal sediments, using the Atlantic slipper limpet Crepidula fornicata as a model of engineering organism in these habitats
Patches with highest MPB biomass occurred within the inner bed Spatial Extent of the Biological Effect
Summary
Microphytobenthos (MPB) refers to a complex assemblage of benthic unicellular eukaryotic algae (mainly diatoms) and cyanobacteria living at the sediment-water interface (MacIntyre et al, 1996). Microphytobenthos space-time dynamics is affected by a number of abiotic (e.g., light, temperature, nutrient availability, hydrodynamic conditions, and sediment grain size) and biotic (e.g., grazing and competition) factors and their interactions (Seuront and Spilmont, 2002; Azovsky et al, 2004; Jesus et al, 2005). Among these factors, fertilization through the activity of benthic macrofauna is emerging as an important mechanism in benthic ecology (Chennu et al, 2015; Engel et al, 2017; Echappé et al, 2018). We aim to explore this phenomenon in subtidal sediments, using the Atlantic slipper limpet Crepidula fornicata as a model of engineering organism in these habitats
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call