Changes in infaunal assemblage structure influence nutrient fluxes in sediment enriched by mussel biodeposition

Biodiversity–Ecosystem Functioning (BEF) approach to further understanding aquaculture–environment interactions with application to bivalve culture and benthic ecosystems

“…The main changes described by several authors in association with biodeposit loading in shellfish areas are increased sediment organic material content (%OM) or total free sulphides (TFS) or decreased redox potential (RedOx) (Hargrave et al 2008a; Cranford et al 2009; Comeau et al 2014). However, several studies have shown that TFS and RedOx are often not sensitive enough to detect the effect of mussel aquaculture on benthic sediments (Callier et al 2007; Comeau et al 2014; Lacoste et al 2019). The authors concluded that sedimented organic material may be rapidly processed by infauna communities or be resuspended, preventing negative effects of shellfish biodeposition on benthic sediments.…”

“…To complete the description of community changes in the context of aquaculture, there is also a need to identify benthic compartments other than macrofauna, such as meiofauna and bacteria. Few studies have described responses of these communities to organic loading due to bivalve biodeposition (Mirto et al 2000; Danovaro et al 2003; Mahmoudi et al 2008; Pollet et al 2015; Lacoste et al 2019) although these compartments may respond quickly to disturbance (Zeppilli et al 2015 and references therein) and play a fundamental role in biogeochemical cycles (Schratzberger & Ingels 2017).…”

“…AZTI’s Marine Biotic Index (AMBI; Borja et al 2000) or ITI), but the results are very context‐dependent and appear to not be useful in all cases. Few studies have evaluated benthic invertebrate functional diversity in the context of fish (Dimitriadis & Koutsoubas 2011) or shellfish (Lacoste et al 2019) aquaculture. However, it is increasingly recognized that integrating functional information (on the basis of species trait values) deepens understanding of community functioning (Díaz & Cabido 2001).…”

“…To date, field experiments have tested the responses of macrofaunal communities, whereas others have measured effects on ecosystem functions including nutrient fluxes; few studies have examined the two and assessed the feedback of macrofauna on fluxes in response to organic enrichment in bivalve aquaculture (Table 1). Lacoste et al (2019) showed that benthic responses (measured as SWI nutrient fluxes) may not be linearly related to organic enrichment (mussel biodeposits), likely due to varying responses of infaunal organisms with different functional roles. Some species that benefit from intermediate organic enrichment may have a positive effect on nutrient release to the water column, whereas at higher levels of enrichment, large bio‐irrigating species ( Cistenides gouldii ) may be lost with a net negative effect on mineralization.…”

“…The subsequent impacts of those changes on benthic ecosystem functioning (e.g. nutrient cycling, trophic cascading) have only rarely been addressed in the context of aquaculture (but see Heilskov et al 2006; Lacoste et al 2019). Studies have shown that diversity of biofouling communities in the water column may influence ecosystem functioning since it is, in part, responsible for variations in nutrient fluxes at the culture structure – water column interface in different ecosystems (Mazouni et al 2001; Richard et al 2006; Jansen et al 2011; Lacoste et al 2014).…”