Sediment geochemistry influences infaunal invertebrate community composition and population abundances

Structuring forces of intertidal infaunal communities on the northern coast of British Columbia, Canada: assessing the relative importance of top-down, bottom-up, middle-out, and abiotic variables

“…2016)), since mesopredators are also a component of the infaunal community, and so had to be analyzed separately. biogeochemical elements in the sediment (Drolet et al 2013a;Pilditch et al 2015b;Sizmur et al 2019;Gerwing et al 2022aGerwing et al , 2022b. Site, representing spatial variation on the scale of kilometres, is likely a product of processes such as larval supply (Weersing and Toonen 2009), post-settlement dispersal (Pilditch et al 2015b), as well as unmeasured site variables such as hydrology, biogeochemistry, exposure to waves and tidal currents (Williams et al 2013;Gerwing et al 2015b;Rubin et al 2017;Gerwing et al 2022a), or site-specific histories, such as previous disturbance and human development (Gerwing et al 2017c;Campbell et al 2019a;Sizmur et al 2019).…”

“…While our study mostly considered FACETS Downloaded from www.facetsjournal.com by 44.224.250.200 on 05/28/24 trophic-related variables, infauna can also stabilize sediments (e.g., bioconstruction), destabilize sediments (including bioturbation), cause bioadvection of porewater (affecting local distribution of dissolved oxygen and various other chemicals) while undertaking all sorts of behaviours, and subsequently facilitate or inhibit other community members (Rhoads and Young 1970;Reise 2002;Woodin et al 2010;Gerwing et al 2017b). Sediment geochemistry (whether mediated by biota or not) could affect communities at the patch level or site level, where the presence/absence and concentrations of key elements within the sediment may influence infaunal survival, physiology, behaviour, and abundance (Volkenborn et al 2012;Sizmur et al 2013;Chiarelli and Roccheri 2014;Sizmur et al 2019;Gerwing et al 2022a). More research is required to evaluate these various hypotheses related to non-trophic species performance (such as facilitation), species availability (such as the regional species pool), and habitat availability (such as disturbance type, scale, and frequency) on tidal flats in northern BC as well as in the Bay of Fundy.…”

“…Here, we examine possible species performance forces (predation, competition, and response to certain abiotic conditions) underlying community structure. For instance, envi-ronmental or abiotic variables, such as water salinity, temperature, or sediment properties, coupled with variations in exhibited tolerances of organisms for these conditions (Stillman 2002;Lu et al 2008;Dashtgard et al 2014;Sizmur et al 2019) can play an important role in structuring communities (Kelaher et al 2001;Ferguson et al 2013;Gerwing et al 2022a). As well, interactions among the living components of an ecosystem can affect communities, namely top-down predation, which in our analysis, and as discussed below, may be indistinguishable from bioturbation (Heck Jr. and Valentine 2007;Hughes et al 2014;Johnson et al 2014) and bottom-up forces, such as the availability and competition for nutrients (Davis et al 2014;Schuldt et al 2014;Pilditch et al 2015a).…”