Disturbance, sediment stability, and trophic structure of soft-bottom communities

Abstract

Previous studies of marine soft-bottom communities have shown (1) that natural disturbances (especially biologically-mediated disturbances, which are usually localized and recur reasonably frequently) help maintain spatio-temporal heterogeneity of communities, and (2) that biogenic modification of sediment can affect sediment stability with respect to fluid forces and geotechnical properties and that this is an important factor in community organization, particularly in the trophic structure of the macrofauna. It is argued in this paper that natural disturbances, and the ensuing biogenic alterations to sediment stability, may be important in maintaining trophically-mixed communities where deposit feeders do not have an overriding influence on sedimentary properties. The hypothesis is presented that an initial post-disturbance response by micro-and meiobenthos leads to an increase in sediment stability as a result of mucous-binding of sediment, and that this stage may be of critical significance to potential suspension-feeding colonists if they are competing with deposit feeders for space. It is suggested, partly as a corollary to this hypothesis, that there may be marked differences in the structure and function of meiofaunal communities co-occurring with deposit-feeding and suspension-feeding macrofaunas. Implications for macrofaunal trophic structure of seasonal changes in sediment stability are also examined. Several areas for future research are recommended.

Temporal dynamics of gastropod fauna on subtidal sandy sediments of the Ensenada de Baiona (NW Iberian Peninsula)

“…Sediments of the surf zone are usually environments of great hydrodynamic energy (Barros et al 2001) which translates in frequent changes in sedimentary composition and an exacerbated physical stress for the benthic fauna. In addition, hydrodynamic events associated with winter storms also affect the infauna by removing, mobilizing or burying established populations in any given area (Dobbs and Mozarik 1983;Probert 1984;Reiss and Kröncke 2005) and resuspending potential sources of food such as carrion (Chatzinikolaou and Richardson 2008); this may also lead to the disappearance of most of the macrofauna in such conditions (Carpentier et al 1997). In fact, the grain-size median at site D15 shifted to the medium sand fraction during February 1997 when strong storms happened in the area; on the contrary, the sediment was mostly composed by the fine and very fine sand fractions for most of the year (Moreira et al 2008).…”

Ecological impact of coastal defence structures on sediment and mobile fauna: Evaluating and forecasting consequences of unavoidable modifications of native habitats

“…Alternatively, trophic-functional groupings can be used (Probert, 1984;Paiva, 1993;Pinedo et al, 1997;Martin et al, 2000). Trophic structure of a species assemblage may remain constant even if the taxonomic composition varies (Heatwole and Levins, 1972).…”

The effects of patch size and substrate isolation on colonization modes and rates in an intertidal sediment

“…Because adult-larval interactions can differ fundamentally from those between benthic adults (e.g. Woodin 1976;Probert 1984;Oliver and Slattery 19853), postlarval immigration may yield community-development patterns distinct from those associated 1263 with larval recruitment. Thus, succession edge of any dependence of colonization prowithin a recently disturbed patch, i.e.…”