Immediate effects of a storm on coastal infauna

Abstract

Effects of storms on benthic infaunal communities have thus far been inferred rather than documented; especially lacking are studies examining immediate effects. To this end, the water column and 2 subtidal benthic sites were sampled before and after Storm David in September 1979. There were large post-storm increases in the numbers of infaunal species and individuals in the water column, presumably due to turbulent benthic boundary conditions. At the benthic stations, there were no pre vs. post-storm differences in the density of infauna; however, the number of species decreased at 1 station. There were storm-associated changes in the rank order of dominant infaunal taxa although these generally were rearrangements rather than substitutions. Cluster analysis of benthic data showed distinct spatial, but not temporal, groups. Because pre-and post-storm differences in benthic infaunal samples were not commensurate with the magnitude of change in the water column infauna, the storm apparently was more catastrophic to distant infaunal communities. Thus, we suggest that disturbance by storms may be a mechanism for wide post-larval dispersal of ostensibly obligate infauna.

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).…”

Planktonic larvae 05 act like passive particles in turbulent near‐bottom flows1

“…In addition, sites where larvae are initially deposited may differ from sites where postlarvae eventually recruit into populations. As previously stated, after initial deposition, larvae or postlarvae may choose microenvironments within a given location, they may actively reject the location by swimming into the water column, they may choose to remain at the sediment surface to be resuspended, or resuspension may be involuntary, but in any case, the organisms could be transported to new locations regularly (Bell and Sherman 1980;Palmer and Brandt 198 1) or only during storms (Hogue 1982;Dobbs and Vozarik 1983), or they may accumulate passively around microtopographic structures (Eckman 1979(Eckman , 1983. Alternatively, larvae initially deposited over a large area may differentially survive in hospitable microenvironments within that locale.…”

Subtle and negligible effects of rainfall on estuarine infauna: evidence from three years of event-driven sampling

“…Experimental work has shown that deposition of terrestrial sediments, mimicking storm-induced depositions, can cause decreased diversity in estuaries (Norkko et al 2002, Lohrer et al 2004). Conversely, Dobbs & Vozarik (1983) reported no significant effect of a single storm event on the macrobenthos at a shallow subtidal study site, although the authors postulated that effects may have been more pronounced at more exposed sites.…”