The effects of prolonged emersion and submersion by tidal manipulation on marine macrobenthos

Abstract

Effects of tidal manipulation, resulting in prolonged periods of emersion and submersion or in protracted tidal cycles, on estuarine benthic animals are reviewed .Prolonged submersion periods did not show effects on mortality of most benthic animals tested, with the exception of the crumb-of-bread sponge Halichondrea panicea, which, at low water-flow rates, was covered with a layer of bacteria and subsequently died .Protracted low-water periods of 18 hours during several weeks hardly caused any mortality . However, protracted low-water periods of 30 hours during some weeks or emersion during several days caused a strong increase in mortality, depending on : the duration of emersion, temperature, condition of the animals, species and age . At temperatures below -1 °C and above 24 °C mortality was generally high. Animals with a low glycogen content were more sensitive to emersion than those with a high content . Species with a shell and those that are relatively big were less sensitive than those without a shell or of small size .The reproductive cycle of benthic animals could be delayed or accelerated by both emersion and submersion . 219

The effect of energy reserves and cryoprotectants on overwintering mortality in Mercenaria mercenaria notata (Say 1822) at two tidal levels

“…Because the tidal level at which the bivalves live can affect their growth rate, mortality, and accumulation of energy reserves, this condition can also have repercussions on winter survival. The quahogs are naturally found in intertidal and subtidal zones (Tucker Abbott 1982;Manzi and Castagna 1989;Walker and Heffernan 1990a;Hummel et al 1994;Kraeuter and Castagna 2001). The intertidal zone exposes the individuals to higher stress associated with the mechanical strain of the waves, the irregular availability of food, the extreme variation of salinity and temperature, and exposure to air at low tide (Bayne 1976;Eldridge et al 1976Eldridge et al , 1979Murphy 1985;Harvey and Vincent 1989;Vincent et al 1989).…”

Spatial and temporal patterns of intertidal macrobenthic populations in the Oosterschelde: are they influenced by the construction of the storm-surge barrier?

“…Height of a site proper is of no importance to benthic animals but the emersion period is, which is of course function of the height (e .g ., Hummel et al, 1994). Due to the reduced tidal amplitude, above mid tidal level the immersion period decreased, below it increased .…”

Spatial variability in structural and functional aspects of macrofauna communities and their environmental parameters in the Jade Bay (Wadden Sea Lower Saxony, southern North Sea)

“…They represent highly productive areas for macrobenthic organisms (Heip et al 1995), thus being used as important feeding and nursery grounds by fishes and shore birds (Kuipers 1977;Widdows et al 2004). Macrofauna species inhabiting tidal flats are highly adapted to this dynamic environment characterized by tidal fluctuations, changing water currents, wave action, altering periods of submersion and exposure to air from low to high intertidal levels (Newell 1970;Hummel et al 1994). The hydrodynamic force itself influences sediment characteristics (grain size, organic carbon and chl a contents), topography (intertidal height) and salinity (Snelgrove and Butman 1994;Ysebaert et al 2003;Widdows et al 2004;Gray and Elliott 2009).…”