Comparative effects of the large bioturbators, Trypaea australiensis and Heloecius cordiformis, on intertidal sediments of Western Port, Victoria, Australia

Abstract

The effect of bioturbation by the ghost shrimp Trypaea australiensis and semaphore crab Heloecious cordiformis was compared in sediment-filled tanks in the laboratory. Effect of bioturbator density was also investigated with high- and low-density treatments. It was hypothesised that the two species would influence the sediment profile in different ways owing to their contrasting burrowing and feeding habits. Both species increased porosity of surface sediments relative to control tanks. Crab activity did not alter redox potential, but low densities of shrimp created more oxidising conditions and high densities of shrimp created more reducing conditions than controls. Burial of tracer particles by crabs was restricted to the top 5 cm, whereas shrimp mixed particles to depths of 25 cm. Bioturbator density had little effect on the extent of particle mixing. The presence of both shrimp and crabs increased benthic microalgae in the sediments relative to the controls. Again, crabs had the greatest effect at the sediment surface, whereas shrimp also enhanced concentrations at 25 cm depth. High densities of shrimp had the greatest effect. Overall, shrimp bioturbation influenced deeper sediments than crab bioturbation, but there was no clear density-dependent effect.

Effects of the Bioturbating Marine Yabby Trypaea australiensis on Sediment Properties in Sandy Sediments Receiving Mangrove Leaf Litter

“…Additionally, bioturbated treatments demonstrated higher sediment porosity than those in the non-bioturbated treatments ( Table 2, Supplementary File 1). Such findings agree with previous studies regarding burrowing shrimp [8,73] due to reworking and turnover of sediments altering the size of the interstitial spaces.…”

Long-distance electron transport by cable bacteria in mangrove sediments

“…However, unlike previously sampled sites, mangroves are subject to a bioturbation regime imposed by macrofauna such as fiddler crabs and ghost shrimps (Kristensen & Alongi 2006). Even though fiddler crabs do not occur at the mangrove sites investigated here, ocypodid crabs and ghost shrimps are known to rework the sediment (Katrak & Bird 2003). Bioturbation has been put forward as a major constraint on the distribution of cable bacteria: macro-benthos is able to mechanically cut the bacterial 'power cords' while reworking the sediment .…”

Bioturbator‐stimulated loss of seagrass sediment carbon stocks

“…T. australiensis (henceforth referred to as "Callianassids") is an upward conveyor deposit-feeding bioturbator (Butler et al 2009;Kristensen et al 2012), that constructs complex burrows (typically with two openings; Katrak and Bird 2003) ranging from <10 cm (Butler and Bird 2008) to approximately 50 cm in depth (Stapleton et al 2001). Callianassids typically live on a diet of diatoms and small particles of organic material, preferring particles <63 μm in size (Stapleton et al 2001).…”