Burrow architecture and turbative activity of the thalassinid shrimp Callianassa subterranea from the central North Sea

Abstract

The architecture and development of the burrows of the endobenthic shrimp Callianassa subterranea from the central North Sea were studied in sediment-filled containers and thln cuvettes in the laboratory. Three-dimens~onal burrows of 81 shrlmps were used to describe the 3-dimensional burrow architecture. In total, 41 shrimps made 2-dimensional burro\vs in cuvettes tailored to their body widths. Development of 8 burrows over time was registered by regularly mapping burrow outllnes and sediment surface levels. Excavation velocities and s e d~m e n t expulsion rates were denved from changes in the burrow outlines and sediment surface levels on the maps The total tunnel length increased at a rate of 23.4 + 6 0 mm h-' durlng the initial stage of bul-row development. The length ~ncl-ease levelled off during the completion of the first and second U-tubes to 5.6 r 1.8 mm h-' In~tial sediment expulsion rates up to 15 0 cm3 d.' were established. The average sedim~.nt expulsion rate was 1.080 t 0.096 cm" d.' Extrapolation to a yearly dry welght (dry I\?) sediment turnover, including population density and water temperature effects, resulted in an estimate of 15.5 + 2.7 kg dry wt m-' yr-l, equivalent to d 1.2 cm layer. Samples of burrow lining, expelled sediment and unprocessed sediment did not show changes in grain size distributions or organic content due to manipulation or processing by C. subterranea. Burrow development experiments carried out in enriched seawater systems did not reveal consistent effects of particulate organic matter (POM) on sediment expulsion rates or on the composition of processed or unprocessed sediment.

Bioturbating shrimp alter the structure and diversity of bacterial communities in coastal marine sediments

“…Thalassinidean shrimp therefore actively alter both the physical structure and the chemical environment within the sediment (Astall et al, 1997), and it may be predicted that this has a significant impact on the microbial communities inhabiting the sediment. In the case of C. subterranea, the sediment surrounding the burrow may be regularly disturbed as the shrimp fills in old tunnels and constructs new ones (Stamhuis et al, 1997). The intermediate disturbance hypothesis predicts that in areas where there is an intermediate level of 'disturbance' (a discrete event that disrupts the ecosystem, changes resource availability or alters the physical environment), higher levels of biodiversity are likely to be promoted by the coexistence of otherwise competing species (Connell, 1978).…”

Temporal and spatial variation in macrofauna community composition imposed by ghost shrimp Callianassa filholi bioturbation

“…Furtherto sampling, 4 sites (4 X 4 m) were arbitrarily chosen to more, the sediment turnover activity of temperate speeach represent low and high Callianassa filholi densities has been shown to differ significantly over time ties. (Stamhuis et al 1997 Initial selection of density groupings was based on & Rowden 1999). However, most studies to date have an average of 2.5 sediment expulsion mounds m-2 for examined the impact of callianassid s h r~m p bioturbalow density sites, and an average of at least twice as tion under laboratory conditions and/or involved exmany for high density sites.…”

Intraspecific burrow plasticity of an intertidal population ofCallianassa filholi(Crustacea: Decapoda: Thalassinidea) in relation to environmental conditions

“…In particular, C. subterranea has been recorded to be virtually inactive at low temperatures (<7°C, Rowden et al 1998), and low sediment expulsion activity of C. filholi is significantly related to minimum seawater temperature in colder months (~7°C, Berkenbusch & Rowden 1999). As sediment reworking by deposit-feeding callianassids is intrinsically linked to burrow maintenance and feeding (Stamhuis et al 1997), it is likely that low sediment turnover rates are reflected in smaller-sized burrows during colder months. Low values for total length of C. filholi burrows in winter support this contention.…”

“…Reasoning that as the abundance of benthic fauna in the sediment surface has been found to increase with organic content (Creutzberg et al 1984), Callianassa subterranea avoids competition with shallow burrowing infauna by constructing relatively deep burrows. Deep burrows in turn result in fewer openings to the surface (i.e., less complex), as a result of the increased effort to maintain openings in deep as opposed to shallow burrows (Stamhuis et al 1997). Spatial competition has also been suggested to influence burrow morphology for an intertidal Biffarius arenosus population; spiral sections featured in some burrows and possibly reflect the necessity to exploit most of the food supply in a given area (Bird & Poore 1999).…”

“…Rowden & Jones (1995) reasoned that to meet its energetic requirements the deposit-feeding callianassid needs to process higher amounts of sediment, resulting in more complex burrows in organically poor sediments, than in enriched substrata. Alternatively, Stamhuis et al (1997) suggested that higher competition for food and space induces shrimp to construct deeper burrows in organic rich sediments. Reasoning that as the abundance of benthic fauna in the sediment surface has been found to increase with organic content (Creutzberg et al 1984), Callianassa subterranea avoids competition with shallow burrowing infauna by constructing relatively deep burrows.…”