Visualizing subsurface burrowing by the polychaete Alitta virens with particle image velocimetry

Abstract

Infauna, animals that live in marine sediments, alter physical, chemical, and biological properties of their habitats through burrowing and other activities. Though important, infaunal behavior is notoriously difficult to study. Sediments are resistant to imaging techniques because they scatter radiation and are dense and opaque, and measurements made across aquarium walls are subject to artifacts. In this study, particle image velocimetry (PIV) was used to indirectly observe the activity of the marine polychaete Alitta virens as it burrowed in sand and to measure its horizontal burrowing speed. The mean burrowing speed of 1.6 mm s‐1 for A. virens is the first published measurement of subsurface burrowing speed in sand. The extent of surficial sediment displacement was also measured. This study demonstrates the utility of PIV as a method for observing burrowing behavior and suggests potential applications in laboratory and field studies of burrowing behavior.

Multiscale Brazil nut effects in bioturbated sediment

“…Furthermore, size segregation resulting from graded bedding is not expected to depend on particle size above the maximum dimension of ingestible particles, while, as shown later, this dependence is required to explain the formation of FN. Plastic deformation of sediment around burrowing benthic organisms 39 , 40 is a possible BNE driving mechanism, because the deformation field includes a vertical gradient of horizontal displacement around burrow tips, which is analogous to the horizontal shearing used in many BNE experiments 6 , 41 . In this case, both the diffusivity and the segregation velocity are proportional to the shear rate 6 , 42 .…”

Quantitative thermodynamic exposure assessment of PCBs available to sandworms (Alitta virens) in activated carbon remediated sediment during ongoing sediment deposition

“…40,43 The walls remain well oxidized, 40,41,43 and the burrows effectively increase the surface area of the sediment–water interface. 44 Along with their role in enhancing geochemical processes, sandworms are ecologically significant, forming the base of the food chain in some habitats, as prey for lobsters, fish, and birds. 26,42…”

Parametric approach to promote a divergence-free flow in the image-based motion estimation with application to bioirrigation

“…Bioirrigation is most commonly estimated from tracer concentration profiles, from which it is quantified as the process required to reconcile the observations with simulated concentration profiles after accounting for the contribution of diffusion, or known sources and sinks [16,31]. More recently, fluid flow induced by bioirrigation has been estimated from images using (classical) correlation and gradient methods [14,22]. Kaza [22] employed the classical Horn-Schunk [21] and Lucas-Kanade methods [24], which promote a globally or locally smoothly varying flow and do not provide a systematic way to measure reliability of a recovered velocity field.…”