Use of X‐ray images and a contrasting agent to study the behavior of animals in soft sediments

Abstract

We developed a means of observing and recording the burrowing behavior of animals in soft sediments by using X‐ray images. The poor contrast between animal burrows and sediment was compensated for by the addition to sediment of a dense inert compound, molybdenum carbide. This contrasting agent allowed us to quantify the developmentturbation rates. The considerable variation observed in the depth of burrows constructed by various taxa could influence their potential exposure to vertically stratified food particles and sedimentary contaminants. We also used the contrasting agent in the field to demonstrate that burrow structures could be observed in situ. The radiographic technique we tested should be useful in determining the influence of animals on the physics and chemistry of sedimentary deposits, as well as the impact of sedimentary contaminants on the burrowing and feeding of benthic animals in either marine or freshwater systems. in space and over time of burrows made by a variety of small animals, as well as to determine the exact location and orientation of animals in a burrow system. Nymphs of the mayfly Hexagenia are confirmed to be very active burrowers in comparison with other sympatric insect taxa and are thus likely to be key animals in influencing community irrigation and bioturbation. The considerable variation observed in the depth of burrows constructed by various taxa could influence their potential exposure to vertically stratified food particles and sedimentary contaminants. We Also used the contrasting agent in the field to demonstrate that burrow structures could should be useful in determining the influence of animals on the physics and chemistry of sedimentary deposits, as well as the impact of sedimentary contaminants on the burrowing and feeding of benthic animals in either marine or freshwater systems.

Impact of Macrozoobenthos on Two-Dimensional Small-Scale Heterogeneity of Pore Water Phosphorus Concentrations: in-situ Study in Lake Arendsee (Germany)

“…To solve these problems, it would be preferable to use a method to visualize the course of the chironomid burrows immediately in front of the 2D peeper. In future, we will try to locate the course of the burrows in laboratory mesocosms using X-rays according to the method of Charbonneau et al (1997). To recapitulate the interim results: Although there is no direct correlation between SRP concentration and chironomid density at the same point of the grid of the 2D peeper deployed in 14 m water depth the comparison of the two peepers supports the thesis that macrozoobenthos causes heterogeneity.…”

Modelling cadmium accumulation by benthic invertebrates in situ: The relative contributions of sediment and overlying water reservoirs to organism cadmium concentrations

“…The considerable overlap in the confidence intervals around the slopes for these taxa does not allow us to determine if some of them take up more Cd from the sediment than do others. At least some of the taxa in this group are known to construct burrows that extend into anoxic sediment; these include the chironomids Procladius and Glyptotendipes, the alderfly S. velata, and the mayfly H. limbata (Charbonneau et al 1997). Information is lacking on the burrowing behavior of the other taxa in the group (the dipterans Ablabesmyia, Ceratopogonidae, and Protanypus).…”

A new method for three‐dimensional visualization and quantification of biogenic structures in aquatic sediments using axial tomodensitometry

“…X-radiography-X-radiography has been used to visualize and quantify endobenthic burrows (Stanley 1970;Rhoads and Boyer 1982;Davey 1994;Diaz et al 1994;Gerino et al 1999;Gosselin and Hare 2003) and, in combination with the use of contrasting agents, to determine the behavior of organisms in the sediment (Charbonneau et al 1997). With this method, only thin sections (up to a few centimeters in thickness) of sediments can be observed, therefore it is of limited use for observing structures made by larger animals or those in three dimensions.…”