Meeting Abstract
Muddy marine sediments are elastic materials through which worms extend burrows by fracture. Elastic fracture depends on two sediment material properties: fracture toughness and stiffness. Variability in the ratio of these properties has been shown to affect the behavior of burrowing worms. Very little data exists, however, on how these properties vary in the natural environment. We have identified several problems with previous methods of measuring sediment fracture toughness and have developed and tested an instrument that addresses these problems. We will present data on fracture toughness profiles across a gradient of muddy sediments and will compare fracture toughness to more commonly used geological measurements such as grain size and organic content. Quantifying these material properties of sediments is critical to understanding how burrowing kinematics and mechanics vary in the natural environment. These measurements are also an important step in linking animal-sediment interactions to broader ecological processes in sediments.
