The interior of the adhesive plaque of a mussel from the waters of Santa Barbara. Blue is overlaid on the collagen penetrating the plaque, appearing like a river crossing the green surroundings. Green is overlaid on the foam structure that comprises the foam-looking bulk of the plaque.
False colored scanning electron microscopy image of a cross section of a Mytilus californianus mussel adhesive plaque. Collagen (blue) penetrates the plaque from the thread, creating a composite with the foam-structured plaque. In the case of M. californianus the plaque consists of a network of pores of two lengthscales: larger pores of ~1um in diameter and a mesh of ~100nm, whose mechanical significance is being studied.