Quantitative Evaluation of Bioturbation by the Burrowing Macrophthalmus japonicus

The objective of this study is to elucidate the burrow structure and to evaluate quantitative physical bioturbation of the dominant species, crab Macrophthalmus japonicus in muddy tidal flat. Burrows consisted mainly of J-shaped structures. Various burrow parameters were strongly correlated with carapace width of M.japonicus. It was estimated that burrows increased the surface area by 5~32% in investigation area. and population of M.japonicus can turn over approximately 3~34% of the upper 20 cm of sediment. These results indicated that burrowing activities of M.japonicus significantly influences the material cycle.