Abstract
To estimate the effect of the dominant mussel, Musculista senhousia, on water and sediment qualities in the closed-off section of Hakata Bay, we developed an ecosystem model of M. senhousia through its life cycle and obtained the following conclusions.
1) The calculated distributions of M. senhousia are spatially inhomogeneous and patchy owing to spatial differences in water and sediment qualities around it.
2) The amount of dead mussels in summer is 5.8- to 9.4- fold that in winter due to oxygen deficiency.
3) M. senhousia introduces a time delay for organic matter to settle as sediment, and a rapid settling of organic matter in oxygen-deficient water encourages the continuance of the oxygen-deficient water state.
4) The dominant macrobenthos work as intermediates in the cycling of substances settling as sediment and constitute an essential component of the ecosystem model. More precise information on their life cycle and effect on water quality is important.
