Abstract
To elucidate the influence of optical attenuation on the primary production, field observation of light photon and water quality were conducted in the Mukawa coast, the Pacific Ocean of northern Japan. During the flood event, the primary production was limited by scattering of light by suspended sediment. Attenuation of light by suspended sediment was large in the coastal, but the chlorophyll-a was large offshore. The extinction coefficient is decided with the suspended sediment in the coast, and decided with the chlorophyll-a offshore. Therefore, we propose a model of extinction coefficient to apply between the coast and offshore. The results of this study, it is considered to become a knowledge effective for prediction and analysis in the low-order ecosystem model and primary production of coastal areas. In addition, it will contribute to understand the habitat of Japanese surf clam (Pseudocardium sachalinensis) of Mukawa coast.
