海中の濁りの藻場への影響 ＩＶ 褐藻類カジメ・ワカメ遊走子の着生率と基質傾斜の関係

Abstract

As one of the studies towards the rehabilitation of the seaweed-bed deteriorated with turbid water, the relationships between the zoospore adhesion of brown algae such as Ecklonia cava and Undaria pinnatifida and the gradients of the seaweed substrate were investigated. The rate of adhesion in the filtered sea water was reduced in inverse proportion to the gradients of the substrate almost in a linear fashion. In the turbid water with suspended particles, however, the deviations in rate of adhered zoospores caused by different gradients of the substrate became smaller as the turbidity increased. Furthermore, when the sediments were deposited very slightly on substrate, the rate of zoospore adhesion decreased suddenly, and the adhesion on a substrate having inclination angle became impossible with sediments only as much as 3mg/cm2, When it was considered that the deposited sediments decreased by the inclination of substrate, the larger the gradient was, the larger was the rate of zoospore adhesion. Under sedimentation of 3mg/cm2, the rate of adhesion with a gradient of 90 degrees showed a maximum value. Also, the adhesion of zoospores relates to the flow of water, and exhibited a maximum value with an approximate flow speed of 3cm/s. Under such circumstances, it was confirmed that the larger its gradient was, the larger was the rate of zoospore adhesion.