Relationship between epiphytes and the photosynthetic activity of temperate seagrasses

The relationship between epiphytes and the photosynthetic activity of Zostera japonica, Zostera marina, Zostera asiatica and Phyllospadix iwatensis was investigated. The epiphyte component of the seagrass leaves was composed primarily of diatoms and red calcareous algae. The epiphyte density was highest in the oldest region of the leaves and the oldest leaf in a shoot. The relationship between epiphytes and the photosynthetic activity of seagrasses is inversely proportional. The highest photosynthetic activity was observed in the younger leaves with low epiphyte density and vice-versa. This result indicates that the colonization of epiphytes in seagrasses is age-dependent.