Diversity and abundance of periphyton in the seagrass ecosystem Pulau Matahari, Pulau Banyak Aceh Singkil

Periphyton has a high primary productivity that enhances the primary productivity of seagrass ecosystem through food web. The objective of this study was to analyse the diversity and abundance of periphyton on seagrass leaf of Pulau Matahari, Pulau Banyak Aceh Singkil District. The research was conducted at four stations with five repetitions in August 2014. Samples of periphyton were collected by scrapping the surface of seagrass leaf with the swept area 5cm x 5cm. Samples were identified using the field of view method at Marine Biology Laboratory, Syiah Kuala University. Result of the research was found that the index values of diversity (H') ranged from 0.85 - 1.94 (low). Abundance of periphyton ranged from 234.556 - 879.585 ind/cm(2), it was found 22 species of periphyton belonged to class of Bacillariophyceae, Chlorophyceae, Rhodophyceae, Rotatoria dan Crustaceae. The highest abundance of periphyton belonged to class Bacillariophyceae (361607 ind/cm(2)), while the dominant species was Synedra sp. (55%).