Distribution and Diversity of Macroalgae in Seagrass and Coral Reef Ecosystems on the Coast

Abstract

Background: The existence of macroalgae is threatened by various kinds of community activities, such as dumping garbage and household waste on the beach and fishing activities using boats that damage macroalgae habitat. This study aims to determine the distribution and diversity of macroalgae species in seagrass ecosystems and coral reefs on the coast in Samui Island, Surat Thani Province, Thailand. Methods: Data collection was carried out using the quadratic linear transect method. The transects used are 5 pieces with a square measuring 1x1 meter, as many as 10 pieces, and are supported by measurements of various physical parameters of aquatic clams. Results: There are 12 types of macroalgae found on the coast, of which 5 species are in seagrass ecosystems, and 7 are on coral reefs. The distribution of macroalgae in seagrass ecosystems is by attaching to sand and mud substrates, while on coral reefs, macroalgae are attached and stuck to coral rocks on reef flats. The value of macroalgae species diversity in seagrass ecosystems is low (1,381), while coral reefs are classified as medium (2,806). The value of overall macroalgae species diversity on the coast is low (2,093). The condition of physicochemical factors of waters in the form of temperature (29.20C), current strength (23.8 cm / second), depth (124 cm), and salinity of seawater (32.9 ppt) is still in a good range for macroalgae growth, while the acidity (pH) of seawater (6.07) is in a range that is not good for macroalgae growth. Conclusions: The value of macroalgae species diversity in seagrass ecosystems is low, while coral reef ecosystems on the coast are classified as medium.