Seagrass is a higher-level plant that can live immersed in water in the aquatic environment near the coast. Seagrass colonies form a seagrass ecosystem that functions as a support in coastal waters which is strongly influenced by processes that occur in the sea and land. This ecosystem has a function as a primary producer, a recycler of nutrients, and a stabilizer of the bottom of the waters, as a habitat for biota, a place for spawning, a place for nurturing and foraging for various marine biota, and can protect the coast from the erosion process because it functions as a wave absorber and traps sediments. The field survey was conducted in April 2014 for seagrass observations and measurement of water condition parameters. The purpose of this study was to determine the types and conditions of seagrass on Kelapa Dua Island. The quadrant transect method was applied to seagrass observations carried out at 3 stations with each station consisting of 9 1m × 1m quadrant transect plots, then analyzed using a descriptive-quantitative approach. The results of the measurement of water quality parameters in the form of temperature ranged from 30.30 – 32.60 °C, the salinity of the waters in this study was in the range of 31.70 – 35.70‰. The pH value ranges from 7.40 – 7.75. DO levels ranged from 6.30 – 6.90 mg·L-1. The nutrients in the form of N and P were in the range of 1.19 - 1.79 mg·L-1 and 0.22 - 0.25 mgL-1, respectively. Meanwhile, seagrass observations found three types of seagrass, namely H. uninervis, T. hemperichii, and H. ovalis. The lowest percentage of seagrass cover was at station 1, which was 7.8% and the highest was at station 2, which was 36.11% with a diversity index ranging from zero to 0.94. The type of sediment at the research site has the characteristics of gravel sand.
Harahap et al. (Wed,) studied this question.