Influence of Water Depth on the Morphology Structure of Seagrass from the Southern of Peninsular Malaysia

Globally, seagrass meadows have declined due to environmental factors and human activities, particularly by limiting light to seagrass in turbid coastal waters. Furthermore, publications of seagrass research findings from the Southeast Asia region are scarce, making understanding these habitats difficult despite their ecological and economic importance. This research aimed to provide mean and standard deviation of seagrass morphology, as well as to examine the morphology structures in response to water depth. Samples of two species of seagrass, Halodule uninervis and Halophila ovalis, were collected by using random sampling in a line transect at Pulau Besar and Pulau Tinggi in Johor, southern Malaysia, in September 2013 and April 2014. Six morphological features of each seagrass species were measured physically using CPCe software and the relationship of water depth to seagrass were evaluated using Pearson’s Correlation. The result highlights that the leaf and root morphology is larger in Pulau Tinggi because it is nearer to the Johor mainland, where the introduction of nutrients from economic activity positively influence seagrass growth. The overall morphology structures of both species in both islands are greater in 2013 than 2014. For the relationship with water depth, it had greater positive relationship to H. univervis leaf width (r = 0.7532), internode width (r = 0.6722), leaf length (r = 0.5739); whereas for H. ovalis, water depth was correlated strongly with leaf width (r = 0.6697) and leaf surface area (r = 0.6313). The morphology of seagrass species varies depending on habitat conditions, this study can fill knowledge gaps, but more fundamental research on seagrass meadows is required particularly for the seagrasses in the Southeast Asia marine region.