Variation in morphological parameters of the seagrass Thalassia hemprichii (Ehrenberg) Ascherson) across substrate types and locations in Northern Sulawesi, Indonesia

Abstract

The morphological parameters of the seagrass Thalassia hemprichii were measured and compared between substrate types (e.g. mud, sand, rubble) and across locations (Arakan, Likupang, Tanjung Merah, all in North Sulawesi, Indonesia). Seagrass samples from Likupang were shorter compared to either Tanjung Merah and Arakan while leaf width was consistent across the survey sites while samples from Arakan had longer node length compared to the two other sites. Underground structures (rhizome, stem and root) were consistently highest in Arakan compared to Likupang and Tanjung Merah. One-Way Analysis of Variance revealed significant variation in mean values of morphometric parameters but such variations overlap across substrate type and locations based on multivariate principal component analysis (PCA). Future investigators should focus on possible correlation between nutrient input (e.g. from surface run-off or other point sources) and morphology of seagrasses, aside from T. hemprichii. Where possible, measurement of the biophysical conditions and nutrient analysis be conducted using long-term approach and should include monitoring of growth-rate of seagrasses.