Spatial Distribution of Halophila ovalis at St. John's Island Jetty Lagoon, Singapore

Project Overview

This fieldwork research project investigates the distribution patterns of the seagrass species Halophila Ovalis at Jetty Lagoon, St. John's Island, Singapore. Conducted as part of the National University of Singapore's Special Programme in Science (SP3275) Fieldwork Project, this study provides quantitative data on seagrass meadow characteristics across the intertidal zone from 24–25 October 2025. The fieldwork was conducted during evening low tide periods, which provided safe access to the intertidal zone for data collection. The mapped area includes seagrass meadows (green zones) and a restricted area (yellow zone) utilized by the Tropical Marine Science Institute (TMSI) for concurrent research activities.

Methodology

Sampling Design:

• 11 transects established across Jetty Lagoon
• 3 sample locations per transect at 10-meter intervals
• 3–5 replicate quadrats per sample location (randomly positioned)

• Shoot Count: Number of shoots per quadrat
• Coverage: Percentage per quadrat (determined via image analysis)
• Biomass (Above & Below Ground): Wet weight in grams
• Shoot Density: Shoots per m²

Map Visualization

Scale: 60 m : 260 units → 1 m : 4.5 units

Interactive Features: Hover over sample points to view averaged replicate data:

• Average shoot count (shoots/quadrat)
• Average coverage (%)
• Average above-ground biomass (g wet weight)
• Average below-ground biomass (g wet weight)
• Average total biomass (g wet weight)
• Average shoot density (shoots/m²)