Seagrass meadows are among the most important yet often overlooked coastal ecosystems. They stabilize sediments, improve water quality, provide nursery grounds for fish and other marine organisms, and contribute significantly to blue carbon storage. As tourism and coastal development continue to expand across Indonesia's island regions, protecting these underwater ecosystems has become increasingly important for maintaining ecological balance and supporting local livelihoods.
Pananualeng Beach, located east of Tariang Baru Village in Central Tabukan District, is known for its white sandy shoreline and clear shallow waters that attract visitors. Despite its tourism potential, ecological information on its seagrass ecosystem has been limited. Without reliable baseline data, environmental changes caused by tourism, coastal development, or climate-related pressures may go unnoticed, making long-term conservation more difficult. The study addresses this knowledge gap by documenting the composition of aquatic vegetation and evaluating environmental conditions that support seagrass growth.
Simple Field Survey Across Three Coastal Stations
The researchers conducted field observations at three representative sampling stations covering the left, middle, and right sections of Pananualeng Beach. They recorded seagrass species using line-transect quadrats while simultaneously measuring water quality indicators, including temperature, salinity, dissolved oxygen, pH, nitrate, nitrite, and ammonia.
Rather than relying on laboratory experiments, the research focused on direct ecological observations in the natural environment. The collected data were analyzed by comparing species composition, ecological dominance, and water quality with Indonesia's seawater quality standards for marine ecosystems.
Four Seagrass Species Recorded
The survey documented four seagrass species growing across the study area:
- Thalassia hemprichii
- Enhalus acoroides
- Halodule pinifolia
- Cymodocea rotundata
Among these species, Thalassia hemprichii consistently showed the highest ecological dominance at all three sampling stations based on its Importance Value Index (IVI). The species was followed by Enhalus acoroides, while Halodule pinifolia and Cymodocea rotundata contributed to overall biodiversity but with lower ecological dominance.
According to the researchers, the dominance of Thalassia hemprichii indicates that environmental conditions at Pananualeng Beach remain highly suitable for sustaining stable seagrass communities and supporting associated marine life. The continued presence of Enhalus acoroides, a larger seagrass species known for stabilizing sediments and protecting coastal habitats, further reflects the ecological health of the area.
Water Quality Indicates Low Human Disturbance
Measurements of seawater quality also suggested that the coastal environment remains relatively undisturbed.
Key environmental observations included:
- Water temperature ranged from 29°C to 31°C.
- Salinity ranged from 31 to 33 ppt.
- Dissolved oxygen measured 5.8–6.5 mg/L.
- pH ranged from 8.0 to 8.2.
- No nitrate, nitrite, or ammonia was detected at any sampling station.
These results indicate that water quality remains within acceptable limits for marine organisms and seagrass ecosystems. The absence of detectable nitrogen compounds suggests minimal nutrient pollution and low anthropogenic pressure during the observation period, reducing the risk of eutrophication that can damage seagrass habitats.
Supporting Sustainable Tourism and Coastal Conservation
The findings provide practical guidance for environmental management in small-island tourism destinations. Healthy seagrass ecosystems contribute not only to marine biodiversity but also to fisheries productivity, shoreline protection, and long-term tourism sustainability.
As visitor numbers and coastal infrastructure continue to increase in many island regions, baseline ecological data become essential for monitoring environmental change. The Pananualeng Beach study offers local governments and environmental managers scientific evidence that can support conservation planning, sustainable tourism policies, and routine ecological monitoring.
The researchers also recommend expanding future studies through additional sampling stations, seasonal observations, and broader environmental measurements to better understand long-term ecological dynamics within the seagrass ecosystem.
Academic Perspective
Yeni Indriani and colleagues from Politeknik Negeri Nusa Utara conclude that the relatively healthy condition of aquatic vegetation at Pananualeng Beach is reflected in the presence of four seagrass species, the ecological dominance of Thalassia hemprichii, and seawater quality that remains suitable for marine life. The authors state that these findings provide baseline ecological information that can support sustainable tourism management, seagrass conservation, and continuous environmental monitoring in the Sangihe Islands.
Author Profile
Yeni Indriani is a researcher from the Department of Fishery and Maritime Technology, Politeknik Negeri Nusa Utara, Tahuna, Sangihe Islands Regency, North Sulawesi, Indonesia. She conducted this study together with Magdalin Ulaan, Numisye I. Mose, Yessi A.P. Manganang, and Jetti T. Saselah. Their research focuses on marine ecology, coastal environmental management, aquatic ecosystems, water quality, and sustainable fisheries and coastal conservation.
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