Methane (CH₄) Fluxes in Mangrove Sediments of Negeri Passo, Inner Ambon Bay: Implications for Climate Change

Abstract

Mangrove ecosystems play a significant role in carbon sequestration. However, the accumulation of organic matter in mangrove sediments undergoes decomposition, which triggers the release of CH₄ gas flux. This study aims to analyze the CH₄ gas flux in the mangrove sediments of Negeri Passo, Inner Ambon Bay. Gas sampling was conducted using a cylindrical chamber at three observation stations. Gas was collected using a syringe five times at 30-second intervals. The gas concentration was analyzed using gas chromatography, while the CH₄ flux was calculated using a flux equation that considers the regression slope, chamber volume and area, temperature, gas molecular weight, ideal gas constant (R), and time constant based on the gas sampling interval. The results showed that the average CH₄ concentration was 22.46 ppm. The highest concentration was found at Station 2, with 33.33 ppm, and the lowest at Station 3, with 14.40 ppm. The average CH₄ flux was 3.2194 mg/m²/h. The highest CH₄ flux was observed at Station 3, with 4.8727 mg/m²/h, while the lowest was at Station 1, with 1.3421 mg/m²/h. Based on these findings, it can be concluded that the mangrove ecosystem in Negeri Passo has a relatively higher CH₄ flux compared to other locations within the Inner Ambon Bay area. Additionally, the significant carbon sequestration potential, as indicated by the Tier 1 model approach, suggests that this mangrove ecosystem plays a crucial role in climate change mitigation. These findings highlight the dual role of the mangrove ecosystem in Negeri Passo, acting as both a carbon sink and a source of CH₄ emissions, emphasizing the need for further research to balance its sequestration potential with methane release dynamics.