Methane Plume Measurements in the Ragay Gulf

Unusual mid-water and bottom-water methane plumes, between 80 and 100 meters thick, were measured in the Ragay Gulf, Philippines. The dataset includes vertical distribution profiles and sea-air flux estimates from nine sampling locations. It was contributed by the Australian Ocean Data Network and was last updated in April 2026.

Use Cases

• Model methane sea-air flux using the reported average of 101 nmole.cm-2.y-1 and supersaturation measurements from the top 5 meters of the sea.
• Analyze the relationship between methane plume thickness (80-100 m) and the steep temperature-depth gradient where plumes are confined between 100 and 220 meters depth.
• Compare thermogenic methane flux estimates from this study with biogenic fluxes measured in other ocean regions.
• Correlate methane concentration anomalies with specific water column depths and geological features suggesting sea floor seepage.

Strengths

• Measurements from nine distinct geographic locations provide spatial coverage.
• Reports specific quantitative metrics like average methane supersaturation (206±16.5%) and sea-air flux.

Limitations

• Unknown sample size (row count) for the underlying measurement data.
• Primary data access may be limited to summary figures and statistics within PDF/HTML reports.
• Flux estimates are described as probable minimums due to low wind speeds during sampling.

Provenance

Source

Australian Ocean Data Network

Collection Method

Vertical water column measurements of methane distribution.

Freshness

Updated in April 2026.

Geography

Ragay Gulf, Philippines archipelago.