Underwater Volcano Fertilizes South Pacific Ecosystem

Paige Wise from USC recently returned from Tonga where she collected water samples around an underwater volcano, Volcano 1, to study its impact on marine life. Located along the Tonga-Kermadec Arc, the volcano releases iron-rich hydrothermal fluids.

These fluids fertilize a vast area of the South Pacific, creating a phytoplankton bloom spanning 360,000 square kilometers, an area roughly the size of Japan. Researchers believe this iron boosts the growth of diazotrophs, which then support the wider phytoplankton population.

The team used specialized instruments to track the plume of hydrothermal activity and conducted experiments to measure phytoplankton response to increased iron levels. The research faced logistical challenges including equipment malfunctions and difficult sea conditions, but also fostered collaboration with Tongan ministries and local fishermen. Understanding the scale of this volcanic fertilization is crucial for assessing the ocean’s carbon cycle and overall health.