Volcano-stimulated marine photosynthesis
Ducklow, Hugh ; Plank, Terry
Lava discharge to the ocean from volcano Kīlauea, Hawai'i, triggers phytoplankton blooms. Marine phytoplankton, microscopic unicellular algae, are responsible for about half of the photosynthesis on Earth (1). Photosynthesis, on land and sea, maintains atmospheric oxygen and CO2 levels, governing the habitability of the planet. This ocean photosynthesis (called primary production) is supported by opposing physical oceanographic mechanisms. Vertical stability, or buoyancy, of the ocean surface layer maintains the photosynthesizing biomass in the solar-irradiated euphotic zone, whereas vertical mixing or upwelling supplies deepwater nutrients, such as nitrogen, phosphorus, and silicon, which are required for phytoplankton growth. On page 1040 of this issue, Wilson et al. (2) report a heretofore unknown mechanism that enhances primary production of organic matter off Hawai'i. They found that lava discharged into the ocean by the erupting Kīlauea volcano created a plume of increased nutrient concentrations, enhanced phytoplankton growth, increased plankton abundance, and altered plankton species composition. Any of these responses could alter the local carbon cycle.</p>
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