Phosphate Scavenging During Lava‐Seawater Interaction Offshore of Kīlauea Volcano, Hawaii

The 2018, subaerial eruption of Kīlauea volcano, Hawaii, resulted in a 5-km-long stretch coastline that actively drained lava into the ocean. Nutrients were added to surrounding ocean through dissolution basaltic rock and thermal upwelling deep water, thereby fueling large phytoplankton bloom. Lava-impacted, surface seawater had high suspended particle loads, concentrations chlorophyll, silicic acid, phosphate (Pi), nitrate, iron elevated up 12, 36, 5, 960, 1,400 times, respectively, above background oligotrophic levels. Widespread precipitation oxyhydroxides (Feox) led extensive scavenging dissolved Pi pool, similar what occurs along mid-ocean ridge hydrothermal systems. This transformed “fertilization” event sink near coast entry; however, nutrient data from outside bloom suggest could also desorb Feox as it is dispersed open From quench experiments, we estimate hydration state precipitate (H2O/Fe) was 5.2–5.7, equilibrium partition coefficient (solid/liquid) 106. In addition, 33Pi radiotracer incubations used differentiate between biotic abiotic uptake at Kīlauea's entry. These findings are important for understanding modern-day volcanic fertilization events, modeling dynamics during major events Earth history (such oxygenation atmosphere formation igneous provinces), predicting marine response greater continental weathering warming climate.