The eruption last year of the Kilauea volcano in Hawaii produced the equivalent of 320,000 Olympic-size swimming pools of lava. Much of it ended up flowing into the Pacific Ocean, creating plumes of acidic, glassy steam in the process. The eruption also unexpectedly coincided with an explosion in the population of phytoplankton, a diverse array of sea surface-dwelling, sunlight-drinking microscopic organisms
  1. This massive bloom began just three days after lava from Kilauea first touched the sea. It expanded rapidly, stretching nearly 100 miles offshore in just two weeks. When the eruption dwindled and the lava stopped flowing seaward, the bloom quickly disappeared.
  2. Scientists were initially baffled as to how 2,100-degree Fahrenheit, life-annihilating lava could trigger a biological bloom
  3. A study published in Science reveals that it came down to a volcanic sleight of hand: As the lava tumbled to the ocean’s depths, it heated the deeper, nutrient-rich waters, allowing them to bubble up to the nutrient-starved surface. This provided a grand banquet for the phytoplankton, leading to their rapid proliferation.
  4. Understanding how phytoplankton respond to their environment is a vital undertaking, as they are critical to the planet’s health. 
  5. Phytoplankton form the foundation of marine food chains, and their seasonal blooms are responsible for more than half the photosynthesis, and the resulting production of oxygen, that occurs on Earth.
  6. The event is unlikely to be an anomaly. Kilauea is just one of several volcanoes around the world capable of dumping fresh lava into the ocean. 
  7. Lava-driven nutrient fountains “could be a pretty important driver of phytoplankton ecology in the broader ocean, said Harriet Alexander, a biological oceanographer at the Woods Hole Oceanographic Institution who was not involved in the latest study.
  8. The bloom was tracked by satellite, betrayed by the appearance of a teal-green film on the sea surface. Its growth strongly tracked with the lava’s entry into the water. It was clear that the two were connected, but not how.
  9. In mid-July 2018, at the height of the seaward lava discharge, a rapid-response scientific expedition shipped out to the region. A team of 18 scientists took as many chemical and biological samples as possible, both from the bloom’s surface and below it. 
  10. They found plenty of nitrates, nutrients that drive phytoplankton blooms. But the lava itself did not contain any nitrogen, so the origin of the nutrients was unclear.
  11. Back on land, the team wondered how lava mixing with seawater might somehow produce nitrates, but by then the lava flow had ceased.
  12. There is some evidence that volcanic ash can trigger a phytoplankton bloom, but only in nitrate-rich surface waters. 
  13. The study of the Kilauea-adjacent phytoplankton bloom is believed to be the first time researchers have shown that volcanic activity can drive a bloom in waters lacking that vital nutrient.

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