Kilauea eruption sparked unusual phytoplankton bloom

The 2018 eruption of the Kilauea volcano on the Big Island of Hawaii resulted in a “rare and large summertime phytoplankton bloom,” scientists now report.

The new findings shed light on how volcanoes can deposit nutrients into ocean water, much as the seasonal dust clouds from the Gobi Desert in China “seed” nutrients in the Pacific Ocean.

It’s the first time Kilauea’s frequent eruptions have been tied to phytoplankton blooms in the Pacific. The findings are now published in the journal JGR Oceans.

Kilauea erupted in the summer of 2018, bellowing out an ash cloud that extended five miles (eight kilometers) into the sky. The ash was deposited thousands of miles from the site of the eruption. As the ash settled onto the water, it sprinkled nutrients that led to a massive phytoplankton formation to grow.

“A rare and massive…summertime phytoplankton bloom was observed in the nutrient-poor North Pacific Subtropical Gyre in the summer of 2018,” the authors declared.

“Deposition of ash released from volcano eruptions have been showed to be capable of enriching surface ocean waters with nutrients such as iron and phosphorus,” they explained further. “However, to date, there has yet to be a report linking volcanic ash released from Kilauea eruptions to phytoplankton blooms in the Pacific Ocean, despite being one of the most active volcanoes in the world with multiple eruptions in the past 40 years.”

The study was conducted by a team from the University of Malaysia, National Taiwan Ocean University, and the University of Hawaii at Manoa.

As the paper indicates, the waters where a massive phytoplankton bloom thousands of square kilometers in size was formed are known to be nutrient-poor, especially in summer. After the 2018 eruption, winds carried the ash cloud thousands of miles to the southwest of Hawaii.

The ash particles eventually settled, and life took advantage of the rare opportunity. The team says the eruption’s introduction of iron to the ocean waters particularly contributed to the sudden formation of the huge phytoplankton bloom.

“The waters in the open ocean of the Pacific are nutrient depleted,” said University of Hawaii oceanographer Dave Karl in an overview. “The addition of volcanic ash, especially iron in the ash, and to a lesser extent other trace elements and possibly phosphate, can stimulate the growth of marine phytoplankton, especially the so-called nitrogen-fixing microbes that can grow in the absence of additional nitrogen,” said Karl.

Very recently, Kilauea eruption again, spewing a fountain of lava several hundred feet high. The volcano has since settled down according to the United States Geologic Survey.