Hunga Tonga-Hunga Haapai island emerged from under the waters of the Pacific Ocean due to volcanic activity in 2014 and 2015, providing scientists with a rare opportunity to study how life evolved on new landmasses. But it didn’t last long: its short seven-year existence ended with the devastating eruption of Tonga in 2022.

A unique island

The small island of Hunga Tonga-Hunga Haapai, named after two neighboring islands, began to form underwater in December 2014 after a volcanic eruption. It had only 1.9 square kilometers. Once upon a time, scientists were surprised by what they found on the newly created island. Instead of the families of bacteria they hoped would first colonize the land, they discovered a strange group of microbes, possibly from deep within the Earth.

We did not see what we expected. We thought we’d see organisms found during glacier retreat or cyanobacteria typical of early colonizers. But instead, they found a unique group of bacteria that metabolize sulfur and atmospheric gases.
— says Nick Dragon, lead author of the study and PhD candidate in the Department of Ecology and Evolutionary Biology at the University of Colorado.

To find out exactly which microbes lived on the new island, the researchers collected 32 soil samples from different surfaces, from the edge of the sea to the top of the island’s 120-metre-high crater. Normally, scientists expect new islands to be populated by bacteria found in the ocean or in bird droppings. But the most common bacteria around the volcano’s cone were those that fed on sulfur and hydrogen sulfide. They may have been dragged to the surface of the island through underground volcanic networks. Of the 100 bacteria sequenced, 40 percent could not be assigned to any bacterial family known to the researchers..

Extinction

After all, the volcano that gave birth to the island became its destroyer. On January 15, 2022, the Hunga Tonga-Hunga Haapai volcano erupted again, with more than 100 bombs simultaneously dropped on Hiroshima, sending a cloud of ash, steam and debris into the atmosphere all over the island.

The eruption put an end to exploration of the island, but the short-lived appearance of the land provided a blueprint for future exploration. Scientists say they now have a lot of data on what happens when new islands are formed, and will examine similar formations at the earliest opportunity, although they are unfortunately extremely rare.