On the ephemeral Hunga Tonga Hunga Ha’apai island, researchers have discovered a unique microbial community that metabolizes sulfur and atmospheric gases, similar to organisms found in deep-sea vents or hot springs.
In 2015, an undersea volcano in the South Pacific erupted, forming the island of Hunga Hapai, Hunga Tonga, destined to live only seven years. A team of researchers led by the University of Colorado Boulder and the Cooperative Institute for Research in Environmental Sciences (CIRES) jumped at the rare opportunity to study early microbial colonists of newly formed landmass, and to their surprise, the researchers found that A unique community of microbes metabolizes sulfur and atmospheric gases, similar to organisms found in deep-sea vents or hot springs.
“These types of eruptions happen all over the world, but they don’t usually create islands. We have a very unique opportunity,” said Nick Dragone, a CIRES doctoral student and the study’s lead author. microorganism“No one had ever comprehensively studied the microbes on this island system at such an early stage before.”
“Studying the microbes that first colonized islands gives us a glimpse into the earliest stages of ecosystem development—even before the arrival of plants and animals,” said Noah, a CIRES researcher and CU Boulder professor of ecology and evolutionary biology and the study’s corresponding author. Fierer said. .
A multi-institutional team of researchers on the ground collected soil samples from the island and shipped them to CU Boulder’s campus. Dragone and Fierer can then extract a DNA sample from the sample and sequence it.
“We didn’t see what we were expecting,” Dragone said. “We thought we’d see the organisms you’d find when glaciers retreated, or cyanobacteria, which are more typical of early colonizer species — but instead we found a unique set of bacteria that metabolize sulfur and atmospheric gases .”
And that’s not the only unexpected twist in the work: On January 15, 2022, seven years after its formation, the volcano erupted again, wiping out the entire landmass in the largest eruption of the 21st century. The eruption completely destroyed the island and made it impossible for the team to continue monitoring their site.
“We all want this island to stay,” Dragone said. “We actually started planning our return trip a week before the island exploded.”
However, the same fickle nature that made Hunga Tonga Hunga Ha’apai (HTHH) explode also explains why the team found such a unique set of microbes on the island. Hungatonga is volcanic, just like Hawaii.
“We think one of the reasons we’re seeing these unique microbes is because of properties associated with volcanic eruptions: lots of sulfur and hydrogen sulfide gas, which likely fueled the unique taxa we found,” Dragone said. “These microbes are most similar to those found in hydrothermal vents, hot springs like Yellowstone, and other volcanic systems. Our best guess is that these microbes came from these types of sources.”
Expeditions to the HTHH required close collaboration with members of the Government of the Kingdom of Tonga who were willing to work with researchers to collect samples from lands not normally visited by international guests. Years of coordinated work by collaborators at the Marine Education Society and NASA: Tongan observers must approve and monitor any sample collections that take place within the Kingdom.
“This work has attracted many people from all over the world, and we’ve learned a lot. We’re certainly disappointed that the islands disappear, but now we have a lot of predictions about what will happen when the islands form,” Dragone said. “So if something forms again, we’d love to go out there and collect more data. We’ll have a game plan for how to study it.”