On the short-lived island of Hunga Tonga Hunga Ha’apai, 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, a submarine volcano erupted in the South Pacific Ocean, forming Hunga Tonga Island Hunga Ha’apai, which is destined to have a short life of seven years. A research team led by the University of Colorado Boulder and the Collaborative Institute for Research in Environmental Sciences (CIRES) jumped at a rare opportunity to study the early microbial colonies of a newly formed landmass, and to their surprise, the researchers discovered a unique microbial community that metabolized sulfur and atmospheric gases, similar to organisms found in deep-sea vents. or hot springs.
said Nick Dragon, a CIRES doctoral student and lead author of the study published this month in the journal Mbeo. “No one has ever comprehensively studied the microorganisms in this type of island system at such an early stage before.”
“Studying the microbes that first colonized islands provides a glimpse into the earliest stage of ecosystem evolution—before the arrival of plants and animals,” said Noah Ferrer, CIRES fellow, professor of ecology and evolutionary biology at CU Boulder and corresponding author on the study. .
A multi-institutional team of researchers on the ground collected soil samples from the island, then shipped them to the University of Colorado Boulder campus. Dragon and Ferrer can then extract DNA from the samples and sequence them.
“We didn’t see what we expected,” Dragon said. “We thought we’d see the organisms you find when glaciers retreat, or cyanobacteria, which are more typical types of early colonies — but instead we found a unique group of bacteria that metabolize sulfur and atmospheric gases.”
And that wasn’t the only unexpected twist in this action: On January 15, 2022, seven years after it formed, the volcano erupted again, obliterating the entire landmass in the largest eruption of the 21st century. The volcanic eruption completely wiped out the island, eliminating the option for the team to continue monitoring their location.
“We were all expecting the island to survive,” Dragon said. “Actually, a week before the island exploded, we were planning a return trip.”
However, the same fickle nature of Hunga Tonga Hunga Ha’apai (HTHH) that made it explode also explains why the team discovered such a unique group of microbes on the island. Hongja Tonga was volcanically formed, like Hawaii.
“One of the reasons we think we’re seeing these unique microbes is because of characteristics associated with volcanic eruptions: lots of sulfur and hydrogen sulfide gas, which likely fueled the unique taxa that we found,” Dragon said. “The microbes were most similar to those found in hydrothermal vents, hot springs like Yellowstone, and other volcanic systems. Our best guess is that the microbes came from those kinds of sources.”
The HTHH expedition required close collaboration with members of the Government of the Kingdom of Tonga, who were willing to work with researchers to collect samples from land not usually visited by international guests. The coordination took years of work by collaborators at the Education of the Sea and NASA: A Tongan observer must approve and supervise any sample collection that takes place within the kingdom.
“This work has brought a lot of people in from all over the world, and we’ve learned a lot. We’re of course disappointed that the island is gone, but now we have a lot of predictions about what happens when islands form,” Dragon said. “So if something forms again, we’d like to go out there and collect more data. We’ll have a game plan for how we study it.”