How a New Volcanic Island Revealed Surprising Life Forms

This Island Appeared Out of Nowhere, With Life Forms Never Seen Before

A submarine volcanic eruption in the South Pacific formed Hunga Tonga-Hunga Haʻapai, a new island situated between the existing islands of Hunga Tonga and Hunga Haʻapai. The eruption, which lasted several weeks, created a landmass rising over 100 meters above sea level and measuring approximately 2 kilometers wide. This event provided scientists with a rare opportunity to examine the processes of island formation and the initial stages of ecological colonization. 

The island’s surface was composed of volcanic ash, fragmented rock, and sulfur compounds, reflecting its origin from volcanic activity. Researchers from fields such as geology, volcanology, and ecology conducted early assessments to evaluate the island’s stability and the environmental factors influencing its development. These studies aimed to document the evolution of a newly formed landmass and its interaction with surrounding conditions over time.

This Island Appeared Out of Nowhere, With Life Forms Never Seen Before. View from the summit of Hunga Tonga -Hunga Ha'apai island. (Photo: Damien Grouille)

Microbial Colonization: An Unexpected Discovery

A team from the University of Colorado Boulder and the Cooperative Institute for Research in Environmental Sciences (CIRES) examined the earliest microbial inhabitants of the island. Initial hypotheses predicted that photosynthetic microbes, such as cyanobacteria, would dominate the barren landscape as the first colonizers. However, the findings revealed a distinct population of microbes that metabolize sulfur and atmospheric gases, resembling organisms typically observed in extreme environments like deep-sea hydrothermal vents and terrestrial hot springs.

The presence of these sulfur-metabolizing bacteria is attributed to the island’s volcanic composition, which released substantial quantities of sulfur and hydrogen sulfide gases. This suggests that chemotrophic microbes—organisms that derive energy from chemical reactions rather than sunlight—may play a significant role in the early ecological development of new volcanic landmasses.

Factors Influencing Microbial Presence

The volcanic nature of Hunga Tonga-Hunga Haʻapai created conditions conducive to the growth of these unusual bacteria. Volcanic eruptions produce sulfur and hydrogen sulfide, providing a chemical foundation for chemotrophic microbes. Nick Dragone, a PhD student at CIRES and lead author of the study, noted, “These microbes were most similar to those found in hydrothermal vents, indicating a likely origin from such environments.” This discovery challenges conventional models of ecological succession, which typically emphasize photosynthetic organisms as initial colonizers, and offers insights into life’s potential establishment in extreme settings, including extraterrestrial volcanic landscapes.

Destruction by Volcanic Eruption

On January 15, 2022, a major eruption of the Hunga Tonga-Hunga Haʻapai volcano destroyed the island, terminating its existence after seven years. Recognized as one of the most significant volcanic events of the 21st century, this eruption underscored the temporary nature of such geological formations. Despite its brief lifespan, the island provided critical data on ecological succession and microbial adaptation in harsh conditions prior to its destruction.

Scientific Contributions and Future Implications

Though no longer present, Hunga Tonga-Hunga Haʻapai has left a lasting impact on scientific research. The identification of sulfur-metabolizing microbes offers evidence of life’s adaptability in extreme environments, with implications extending beyond terrestrial studies. Published in mBio, the research contributes to astrobiology by suggesting mechanisms through which life might emerge on volcanic worlds, such as Mars or the moons of Jupiter.

Dragone emphasized the project’s significance, stating, “These eruptions occur globally, but few result in islands. This provided a unique opportunity to study early microbial colonization on a new landmass.” The findings enhance understanding of life’s origins in isolated, extreme settings and hold relevance for investigating early Earth conditions. “This effort brought together scientists worldwide, and the knowledge gained is substantial,” he added. “We now have predictions prepared for the next instance of island formation.”

The island’s short existence enabled researchers to observe both its geological development and the establishment of microbial life. The presence of chemotrophic bacteria challenges prior assumptions about ecological colonization and demonstrates life’s capacity to thrive in challenging environments. Although the island has vanished, the scientific insights derived from it will inform future investigations of similar phenomena.

From its emergence in 2015 to its destruction in 2022, Hunga Tonga-Hunga Haʻapai exemplified the dynamic nature of volcanic activity. Over seven years, it transitioned from a lifeless expanse into a site of microbial activity, only to be erased by a subsequent eruption. Nevertheless, its brief presence advanced knowledge of how life initiates in some of Earth’s most inhospitable regions. Looking forward, researchers anticipate further opportunities to study newly formed islands. “Should another emerge, we are prepared to continue this work,” Dragone concluded.

The above story is based on Materials provided by Materials provided by University of Colorado at Boulder.