A large asteroid hitting Earth can wipe out life in the area, but it can also kickstart new life. A recent study of an impact site in Finland shows that microbes started to thrive just four million years after the disaster. This finding was shared in Nature Communications and highlights how quickly life can return to a barren landscape.
Finland is famous for its lakes, especially Lake Lappajärvi. This unique lake formed about 78 million years ago from an asteroid impact. In 2024, UNESCO will recognize this area as a geopark, aiming to protect its fascinating history and geological features.
Dr. Jacob Gustafsson, a geoscientist from Linnaeus University in Sweden, led a team that examined rocks taken from deep beneath Lake Lappajärvi. They wanted to understand how quickly microbes colonized the site after the impact, which heated rocks to around 2,000°C (3,632°F). Dr. Henrik Drake, another team member, pointed out that fresh impact sites could resemble environments where life might begin, even on other planets.
In 2022, the team explored the Geological Survey of Finland’s core samples and selected specific sections that showed signs of microbial activity. The researchers focused on crystals formed within these samples, using advanced techniques to determine their age and what types of microbes might have existed. They found signs of ancient microbial processes that could provide insights into how life evolved on Earth.
Interestingly, the groundwater around Lake Lappajärvi managed to cool down to about 50°C (122°F) after four million years. This cooling process took much longer than at similar impact sites like the Ries Crater in Germany, where temperatures dropped far quicker. According to Teemu Öhman, an impact geologist, this slower cooling likely results from the region’s unique rock composition, which has thick bedrock layers. Unlike its counterparts, these rocks melted during the impact, retaining heat for a more extended period.
As a result, microbial activity was able to start earlier in Lake Lappajärvi’s history. Around 10 million years later, when temperatures finally dropped to around 30°C (86°F), methane-producing microbes likely began their work. The team plans to investigate other Finnish impact sites to find similar microbial activity and learn more about our planet’s early life.
This research may not only refine our understanding of life’s origins on Earth; it could also reshape how scientists look for life on other planets. Exploring celestial bodies with similar geological histories could reveal amazing discoveries. To learn more about this research, you can check the UNESCO geopark initiative related to Lake Lappajärvi.
