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Microbial Life Colonizes Post-Impact Craters And Thrives For Millions Of Years

78 million years ago, a 1.6 km asteroid slammed into what is now Finland, creating a crater 23 km (14 mi) wide and 750 km deep. The catastrophic impact created a fractured hydrothermal system in the shattered bedrock under the crater. There’s evidence from other impact structures that in the aftermath of a collision, life colonized the shattered rock and heated water that flowed through it. But determining when the colonization happened is challenging.

New research shows for the first time exactly when that colonization happened. A team of researchers has zeroed in on the date that microbial life populated the hydrothermal system under the 78 million year old Lappajärvi impact structure.

Their research is titled “Deep microbial colonization during impact-generated hydrothermal circulation at the Lappajärvi impact structure, Finland” and is published in Nature Communications. Jacob Gustafsson, a PhD student at Linnaeus University in Sweden, is the first author.

“This is incredibly exciting research as it connects the dots for the first time.” – Dr. Gordon Osinski, Western University, Canada.

“Deeply fractured rocks of meteorite impact structures have been hypothesized as hot spots for microbial colonization on Earth and other planetary bodies,” the authors write. “Biosignatures of such colonization are rare, however, and most importantly, direct geochronological evidence linking the colonization to the impact-generated hydrothermal systems are completely lacking.”

$Illustration of new research findings in the Lappajärvi crater, Finland, where traces of ancient life have been discovered in the crater’s fractures. The magnified section highlights the blue-marked fracture zones where microbial signatures have been identified. Image Credit: Henrik Drake, Gordon Osinski$ Illustration of new research findings in the Lappajärvi crater, Finland, where traces of ancient life have been discovered in the crater’s fractures. The magnified section highlights the blue-marked fracture zones where microbial signatures have been identified. Image Credit: Henrik Drake, Gordon Osinski

The discovery is based on sulphite reduction. Some microbes employ an anaerobic respiratory process that uses sulfate to accept electrons rather than oxygen. It’s a fundamental process that contributes to Earth’s global sulfate and carbon cycles. Basically, microbes break down organic compounds as an energy source and reduce sulfate to hydrogen sulfide.

The researchers used powerful, cutting-edge isotopic biosignature analysis and radioisotopic dating to trace microbial sulfate reduction in minerals and fractures in the hydrothermal system under the crater.

“This is the first time we can directly link microbial activity to a meteorite impact using geochronological methods. It shows that such craters can serve as habitats for life long in the aftermath of the impact,” says Henrik Drake, a professor at Linnaeus University, Sweden, and senior author of the study.

“The first detected mineral precipitation at habitable temperatures for life (47.0 ± 7.1 °C) occurred at 73.6 ± 2.2 Ma and featured substantially 34S-depleted pyrite consistent with microbial sulfate reduction,” the authors explain in their research.

This figure shows some of the findings. The pyrite is of particular interest. The 34Sulfur-depleted pyrite is consistent with microbial sulfate reduction. It formed about five million years after the impact when the hydrothermal system had cooled to temperatures that were habitable for life. The calcite is another powerful biosignature, and it appeared 10 million years post-impact, indicating that microbes thrived here for millions of years. Image Credit: Gustafsson et al. 2025 NatComm

“What is most exciting is that we do not only see signs of life, but we can pinpoint exactly when it happened. This gives us a timeline for how life finds a way after a catastrophic event” says Jacob Gustafsson, PhD student at Linnaeus University and first author of the study.

More evidence of microbial colonization appears about 10 million years post-impact as the temperature continued to gradually decrease. Minerals precipitated into vugs, which is a geological term for cavities lined with mineral crystals. These minerals feature 13 Calcite, which forms in association with microbial sulfate reduction. It’s a powerful and convincing biosignature that strengthens the findings. At 10 million years post-impact, these minerals are further evidence that microbes thrived for a long time in the hydrothermal system.

Co-author Dr. Gordon Osinski, from Western University in Canada, said “This is incredibly exciting research as it connects the dots for the first time. Previously, we’ve found evidence that microbes colonized impact craters, but there has always been questions about when this occurred and if it was due to the impact event, or some other process millions of years later. Until now.”

These findings open a window into how life might get started on habitable worlds. Asteroids are known to carry the basic building blocks of life, including amino acids. It’s possible they not only spread these materials throughout solar systems and galaxies in accordance with panspermia, but that they also create a ready-made home for life to gain a foothold in. The research also shows how life can rebound after a catastrophic impact that could overwhelm a biosphere.

The researchers say that the microbial colonization of the Lappajärvi impact structure is an analog for the emergence of life on early Earth, and even on Mars. Their methods of analysis can be used to study the microbial colonization of other impact structures on Earth. Beyond that, they’re also applicable to any sample return missions from Mars or other bodies.

“These insights confirm the capacity of medium-sized (and large) meteorite impacts to generate long-lasting hydrothermal systems, enabling microbial colonization as the crater cools to ambient conditions, an effect that may have important implications for the emergence of life on Earth and beyond,” the authors conclude.

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Widow of L.A. County deputy killed in grenade blast files lawsuit

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The widow of an L.A. County sheriff’s deputy killed in a grenade blast last year sued the department this week, alleging a lack of proper training and ignored safety protocols led to the incident, which also caused the deaths of two other deputies.

The lawsuit, filed Monday in L.A. County Superior County by Nancy Lemus, alleges her husband, Victor Lemus, died in a training exercise gone wrong and seeks damages for emotional distress and loss of income.

The blast last summer was the deadliest incident for the Sheriff’s Department in 150 years, triggering criminal investigations and more than $350,000 in fines from the California Division of Occupational Safety and Health.

In addition to Victor Lemus, 40, deputies Joshua Kelley-Eklund and William Osborn died in the July 2025 explosion.

Asked to respond to the lawsuit, a Sheriff’s Department spokesperson did not directly address the allegations, but said investigations into the incident remain open and that the department “is implementing several measures to further strengthen operational safety,” including standardizing policies and introducing new equipment.

In her lawsuit, Nancy Lemus alleged that on the day prior to the blast, Kelley-Eklund, 41, and Osborn, 58, responded to a call from the Santa Monica Police Department after officers found explosive devices in the garage of an apartment complex.

The deputies responded to the scene in personal work trucks rather than the department’s bomb truck and Osborn improperly examined the grenade and falsely reported it inert, according to the complaint.

Either Osborn or Kelley-Eklund then took the ordnance home and left it in their truck overnight, or brought it into their house, the lawsuit alleges.

The next day, one of the deputies took the grenade to the department’s Biscailuz Regional Training Center, where live explosive devices are prohibited, the lawsuit said. The deputies then used it in a training exercise with Victor Lemus, who lacked formal bomb squad training and “was reliant on the expertise of [Kelley-Eklund] and Osborn,” according to the lawsuit.

Nancy Lemus, who is also a sheriff’s deputy, alleged in the lawsuit that either Kelley-Eklund or Osborn pulled the pin of the grenade, killing all three.

“The explosion made Plaintiff Nancy Lemus a widow and her children, Victoria and Emily, fatherless,” the complaint says.

Nancy Lemus’ lawsuit also contains allegations that echo a previous scandal in which sheriff’s personnel were accused of passing around graphic images from the aftermath of the helicopter crash that killed retired Lakers star Kobe Bryant six years ago. A lawsuit filed by Bryant’s family resulted in a multimillion-dollar verdict against the department.

In the immediate aftermath of the 2025 blast, Nancy Lemus alleged in her lawsuit that Sheriff Cmdr. Thomas Giandomenico took unauthorized and unofficial photos of her husband’s body. The photos “violated the respect owed to the dead and the privacy of the bereaved by collecting trophies in the form of death images,” Lemus claimed in the lawsuit, alleging that the pictures could eventually circulate online.

The Times reported in March that the department was conducting an internal investigation into whether graphic crime scene photos of the July 2025 blast were improperly shared.

The Times previously reported that Giandomenico had been relieved from duty during the investigation. A Sheriff’s Department spokesman said Saturday that the commander is “currently active, but on department-approved leave.”

Giandomenico could not be reached for comment.

The lawsuit alleges that Sheriff Robert Luna failed to confiscate Giandomenico’s phone after learning of the photos and tried to conceal from Nancy Lemus that the images existed.

“The failure to adequately train, supervise, and discipline personnel regarding the taking of such photographs is a complete dereliction of duty, and can be directly attributed to Sheriff Luna and other members of his command staff,” the complaint said.

Times staff writers Richard Winton and Salvador Hernandez contributed to this report.

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Wildfires Continue To Burn in Ontario, Canada, Sending Smoke to U.S. Cities

Nearly 200 fires continued to devastate swaths of the province as smoke continued to drift across parts of Canada and the United States.

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The Dark Energy Camera’s New Image is Reminiscent of van Gogh

The Dark Energy Camera’s newest image features the Corona Australis molecular cloud and its many stellar and gaseous features. The swirls of gas in the new image are reminiscent of Vincent van Gogh’s “The Starry Night.”

Corona Australis (CrA) is a dark nebula about 425 light years away. It’s one of the closest star-forming regions to Earth, and contains a handful of embedded nebulae. Though it’s not as well studied as other nearby star-forming regions like Orion and Ophiuchus.

The swirls of gas in the new image are reminiscent of Vincent van Gogh’s “The Starry Night.”

The binary star R Coronae Australis illuminates the orange cloud on the left, made up of a red dwarf and a pre-main-sequence star that has gathered its mass but hasn’t started hydrogen fusion yet.

Young bright stars like the primary in R Coronae Australis light up nearby reflection nebulae when their light reflects off of them. The same stars also emit powerful UV radiation that ionizes some of the gas surrounding them, creating an emission nebula. That nebula is named NGC 6729, or Caldwell 68. Its shape and its brightness vary due to the orbits of the binary star.

This image highlights some of the objects in the fascinating Corona Australis Molecular Cloud. Image Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA. Image processing: R. Colombari & M. Zamani (NSF NOIRLab)

Newborn stars in Corona Australis light gas up and turn it blue. The stormy-looking region of beige and yellow is made up of the reflection nebulae NGC 6726 and NGC 6727. They extend to the image’s lower right, where they join with IC 4812, another reflection nebula.

The stunning NGC 6723, also known as the Chandelier Cluster, sits in the upper right. It’s much further away than Corona Australis, about 29,000 light years away, and contains hundreds of thousands of stars.

This image labels objects of interest in the Corona Australis Molecular Cloud, including multiple nebulae and Herbig-Haro objects. Image Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA. Image processing: R. Colombari & M. Zamani (NSF NOIRLab)

Though other star-forming regions capture more scientific attention than Corona Australis, it hasn’t been ignored. Gaia has observed it, as has Chandra, XMM-Newton, and others. Altogether, research shows that Corona Australis is anything but static. A paper published in 2023 showed that the CrA complex is accelerating away from the Galactic plane. Those researchers calculated that two supernova explosions would’ve been needed to impart this kinetic energy.

This zoomed in image shows the unusual Herbig-Haro object HH100 on the left in detail, where a young star emits jets of ionized gas. It also highlights other stars and sections of gas cloud that appear almost wind-blown. Image Credit: Dark Energy Survey/DOE/FNAL/DECam/CTIO/NOIRLab/NSF/AURA. Image processing: R. Colombari & M. Zamani (NSF NOIRLab)

A 2025 paper divided the CrA complex into two subregions — a younger CrA-Main and an older CrA-North—and showed that they were once closer together but are actually moving further apart. Even the Herbig-Haro object in the above image is transient and will last only a few ten thousand years, almost nothing in astronomical time.

*This false-colour image of Corona Australis comes from the ESO’s Very Large Telescope. It shows the same Herbig-Haro object (HH100) as the zoomed-in image above. Image Credit: By ESO/Sergey Stepanenko – http://www.eso.org/public/images/eso1109a/, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=14636787*

Interested readers can download a high-res version of the image and explore more fascinating detail in this rich region on their own.