Western Australia contains an extraordinary record of microbialites: from the oldest known examples, preserved in rocks almost 3.5 billion years old in the Pilbara, to living examples in the UNESCO World Heritage area of Shark Bay<\/a>.<\/p>\n Our review of 50 years of microbialite research in Western Australia<\/a>, published today in the journal Alcheringa, summarises what this archive can tell us about the evolution and resilience of life on Earth.<\/p>\n Despite a fossil record that spans billions of years, microbialites are surprisingly fragile. Fossil sites remain vulnerable to over-collection and degradation, while living microbialites are facing growing pressures.<\/p>\n At sites such as Lake Clifton and Shark Bay, some events may have already caused irreparable damage. One such example was in May 2024<\/a>, when dozens of aurora chasers trampled 2,000-year-old thrombolites in a restricted area at Lake Clifton.<\/p>\n Fossil microbialites preserved in rocks almost 3.5 billion years old in Western Australia\u2019s Pilbara region. Earth\u2019s oldest evidence of life<\/p>\n Microbialites are mounded structures that come in many shapes and sizes. They form when communities of microbes either precipitate minerals, or trap and bind sediment.<\/p>\n Types of microbialites can be characterised by their internal structure. Stromatolites are the best known, and have distinctive layers. Thrombolites, by contrast, have a clotted texture. <\/p>\n Proterozoic stromatolites preserved in an array of shapes and sizes. The microbialite record can tell us a great deal about life on Earth. It gives us clues about where some of the earliest life lived, where we might look for life beyond Earth<\/a>, and how our atmosphere became oxygen rich, paving the way for more complex life to follow.<\/p>\n Modern sites are particularly important because they help us better understand processes that formed microbialites in the ancient rock record. Living microbialites from Shark Bay have even been described as a \u201cRosetta Stone\u201d<\/a> for understanding their fossil counterparts.<\/p>\n Microbialites also preserve evidence of how life responded to environmental upheaval in the past. Western Australia\u2019s microbialite record spans at least one, and potentially two, of Earth\u2019s five major mass extinctions.<\/p>\n This deep-time record suggests microbialites may act as early indicators of ecological stress. Evidence suggests that the sudden increase of microbialites often preceded or coincided with major ecological disruption and mass extinction in the past. <\/p>\n The living thrombolite reef at Lake Clifton, Western Australia, where microbial communities continue to build structures much like those preserved in the ancient rock record. Yet our review highlights several significant knowledge gaps. <\/p>\n Scientists are still debating how to distinguish structures built by life from those produced by non-biological processes. We also cannot always say with certainty what environments ancient microbialites formed in. <\/p>\n There is further uncertainty about what controls the shape and structure (morphology) of microbialites. We also don\u2019t fully know how closely modern examples reflect fossil forms. <\/p>\n Why the internal structure of thrombolites is clotted rather than layered, as in stromatolites, remains a conundrum. So does how far back they extend in the geological record. Western Australia may contain some of the oldest known thrombolites, but these examples have not yet been documented in detail. <\/p>\n 2.7-billion-year-old thrombolites from Western Australia that remain undescribed. These may represent some of the oldest known thrombolites in the world. In short, Earth\u2019s oldest biological record is not a finished story, although the gaps are slowly being filled. Preserving the evidence, both living and fossil, is essential if future scientists are to answer questions we don\u2019t have answers for yet, or perhaps even to ask questions we have not yet thought to ask.<\/p>\n An ancient archive at risk<\/p>\n A sign at Lake Clifton reminding visitors to stay off the fragile living thrombolites, which can take decades or even centuries to recover from physical damage. Despite their geological longevity and seemingly unchanging nature, microbialites are surprisingly fragile. Their rock-like appearance can make this difficult to appreciate. <\/p>\n Living microbialites can be highly sensitive to environmental disturbance. Their extremely slow growth rates mean physical damage can take decades or centuries to repair, if at all.<\/p>\n Many modern microbialite sites face growing pressures from changes in water quality, climate change and increasing visitation.<\/p>\n Fossil microbialites are also vulnerable. Across Western Australia, tourism, inappropriate collecting and even scientific sampling can damage or diminish these irreplaceable sites. As geological features, their protection falls under geoheritage. <\/p>\n Aerial view in Hamelin Pool, Shark Bay. Paths still evident through the microbialites cut by carts more than 90 years ago are still visible today. Image courtesy of the Geological Survey of Western Australia, Department of Mines, Petroleum and Exploration. Yet geoheritage remains poorly recognised and under resourced in Australia at both the federal and state levels. The 2021 Australian State of the Environment report<\/a> concluded that \u201cthe overall outlook for geoheritage is poor\u201d due to the lack of national frameworks, focus and resourcing for this area of heritage. Unfortunately, little has changed. <\/p>\n![\"Red](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261014-50-hngw5z.jpeg\")
<\/a><\/p>\n
\n Heidi Allen<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261001-50-5zn1as.jpg\")
<\/a><\/p>\n
\n Heidi Allen<\/p>\n![\"A](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261001-50-mfoww5.jpg\")
<\/a><\/p>\n
\n Heidi Allen<\/p>\n![\"Striated](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261001-50-glgl6u.JPG\")
<\/a><\/p>\n
\n Heidi Allen<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261001-50-9uryy2.jpg\")
<\/a><\/p>\n
\n Heidi Allen<\/p>\n![\"\"](\"https:\/\/www.newsbeep.com\/ca\/wp-content\/uploads\/2026\/10\/file-20261001-50-9xy8ac.jpg\")
<\/a><\/p>\n
\n Heidi Allen, CC BY<\/a><\/p>\n