The places behind the research on this site, plus two landmarks of the fossil record.
RAW Lab site
Hamelin Pool, Shark Bay
Gathaagudu (Shark Bay), Western Australia. Hypersaline marine lagoon.
The world’s most diverse and abundant living marine stromatolites, in water about twice as salty as the open ocean, within a World Heritage Area inscribed in 1991. Smooth, pustular and supratidal mats and columnar stromatolites have been studied here with amplicons, metagenomes, transcriptomes and viromes.
Burns et al. 2004Ruvindy et al. 2016White et al. 2018Wong et al. 2018Wong et al. 2020Kindler et al. 2022
Photo: Paul Harrison, CC BY-SA 3.0, via Wikimedia Commons
Highborne Cay
Exuma Cays, Bahamas. Open-marine stromatolites.
Stromatolites growing in ordinary seawater. Work here showed how cycles of sediment trapping and microbial hardening, tied to sulfur cycling, build millimetre-scale laminae.
Reid, Visscher et al. 2000Visscher et al. 1998
RAW Lab site
Pavilion Lake
British Columbia, Canada. Cold, nutrient-poor lake.
Thrombolitic microbialites whose shape changes dramatically with depth. Metagenomes revealed a community distinct from the surrounding sediment and water, and two isolates, Agrococcus pavilionensis and Exiguobacterium chiriqhucha RW2, now have complete genomes.
White et al. 2016White et al. 2018White et al. 2019
Photo: Donnie Reid, NASA Pavilion Lake Research Project, public domain, via Wikimedia Commons
RAW Lab site
Kelly Lake
British Columbia, Canada. Clear, slightly alkaline lake about 20 km from Pavilion Lake.
Metre-scale microbialites and smaller thrombolites, surveyed by the Pavilion Lake Research Project from 2004. Comparisons with its neighbour test which microbial metabolisms leave lasting signatures in carbonate; as in Pavilion Lake, photoautotrophy appears enriched in the microbialites.
Ferris et al. 1997Biosignatures study, Life 2020
RAW Lab site
Clinton Creek
Yukon, Canada. Flooded open-pit asbestos mine.
Rapidly growing microbialites in a mine pit flooded within living memory. Their gene content resembled polar microbial mats more than hot-spring mats.
White et al. 2015Power et al. 2011
Lake Clifton
Yalgorup National Park, Western Australia. Brackish coastal lake.
A reef-like band of thrombolites, listed as a critically endangered ecological community under state and federal law. Rising nutrients and salinity threaten it; a boardwalk lets visitors look without trampling.
Threatened community profile
Photo: Monkimajik, CC BY-SA 4.0, via Wikimedia Commons
Bacalar Lagoon
Quintana Roo, Mexico. Karstic freshwater lagoon.
Documented as the largest freshwater microbialite occurrence in the world. Tourism and land-use change are altering the lagoon, and visitors standing on microbialites damage them.
Microbiome study, PLOS ONE 2020
Photo: Jiinjung, CC BY-SA 4.0, via Wikimedia Commons
Cuatro Ciénegas
Coahuila, Mexico. Desert spring-fed pools.
An oasis of springs and pools with living stromatolites and mats, and the site of the first metagenomic study of freshwater microbialites.
Breitbart et al. 2009
Laguna La Brava
Salar de Atacama, Chile. Hypersaline lake with oxygen-free mats.
Purple mats that live entirely without oxygen in arsenic-rich, sulfidic water, proposed as an analogue for life in the Archean.
Visscher et al. 2020
Laguna Socompa
Puna, Argentina. High-altitude Andean lake.
Living stromatolites at the foot of Socompa volcano. One yielded Exiguobacterium strain S17, a relative of the Pavilion Lake isolate RW2.
Discussed in White et al. 2019
Guerrero Negro
Baja California Sur, Mexico. Saltern ponds.
One of the most intensively studied hypersaline mats, dominated by Chloroflexi rather than the proteobacteria that dominate Shark Bay.
Wong, Ahmed-Cox and Burns 2016
Kiritimati
Line Islands, Kiribati. Hypersaline atoll lakes.
Mats in the atoll’s lakes are dominated by Bacteroidetes, a reminder that every hypersaline mat assembles its own community.
Wong, Ahmed-Cox and Burns 2016
RAW Lab site
Green Lake
Green Lakes State Park, Fayetteville, New York, USA. Meromictic, hard-water marl lake.
The first meromictic lake described in North America: its deep, mineral-rich water never mixes with the surface. Off Dead Man’s Point, a thrombolitic reef built by coccoid and filamentous cyanobacteria grows on a carbonate platform, and the lake is studied as an analogue for Proterozoic ecosystems. A field site for the RAW and Visscher labs.
Wilhelm and Hewson 2012Frontiers in Microbiology 2023
Yellowstone hot springs
Wyoming, USA. Hot-spring microbial mats.
Classic phototrophic mats. Their functional potential was distinct from that of the Clinton Creek microbialites.
White et al. 2015
Photo: Daniel Mayer, CC BY-SA 3.0, via Wikimedia Commons
Canadian High Arctic
Nunavut, Canada. Polar microbial mats.
Non-lithifying polar mats whose gene content closely matched that of the subarctic Clinton Creek microbialites.
White et al. 2015
Antarctica
Antarctica. Polar microbial mats.
Antarctic mats were also functionally similar to the Clinton Creek microbialites.
White et al. 2015
Pilbara
Western Australia. Fossil stromatolites, 3.48 and 3.43 billion years old.
The Dresser and Strelley Pool formations preserve some of the oldest widely accepted evidence of life, including stromatolites in ancient hot-spring deposits.
Djokic et al. 2017Allwood et al. 2006
Isua
Greenland. Contested 3.7 billion-year-old structures.
Proposed as stromatolites in 2016 and reinterpreted as deformation features in 2018, a reminder that shape alone does not prove life.
Allwood et al. 2018
Further living microbialites documented in the literature, each linked to its source. The list is not exhaustive; suggest a site.
