Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica
Abstract The ephemeral, supraglacial meltwater ponds of the McMurdo Ice Shelf’s undulating ice serve as analogues for refugia where eukaryotic organisms could have thrived during the Cryogenian period. The seafloor sediment and debris lined ponds support the growth of a diverse array of cyanobacteri...
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Nature Portfolio
2025-06-01
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| Series: | Nature Communications |
| Online Access: | https://doi.org/10.1038/s41467-025-60713-5 |
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| author | Fatima Husain Jasmin L. Millar Anne D. Jungblut Ian Hawes Thomas W. Evans Roger E. Summons |
| author_facet | Fatima Husain Jasmin L. Millar Anne D. Jungblut Ian Hawes Thomas W. Evans Roger E. Summons |
| author_sort | Fatima Husain |
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| description | Abstract The ephemeral, supraglacial meltwater ponds of the McMurdo Ice Shelf’s undulating ice serve as analogues for refugia where eukaryotic organisms could have thrived during the Cryogenian period. The seafloor sediment and debris lined ponds support the growth of a diverse array of cyanobacterial mat communities and provide habitats for a variety of protists and meiofauna. Here, we show that these eukaryotic assemblages, assessed by steroid biomarker and 18S rRNA gene analyses, inform long-standing questions regarding the diversity of, and controls on, community composition in these environments. Sixteen photosynthetically active microbial mats from meltwater ponds, a 700-year-old relict microbial mat, and a microbial mat from the Bratina Lagoon were analysed for their sterol compositions. These sterols were subjected to simulated diagenesis via catalytic hydrogenation/hydrogenolysis affording their sterane hydrocarbon counterparts, facilitating comparisons with ancient settings. Pond salinity appeared to be a factor influencing the sterol distributions observed. Analyses of 18S rRNA gene sequences conducted on the modern mats independently confirm that the ponds host diverse eukaryotes, including many types of microalgae, protists, and an array of unclassifiable organisms. Our findings support the hypothesis that supraglacial meltwater ponds like those of the McMurdo ice are strong candidates for refugia that sheltered complex life during Snowball Earth episodes. |
| format | Article |
| id | doaj-art-d19e6fa60eeb4af7a326b3d2fa24e3b1 |
| institution | Kabale University |
| issn | 2041-1723 |
| language | English |
| publishDate | 2025-06-01 |
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| spelling | doaj-art-d19e6fa60eeb4af7a326b3d2fa24e3b12025-08-20T03:47:13ZengNature PortfolioNature Communications2041-17232025-06-0116111610.1038/s41467-025-60713-5Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in AntarcticaFatima Husain0Jasmin L. Millar1Anne D. Jungblut2Ian Hawes3Thomas W. Evans4Roger E. Summons5Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of TechnologySchool of Earth and Environmental Sciences, Cardiff UniversityDepartment of Science, Natural History MuseumCoastal Marine Field Station, University of WaikatoDepartment of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of TechnologyDepartment of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of TechnologyAbstract The ephemeral, supraglacial meltwater ponds of the McMurdo Ice Shelf’s undulating ice serve as analogues for refugia where eukaryotic organisms could have thrived during the Cryogenian period. The seafloor sediment and debris lined ponds support the growth of a diverse array of cyanobacterial mat communities and provide habitats for a variety of protists and meiofauna. Here, we show that these eukaryotic assemblages, assessed by steroid biomarker and 18S rRNA gene analyses, inform long-standing questions regarding the diversity of, and controls on, community composition in these environments. Sixteen photosynthetically active microbial mats from meltwater ponds, a 700-year-old relict microbial mat, and a microbial mat from the Bratina Lagoon were analysed for their sterol compositions. These sterols were subjected to simulated diagenesis via catalytic hydrogenation/hydrogenolysis affording their sterane hydrocarbon counterparts, facilitating comparisons with ancient settings. Pond salinity appeared to be a factor influencing the sterol distributions observed. Analyses of 18S rRNA gene sequences conducted on the modern mats independently confirm that the ponds host diverse eukaryotes, including many types of microalgae, protists, and an array of unclassifiable organisms. Our findings support the hypothesis that supraglacial meltwater ponds like those of the McMurdo ice are strong candidates for refugia that sheltered complex life during Snowball Earth episodes.https://doi.org/10.1038/s41467-025-60713-5 |
| spellingShingle | Fatima Husain Jasmin L. Millar Anne D. Jungblut Ian Hawes Thomas W. Evans Roger E. Summons Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica Nature Communications |
| title | Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica |
| title_full | Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica |
| title_fullStr | Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica |
| title_full_unstemmed | Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica |
| title_short | Biosignatures of diverse eukaryotic life from a Snowball Earth analogue environment in Antarctica |
| title_sort | biosignatures of diverse eukaryotic life from a snowball earth analogue environment in antarctica |
| url | https://doi.org/10.1038/s41467-025-60713-5 |
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