Fossilised fungi in the deep biosphere
New discoveries in Eocene subsea cores extend the realm of the fungi into the deep biosphere, suggests Joe McCall
Geoscientist 22.06 July 2012
Picture: Fossil fungal hyphae in amber. Picture: Alexander Schmidt, University of Göttingen.
Richard Fortey’s
Survivors 1 is a book full of fascinating detail. In it, the author perceptively remarks: “the origins of fungi do indeed root back to the time of the stromatolites when the single-celled protists began to diverge into their several kinds”. Fungi are indeed the elusive kingdom, since they do not normally fossilise at all - though there is a single example in amber (picture), and from the Rhynie Chert. They certainly originated in the Proterozoic, but opinions differ between ~2 billion years and 750 million years: the former seeming more likely, now that eukaryotes have been recognised confidently in Gabon at ~ 2100Ma
2 . The first fungi undoubtedly dwelt in the sea1, though logically they must have colonised the land before the first plants.
Hitherto, it has been assumed that only prokaryotes (bacteria and archaea, single celled) occupy the deep biosphere beneath the sea floor, conditions being too rigorous for other than such extremophiles. However, now fossilised filamentous organisms have been found in drill core through sub-sea floor basalts in ODQ 157 at the Emperor Sea Mounts, Pacific Ocean
3. These fossilised fungi are observed in carbonate-filled veins and vesicles. X-ray tomographic miscroscopy has revealed fungal morphology, while and possible chitin has been detected by staining. This discovery must surely change our conception that the deep biosphere on the sea-floor can only be occupied by prokaryotes.
References
- Fortey, R, 2011. Survivors. Harper Press, 336 pp.
- McCall, G J H 2010. The first eukaryotes. Geoscientist 20(12), 12.
- Ivarsson, M, Bengston, S, Belivanova, V, Stampanoni, M, Marone, F, Tehler, A 2012. (Abstract) Fossilized fungi in subseafloor Eocene basaltshttp://geology.gsapubs.org/content/early/2012/o1/05/G32590.1.abstract