The discovery of Lake Hephaestus, the youngest athalassohaline deep-sea formation on Earth
La Cono, V.; Bortoluzzi, G.; Messina, E.; La Spada, G.; Smedile, F; Giuliano, L.; Borghini, M.; Stumpp, C.; Schmitt-Kopplin, P.; Harir, M.; O’Neill, W.K.; Hallsworth, J.E.; Yakimov, M. (2019). The discovery of Lake Hephaestus, the youngest athalassohaline deep-sea formation on Earth. NPG Scientific Reports 9(1): 11 pp. https://dx.doi.org/10.1038/s41598-018-38444-z In: Scientific Reports (Nature Publishing Group). Nature Publishing Group: London. ISSN 2045-2322; e-ISSN 2045-2322, more |   |
| Authors | | Top | - La Cono, V.
- Bortoluzzi, G.
- Messina, E.
- La Spada, G.
- Smedile, F
| - Giuliano, L., more
- Borghini, M.
- Stumpp, C.
- Schmitt-Kopplin, P.
| - Harir, M.
- O’Neill, W.K.
- Hallsworth, J.E.
- Yakimov, M.
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| Abstract | Hydrated, magnesium-rich minerals and subglacial brines exist on the martian surface, so the habitability of high-Mg2+ environments on Earth has extraterrestrial (as well as terrestrial) implications. Here, we report the discovery of a MgCl2-dominated (4.72 M) brine lake on the floor of the Mediterranean Ridge that underlies a 3500-m water column, and name it Lake Hephaestus. Stable isotope analyses indicated that the Hephaestus brine is derived from interactions between ancient bishofite-enriched evaporites and subsurface fluids. Analyses of sediment pore waters indicated that the Hephaestus depression had contained the MgCl2 brine for a remarkably short period; only 700 years. Lake Hephaestus is, therefore, the youngest among currently known submarine athalassohaline brine lakes on Earth. Due to its biologically hostile properties (low water-activity and extreme chaotropicity), the Hephaestus brine is devoid of life. By contrast, the seawater-Hephaestus brine interface has been shown to act as refuge for extremely halophilic and magnesium-adapted stratified communities of microbes, even at MgCl2 concentrations that approach the water-activity limit for life (0.653). |
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