[16-2] Crypts in porous basanite: Extreme environments hosting fungal-bacterial micro-ecosystems in a deep-sea volcano, Vesteris Seamount, Greenland Sea

• Main Authors: Societa Geologica Italiana 2021, Schmid-Beurmann, Hinrich
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Underline Science Inc. 2021
• Subjects: Greenland; Vesteris Seamount; Greenland Sea
• Online Access: https://dx.doi.org/10.48448/5417-s941; https://underline.io/lecture/33892-16-2-crypts-in-porous-basanite-extreme-environments-hosting-fungal-bacterial-micro-ecosystems-in-a-deep-sea-volcano,-vesteris-seamount,-greenland-sea

Abstract: Microbes colonize some of Earth’s most extreme environments, sometimes providing refugees for symbionts and decomposers. The vesicles in porous basalt and basanite of deep-sea volcanoes support flourishing subsurface micro-ecosystems, which are part of the deep biosphere of the igneous oceanic crust. Despite the abundance and antiquity of cryptoendoliths in structural cavities of the oceanic crust, the evolution and ecology of these cryptic ecosystems remain mostly elusive. Here we report morphological and geochemical properties of microbial body fossils in rock samples collected from Vesteris Seamount during cruise MSM86 of MS Maria S. Merian in 2019. The highly porous basanites exhibit densely intergrown filamentous networks and laminated deposits on vesicle walls of probable biotic origin preserved as secondary minerals like manganese- or iron-oxides and others. Morphological evidence suggests the dominance of fungi among filamentous fossils, whereas basal coatings on internal vesicle walls resembling minute stromatolites are interpreted as remains of iron- or manganese-oxidizing chemolithoautotrophic bacteria. Hand samples, thin sections, and polished slabs of vesicular basanite also yielded in vivo fungal mycelia associated with globular, botryoidal, and dendritic stromatolites. The spatial relation and growth of fungal filaments upon a basal microbialite suggests a symbiotic-like relation of the supposably autotrophic bacteria and the heterotrophic fungi. Such association would explain the recent findings of a vital fungi community in the oceanic lithosphere. Authors:* Schmid-Beurmann H.*, Ivarsson M., Bach W. & Peckmann J.