HR: 1330h
AN: T12B-0455 INVITED     [PDF]
TI: Ancient Fungal Life in North Pacific Eocene Oceanic Crust
AU: * Schumann, G
EM: gschuma@gwdg.de
AF: Gabriela Schumann, Center of Geosciences at the University of Goettingen Dep. Geobiology Goldschmidtstr. 3, Goettingen, 37077 Germany
AU: Manz, W
EM: manz@bafg.de
AF: Werner Manz, Bundesanstalt fuer Gewaesserkunde (BfG) Kaiserin-Augusta-Anlagen 15-17, Koblenz, 56068 Germany
AU: Reitner, J
EM: jreitne@gwdg.de
AF: Gabriela Schumann, Center of Geosciences at the University of Goettingen Dep. Geobiology Goldschmidtstr. 3, Goettingen, 37077 Germany
AU: Lustrino, M
EM: michele.lustrino@uniroma1.it
AF: Michele Lustrino, Dipartimento di Scienze della Terra, Universit… degli Studi di Roma La Sapienza, P.le A. Moro, 5, Rome, 00185 Italy
AB: Little is known about the manifold life forms of the deep biosphere although there is increasing scientific evidence that an extensive biosphere does exist in extreme environments such as the rocks below the seafloor. The ODP Leg 200 was devoted to the study of Eocene oceanic crust of the North Pacific Ocean. Within a massive tholeiitic lava flow unit, at depth of 51 mbsf underneath a water column of about 5000 m, we found unique filamentous structures. Based on morphological traits like branching, septa and central pores the filaments are interpreted as fungi. These filaments were found within carbonate-filled vesicles ranging in size from 0.5 to 3 mm in diameter. The net of fungal hyphae completely fills the whole pore space from the basalt-carbonate boundary towards the center of the pores. The cross section dimension of these filaments is about 5-10 micrometer and the length differ from 50 to several hundreds micrometer. Thereby the cell septa of the hyphae are clearly visible. The number of hyphae ranges from some tenth to some hundreds per particular pore. The presence of pyrite within the carbonate cements points out anaerobic conditions in this habitat. After removing the carbonate by etching the vesicles with diluted formic acid, the 3-dimensional structure of the fungus could be clearly visualized. Fine structure analysis of the hyphae obtained by field emission scanning electron microscopy (FE-SEM) revealed a network of tiny small fibers coating the surface of the hyphae. Semi-quantitative chemical analyses of the etched hyphae were conducted with an energy dispersive spectrometer system (EDS) coupled with the FE-SEM. The results evidence a chemical composition of the hyphae different from the surrounding carbonate matrix. Undisturbed filamentous growth through different calcite crystals within the vesicles and small open space between the fungi and matrix indicate endolithic fungal growth after the calcium carbonate filling of the vesicles. To the best of our knowledge, this is the first finding of eukaryotic life signs within deep ocean basaltic rocks with few signs of alteration. Moreover, these microorganisms are associated with relatively ancient, and therefore cold, volcanic rocks.
DE: 0400 Biogeosciences
SC: Tectonophysics [T]
MN: 2003 Fall Meeting