During Leg 168 of the Ocean Drilling Program, basalts were recovered by drilling and subsurface water was collected with a water sampling tool at Hole 1026B on the east flank of Juan de Fuca Ridge. Microorganisms were found in both types of samples. The microorganisms in the basalt appear to...
Within the altered parts of the glass rim of pillow lavas of Hole 896A, at depths at least 432 m below seafloor (237 m below the top of volcanic basement), microbes have been identified. This is indicated by the size and shapes of alteration textures and verified by the presence...
The safety of coastal infrastructure has been a concern after the Indian Ocean Tsunami in 2004 and the Great East Japan Tsunami in 2011. The western coast of the United States is also exposed to tsunami hazards due to the Cascadia subduction zone. Therefore, it is critical to design coastal...
Microchannels in ocean basalt glass are often attributed to the activity of microorganisms, however, neither the mechanism of formation of microchannels in glass nor the involvement of microorganisms have been confirmed by experimentation. Experimental abiotic corrosion of basalt glass with 1% hydrofluoric acid (HF), a proxy for more slowly acting...
Hydrothermal vents appear to be the tip of the subsurface biosphere in the ocean crust. The primary prducers in this biosphere are prokaryotes that tolerate a wide variety of physical and chemical conditions and are versatile in their use of inorganic compounds to drive metabolism. A synthesis of chemical and...
Oceanic crust covers nearly 70% of the Earth's surface, of which, the upper,
sediment layer is estimated to harbor substantial microbial biomass. Marine crust;
however, extends several kilometers beyond this surficial layer, and includes the
basalt and gabbro layers. In particular, the basalt layer has high permeabilities which
allows for...
In the early 1980's the first evidence of biological alteration of basalt glass (sideromelane) was published. Since that time additional evidence, including DNA staining, isotopic abundance and chemical mapping, has come to light suggesting that this unique alteration of glass can be attributed to microbial activity. Microbial alteration textures have...
These first measurements of specific surface area (SSA)
of bulk samples of subsurface marine basalts were undertaken
to determine the potential area available for microbial
colonization. SSA ranged from 0.3 to 52 m2/g of basalt
with the lowest value coming from pillow basalt and the
highest value from breccia. The...
The subsurface microbial biosphere in the igneous oceanic crust has implications for global geochemical cycling, early life on Earth, and the search for life on Mars. Microscopic evidence of a subsurface microbial ecosystem includes biotic alteration textures associated with basaltic glass. The exact conditions in the basaltic layer that make...
The Hawaii Scientific Drilling Program (HSDP) cored and recovered igneous rock from the surface to a
depth of 3109 m near Hilo, Hawaii. Much of the deeper parts of the hole is composed of hyaloclastite
(fractured basalt glass that has been cemented in situ with secondary minerals). Some hyaloclastite units...
The alteration of subseafloor volcanic glass from three locations is qualitatively attributed to biological
(biotic) or chemical (abiotic) reactions on the basis of microscopic morphology of the boundary between
the unaltered and altered glass. Eleven-element composition of fresh basalt glass (sideromelane) and its
alteration products were determined by electron microprobe....
The majority of the Earth's shallow crust is composed of basalt that erupted on the seafloor and was subsequently altered by chemical exchange with seawater. One aspect of this alteration is the replacement of glass by secondary minerals, including clays. Petrographic thin sections from ODP Holes 504B and 896A revealed...
The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long-term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the...
We estimate the depth of the 120°C isotherm by constructing crustal thermal gradients based on theoretical and observed conductive heat flux as a function of lithospheric age. We chose the 120°C isotherm because it is close to the upper limit for prokaryotic life, and therefore, the isotherm approximates the maximum...
This index provides access to infonnation about women in 102 books and journals. The information contained in each entry is only as good as the original and the quality varies considerably. Much of this infonnation has not before been easily accesible in this form. My hope is that this index...
Marine sediments are one of the largest habitats for microbial life on earth. These microorganisms play critical roles in biogeochemical cycling both within the subsurface and between the sediment and water columns. However, microbial communities in sediments are highly heterogeneous and the factors defining microbial community structure and metabolic function...
Igneous oceanic crust encompasses ~60% of Earth’s surface and is composed of basalt glass and mafic, ultramafic, and felsic minerals. A vast marine aquifer lies within the crust, exchanging geochemically altered fluids with seawater from the overlying ocean at ridge crests, flanks, seamounts, and outcrops where permeable crust is exposed....