Abiotic hydrogen (H) sources and sinks near the Mid-Ocean Ridge (MOR) with implications for the subseafloor biosphere.

Free hydrogen (H) is a basal energy source underlying chemosynthetic activity within igneous ocean crust. In an attempt to systematically account for all H within young oceanic lithosphere (<10 Ma) near the Mid-Ocean Ridge (MOR), we construct a box model of this environment. Within this control volume, we assess abiotic H sources (∼6 × 10 mol H/y) and sinks (∼4 × 10 mol H/y) and then attribute the net difference (∼2 × 10 mol H/y) to microbial consumption in order to balance the H budget.

Survey of Emergency Department Chemical Hazard Preparedness in Michigan, USA: A Seven Year Comparison.

Objective: To compare the state of chemical hazard preparedness in emergency departments (EDs) in Michigan, USA between 2005 and 2012.

Methods: This was a longitudinal study involving a 30 question survey sent to ED directors at each hospital listed in the Michigan College of Emergency Physician (MCEP) Directory in 2005 and in 2012. The surveys contained questions relating to chemical, biological, radiological, nuclear, and explosive events with a focus on hazardous material capabilities.

Inconsistent correlation of seismic layer 2a and lava layer thickness in oceanic crust.

At mid-ocean ridges with fast to intermediate spreading rates, the upper section of oceanic crust is composed of lavas overlying a sheeted dyke complex. These units are formed by dykes intruding into rocks overlying a magma chamber, with lavas erupting at the ocean floor. Seismic reflection data acquired over young oceanic crust commonly image a reflector known as 'layer 2A', which is typically interpreted as defining the geologic boundary between lavas and dykes.

A serpentinite-hosted ecosystem: the Lost City hydrothermal field.

The serpentinite-hosted Lost City hydrothermal field is a remarkable submarine ecosystem in which geological, chemical, and biological processes are intimately interlinked. Reactions between seawater and upper mantle peridotite produce methane- and hydrogen-rich fluids, with temperatures ranging from <40 degrees to 90 degrees C at pH 9 to 11, and carbonate chimneys 30 to 60 meters tall. A low diversity of microorganisms related to methane-cycling Archaea thrive in the warm porous interiors of the edifices.

30,000 years of hydrothermal activity at the lost city vent field.

Strontium, carbon, and oxygen isotope data and radiocarbon ages document at least 30,000 years of hydrothermal activity driven by serpentinization reactions at Lost City. Serpentinization beneath this off-axis field is estimated to occur at a minimum rate of 1.2 x 10(-4) cubic kilometers per year.