The production of hydrogen and methane by geochemical reactions associated with the serpentinization of ultramafic rocks can potentially support subsurface microbial ecosystems independent of the photosynthetic biosphere. Methanogenic and methanotrophic microorganisms are abundant in marine hydrothermal systems heavily influenced by serpentinization, but evidence for methane-cycling archaea and...

Contradictions between system-specific evidence and broader paradigms to explain ecosystem behavior present a challenge for natural resource management. In Florida (U.S.A.) springs, increasing nitrate (NO3-) concentrations have been implicated as the cause of algal overgrowth via alleviation of N-limitation. As such, policy and management efforts have centered heavily on reduction of nitrogen (...

The carbon isotope content of dissolved inorganic carbon was measured for large cold springs in the central Oregon Cascades. Low 14C activities in some of the springs are interpreted to result from the dissolution of diffuse emissions of magmatic CO2, even though volcanic activity has not occurred in this area for more than 1300 yr. On the basis of dissolved magmatic carbon concentrations in th...

We know of some 650 holy springs in Denmark. Their abundance seems to be the reason why a decade ago one of Denmark's leading authorities on late-medieval archaeology wrote that the popular worship of saints in that country appeared to be more closely connected to the cult of holy springs than anywhere else in Europe.' This statement was apparently based largely on post-Reformation sources. A v...

The potential performance of carbon nanotubes (CNTs) as springs for elastic energy storage is evaluated. Models are used to determine an upper bound on the energy density that can be stored in defect-free individual CNTs and in assemblies of such CNTs. The models reveal that optimal energy density may be achieved in small-diameter single-walled CNTs loaded in tension, with a maximum theoretical...