Nitrogen is one of the major nutrients limiting microbial productivity in the ocean, and as a result, most marine microorganisms
have evolved systems for responding to nitrogen stress. The highly abundant alphaproteobacterium “Candidatus
Pelagibacter ubique,” a cultured member of the order Pelagibacterales (SAR11), lacks the canonical GlnB, GlnD, GlnK, and...
Observations of Earth’s magnetic field extending back to 3.45 billion years ago indicate that generation by a core dynamo must be sustained over most of Earth’s history. However, recent estimates of thermal and electrical conductivity of liquid iron at core conditions from mineral physics experiments indicate that adiabatic heat flux...
High spatiotemporal resolution satellite imagery is useful for natural resource management and monitoring for land-use and land-cover change and ecosystem dynamics. However, acquisitions from a single satellite can be limited, due to trade-offs in either spatial or temporal resolution. The spatial and temporal adaptive reflectance fusion model (STARFM) and the...