A quarter of all species around the globe are threatened with extinction; this article reviews research in economics on how best to counter those threats. Normative research has developed useful tools for cost-effectively choosing areas of habitat to protect. Such work has also designed working-lands contracts that can induce efficient...
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...