Chronic nitrogen (N) fertilization can greatly affect soil carbon (C) sequestration by altering biochemical interactions between plant detritus and soil microbes. In lignin-rich forest soils, chronic N additions tend to increase soil C content partly by decreasing the activity of lignin-degrading enzymes. In cellulose-rich grassland soils it is not clear...
Full Text:
(Sterner and
Elser 2002).
Our second hypothesis is that in grassland ecosys-
tems where soils receive
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...