We report the first simultaneous measurements of δ15N and δ13C of DNA extracted from surface soils. The isotopic composition of DNA differed significantly among nine different soils. The δ13C and δ15N of DNA was correlated with δ13C and δ15N of soil, respectively, suggesting that the isotopic composition of DNA is […]
Organic carbon (C) and nitrogen (N) are essential for heterotrophic soil microorganisms, and their bioavailability strongly influences ecosystem C and N cycling. We show here that the natural 15N abundance of the soil microbial biomass is affected by both the availability of C and N and ecosystem N processing. Microbial […]
Organisms acquire some elements from the environment with ease. Diffusion alone often provides enough carbon dioxide, oxygen and water. But getting other elements requires more effort, spurring unique evolutionary adaptations: instead of taking up nutrients from the soil, some plants in acidic bogs trap insects to obtain nitrogen and phosphorus […]
Escherichia coli cells were forced to mineralize or assimilate nitrogen in vitro by manipulating substrate carbon and nitrogen availability. When grown on an organic nitrogen source, E. coli cells released NH4+ and were enriched in 15N relative to the nitrogen source (1.6–3.1‰). However, when cells were grown on an inorganic […]
1. Ecological restoration often involves returning ecosystem structure to some predisturbance reference state, but ecosystem function must also recover if restoration efforts are to be self-sustaining over the long term. In the south-western United States, ponderosa pine forest structure was altered by disruption of the fire regime following Euro-American settlement. […]
Ponderosa pine (Pinus ponderosa) forests of the southwestern United States are a mosaic of stands where undisturbed forests are carbon sinks, and stands recovering from wildfires may be sources of carbon to the atmosphere for decades after the fire. However, the relative magnitude of these sinks and sources has never […]
1. Despite the importance of microorganisms for leaf litter decomposition in streams, little is known about which factors affect community composition of bacterial and fungal communities. Standard morphological techniques probably underestimate microbial diversity. 2. We used terminal restriction fragment length polymorphisms of the ITS regions for fungi, and the 16S […]
Flow diversion and invasive species are two major threats to freshwater ecosystems, threats that restoration efforts attempt to redress. Yet, few restoration projects monitor whether removal of these threats improve target charac- teristics of the ecosystem. Fewer still have an appropriate experimental design from which causal inferences can be drawn […]
The linkages between fluvial geomorphology and aquatic ecosystems are commonly conceptualized as a one-way causal chain in which geomorphic processes create the physical template for ecological dynamics. In streams with a travertine step-pool morphology, however, biotic processes strongly influence the formation and growth of travertine dams, creating the potential for […]
Retail poultry products are known sources of antibiotic-resistant Escherichia coli, a major human health concern. Consumers have a range of choices for poultry, including conventional, organic, kosher, and raised without antibiotics (RWA) – designations that are perceived to indicate differences in quality and safety. However, whether these categories vary in the frequency of […]