Understanding the response of permafrost microbial communities to climate warming is crucial for evaluating ecosystem feedbacks to global change. This study investigated soil bacterial and archaeal communities by Illumina MiSeq sequencing of 16S rRNA gene amplicons across a permafrost thaw gradient at different depths in Alaska with thaw progression for […]
The efficiency with which microbes use substrate (Carbon Use Efficiency or CUE) to make new microbial biomass is an important variable in soil and ecosystem C cycling models. It is generally assumed that CUE of microbial activity in soils is low, however measured values vary widely. It is hypothesized that […]
Carbon dioxide is the main greenhouse gas inducing climate change. Increased global CO2 emissions, estimated at 8.4 Pg C yr−1 at present, have accelerated from 1% yr−1during 1990–1999 to 2.5% yr−1 during 2000–2009 (ref. 1). The carbon balance of terrestrial ecosystems is the greatest unknown in the global C budget because […]
The linkages between fluvial geomorphology and aquatic ecosystems are commonly conceptualized as a one-way causal chain inwhich 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 travertinedams, creating the potential fornumerous feedbacks.Herewetakeadvantage of […]
Evapotranspiration (ET) comprises a major portion of the water budget in forests, yet few studies have measured or estimated ET in semi-arid, high-elevation ponderosa pine forests of the south-western USA or have investigated the capacity of models to predict ET in disturbed forests. We measured actual ET with the eddy […]
Rising temperatures are expected to reduce global soil carbon (C) stocks, driving a positive feedback to climate change1, 2, 3. However, the mechanisms underlying this prediction are not well understood, including how temperature affects microbial enzyme kinetics, growth efficiency (MGE), and turnover4, 5. Here, in a laboratory study, we show […]
Soils and other unconsolidated deposits in the northern circumpolar permafrost region store large amounts of soil organic carbon (SOC). This SOC is potentially vulnerable to remobilization following soil warming and permafrost thaw, but SOC stock estimates were poorly constrained and quantitative error estimates were lacking. This study presents revised estimates […]
Rising atmospheric CO2 concentrations may alter the nitrogen (N) content of ecosystems by changing N inputs and N losses, but responses vary in field experiments, possibly because multiple mechanisms are at play. We measured N fixation and N losses in a subtropical oak woodland exposed to 11 years of elevated […]
Bacteria grow and transform elements at different rates, and as yet, quantifying this variation in the environment is difficult. Determining isotope enrichment with fine taxonomic resolution after exposure to isotope tracers could help, but there are few suitable techniques. We propose a modification to stable isotope probing (SIP) that enables […]
Old soil carbon (C) respired to the atmosphere as a result of permafrost thaw has the potential to become a large positive feedback to climate change. As permafrost thaws, quantifying old soil contributions to ecosystem respiration (Reco) and understanding how these contributions change with warming is necessary to estimate the […]