Decomposing leaf litter in streams provides habitat and nutrition for aquatic insects. Despite large differences in the nutritional qualities of litter among different plant species, their effects on aquatic insects are often difficult to detect. We evaluated how leaf litter of two dominant riparian species (Populus fremontii and P. angustifolia) […]
Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the 15N:14N ratio of soil organic matter across climate gradients provide key insights […]
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 […]
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 […]
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 […]
Fossil Creek Restoration Can we restore a river after a century of disturbance? Research in the Marks Lab has addressed the following questions: How did native species respond to restoration? Employing a BACI design (Before After Control Impact), we determined the relative importance of flow restoration versus non-native fish removal […]
Ecoss studies the interactions of plants with their physical and biotic environments at a fundamental level common to all organisms: gas exchange, energy balance, and water relations. We explore how plants make a living in diverse environments ranging from deserts to rainforests. A longstanding interest is the biophysical and ecological […]
Overview Fire, a natural ecological disturbance, has been suppressed in U.S. forests for much of the past century. This has prevented damage to property and protected timber resources, but has caused many forests to develop in an unnatural manner, resulting in dense stands of small trees that are now poised […]
Permafrost Carbon Network
Thousands of researchers worldwide are studying how global change affects ecosystems. Using models and field experiments, they add to our understanding of this area each day. However, individual studies sometimes only tell part of the whole story. By combining results from large numbers of studies, we can discern large-scale patterns across ecosystems, and make better estimates of how global change will affect our environment. Our work on global change synthesis combines several statistical techniques with modeling approaches. (more…)