Forests are a significant part of the global carbon cycle and are increasingly viewed as tools for mitigating climate change. Natural disturbances, such as fire, can reduce carbon storage. However, many forests and dependent species evolved with frequent fire as an integral ecosystem process. We used a landscape forest simulation […]
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) […]
Reciprocal subsidies between rivers and terrestrial habitats are common where terrestrial leaf litter provides energy to aquatic invertebrates while emerging aquatic insects provide energy to terrestrial predators (e.g., birds, lizards, spiders). We examined how aquatic insect emergence changed seasonally with litter from two foundation riparian trees, whose litter often dominates […]
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 […]
Background It is now apparent that the complex microbial communities found on and in the human body vary across individuals. What has largely been missing from previous studies is an understanding of how these communities vary over time within individuals. To the extent to which it has been considered, it […]
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 […]
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 […]
As part of a large interdisciplinary team, with funding from the National Science Foundation, we have studied how genetic and environmental factors affect leaf litter quality in cottonwoods and other riparian species, and how these effects are manifest in aquatic ecosystems.