Knowing how evapotranspiration (ET) is mediated by abiotic and biotic pathways is essential to understanding how water affects ecosystem productivity. Recent studies have investigated the average transpiration fraction (T/ET) across sites and biomes, but the temporal variability of the partitioning and its controls are less understood. Here, we examine how water availability may regulate the… More

in    0

Whether annual evapotranspiration of native ecosystems is increasing or decreasing with time as CO2 concentrations are rising, the climate is warming and rainfall experiences booms and busts, remains an unanswered question in the field of global change biology. To answer this question, we measured evapotranspiration and carbon dioxide exchange over and under an oak savanna… More

in    0

How, where, and why carbon (C) moves into and out of an ecosystem through time are long‐standing questions in biogeochemistry. Here, we bring together hundreds of thousands of C‐cycle observations at the Harvard Forest in central Massachusetts, USA, a mid‐latitude landscape dominated by 80–120‐yr‐old closed‐canopy forests. These data answered four questions: (1) where and how… More

in    0

Methane flux from freshwater mineral-soil (FWMS) wetlands and its variability among sites is largely modulated by plant-mediated transport. However, plant-mediated transport processes are rarely resolved in land surface models and are poorly parametrized for plants commonly found in FWMS wetlands. Here, relationships between methane flux and CO2 uptake, as well as plant conductance of methane… More

in    0

We test the relationship between canopy photosynthesis and reflected near-infrared radiation from vegetation across a range of functional (photosynthetic pathway and capacity) and structural conditions (leaf area index, fraction of green and dead leaves, canopy height, reproductive stage, and leaf angle inclination), weather conditions, and years using a network of field sites from across central… More

in    0

Wetlands store large C stocks and play important roles in biogeochemical C cycling. However, the effects of environmental and anthropogenic pressures on C dynamics in lower coastal plain forested wetlands in southern U.S. are not well understood. We established four eddy flux stations in two post-harvest and newly-planted loblolly pine (YP2–6, 2–6 yrs old; YP2–8,… More

in    0

Target audience: AmeriFlux community, AmeriFlux Science Steering Committee & Department of Energy (DOE) program managers [ARM/ASR (atmosphere), TES(surface), and SBR (subsurface)] Problem Statement: The atmospheric boundary layer mediates the exchange of energy and matter between the land surface and the free troposphere integratinga range of physical, chemical, and biological processes. However, continuous atmospheric boundary layer… More

in    0

Hydraulic fracturing (hydrofracking) for natural gas has increased rapidly in the area of the Marcellus Shale in the last thirty years and estimates of CH4 emissions from hydrofracking operations are still uncertain. Previous studies on CH4 emissions at hydrofracking operations have used bottom-up approaches collected at discrete timepoints or discrete aerial surveys covering a wide… More

in    0

Forest carbon sequestration via forest preservation can be a viable climate change mitigation strategy. We identify forests in the western conterminous United States with high potential carbon sequestration and low vulnerability to future drought and fire, as simulated using the Community Land Model and two high carbon emission scenario (RCP 8.5) climate models. High-productivity, low-vulnerability… More

in    0

The National Ecological Observatory Network (NEON) is a multidecadal and continental-scale observatory with sites across the United States. Having entered its operational phase in 2018, NEON data products, software, and services become available to facilitate research on the impacts of climate change, land-use change, and invasive species. An essential component of NEON are its 47… More

in    0