We examined the effects of growth carbon dioxide (CO2)concentration and soil nutrient availability on nitrogen (N)transformations and N trace gas fluxes in California grasslandmicrocosms during early-season wet-up, a time when rates of Ntransformation and N trace gas flux are high. After plant senescenceand summer drought, we simulated the first fall […]
Soil carbon (C) is a critical component of Earth system models (ESMs), and its diverse representations are a major source of the large spread across models in the terrestrial C sink from the third to fifth assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Improving soil C projections […]
In Alaska, an outbreak of spruce beetles (Dendroctonus rufipennis) recently infested over one million hectares of spruce (Picea spp.) forest. As a result, land management agencies have applied different treatments to infested forests to minimize fire hazard and economic loss and facilitate forest regeneration. In this study we investigated the […]
Increasing atmospheric CO2 concentrations alter leaf physiology, with effects that cascade to communities and ecosystems. Yet, responses over cycles of disturbance and recovery are not well known, because most experiments span limited ecological time. We examined the effects of CO2 on root growth, herbivory and arthropod biodiversity in a woodland […]
Scientists who study climate and ecosystems in the Arctic have weighed in on future changes in the region affecting soils, streams and wildfire, which will be releasing greater amounts of carbon dioxide and other greenhouse gases into the atmosphere.Because the Arctic is home to billions of tons of naturally occurring carbon […]
In the boreal forest of Alaska, increased fire severity associated with climate change is expanding deciduous forest cover in areas previously dominated by black spruce (Picea mariana). Needle-leaf conifer and broad-leaf deciduous species are commonly associated with differences in tree growth, carbon (C) and nutrient cycling, and C accumulation in […]
The impacts of climate extremes on terrestrial ecosystems are poorly understood but important for predicting carbon cycle feedbacks to climate change. Coupled climate–carbon cycle models typically assume that vegetation recovery from extreme drought is immediate and complete, which conflicts with the understanding of basic plant physiology. We examined the recovery […]
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 […]
Michelle Mack describes the effects the wildfires in Alaska this summer will have on the carbon emissions from permafrost in this story in the Washington Post. “Beyond the direct carbon emissions from fire, loss of the insulating organic layer is likely to destabilize permafrost, leading to thaw, decomposition and release […]
We study soil microbial communities in Antarctica, microbes in hot spring ecosystems in Tengchong, China, methane production at Axel Heiberg Island near Greenland as an analog for life on other planets, and the distribution of soil microbial communities across the arid Southwest.