Colleen M. Iversen
A5047874160- Climate change and permafrost
- Peatlands and Wetlands Ecology
- Soil Carbon and Nitrogen Dynamics
- Plant Water Relations and Carbon Dynamics
- Cryospheric studies and observations
- Geology and Paleoclimatology Research
- Botany and Plant Ecology Studies
- Coastal wetland ecosystem dynamics
- Plant responses to elevated CO2
- Plant nutrient uptake and metabolism
- Fire effects on ecosystems
- Geological Studies and Exploration
- Indigenous Studies and Ecology
- Mycorrhizal Fungi and Plant Interactions
- Polar Research and Ecology
- Atmospheric and Environmental Gas Dynamics
- Methane Hydrates and Related Phenomena
- Climate variability and models
- Ecology and Vegetation Dynamics Studies
- Bryophyte Studies and Records
- Forest ecology and management
- Arctic and Antarctic ice dynamics
- Lichen and fungal ecology
- Species Distribution and Climate Change
- Plant and animal studies
Oak Ridge National Laboratory
2016-2025
University of Tennessee at Knoxville
2005-2019
University of Notre Dame
2010
Stimulation of terrestrial plant production by rising CO 2 concentration is projected to reduce the airborne fraction anthropogenic emissions. Coupled climate–carbon cycle models are sensitive this negative feedback on atmospheric , but model projections uncertain because expectation that feedbacks through nitrogen (N) will so-called fertilization effect. We assessed whether N limitation caused a reduced stimulation net primary productivity (NPP) elevated over 11 y in free-air enrichment...
Collaboration broadens the “root economics space” ranging from “do-it-yourself” to “outsourcing” mycorrhizal partners.
Summary The effects of plants on the biosphere, atmosphere and geosphere are key determinants terrestrial ecosystem functioning. However, despite substantial progress made regarding plant belowground components, we still only beginning to explore complex relationships between root traits functions. Drawing literature in physiology, ecophysiology, ecology, agronomy soil science, reviewed 24 aspects functioning their with a number system traits, including architecture, morphology, anatomy,...
Summary We analysed the responses of 11 ecosystem models to elevated atmospheric [ CO 2 ] (e ) at two temperate forest ecosystems ( D uke and Oak Ridge National Laboratory ORNL F ree‐ A ir E nrichment FACE experiments) test alternative representations carbon C )–nitrogen N cycle processes. decomposed model into component processes affecting response e confronted these with observations from experiments. Most reproduced observed initial enhancement net primary production NPP both sites, but...
Forest ecosystems are important sinks for rising concentrations of atmospheric CO(2). In previous research, we showed that net primary production (NPP) increased by 23 +/- 2% when four experimental forests were grown under CO(2) predicted the latter half this century. Because nitrogen (N) availability commonly limits forest productivity, some combination N uptake from soil and more efficient use already assimilated trees is necessary to sustain high rates NPP free-air enrichment (FACE)....
Variation and tradeoffs within among plant traits are increasingly being harnessed by empiricists modelers to understand predict ecosystem processes under changing environmental conditions. While fine roots play an important role in functioning, fine-root underrepresented global trait databases. This has hindered efforts analyze variation link it with function conditions at a scale. Viewpoint addresses the need for centralized database, introduces Fine-Root Ecology Database (FRED,...
Summary Ecosystem functioning relies heavily on below‐ground processes, which are largely regulated by plant fine‐roots and their functional traits. However, our knowledge of fine‐root trait distribution to date local‐ regional‐scale studies with limited numbers species, growth forms environmental variation. We compiled a world‐wide dataset, featuring 1115 species from contrasting climatic areas, phylogeny test series hypotheses pertaining the influence types, soil climate variables, degree...
Summary Elevated atmospheric CO 2 concentration ( eCO ) has the potential to increase vegetation carbon storage if increased net primary production causes long‐lived biomass. Model predictions of effects on depend how allocation and turnover processes are represented. We used data from two temperate forest free‐air enrichment FACE experiments evaluate representations in 11 ecosystem models. Observed were dynamic. Allocation schemes based functional relationships among biomass fractions that...
Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well impacts on ecosystem processes. Despite significant progress capturing trait variation within among stems leaves, identification of syndromes fine-root systems between fine roots other organs is limited. Here we discuss three underappreciated areas where focused measurements traits can make contributions science. These include assessment spatiotemporal...
Abstract Motivation Trait data are fundamental to the quantitative description of plant form and function. Although root traits capture key dimensions related responses changing environmental conditions effects on ecosystem processes, they have rarely been included in large‐scale comparative studies global models. For instance, remain absent from nearly all that define spectrum Thus, overcome conceptual methodological roadblocks preventing a widespread integration trait into analyses we...
Since their emergence onto land, terrestrial plants have developed diverse strategies to acquire soil resources. However, we lack a framework that adequately captures how these vary among species. Observations from around the world now allow us quantify variation observed in commonly-measured fine-root traits but it is unclear root are interrelated and whether they fall along an "economic" spectrum of acquisitive conservative strategies. We assessed trait mycorrhizal colonization rates by...
We characterized peat decomposition at the Marcell Experimental Forest (MEF), Minnesota, USA, to a depth of 2 m ascertain underlying chemical changes using Fourier transform infrared (FT IR) and 13C nuclear magnetic resonance (NMR) spectroscopy) related these proxies C:N ratio, δ13C δ15N, bulk density, water content. FT IR determined that humification increased rapidly between 30 75 cm, indicating highly reactive intermediate-depth zone consistent with in Peat MEF, especially zone, is mainly...