A5049016489- Plant Water Relations and Carbon Dynamics
- Plant responses to elevated CO2
- Soil Carbon and Nitrogen Dynamics
- Forest ecology and management
- Ecology and Vegetation Dynamics Studies
- Peatlands and Wetlands Ecology
- Atmospheric and Environmental Gas Dynamics
- Microbial Community Ecology and Physiology
- Mitochondrial Function and Pathology
- Plant nutrient uptake and metabolism
- Photosynthetic Processes and Mechanisms
- Climate variability and models
- Soil and Water Nutrient Dynamics
- Plant Stress Responses and Tolerance
- ATP Synthase and ATPases Research
- Plant Physiology and Cultivation Studies
- Remote Sensing and LiDAR Applications
- Nuts composition and effects
- Soil erosion and sediment transport
- Metabolomics and Mass Spectrometry Studies
- Fire effects on ecosystems
- Plant responses to water stress
- Hemoglobin structure and function
- Plant Ecology and Soil Science
- Legume Nitrogen Fixing Symbiosis
Australian National University
2017-2024
ARC Centre of Excellence in Plant Energy Biology
2017-2024
Australian Research Council
2018-2020
Colorado State University
2013-2019
United States Department of Agriculture
2016
University of California, Santa Barbara
2012
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...
Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about responses environmental conditions. Laboratories publishing estimates of NSC woody plants use many different methods evaluate NSC. We asked whether the recent literature could be quantitatively compared among studies. also any differences laboratories were related extraction and quantification used determine starch sugar concentrations. These questions addressed by sending sub-samples...
Abstract Free‐air CO 2 enrichment (FACE) experiments provide a remarkable wealth of data which can be used to evaluate and improve terrestrial ecosystem models (TEMs). In the FACE model‐data synthesis project, 11 TEMs were applied two decadelong in temperate forests southeastern U.S.—the evergreen Duke Forest deciduous Oak Ridge Forest. this baseline paper, we demonstrate our approach by evaluating models' ability reproduce observed net primary productivity (NPP), transpiration, leaf area...
Abstract Large uncertainty exists in model projections of the land carbon (C) sink response to increasing atmospheric CO 2 . Free‐Air Enrichment (FACE) experiments lasting a decade or more have investigated ecosystem responses step change concentration. To interpret FACE results context gradual increases over decades centuries, we used suite seven models simulate Duke and Oak Ridge extended for 300 years enrichment. We also determine key modeling assumptions that drive divergent terrestrial...
Abstract Increasing atmospheric CO 2 stimulates photosynthesis which can increase net primary production (NPP), but at longer timescales may not necessarily plant biomass. Here we analyse the four decade-long -enrichment experiments in woody ecosystems that measured total NPP and enrichment increased biomass increment by 1.05 ± 0.26 kg C m −2 over a full decade, 29.1 11.7% stimulation of gain these early-secondary-succession temperate ecosystems. This response is predictable combining (0.16...
Multifactor experiments are often advocated as important for advancing terrestrial biosphere models (TBMs), yet to date, such have only been tested against single-factor experiments. We applied 10 TBMs the multifactor Prairie Heating and CO2 Enrichment (PHACE) experiment in Wyoming, USA. Our goals were investigate how can be used constrain identify a road map model improvement. found performed poorly ambient conditions; there was wide spread simulated above-ground net primary productivity...
How trees sense source–sink carbon balance remains unclear. One potential mechanism is a feedback from non-structural carbohydrates regulating photosynthesis and removing excess as waste respiration when the of against growth metabolic activity changes. We tested this carbohydrate regulation using branch girdling in four tree species wet tropical rainforest Costa Rica. Because severs phloem to stop export while leaving xylem intact allow photosynthesis, we expected accumulate leaves simulate...
Determining whether the terrestrial biosphere will be a source or sink of carbon (C) under future climate elevated CO2 (eCO2 ) and warming requires accurate quantification gross primary production (GPP), largest flux C in global cycle. We evaluated 6 years (2007-2012) flux-derived GPP data from Prairie Heating Enrichment (PHACE) experiment, situated grassland Wyoming, USA. The were used to calibrate light response model whose basic formulation has been successfully variety ecosystems. was...
Abstract Recent studies have found that solar ultraviolet ( UV ) radiation significantly shifts the mass loss and nitrogen dynamics of plant litter decomposition in semi‐arid arid ecosystems. In this study, we examined role photodegradation by using DayCent‐ biogeochemical model. incorporated following mechanisms related to radiation: (1) direct photolysis, (2) facilitation microbial via production labile materials, (3) inhibition effects. We also allowed maximum photodecay rate structural...
Abstract. For more accurate projections of both the global carbon (C) cycle and changing climate, a critical current need is to improve representation tropical forests in Earth system models. Tropical exchange C, energy, water with atmosphere than any other class land ecosystems. Further, tropical-forest C cycling likely responding rapid warming, intensifying stress, increasing atmospheric CO2 levels. Projections future balance tropics vary widely among A effort modeling community, ILAMB...
Summary Short‐term temperature response curves of leaf dark respiration ( R–T ) provide insights into a critical process that influences plant net carbon exchange. This includes how respiratory traits acclimate to sustained changes in the environment. Our study analysed 860 high‐resolution (10–70°C range) for: (a) 62 evergreen species measured two contrasting seasons across several field sites/biomes; and (b) 21 (subset those sampled field) grown glasshouses at 20°C : 15°C, 25°C 30°C 25°C,...
Summary We used a widely distributed tree Eucalyptus camaldulensis subsp. to partition intraspecific variation in leaf functional traits genotypic and phenotypic plasticity. examined if is related the climate of genotype provenance whether plasticity maintains performance changing environment. Ten genotypes from different climates were grown common garden under watering treatments reproducing wettest driest edges subspecies’ distribution. measured reflecting metabolism associated with growth...
Summary Leaf respiration in the dark ( R ) is often measured at a single time during day, with hot‐acclimation lowering common measuring temperature. However, it unclear whether diel cycle influences extent of thermal acclimation , or how temperature and day interact to influence respiratory metabolites. To examine these issues, we grew rice under 25°C : 20°C, 30°C 40°C 35°C night cycles, changes metabolites five points spanning 24‐h period. differed among treatments day. there was no...
Summary Nonstructural carbohydrate (NSC) concentrations might reflect the strategies described in leaf economic spectrum (LES) due to their dependence on photosynthesis and respiration. We examined if NSC correlate with structure, chemistry, physiology traits for 114 species from 19 sites 5 biomes around globe. Total varied greatly 16 199 mg g −1 dry mass were mostly independent of gas exchange LES traits. By contrast, residence time was shorter higher rates photosynthesis, following...
As tropical forests respond to environmental change, autotrophic respiration may consume a greater proportion of carbon fixed in photosynthesis at the expense growth, potentially turning into source. Predicting such response requires that we measure and place complete budget, but extrapolating measurements from chambers ecosystem remains challenge. High plant species diversity complex canopy structure cause rates vary do not account for this complexity introduce bias extrapolation more...
Abstract Photodegradation accelerates litter decay in arid grasslands where plant growth and are strongly controlled by precipitation evapotranspiration. However, the effects of photodegradation on ecosystem C N dynamics not well understood. We examined using an biogeochemical model DayCent‐ UV with explicitly represented validated. The was parameterized for a California grassland documented to release CO 2 from litter. inverse modeling approach extensive data set six years daily observed...
Our understanding of the regulation respiration in C4 plants, where mitochondria play different roles types photosynthetic pathway, remains limited. We examined how leaf dark rates (Rdark ), presence and absence added malate, vary monocots representing three classical biochemical photosynthesis (NADP-ME, NAD-ME PCK) using intact leaves extracted bundle sheath strands. In particular, we explored to what extent Rdark are associated with mitochondrial number, volume ultrastructure. Based on...