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Arid and semi-arid ecosystems of the southwestern US are undergoing changes in vegetation composition and are predicted to experience shifts in climate. To understand implications of these current and predicted changes, we conducted a precipitation manipulation experiment on the Santa Rita Experimental Range in southeastern Arizona. The objectives of our study were to determine how soil surface and seasonal timing of rainfall events mediate the dynamics of leaf-level photosynthesis and plant water status of a native and non-native grass species in response to precipitation pulse events. We followed a simulated precipitation event (pulse) that occurred prior to the onset of the North American monsoon (in June) and...
Gas exchange and water relations responses to warming were compared for two shrub species, Artemisia tridentata spp. vaseyana (Asteraceae), a widely distributed evergreen species of the Great Basin and the western slope of the Rocky Mountains, and Pentaphylloides floribunda (Rosaceae), a deciduous shrub limited in distribution to moist, high-elevation meadows. Plants were exposed to an in situ infrared (IR) climate change manipulation at the Rocky Mountain Biological Laboratory, near Crested Butte, CO. Measurements of gas exchange and water relations were made on the two species in July and August, 1993 from plants growing in situ in infrared-heated and control plots. Carbon dioxide uptake, water loss, leaf temperature,...
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This dataset provides timeseries data on water quality and quantity, as collected or computed from outside sources. The format is many tables with one row per time series observation (1 tab-delimited file per site-variable combination, 1 zip file per site). This compilation of data is intended for use in estimating or interpreting metabolism. Sites were included if they met the initial criteria of having at least 100 dissolved oxygen observations and one of the accepted NWIS site types ('ST','ST-CA','ST-DCH','ST-TS', or 'SP'). This dataset is part of a larger data release of metabolism model inputs and outputs for 356 streams and rivers across the United States (https://doi.org/10.5066/F70864KX). The complete release...
Tags: 007, 012, AK, AL, AR, All tags...
The mechanisms controlling the photosynthetic performance of C4 plants at low temperature were investigated using ecotypes of Bouteloua gracilis Lag. from high (3000 m) and low (1500 m) elevation sites in the Rocky Mountains of Colorado. Plants were grown in controlled-environment cabinets at a photon flux density of 700 μmol m−2 s−1 and day/night temperatures of 26/16 °C or 14/7 °C. The thermal response of the net CO2 assimilation rate (A) was evaluated using leaf gas-exchange analysis and activity assays of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), phosphoenolpyruvate carboxylase (PEPCase) and pyruvate,orthophosphate dikinase (PPDK). In both ecotypes, a reduction in measurement temperature...
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These plant and soil data were collected by Timothy M. Wertin and Sasha C. Reed in the spring, summer, and fall of 2011 at a climate manipulation experiment site near Moab, UT (38.521411, -109.470567). These data were collected to assess how warming affects leaf photosynthesis, soil CO 2 efflux, and soil chemistry in plots of ambient and warming treatments.
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These data were compiled for a study that investigated the effects of drought seasonality and plant community composition in a dryland ecosystem. In 2015 U.S. Geological Survey ecologists recorded vegetation and soil moisture data in 36 experimental plots which manipulated precipitation in two plant community types. The experiment consisted of three precipitation treatments: control (ambient precipitation), cool-season drought (-66% ambient precipitation November-April), and warm-season drought (-66% ambient precipitation May-October), applied in two plant communities (perennial grasses with or without a large shrub, Ephedra viridis) over a three-year period. These data were collected from 2015 to 2022 near Canyonlands...
Categories: Data; Tags: Achnatherum hymenoides, Botany, C3 photosynthesis, C4 photosynthesis, Canyonlands National Park, All tags...
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This dataset provides details from stream metabolism models for 20 stream sites in the United States that were sampled as part of the National Water Quality Program's Regional Stream Quality Assessments (RSQA). Metabolism was estimated at each site using the streamMetabolizer package in R. For each of the 20 sites, three files are provided; (1) the input data, which includes continuous dissolved oxygen, water temperature, light, and stream depth, (2) the output data containing the daily metabolism estimates, and (3) a site-specific html 'guide' for running the streamMetabolizer package in R. The site 'short_name' is included in each file name to distinguish the files associated with each field site. Final metabolism...
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This dataset provides input data formatted for use in estimating metabolism. The format is tables of prepared time series inputs (1 tab-delimited file per site, in 1 zip file per site). This dataset is part of a larger data release of metabolism model inputs and outputs for 356 streams and rivers across the United States (https://doi.org/10.5066/F70864KX). The complete release includes: modeled estimates of gross primary productivity, ecosystem respiration, and the gas exchange coefficient; model input data and alternative input data; model fit and diagnostic information; site catchment boundaries and site point locations; and potential predictors of metabolism such as discharge and light availability.
Tags: 007, 012, AK, AR, Aerobic respiration, All tags...
Cyanobacteria have evolved a significant environmental adaptation, known as a CO(2)-concentrating-mechanism (CCM), that vastly improves photosynthetic performance and survival under limiting CO(2) concentrations. The CCM functions to transport and accumulate inorganic carbon actively (Ci; HCO(3)(-), and CO(2)) within the cell where the Ci pool is utilized to provide elevated CO(2) concentrations around the primary CO(2)-fixing enzyme, ribulose bisphosphate carboxylase-oxygenase (Rubisco). In cyanobacteria, Rubisco is encapsulated in unique micro-compartments known as carboxysomes. Cyanobacteria can possess up to five distinct transport systems for Ci uptake. Through database analysis of some 33 complete genomic...
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Ecosystem metabolism is a measure of energy flow in terrestrial and aquatic environments that quantifies a balance between the rate of biomass production by photosynthesizing plants and the rate of biomass oxidation by respiring plants and animals to maintain and build living biomass. It is therefore a fundamental measure of ecosystem function that quantifies the balance between the rate of production, maintenance, and decay of organic matter. It also provides an understanding of energy flow to higher trophic levels that supports food webs with secondary and tertiary productivity. Furthermore, metabolism helps explain when aquatic ecosystems undergo out-of-balance behaviors such as hypoxia. Recent advances in sensor...
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1. Windblown dust, an environmental problem in many disturbed arid lands, has the potential to affect the physiological performance of desert shrubs. Physiological parameters of gas exchange for three species (Larrea tridentata, Hymenoclea salsola and Atriplex canescens) were measured at a Mojave Desert site, at which both undisturbed and heavily dusted individual shrubs occurred. 2. Maximum rates of net photosynthesis (A) of dusted organs were reduced to 21% of those of control plants in resinous leaflets of Larrea, to 44% in resinous leaves and photosynthetic stems of Hymenoclea, and to 58% in non-resinous C4 leaves of Atriplex, which have vesiculated trichomes. Dusted plants of all three species showed reduced...
Shifts from nitrogen (N)- to phosphorus (P)-limited growth due to high N deposition may alter the functioning of wetland vegetation. This experiment tested how N vs P deficiency affects the growth and nutrient use of wetland sedges. Five wetland Carex species were grown at nine N : P supply ratios (0.6-405) with two absolute levels of N and P. Biomass and nutrient concentrations were determined after one and two growing seasons. Shoot biomass was maximal at N : P supply ratios of 15-26 after one season but 5-15 after two seasons. Photosynthesis after the first season, second-year growth, leaf longevity, and the fraction of nutrient supply retained by plants over two seasons were all negatively related to N : P supply...
Climate change is causing measurable changes in rainfall patterns, and will likely cause increases in extreme rainfall events, with uncertain implications for key processes in ecosystem function and carbon cycling. We examined how variation in rainfall total quantity (Q), the interval between rainfall events (I), and individual event size (SE) affected soil water content (SWC) and three aspects of ecosystem function: leaf photosynthetic carbon gain (inline image), aboveground net primary productivity (ANPP), and soil respiration (inline image). We utilized rainout shelter-covered mesocosms (2.6 m3) containing assemblages of tallgrass prairie grasses and forbs. These were hand watered with 16 I�Q treatment combinations,...
Downy brome (Bromus tectorum L.) is an alien grass that dominates disturbed ground in shrub-steppe ecosystems of the western United States. Responses of downy brome to added nitrogen and water were evaluated using intact soil cores obtained from an old field. Gas exchange data were gathered at the leaf and canopy scales. Stomatal conductance and net photosynthesis rates were greater at the leaf scale than at the canopy scale, decreased with time from germination, and were weakly affected by treatments. Water-use efficiency was weakly related to time from germination and treatments. Biomass was greater in the nitrogen-plus-water (7.4 g) treatment, compared with water (3.6 g), nitrogen (4.5 g), and control (3.3 g)...
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Ecosystem metabolism is a measure of energy flow in terrestrial and aquatic environments that quantifies a balance between the rate of biomass production by photosynthesizing plants and the rate of biomass oxidation by respiring plants and animals to maintain and build living biomass. It is therefore a fundamental measure of ecosystem function that quantifies the balance between the rate of production, maintenance, and decay of organic matter. It also provides an understanding of energy flow to higher trophic levels that supports food webs with secondary and tertiary productivity. Furthermore, metabolism helps explain when aquatic ecosystems undergo out-of-balance behaviors such as hypoxia. Recent advances in sensor...
We used microsensors to characterize physicochemical microenvironments and photosynthesis occurring immediately after water saturation in two desert soil crusts from southeastern Utah, which were formed by the cyanobacteria Microcoleus vaginatus Gomont, Nostoc spp., and Scytonema sp. The light fields within the crusts presented steep vertical gradients in magnitude and spectral composition. Near-surface light-trapping zones were formed due to the scattering nature of the sand particles, but strong light attenuation resulted in euphotic zones only ca. 1 mm deep, which were progressively enriched in longer wavelengths with depth. Rates of gross photosynthesis (3.4?9.4 mmol O2�m?2�h?1) and dark respiration (0.81?3.1...
In semiarid ecosystems, physiography (landscape setting) may interact with woody-plant and soil microbe communities to constrain seasonal exchanges of material and energy at the ecosystem scale. In an upland and riparian shrubland, we examined the seasonally dynamic linkage between ecosystem CO2 exchange, woody-plant water status and photosynthesis, and soil respiration responses to summer rainfall. At each site, we compared tower-based measurements of net ecosystem CO2 exchange (NEE) with ecophysiological measurements among velvet mesquite (Prosopis velutina Woot.) in three size classes and soil respiration in sub-canopy and inter-canopy micro-sites. Monsoonal rainfall influenced a greater shift in the magnitude...
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This dataset provides timeseries of model input and output data and is part of a larger data release of inputs and outputs from a model to predict light at the stream surface and within the water column for 173 streams and rivers across the continental United States. The complete release contains model input data, modeled estimates of light at the stream surface and within the water column, and modeled estimates of gross primary productivity.
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The following files contain source data for use of the Community Land Model 4.0 at two study sites in Volcanoes National Park, Hawai'i. Included are: Biometric data: 1) Growth increment data for Thurston and Olaa, based on dbh surveys done in four 10 m by 10 m plots at over a 12 year time period at Thurston and at six plots overs a 12 year period at Olaa, 2) Field measured leaf area index data. Measurements were made using LAI-2000 and LAI-2200 instruments, 3) Litterfall from Thurston and Olaa over a 17-mo period from June 2014 to Sep 2015. Data were sorted by species/litter type. Data are weights., 4) Field measured soil respiration data scaled to annual values and compared with tower-based measurements of ecosystem...
In the arid and semiarid regions of North America, discrete precipitation pulses are important triggers for biological activity. The timing and magnitude of these pulses may differentially affect the activity of plants and microbes, combining to influence the C balance of desert ecosystems. Here, we evaluate how a "pulse" of water influences physiological activity in plants, soils and ecosystems, and how characteristics, such as precipitation pulse size and frequency are important controllers of biological and physical processes in arid land ecosystems. We show that pulse size regulates C balance by determining the temporal duration of activity for different components of the biota. Microbial respiration responds...
map background search result map search result map Surface Dust Impacts on Gas Exchange in Mojave Desert Shrubs Experimental Design Plant and Soil Measurement Data for Achnatherum hymenoides from a warming experiment, Colorado Plateau, 2011 - Data Metabolism estimates for 356 U.S. rivers (2007-2017): 3. Timeseries data Metabolism estimates for 356 U.S. rivers (2007-2017): 4. Model inputs Observed ecological inputs to the Community Land Model at two wet montane study sites, 2004-2016, Volcanoes National Park, Hawai'i Stream metabolism estimates for the Regional Stream Quality Assessments of the National Water Quality Program, 2013 to 2016 Light model and GPP estimates for 173 U.S. rivers: 2. Model inputs and outputs RiverMET: Workflow and scripts for river metabolism estimation including Illinois River Basin application, 2005 - 2020 (Output files from) RiverMET: Workflow and scripts for river metabolism estimation including Illinois River Basin application, 2005 - 2020 Plant composition, shrub biomass, and soil biogeochemistry from an experimental drought treatment on the Colorado Plateau Plant composition, shrub biomass, and soil biogeochemistry from an experimental drought treatment on the Colorado Plateau Observed ecological inputs to the Community Land Model at two wet montane study sites, 2004-2016, Volcanoes National Park, Hawai'i Experimental Design Plant and Soil Measurement Data for Achnatherum hymenoides from a warming experiment, Colorado Plateau, 2011 - Data Surface Dust Impacts on Gas Exchange in Mojave Desert Shrubs RiverMET: Workflow and scripts for river metabolism estimation including Illinois River Basin application, 2005 - 2020 (Output files from) RiverMET: Workflow and scripts for river metabolism estimation including Illinois River Basin application, 2005 - 2020 Light model and GPP estimates for 173 U.S. rivers: 2. Model inputs and outputs Stream metabolism estimates for the Regional Stream Quality Assessments of the National Water Quality Program, 2013 to 2016 Metabolism estimates for 356 U.S. rivers (2007-2017): 4. Model inputs Metabolism estimates for 356 U.S. rivers (2007-2017): 3. Timeseries data