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The photosynthetic characteristics of the terrestrial cyanobacterium, Nostoc flagelliforme, after complete recovery by rewetting, was investigated to see whether it could use bicarbonate as the external inorganic carbon source when submerged. The photosynthesis?pH relationship and high pH compensation point suggested that the terrestrial alga could use bicarbonate to photosynthesize when submerged. The photosynthetic oxygen evolution rates were significantly inhibited in Na+-free and Na++ Li+ media but were not affected by the absence of Cl?, implying that the bicarbonate uptake was associated with Na+/ HCO3? symport rather than Cl?/HCO3? exchange system. Published in Journal of Phycology, volume 37, issue 5, on...
Numerous basins of the intermountain area often have extensive playa surfaces that are nearly devoid of vegetation. Margins of these playas support sparse communities dominated by chenopod shrubs Allenrolfea occidentalis (iodine bush) and Sacrobatus vermiculatus (black greasewood). These plants establish and persist in an environment where halomorphic soils induce extreme osmotic stress and atmospheric precipitation is very low and erratic and occurs largely during the winter when temperatures are too low for growth. We measured net CO2 assimilation rates, leaf conductances, transpiration rates, water-use efficiencies, and stem xylem potentials for these two C3 species. Data were collected in above-average (1991)...
Continually rising atmospheric CO2 concentrations and possible climatic change may cause significant changes in plant communities. This study was undertaken to investigate gas exchange in two important grass species of the short-grass steppe, Pascopyrum smithii (western wheat-grass), C3, and Bouteloua gracilis (blue grama), C4, grown at different CO2 concentrations and temperatures. Intact soil cores containing each species were extracted from grasslands in north-eastern Colorado, USA, placed in growth chambers, and grown at combinations of two CO2 concentrations (350 and 700 ?mol mol?1) and two temperature regimes (field average and elevated by 4�C). Leaf gas exchange was measured during the second, third and fourth...
? The influences of prior monsoon-season drought (PMSD) and the seasonal timing of episodic rainfall (?pulses?) on carbon and water exchange in water-limited ecosystems are poorly quantified. ? In the present study, we estimated net ecosystem exchange of CO2 (NEE) and evapotranspiration (ET) before, and for 15 d following, experimental irrigation in a semi-arid grassland during June and August 2003. Rainout shelters near Tucson, Arizona, USA, were positioned on contrasting soils (clay and sand) and planted with native (Heteropogon contortus) or non-native invasive (Eragrostis lehmanniana) C4 bunchgrasses. Plots received increased (?wet?) or decreased (?dry?) monsoon-season (July?September) rainfall during 2002 and...
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These data were compiled for a study that investigated the effects of drought seasonality and plant community composition on two dominant perennial grasses, Achnatherum hymenoides (C3 photosynthesis), and Pleuraphis jamesii (C4 photosynthesis), in a dryland ecosystem. In 2015 USGS 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...
Tags: Achnatherum hymenoides, Botany, C3 photosynthesis, C4 photosynthesis, Canyonlands National Park, All tags...
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This U.S. Geological Survey data release provides the data and citations for selected tables and figures in “Agriculture-A river runs through it-The connections between agriculture and water quality”. This Circular is based on the National Water-Quality Assessment Project’s study of Agricultural Chemicals: Sources, Behavior, and Transport. This study focused on the connections between agriculture and water quality by examining multiple components of the hydrological system within agricultural areas to improve the understanding of how agricultural chemicals are transported into and through streams and groundwater. These data support the following publication: Capel, P.D., McCarthy, K.A., Coupe, R.H., Grey, K.M.,...
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This dataset provides a common validation set for estimates of gross primary productivity. This data represents a subset of all predictions made in the model inputs and outputs that were converted to GPP based on a light use efficiency. The data was subsetted for only days were all light estimates could be produced. This dataset 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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This dataset provides site identifiers, details, and quality indicators. The format is a table with 1 row per site (tab-delimited file). 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, AL, AR, All tags...
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This dataset provides site locations as shapefile points. The format is a shapefile for all sites combined (.shp, .shx, .dbf, and .prj files). 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.
Categories: Data; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: 007, 012, AK, AL, AR, All tags...
Carbon gain depends on efficient photosynthesis and adequate respiration. The effect of temperature on photosynthetic efficiency is well understood. In contrast, the temperature response of respiration is based almost entirely on short-term (hours) measurements in mature organisms to develop Q(10) values for maintenance and whole-plant respiration. These Q(10) values are then used to extrapolate across whole life cycles to predict the influence of temperature on plant growth. Published in Annals of Botany, volume 94, issue 1, on pages 155 - 66, in 2004.
The carbon costs of reproduction were examined in four subalpine herbaceous plant species for which number and size of flowers respond differently under a long-term infrared warming experiment. * Instantaneous measurements of gas exchange and an integrative model were used to calculate whole-plant carbon budgets and reproductive effort (RE). * Of the two species for which flowering was reduced, only one (Delphinium nuttallianum) exhibited higher RE under warming. The other species (Erythronium grandiflorum) flowers earlier when freezing events under warming treatment could have damaged floral buds. Of the two species for which flowering rates were not reduced, one (Helianthella quinquenervis) had higher RE, while...
The articles in this issue of the Canadian Journal of Botany arose from presentations given at The Fifth International Symposium on Inorganic Carbon Utilization by Aquatic Photosynthetic Organisms held from 24 to 28 August 2004 at Saint-Sauveur, Quebec, Canada. They represent the current state of our understanding of CO2-concentrating mechanisms in these organisms and highlight recent molecular, physiological, and ecological advances made in this field of study. The influence of CO2-concentrating mechanisms on global carbon sequestration, species diversity, and population dynamics are also explored.Key words: algae, CO2-concentrating mechanisms, cyanobacteria, photosynthesis.Les articles dans ce numéro de la Revue...
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This dataset provides information on site identifiers, location information, and model parameters. The format is a tab-delimted file with 1 row per site. This dataset 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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This study evaluated the net ecosystem exchange of CO2 and CH4 from experimental wetland mesocosms established in elevated CO2 and ambient CO2 glasshouses at the U.S. Geological Survey’s Wetland and Aquatic Research Center (Lafayette, Louisiana). The study duration was approximately two years, and these data represent measured and calculated data from four time points, which the investigators associate with season.
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This dataset provides model specifications used to estimate metabolism. The format is a table with 1 row per model (1 tab-delimited file, compressed into zip file). The specific format of this configuration file is arbitrary and specific to this analysis, and the format need not be replicated to use streamMetabolizer; however, this tabular format is useful because it allows for the reading by both humans and computers of (1) the combinations of sites and temporal resolutions for which models were run, (2) the timeseries data that were selected and combined to prepare the input to each model, and (3) the model specifications and parameters that were used in each model application. This dataset is part of a larger...
Tags: 007, 012, AK, AR, Aerobic respiration, All tags...
The cycles of the key nutrient elements nitrogen (N) and phosphorus (P) have been massively altered by anthropogenic activities. Thus, it is essential to understand how photosynthetic production across diverse ecosystems is, or is not, limited by N and P. Via a large-scale meta-analysis of experimental enrichments, we show that P limitation is equally strong across these major habitats and that N and P limitation are equivalent within both terrestrial and freshwater systems. Furthermore, simultaneous N and P enrichment produces strongly positive synergistic responses in all three environments. Thus, contrary to some prevailing paradigms, freshwater, marine and terrestrial ecosystems are surprisingly similar in terms...
BACKGROUND AND AIMS: The basic parameters of water relations were measured in Sphagnum mosses. The relationships of these parameters to the photosynthetic response to desiccation and the ecology of these mosses were then tested. METHODS: The water relations parameters of six Sphagnum species (mosses typical of wet habitats) and Atrichum androgynum (a moss more typical of mesophytic conditions) were calculated from pressure-volume isotherms. Photosynthetic properties during and after moderate desiccation were monitored by chlorophyll fluorescence. KEY RESULTS: When desiccated, the hummock-forming species S. fuscum and S. magellanicum lost more water before turgor started dropping than other sphagna inhabiting less...
Plants of four Great Basin grass species were grown from seed in two greenhouses at low (340 ? l l-1) and high (680 ? l l-1) CO2 concentration. In all four species, high CO2 promoted mean increases in the number of basal stems, leaf area, specific leaf weight and above-ground dry weight. High CO2 resulted in an increase in CO2 assimilation in two C3 grasses but not in a C4 grass, while all three species showed decreases in stomatal conductance. Mean increases of 60% in aboveground dry weight and 80% in water-use-efficiency are consistent with previously reported high CO2 effects on grasses. No consistent differential effects of high CO2 were observed when comparing annual vs perennial species. Global CO2 enrichment...
Pascopyrum smithii (C3) andBouteloua gracilis (C4) are important forage grasses native to the Colorado shortgrass steppe. This study investigated photosynthetic responses of these grasses to long-term CO2enrichment and temperature in relation to leaf nonstructural carbohydrate (TNC) and [N]. Glasshouse-grown seedlings were transferred to growth chambers and grown for 49 d at two CO2concentrations (380 and 750 ?mol mol?1) at 20 and 35 �C, and two additional temperatures (25 and 30 �C) at 750 ?mol mol?1CO2. Leaf CO2exchange rate (CER) was measured at a plant's respective growth temperature and at two CO2concentrations of approx. 380 and 700 ?mol mol?1. Long-term CO2enrichment stimulated CER in both species, although...
Abstract (from http://rspb.royalsocietypublishing.org/content/283/1840/20161574): A substantial amount of global carbon is stored in mature trees. However, no experiments to date test how warming affects mature tree carbon storage. Using a unique, citywide, factorial experiment, we investigated how warming and insect herbivory affected physiological function and carbon sequestration (carbon stored per year) of mature trees. Urban warming increased herbivorous arthropod abundance on trees, but these herbivores had negligible effects on tree carbon sequestration. Instead, urban warming was associated with an estimated 12% loss of carbon sequestration, in part because photosynthesis was reduced at hotter sites. Ecosystem...
map background search result map search result map Data and citations describing the connections between agriculture and water quality in the United States Metabolism estimates for 356 U.S. rivers (2007-2017): 1. Site data Metabolism estimates for 356 U.S. rivers (2007-2017): 5. Model configurations Metabolism estimates for 356 U.S. rivers (2007-2017): 2a. Site coordinates Light model and GPP estimates for 173 U.S. rivers: 1. Site information and parameters Light model and GPP estimates for 173 U.S. rivers: 3. Model validation dataset Precipitation, soil moisture, and vegetation data from 36 experimental plots in southeastern Utah, near Canyonlands National Park (2015 - 2018) Data for leaf photosynthesis and net ecosystem exchange of CO2 and CH4 from wetland forest, marsh, and mudflats under simulated ambient and elevated atmospheric carbon dioxide (2013-2014) Data for leaf photosynthesis and net ecosystem exchange of CO2 and CH4 from wetland forest, marsh, and mudflats under simulated ambient and elevated atmospheric carbon dioxide (2013-2014) Precipitation, soil moisture, and vegetation data from 36 experimental plots in southeastern Utah, near Canyonlands National Park (2015 - 2018) Light model and GPP estimates for 173 U.S. rivers: 1. Site information and parameters Light model and GPP estimates for 173 U.S. rivers: 3. Model validation dataset Data and citations describing the connections between agriculture and water quality in the United States Metabolism estimates for 356 U.S. rivers (2007-2017): 5. Model configurations Metabolism estimates for 356 U.S. rivers (2007-2017): 2a. Site coordinates Metabolism estimates for 356 U.S. rivers (2007-2017): 1. Site data