Academic literature on the topic 'GPP photosynthesis by vegetation'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'GPP photosynthesis by vegetation.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "GPP photosynthesis by vegetation"
1
Stocker, Benjamin D., Han Wang, Nicholas G. Smith, Sandy P. Harrison, Trevor F. Keenan, David Sandoval, Tyler Davis, and I. Colin Prentice. "P-model v1.0: an optimality-based light use efficiency model for simulating ecosystem gross primary production." Geoscientific Model Development 13, no. 3 (March 26, 2020): 1545–81. http://dx.doi.org/10.5194/gmd-13-1545-2020.
Full textAbstract:
Abstract. Terrestrial photosynthesis is the basis for vegetation growth and drives the land carbon cycle. Accurately simulating gross primary production (GPP, ecosystem-level apparent photosynthesis) is key for satellite monitoring and Earth system model predictions under climate change. While robust models exist for describing leaf-level photosynthesis, predictions diverge due to uncertain photosynthetic traits and parameters which vary on multiple spatial and temporal scales. Here, we describe and evaluate a GPP (photosynthesis per unit ground area) model, the P-model, that combines the Farquhar–von Caemmerer–Berry model for C3 photosynthesis with an optimality principle for the carbon assimilation–transpiration trade-off, and predicts a multi-day average light use efficiency (LUE) for any climate and C3 vegetation type. The model builds on the theory developed in Prentice et al. (2014) and Wang et al. (2017a) and is extended to include low temperature effects on the intrinsic quantum yield and an empirical soil moisture stress factor. The model is forced with site-level data of the fraction of absorbed photosynthetically active radiation (fAPAR) and meteorological data and is evaluated against GPP estimates from a globally distributed network of ecosystem flux measurements. Although the P-model requires relatively few inputs, the R2 for predicted versus observed GPP based on the full model setup is 0.75 (8 d mean, 126 sites) – similar to comparable satellite-data-driven GPP models but without predefined vegetation-type-specific parameters. The R2 is reduced to 0.70 when not accounting for the reduction in quantum yield at low temperatures and effects of low soil moisture on LUE. The R2 for the P-model-predicted LUE is 0.32 (means by site) and 0.48 (means by vegetation type). Applying this model for global-scale simulations yields a total global GPP of 106–122 Pg C yr−1 (mean of 2001–2011), depending on the fAPAR forcing data. The P-model provides a simple but powerful method for predicting – rather than prescribing – light use efficiency and simulating terrestrial photosynthesis across a wide range of conditions. The model is available as an R package (rpmodel).
2
Sri Rahayu Romadhoni, Linda, Abd Rahman As-syakur, Zainul Hidayah, Dwi Budi Wiyanto, Rahma Safitri, Raden Yusuf Satriyana Utama, I. Made Sara Wijana, Alfandy Putra Anugrah, and I. Made Oka Guna Antara. "Annual characteristics of gross primary productivity (GPP) in mangrove forest during 2016-2020 as revealed by Sentinel-2 remote sensing imagery." IOP Conference Series: Earth and Environmental Science 1016, no. 1 (April 1, 2022): 012051. http://dx.doi.org/10.1088/1755-1315/1016/1/012051.
Full textAbstract:
Abstract Carbon dioxide (CO2) is the most responsible gas in the phenomenon of global warming on earth because of its greatest concentration and longevity in the long atmosphere. Meanwhile mangrove is one of the blue carbon parameters that can take CO2 for photosynthesis and store it into biomass and sediment, so the existence of Mangrove plays a key role in the balance of the global carboncycle. Gross Primary Productivity (GPP) is one of the key variables in conducting a carboncycle study because the GPP values constitute the total value of carbon fixation by terrestrial ecosystem through vegetation photosynthesis. The aim of this study is to recognize the annual characteristics of GPP values in the mangrove ecosystem using remote sensing satellite Sentinel-2 during the period of 2016 to 2020 in TAHURA Ngurah Rai, Bali, Indonesia. The vegetation photosynthesis model (VPM) model is used to calculate annual GPP by using remote sensing indices of Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI). Both remote sensing indices are supported by temperature and solar radiation data to determine photosynthesis fraction. The results of the current study indicated that the annual GPP values in the mangrove forest of TAHURA Ngurah Rai have decreased during the observation year. The total value of GPP in 2016 is reached to 28790 tC m−2 year−1, while the total amount of GPP value in 2020 decrease to 26223 tC m−2 year−1. The decline in GPP values may be due to changes of land cover and mangrove mortality that occurred around Benoa port in 2018.
3
Raj, Rahul, Bagher Bayat, Petr Lukeš, Ladislav Šigut, and Lucie Homolová. "Analyzing Daily Estimation of Forest Gross Primary Production Based on Harmonized Landsat-8 and Sentinel-2 Product Using SCOPE Process-Based Model." Remote Sensing 12, no. 22 (November 17, 2020): 3773. http://dx.doi.org/10.3390/rs12223773.
Full textAbstract:
Vegetation top-of-canopy reflectance contains valuable information for estimating vegetation biochemical and structural properties, and canopy photosynthesis (gross primary production (GPP)). Satellite images allow studying temporal variations in vegetation properties and photosynthesis. The National Aeronautics and Space Administration (NASA) has produced a harmonized Landsat-8 and Sentinel-2 (HLS) data set to improve temporal coverage. In this study, we aimed to explore the potential and investigate the information content of the HLS data set using the Soil Canopy Observation of Photosynthesis and Energy fluxes (SCOPE) model to retrieve the temporal variations in vegetation properties, followed by the GPP simulations during the 2016 growing season of an evergreen Norway spruce dominated forest stand. We optimized the optical radiative transfer routine of the SCOPE model to retrieve vegetation properties such as leaf area index and leaf chlorophyll, water, and dry matter contents. The results indicated percentage differences less than 30% between the retrieved and measured vegetation properties. Additionally, we compared the retrievals from HLS data with those from hyperspectral airborne data for the same site, showing that HLS data preserve a considerable amount of information about the vegetation properties. Time series of vegetation properties, retrieved from HLS data, served as the SCOPE inputs for the time series of GPP simulations. The SCOPE model reproduced the temporal cycle of local flux tower measurements of GPP, as indicated by the high Nash–Sutcliffe efficiency value (>0.5). However, GPP simulations did not significantly change when we ran the SCOPE model with constant vegetation properties during the growing season. This might be attributed to the low variability in the vegetation properties of the evergreen forest stand within a vegetation season. We further observed that the temporal variation in maximum carboxylation capacity had a pronounced effect on GPP simulations. We focused on an evergreen forest stand. Further studies should investigate the potential of HLS data across different forest types, such as deciduous stand.
4
Kulmala, L., J. Pumpanen, P. Kolari, P. Muukkonen, P. Hari, and T. Vesala. "Photosynthetic production of ground vegetation in different-aged Scots pine (Pinus sylvestris) forests." Canadian Journal of Forest Research 41, no. 10 (October 2011): 2020–30. http://dx.doi.org/10.1139/x11-121.
Full textAbstract:
The photosynthesis of ground vegetation is dependent on species composition and environmental factors that are extremely diverse during forest succession. However, present in situ measurements over the gross primary production (GPP) of ground vegetation are unable to cover this variability. The primary objective of the present study was to estimate the GPP of ground vegetation in five differently aged Scots pine (Pinus sylvestris L.) forests in southern Finland during the growing season of 2006 by using temperature, soil moisture, photosynthetically active radiation, and biomass of the ground vegetation to run a known process-based model. The GPP of ground vegetation was ~350 g·m–2 at the 6- and 12-year-old sites and 168, 146, and 41 g·m–2 thereafter at the 20-, 45-, and 120-year-old sites, respectively. The values decreased with stand age, because as the stand ages, light availability decreases, the dominant species below the canopy show lower rates of photosynthesis than species in open areas, and the biomass of the ground vegetation decreases. Grasses and herbs took up nearly half of the value at the youngest site but their role decreased thereafter, whereas low shrubs were responsible for most of the GPP of ground vegetation below closed canopies.
5
Yin, Gaofei, Aleixandre Verger, Adrià Descals, Iolanda Filella, and Josep Peñuelas. "A Broadband Green-Red Vegetation Index for Monitoring Gross Primary Production Phenology." Journal of Remote Sensing 2022 (March 19, 2022): 1–10. http://dx.doi.org/10.34133/2022/9764982.
Full textAbstract:
The chlorophyll/carotenoid index (CCI) is increasingly used for remotely tracking the phenology of photosynthesis. However, CCI is restricted to few satellites incorporating the 531 nm band. This study reveals that the Moderate Resolution Imaging Spectroradiometer (MODIS) broadband green reflectance (band 4) is significantly correlated with this xanthophyll-sensitive narrowband (band 11) (R2=0.98,p<0.001), and consequently, the broadband green-red vegetation index GRVI—computed with MODIS band 1 and band 4—is significantly correlated with CCI—computed with MODIS band 1 and band 11 (R2=0.97,p<0.001). GRVI and CCI performed similarly in extracting phenological metrics of the dates of the start and end of the season (EOS) when evaluated with gross primary production (GPP) measurements from eddy covariance towers. For EOS extraction of evergreen needleleaf forest, GRVI even overperformed solar-induced chlorophyll fluorescence which is seen as a direct proxy of plant photosynthesis. This study opens the door for GPP and photosynthetic phenology monitoring from a wide set of sensors with broadbands in the green and red spectral regions.
6
Turner, Alexander J., Philipp Köhler, Troy S. Magney, Christian Frankenberg, Inez Fung, and Ronald C. Cohen. "A double peak in the seasonality of California's photosynthesis as observed from space." Biogeosciences 17, no. 2 (January 29, 2020): 405–22. http://dx.doi.org/10.5194/bg-17-405-2020.
Full textAbstract:
Abstract. Solar-induced chlorophyll fluorescence (SIF) has been shown to be a powerful proxy for photosynthesis and gross primary productivity (GPP). The recently launched TROPOspheric Monitoring Instrument (TROPOMI) features the required spectral resolution and signal-to-noise ratio to retrieve SIF from space. Here, we present a downscaling method to obtain 500 m spatial resolution SIF over California. We report daily values based on a 14 d window. TROPOMI SIF data show a strong correspondence with daily GPP estimates at AmeriFlux sites across multiple ecosystems in California. We find a linear relationship between SIF and GPP that is largely invariant across ecosystems with an intercept that is not significantly different from zero. Measurements of SIF from TROPOMI agree with MODerate Resolution Imaging Spectroradiometer (MODIS) vegetation indices – the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and near-infrared reflectance of vegetation index (NIRv) – at annual timescales but indicate different temporal dynamics at monthly and daily timescales. TROPOMI SIF data show a double peak in the seasonality of photosynthesis, a feature that is not present in the MODIS vegetation indices. The different seasonality in the vegetation indices may be due to a clear-sky bias in the vegetation indices, whereas previous work has shown SIF to have a low sensitivity to clouds and to detect the downregulation of photosynthesis even when plants appear green. We further decompose the spatiotemporal patterns in the SIF data based on land cover. The double peak in the seasonality of California's photosynthesis is due to two processes that are out of phase: grasses, chaparral, and oak savanna ecosystems show an April maximum, while evergreen forests peak in June. An empirical orthogonal function (EOF) analysis corroborates the phase offset and spatial patterns driving the double peak. The EOF analysis further indicates that two spatiotemporal patterns explain 84 % of the variability in the SIF data. Results shown here are promising for obtaining global GPP at sub-kilometer spatial scales and identifying the processes driving carbon uptake.
7
Walther, Sophia, Luis Guanter, Birgit Heim, Martin Jung, Gregory Duveiller, Aleksandra Wolanin, and Torsten Sachs. "Assessing the dynamics of vegetation productivity in circumpolar regions with different satellite indicators of greenness and photosynthesis." Biogeosciences 15, no. 20 (October 26, 2018): 6221–56. http://dx.doi.org/10.5194/bg-15-6221-2018.
Full textAbstract:
Abstract. High-latitude treeless ecosystems represent spatially highly heterogeneous landscapes with small net carbon fluxes and a short growing season. Reliable observations and process understanding are critical for projections of the carbon balance of the climate-sensitive tundra. Space-borne remote sensing is the only tool to obtain spatially continuous and temporally resolved information on vegetation greenness and activity in remote circumpolar areas. However, confounding effects from persistent clouds, low sun elevation angles, numerous lakes, widespread surface inundation, and the sparseness of the vegetation render it highly challenging. Here, we conduct an extensive analysis of the timing of peak vegetation productivity as shown by satellite observations of complementary indicators of plant greenness and photosynthesis. We choose to focus on productivity during the peak of the growing season, as it importantly affects the total annual carbon uptake. The suite of indicators are as follows: (1) MODIS-based vegetation indices (VIs) as proxies for the fraction of incident photosynthetically active radiation (PAR) that is absorbed (fPAR), (2) VIs combined with estimates of PAR as a proxy of the total absorbed radiation (APAR), (3) sun-induced chlorophyll fluorescence (SIF) serving as a proxy for photosynthesis, (4) vegetation optical depth (VOD), indicative of total water content and (5) empirically upscaled modelled gross primary productivity (GPP). Averaged over the pan-Arctic we find a clear order of the annual peak as APAR ≦ GPP<SIF<VIs/VOD. SIF as an indicator of photosynthesis is maximised around the time of highest annual temperatures. The modelled GPP peaks at a similar time to APAR. The time lag of the annual peak between APAR and instantaneous SIF fluxes indicates that the SIF data do contain information on light-use efficiency of tundra vegetation, but further detailed studies are necessary to verify this. Delayed peak greenness compared to peak photosynthesis is consistently found across years and land-cover classes. A particularly late peak of the normalised difference vegetation index (NDVI) in regions with very small seasonality in greenness and a high amount of lakes probably originates from artefacts. Given the very short growing season in circumpolar areas, the average time difference in maximum annual photosynthetic activity and greenness or growth of 3 to 25 days (depending on the data sets chosen) is important and needs to be considered when using satellite observations as drivers in vegetation models.
8
Agustin, Dewa Ayu Mery, Takahiro Osawa, and I. Putu Gede Ardhana. "Estimation of Carbon Sequestration in Tropical Peat Swamp Forest in Central Kalimantan Using Satellite Based on Primary Productivity." International Journal of Environment and Geosciences 2, no. 2 (December 1, 2018): 55. http://dx.doi.org/10.24843/ijeg.2018.v02.i02.p01.
Full textAbstract:
One of approach that can be used to estimate the carbon sequestration by vegetation is to calculate the Gross Primary Productivity (GPP) in Central Kalimantan. GPP is total carbon that can be absorbed by vegetation to be used in the process of photosynthesis. The purpose of this study is to estimate the value of GPP using Vegetation Photosynthesis and Respiration Model (VPRM) and analyze the data comparison between GPP value data derived from flux tower and GPP value data from MODIS data. The field data from flux tower was taken by Hirano et al. (2007) from January 1, 2004 to December 31, 2005. The MODIS data is used MODIS Surface Reflectance Level 3 data year 2004 to 2005. According to the result of this study, the maximum GPP value year 2004 and 2005 showed 302.365 gC m-2 per month (February 2004) and 366.841 gC m-2 per month (June 2005). The minimum GPP value year 2004 and 2005 was 166.003 gC m-2 per month (November 2004) and 187.663 gC m-2 per month (March 2005). The total value of GPP in year 2004 was 1,134.231 gC m-2 yr-1 and in year 2005 the value was 1,109.001 gC m-2 yr-1. The correlation coefficient between GPP value from flux tower and GPP value from MODIS – VPRM showed in dry season, r = 0.766 and in rainy season, r = 0,839.
9
Zhang, Liangxia, Decheng Zhou, Jiangwen Fan, Qun Guo, Shiping Chen, Ranghui Wang, and Yuzhe Li. "Contrasting the Performance of Eight Satellite-Based GPP Models in Water-Limited and Temperature-Limited Grassland Ecosystems." Remote Sensing 11, no. 11 (June 3, 2019): 1333. http://dx.doi.org/10.3390/rs11111333.
Full textAbstract:
Models constitute the primary approaches for predicting terrestrial ecosystem gross primary production (GPP) at regional and global scales. Many satellite-based GPP models have been developed due to the simple algorithms and the low requirements of model inputs. The performances of these models are well documented at the biome level. However, their performances among vegetation subtypes limited by different environmental stresses within a biome remains largely unexplored. Taking grasslands in northern China as an example, we compared the performance of eight satellite-based GPP models, including three light-use efficiency (LUE) models (vegetation photosynthesis model (VPM), modified VPM (MVPM), and moderate resolution imaging spectroradiometer GPP algorithm (MODIS-GPP)) and five statistical models (temperature and greenness model (TG), greenness and radiation model (GR), vegetation index model (VI), alpine vegetation model (AVM), and photosynthetic capacity model (PCM)), between the water-limited temperate steppe and the temperature-limited alpine meadow based on 16 site-year GPP estimates at four eddy covariance (EC) flux towers. The results showed that all the GPP models performed better in the alpine meadow, particularly in the alpine shrub meadow (R2 ≥ 0.84), than in the temperate steppe (R2 ≤ 0.68). The performance varied greatly among the models in the temperate steppe, while slight intermodel differences existed in the alpine meadow. Overall, MVPM (of the LUE models) and VI (of the statistical models) were the two best-performing models in the temperate steppe due to their better representation of the effect of water stress on vegetation productivity. Additionally, we found that the relatively worse model performances in the temperate steppe were seriously exaggerated by drought events, which may occur more frequently in the future. This study highlights the varying performances of satellite-based GPP models among vegetation subtypes of a biome in different precipitation years and suggests priorities for improving the water stress variables of these models in future efforts.
10
Xin, Q., P. Gong, and W. Li. "Modeling photosynthesis of discontinuous plant canopies by linking the Geometric Optical Radiative Transfer model with biochemical processes." Biogeosciences 12, no. 11 (June 5, 2015): 3447–67. http://dx.doi.org/10.5194/bg-12-3447-2015.
Full textAbstract:
Abstract. Modeling vegetation photosynthesis is essential for understanding carbon exchanges between terrestrial ecosystems and the atmosphere. The radiative transfer process within plant canopies is one of the key drivers that regulate canopy photosynthesis. Most vegetation cover consists of discrete plant crowns, of which the physical observation departs from the underlying assumption of a homogenous and uniform medium in classic radiative transfer theory. Here we advance the Geometric Optical Radiative Transfer (GORT) model to simulate photosynthesis activities for discontinuous plant canopies. We separate radiation absorption into two components that are absorbed by sunlit and shaded leaves, and derive analytical solutions by integrating over the canopy layer. To model leaf-level and canopy-level photosynthesis, leaf light absorption is then linked to the biochemical process of gas diffusion through leaf stomata. The canopy gap probability derived from GORT differs from classic radiative transfer theory, especially when the leaf area index is high, due to leaf clumping effects. Tree characteristics such as tree density, crown shape, and canopy length affect leaf clumping and regulate radiation interception. Modeled gross primary production (GPP) for two deciduous forest stands could explain more than 80% of the variance of flux tower measurements at both near hourly and daily timescales. We demonstrate that ambient CO2 concentrations influence daytime vegetation photosynthesis, which needs to be considered in biogeochemical models. The proposed model is complementary to classic radiative transfer theory and shows promise in modeling the radiative transfer process and photosynthetic activities over discontinuous forest canopies.
Dissertations / Theses on the topic "GPP photosynthesis by vegetation"
1
Street, Lorna Elizabeth. "Carbon dynamics in Arctic vegetation." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5651.
Full textAbstract:
Rapid climate change in Arctic regions is of concern due to important feedbacks between the Arctic land surface and the global climate system. A large amount of organic carbon (C) is currently stored in Arctic soils; if decomposition is stimulated under warmer conditions additional release of CO2 could result in an accelerating feedback on global climate. The strength and direction of Arctic C cycle - climate feedbacks will depend on the growth response of vegetation; if plant growth increases some or all of the extra CO2 emissions may be offset. Currently the Arctic is thought to be a small net sink for CO2, the expected balance of terrestrial C sinks and sources in the future is unknown. In this thesis I explore some of the critical unknowns in current understanding of C cycle dynamics in Arctic vegetation. Quantifying gross primary productivity (GPP) over regional scales is complicated by large spatial heterogeneity in plant functional type (PFT) in Arctic vegetation. I use data from five Arctic sites to test the generality of a relationship between leaf area index (LAI) and canopy total foliar nitrogen (TFN). LAI and TFN are key drivers of GPP and are tightly constrained across PFTs in Low Arctic Alaska and Sweden, therefore greatly simplifying the task of up-scaling. I use data from Greenland, Barrow and Svalbard to asses the generality of the LAI-TFN relationship in predicting GPP at higher Arctic latitudes. Arctic ecosystems are unique among biomes in the large relative contribution of bryophytes (mosses, liverworts and hornworts) to plant biomass. The contribution of bryophytes to ecosystem function has been relatively understudied and they are poorly represented in terrestrial C models. I use ground based measurements in Northern Sweden to fill an existing data gap by quantifying CO2 fluxes from bryophytes patches in early spring and summer, and develop a simple model of bryophyte GPP. Using the model I compare bryophyte GPP to that of vascular plants before, during and after the summer growing season, finding that productive bryophyte patches can contribute up to 90 % of modelled annual GPP for typical vascular plant communities at the same site, and that the relative magnitude of bryophyte GPP is greatest in spring whilst the vascular plant canopy is still developing. Understanding how GPP relates to plant growth is important in relating remotely sensed increases in Arctic ‘greenness’ to changes in plant C stocks. I use a 13C pulselabelling techniques to follow the fate of recently fixed C in mixed vascular and bryophyte vegetation, with a focus on quantifying the contribution of bryophytes to ecosystem carbon use efficiency (CUE). I show that bryophytes contribute significantly to GPP in mixed vegetation, and act to increase ecosystem CUE. I highlight the importance of including bryophytes, which do not have roots, in aboveground: belowground partitioning schemes in C models. To further explore C turnover in bryophytes, I use the results of a second 13C labelling experiment to develop a model of C turnover in two contrasting Arctic mosses (Polytrichum piliferum and Sphagnum fuscum). I find significant differences in C turnover between Polytrichum piliferum which respires or translocates about 80 % of GPP, while Sphagnum fuscum respires 60 %. This analysis is the first to explicitly model differences in C partitioning between Arctic bryophyte species. Finally, I discuss the implications of each chapter for our understanding of Arctic C dynamics, and suggest areas for further research.
2
Sabetraftar, Karim, and Karim Sabetraftar@anu edu au. "The hydrological flux of organic carbon at the catchment scale: a case study in the Cotter River catchment, Australia." The Australian National University. Centre for Resource and Environmental Studies, 2005. http://thesis.anu.edu.au./public/adt-ANU20070502.141450.
Full textAbstract:
Existing terrestrial carbon accounting models have mainly investigated atmosphere-vegetationsoil
stocks and fluxes but have largely ignored the hydrological flux of organic carbon. It is
generally assumed that biomass and soil carbon are the only relevant pools in a landscape
ecosystem. However, recent findings have suggested that significant amounts of organic carbon
can dissolve (dissolved organic carbon or DOC) or particulate (particulate organic carbon or
POC) in water and enter the hydrological flux at the catchment scale. A significant quantity of
total organic carbon (TOC) sequestered through photosynthesis may be exported from the
landscape through the hydrological flux and stored in downstream stocks.¶
This thesis presents a catchment-scale case study investigation into the export of organic carbon
through a river system in comparison with carbon that is produced by vegetation through
photosynthesis. The Cotter River Catchment was selected as the case study. It is a forested
catchment that experienced a major wildfire event in January 2003. The approach is based on an
integration of a number of models. The main input data were time series of in-stream carbon
measurements and remotely sensed vegetation greenness. The application of models to
investigate diffuse chemical substances has dramatically increased in the past few years because
of the significant role of hydrology in controlling ecosystem exchange. The research firstly
discusses the use of a hydrological simulation model (IHACRES) to analyse organic carbon
samples from stream and tributaries in the Cotter River Catchment case study. The IHACRES
rainfall-runoff model and a regionalization method are used to estimate stream-flow for the 75
sub-catchments. The simulated streamflow data were used to calculate organic carbon loads
from concentrations sampled at five locations in the catchment.¶
The gross primary productivity (GPP) of the vegetation cover in the catchment was estimated
using a radiation use efficiency (RUE) model driven by MODIS TERRA data on vegetation
greenness and modeled surface irradiance (RS). The relationship between total organic carbon
discharged in-stream and total carbon uptake by plants was assessed using a cross-correlation
analysis.¶
The IHACRES rainfall-runoff model was successfully calibrated at three gauged sites and
performed well. The results of the calibration procedure were used in the regionalization method
that enabled streamflow to be estimated at ungauged locations including the seven sampling
sites and the 75 sub-catchment areas. The IHACRES modelling approach was found appropriate
for investigating a wide range of issues related to the hydrological export of organic carbon at
the catchment scale. A weekly sampling program was implemented to provide estimates of
TOC, DOC and POC concentrations in the Cotter River Catchment between July 2003 and June
2004. The organic carbon load was estimated using an averaging method.¶
The rate of photosynthesis by vegetation (GPP) was successfully estimated using the radiation
use efficiency model to discern general patterns of vegetation productivity at sub-catchment
scales. This analysis required detailed spatial resolution of the GPP across the entire catchment
area (comprising 75 sub-catchment areas) in addition to the sampling locations. Important
factors that varied at the catchment scale during the sampling period July 2003 June 2004,
particularly the wildfire impacts, were also considered in this assessment.
¶
The results of the hydrologic modelling approach and terrestrial GPP outcome were compared
using cross correlation and regression analysis. This comparison revealed the likely proportion
of catchment GPP that contributes to in-stream hydrological flux of organic carbon. TOC Load
was 0.45% of GPP and 22.5 - 25% of litter layer. As a result of this investigation and giving due
consideration to the uncertainties in the approach, it can be concluded that the hydrological flux
of organic carbon in a forested catchment is a function of gross primary productivity.
3
Hilker, Thomas. "Estimation of photosynthetic light-use efficience from automated multi-angular spectroradiometer measurements of coastal Douglas-fir." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2685.
Full textAbstract:
Global modeling of gross primary production (GPP) is a critical component of climate change research. On local scales, GPP can be assessed from measuring CO₂ exchange above the plant canopy using tower-based eddy covariance (EC) systems. The limited footprint inherent to this method however, restricts observations to relatively few discrete areas making continuous predictions of global CO₂ fluxes difficult. Recently, the advent of high resolution optical remote sensing devices has offered new possibilities to address some of the scaling issues related to GPP using remote sensing. One key component for inferring GPP spectrally is the efficiency (ε) with which plants can use absorbed photosynthetically active radiation to produce biomass. While recent years have seen progress in measuring ε using the photochemical reflectance index (PRI), little is known about the temporal and spatial requirements for up-scaling these findings continuously throughout the landscape. Satellite observations of canopy reflectance are subject to view and illumination effects induced by the bi-directional reflectance distribution function(BRDF) which can confound the desired PRI signal. Further uncertainties include dependencies of PRI on canopy structure, understorey, species composition and leaf pigment concentration. The objective of this research was to investigate the effects of these factors on PRI to facilitate the modeling of GPP in a continuous fashion. Canopy spectra were sampled over a one-year period using an automated tower-based, multi-angular spectroradiometer platform (AMSPEC), designed to sample high spectral resolution data. The wide range of illumination and viewing geometries seen by the instrument permitted comprehensive modeling of the BRDF. Isolation of physiologically induced changes in PRI yielded a high correlation (r²=0.82, p<0.05) to EC-measured ε, thereby demonstrating the capability of PRI to model ε throughout the year. The results were extrapolated to the landscape scale using airborne laser-scanning (light detection and ranging, LiDAR) and high correlations were found between remotely-sensed and EC-measured GPP (r²>0.79, p<0.05). Permanently established tower-based canopy reflectance measurements are helpful for ongoing research aimed at up-scaling ε to landscape and global scales and facilitate a better understanding of physiological cycles of vegetation and serve as a calibration tool for broader band satellite observations.
4
Noumonvi, Koffi Dodji. "Estimation of carbon fluxes from eddy covariance data and satellite-derived vegetation indices in a karst grassland (Podgorski Kras, Slovenia)." Master's thesis, ISA/UL, 2018. http://hdl.handle.net/10400.5/17944.
Full textAbstract:
Mestrado MEDfOR - Mediterranean Forestry and Natural Resources Management - Instituto Superior de AgronomiaThe Eddy covariance method is a widespread method used for measuring carbon fluxes between the atmosphere and the ecosystem. It provides a high temporal resolution of measurements, but it is restricted to an area around the tower called footprint, and other methods are usually used in combination with eddy covariance data in order to estimate carbon fluxes for larger areas. Spectral vegetation indices derived from increasingly available satellite data can be combined with eddy covariance data to estimate carbon fluxes outside of the tower footprint. Following that approach, the present study attempted to model carbon fluxes for a karst grassland in Slovenia. Three types of model were considered: (1) a linear relationship between NEE or GPP and each vegetation index, (2) a linear relationship between GPP and the product of a vegetation index with PAR, and (3) a simplified LUE model assuming a constant LUE. We compared the performance of several vegetation indices from two sources (Landsat and SPOT-Vegetation) as predictors of NEE and GPP, based on three accuracy metrics (R², RMSE and AIC). Two types of aggregation of flux data were explored, midday average fluxes and daily average fluxes. The Vapor Pressure Deficit was used to separate the growing season in two phases, a greening phase and a dry phase, which were considered separately in the modelling process, in addition to the growing season as a whole. The results showed that NDVI was the best predictor of GPP and NEE during the greening phase, whereas water related vegetation indices, namely LSWI and MNDWI were the best predictors during the dry phase, both for midday and daily aggregates. Model type 1 (linear relationship) was found to be the best in many cases. The best regression equations obtained were used to illustrate the mapping of GPP and NEE for the study area
N/A
5
Moreira, Andreise. "Caracterização fenológica de tipologias campestres do Rio Grande do Sul a partir de produtos MODIS (NDVI, EVI e GPP)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/179926.
Full textAbstract:
Considerando que estudos sobre fenologia vegetal são importantes para a compreensão do funcionamento e verificação da ocorrência de padrões no ciclo vegetativo das plantas, resultando em melhorias nas atividades de conservação e manejo, o objetivo desta pesquisa foi caracterizar a dinâmica fenológica de diferentes tipologias campestres no estado do Rio Grande do Sul (RS), a partir da relação entre a variabilidade de elementos climáticos intra e interanual e eventos em larga escala e a distribuição espaço-temporal das tipologias predominantes. A área de estudo abrangeu 10 tipologias predominantes de campo no estado do RS. A base de dados orbitais utilizada foi obtida de diferentes produtos relacionados ao estudo da vegetação do sensor MODIS (Moderate Resolution Imaging Spectroradiometer), constando os índices de vegetação NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index) e GPP (Gross Primary Productivity). Também, foram utilizados dados meteorológicos provenientes da base TRMM (Tropical Rainfall Measuring Mission) e ERA Interim, para o período de fevereiro de 2000 a dezembro de 2014. O uso de séries temporais de dados NDVI e EVI/MODIS permitiram obter informações sobre a fenologia da vegetação campestre e a definição de padrões diretamente relacionados a variações meteorológicas. A sazonalidade da vegetação campestre apresenta cliclo anual bem marcado, com início e fim da estação de crescimento determinada pelas condições térmicas (temperatura do ar), porém alterado pela disponibilidade hídrica. A relação entre temperatura do ar e vigor vegetal apresentou maior correlação e tem influência direta sobre o início e fim da estação de crescimento (primavera e verão) A precipitação pluvial, no entanto, influencia as condições de crescimento/desenvolvimento das tipologias campestres, especialmente no verão, associado aos períodos de estiagem que tendem a ocorrer com maior frequência. Ambos os índices (EVI e NDVI) apresentam maior variabilidade durante a primavera e o verão, com diminuição da variabilidade durante o outono e inverno. A aplicação da Transformada de Ondaleta mostrou onde e quando ocorreram alterações no padrão fenológico da vegetação campestre e a Transformada Coerência apontou a intensidade (correlação) entre os índices de vegetação e a variabilidade das condições meteorológicas. O agrupamento das tipologias, com uso da técnica de Cluster, revelou seus comportamentos sazonais, sendo que a partir do índice EVI há a possibilidade de identificar diferenças entre as tipologias durante o outono e inverno, enquanto o NDVI apresentou diferença somente no inverno. As métricas fenológicas obtidas do Timesat para as imagens EVI permitiram obter dados importantes sobre o ciclo fenológico da vegetação campestre do RS, com a caracterização do padrão fenológico das tipologias predominantes. O uso de modelos para a estimativa da produtividade da vegetação campestre a partir do EVI revelou dentre as tipologias testadas que a CSR (campos de solos rasos) apresentou maior capacidade de explicar a variabilidade da produtividade dos campos por ser mais suscetível às variações meteorológicas. Os resultados obtidos permitiram confirmar a diversidade entre as tipologias campestres predominantes no RS, expressas por índices de vegetação, tanto no aspecto temporal como espacial. O uso dos índices de vegetação demonstrou potencial no monitoramento do padrão fenológico da vegetação campestre frente a variabilidade climática do RS.Considering that studies on vegetal phenology are important to understand the mechanisms and pattern recognition on the vegetative cycle of plants, resulting in improvements in conservation and management activities, the aim of this research was to characterize the phenological dynamics of different grassland typologies in Rio Grande do Sul State (RS), based on the relationship between the variability of intra-annual and inter-annual climatic elements, large-scale events and the spatio-temporal distribution of predominant typologies . The study area included 10 predominant grassland typologies in RS state. The orbital database used was obtained from different products related to vegetation studies of MODIS sensor (Moderate Resolution Imaging Spectroradiometer), presenting the vegetation indices NDVI (Normalized Difference Vegetation Index), EVI (Enhanced Vegetation Index) and GPP (Gross Primary Productivity). Also, meteorological data from TRMM base (Tropical Rainfall Measuring Mission) and ERA Interim were used for the period of February 2000 to December 2014. The use of time series data from NDVI and EVI/MODIS led to information on grassland vegetal phenology and the definition of patterns directly related to meteorological variations. The seasonality of grassland vegetation presents a well marked annual cycle, with the beginning and the end of growing season determined by thermal conditions (air temperature) but altered by water availability. The relationship between air temperature and vegetal vigor presented a strong correlation and influences directly on the beginning and on the end of the growth season (spring and summer). The rainfall, however, influences growth/development conditions of grassland typologies, especially in summer, associated to drought periods that tend to occur more frequently Both indices (EVI and NDVI) presented a greater variability during spring and summer, with a lesser variability during fall and winter. The application of Ondaleta Transform showed where and when alterations occurred in the phenological pattern of grassland vegetation and the Coherence Transform pointed the intensity (correlation) between vegetation indices and the variability of meteorological conditions. The grouping of typologies, using the Cluster technique, revealed their seasonal behaviors, and from the EVI index there is the possibility of identifying differences between typologies during fall and winter, whereas NDVI showed differences only in winter. The phenological metrics obtained from Timesat to EVI images allowed to obtain important data on the phenological cycle of grassland vegetation of RS state, with a characterization of the phenological pattern. The use of models for estimation of productivity of grassland vegetation based on EVI revealed among the typologies tested that the CSR (shallow soils grasslands) presented greater ability to explain the variability of grasslands productivity because it is more susceptible to meteorological variations. The obtained results allowed for the confirmation of diversity among the grassland typologies predominant in RS state, expressed by vegetation indices, both in temporal and spatial aspects. The use of vegetation indices demonstrated potential on the monitoring of phenological pattern of grassland vegetation considering the climatic variability of RS state.
6
Van, de Weg Martine Janet. "Leaf traits and foliar CO2 exchange in a Peruvian tropical montane cloud forest." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5300.
Full textAbstract:
Tropical montane cloud forests (TMCF) are one of the most fascinating, but least understood ecosystems in the world, and the interest in the carbon (C) cycle of TMCFs with regard to carbon sequestration and storage practices has increased rapidly in recent years. One feature that prevails in all TMCFs is a decrease in aboveground net primary productivity (ANPP) and standing biomass and leaf area index (LAI) with increasing altitude, together with the stunted growth form of the trees. This thesis focuses on the input part of the TMCF C-cycle, and investigates the controlling factors on photosynthesis on a leaf, canopy, and ecosystem level in the Kosñipata valley in south east Peru, on the eastern slope of the Andes (13º11’28’’S / 71º35’24’’W). Leaf traits are known to relate to foliar C-exchange, and compared with other altitudinal transect studies of TMCFs, the studied sites had similar altitudinal trends for foliar nitrogen (N) content (though not for phosphorus) and leaf mass per area (LMA), with N content decreasing and LMA increasing with altitude. N concentrations were relatively high and LMA values relatively low, but this observed relationship was consistent with those found in global leaf trait surveys. Examining plant stoichiometry (i.e. N:P ratios), the data suggests that unlike the general hypothesis, the Kosñipata forests are not N limited, except for the study site at 2990 m a.s.l. At the 2990 m a.s.l. site, which is the focal study site of the thesis, photosynthetic parameters Vcmax (the carboxylation efficiency of the Rubisco protein) and Jmax (the electron transport efficiency) proved to be similar to those found in lowland tropical rainforest leaves when expressed on an area basis and standardised to 25 °C (55.6 ± 2.6 and 106.5 ± 5.2 mmol m-2 s-1, for Vcmax and Jmax, respectively). However, when standardised to the mean ambient TMCF temperature of 12.5 °C, both photosynthetic parameters were much lower than ambient tropical rainforest Vcmax and Jmax values. The TMCF Jmax -Vcmax relationships were steeper than found in other tropical biomes, indicating a possible adaptation to the lower light availability in TMCFs because of frequent cloud cover, or a consequence of little atmospheric evaporative demand, which is also due to the humid conditions in this forest type. Although N-Vcmax relationships were significant (P<0.05), the fit was not very strong and the relationship between nitrogen use efficiency (NUE) and Vcmax indicates that TMCF species can be regarded as a different plant functional type compared with other tropical forest types. Diurnal measurements of net photosynthesis (A), stomatal conductance (gs) and leaf water potential (Yleaf) showed that different TMCF species experienced non-contrasting diurnal patterns of Yleaf and gs in the dry season. The observed patterns suggest that some TMCF species can be classified as isohydric species, while others behave anisohydrically. Additionally, in situ gs was not very responsive to these to the range of experienced photosynthetically active radiation (PAR), vapour pressure deficit (VPD) or soil water content (SWC), leading to the conclusion that in the studied TMCF, drought stress does not play a role in C-uptake. When using the measured photosynthetic parameters for up-scaling C-uptake to stand scale with a Soil-Plant-Atmosphere model, simulated annual gross primary productivity (GPP) was 16.24 ±1.6 T C ha-1 yr-1, which is about half the GPP observed in neotropical lowland rainforests. Analyses of the modelled results showed that GPP in this TMCF is mostly controlled by temperature, PAR and leaf area index (LAI) and when increasing these three factors to values found in tropical lowland forest, GPP increased up to 75%. In addition, the modelled results indicate that hydraulic limitations on TMCF C-uptake are very unlikely under current climatic conditions. The modelled results also showed that increases in radiation as a result of less cloud cover do not translate to straightforward increases of GPP. The cloudy conditions of TMCFs, which reduced incident PAR in TMCFs, should therefore not be regarded simply as a negative control on TMCF GPP. Instead, the increase in fraction of diffuse radiation partially offsets the decrease in GPP following the reduction in PAR. Overall, the results of this study show that leaves of Andean TMCF forests have similar C-uptake capacity to tropical lowland rainforests when standardized to similar temperatures, but that for in situ C-uptake temperature, radiation and LAI are the key controls.
7
Schymanski, Stanislaus Josef. "Transpiration as the leak in the carbon factory : a model of self-optimising vegetation." University of Western Australia. School of Environmental Systems Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0095.
Full text
8
Van, Gaalen Kenneth Eric, and University of Lethbridge Faculty of Arts and Science. "Photosynthetic CO2 exchange and spectral vegetation indices of boreal mosses." Thesis, Lethbridge, Alta. : University of Lethbridge, Faculty of Arts and Science, 2005, 2005. http://hdl.handle.net/10133/293.
Full textAbstract:
Moss dominated ecosystems are an important part of the global terrestrial carbon cycle. Over large areas, remote sensing can be useful to provide an improved understanding of these ecosystems. Two boreal mossess (Pleurozium and Sphagnum) were assessed using remote sensing based spectral vegetation indices for estimating biochemical capacity and photosynthetic efficiency by varying net photosynthesis rate via changes in water content. In the laboratory, changes in the normalized difference vegetation index (NDVI) and chlorophyll index coincided with declining photosynthetic capacity due to desiccation. This effect was more dramatic in Sphagnum. The photochemical reflectance index (PRI) did not vary with changes in CO2 supply as anticipated, possibly due to overriding effects of changing water content. The water band index (WBI) was strongly related to water content but this relationship showed an uncoupling in the field. Bi-directional reflectance measurements indicated what WBI was sensitive to sensor, sun, and moss surface slope angles.xi, 110 leaves : ill. (some col.) ; 29 cm.
9
Van, der Heyden Francois. "An investigation of photosynthetic C-fixation in fynbos growth forms and its variation with season and environmental conditions." Master's thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/17725.
Full textAbstract:
Bibliography: pages 162-177.The seasonal and diurnal patterns of photosynthetic gas exchange and the water relations of seven species of the mediterranean-climate region of South Africa (fynbos) were investigated. The following species, representing the major fynbos elements, were chosen for intensive investigation: Erica plukenetii and Erica hispidula (ericoid element), Thamnochortus lucens and Askidiosperma paniculatum (restioid element), Protea laurifolia and Leucadendron salignum (proteoid element). Metrosideros angustifolia, a shrub of riparian habitats, was also studied.
10
Sánchez, Bragado Rut. "Ús d'isòtops estables d'O, H, C com eines de selecció de rendiment potencial i adaptació a la sequera i deficiència de nitrogen en cereals C3 i C4." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/350309.
Full textAbstract:
A la conca Mediterrània els principals factors que afecten el rendiment dels cultius agrícoles són la sequera i el dèficit de nitrogen. És necessària la recerca de noves eines de fenotipejat per accelerar la millora genètica pel rendiment potencial i l'adaptació dels cultius a condicions limitants. Aquesta Tesi ha estudiat composició isotòpica de carboni (δ13C), oxigen (δ18O) i hidrogen (δ2H), en la seva abundància natural, de diferents cereals. Referent a la δ13C només la composició dels grans madurs van mostrar correlacions fenotípiques (negatives) consistents amb el rendiment del gra (GY) en blat dur, sobretot sota condicions d'estrès moderat (Capítol 5). Aquesta Tesi també proposa l’ús de la δ13C com una aproximació per quantificar la contribució relativa dels diferents òrgans de la planta a l'ompliment del gra (Capítols 1 i 2). L’objectiu es poder emprar la δ13C per seleccionar cereals amb una major fotosíntesi de l'espiga. En blat dur l'aproximació de la δ13C va assignar un paper més gran a l'espiga (tant de l'òrgan sencer com de les arestes) en comparació a la fulla bandera i al peduncle (que representa els assimilats que provenen de les parts inferiors de l'espiga), especialment en les varietats antigues, amb independència de les condicions de creixement. Sota bones condicions agronòmiques, la contribució de les arestes de l’espiga a l'ompliment del gra de blat fariner també va ser més important que la de la fulla bandera. Finalment aquesta aproximació basada en la δ13C de diferents parts de planta es va comparar amb altres aproximacions convencionals com són l'ombrejat o l'aplicació de l'herbicida DCMU a la planta (Capítol 3). Els tractaments d'ombrejat de l'espiga i de la tija van contribuir de forma similar a l'ompliment del gra. Per contra, l'aproximació del DCMU va assignar un paper major a la fotosíntesi de la tija, però l'aplicació de l’herbicida a la tija també va afectar l'espiga, esbiaixant el pes final dels grans.
Aquesta Tesi també va estudiar l'isòtop d'oxigen tant en blat de moro (Capítol 4) com en blat dur (Capítol 5). En el blat de moro, les correlacions genotípiques entre la δ18O i el GY van ser marginals, tot i que les sedes va ser l'òrgan que millor va correlacionar amb el GY. En el blat dur les correlacions fenotípiques entre la δ18O dels grans i el GY també van ser marginals. Només va correlacionar fortament la δ18O de l'aigua de la fulla quan es van combinar els dos règims hídrics (reg suplementari i sequera). L'absència de correlacions de la δ18O podria ajudar a descartar els teixits de les plantes que són més susceptibles als processos de fraccionament post-fotosintètic. Escollir l’òrgan idoni pot ajudar a millorar l’ús de la δ18O com a eina de millora de cultius.
Per últim es va comparar la δ13C i la δ18O amb la δ2H (Capítol 5). La δ2H en els grans de blat dur va correlacionar contra el GY millor que els altres dos isòtops en condicions de sequera però combinant nivells de nitrogen contrastats. També es van observar correlacions genotípiques entre la δ2H dels foto-assimilats de l'espiga contra el GY. A més, la δ2H de les fulles va correlacionar més amb la δ13C que no pas amb la δ18O, el que suggereix que la δ2H dels foto-assimilats de la fulla no només està afectada per la transpiració i la conductància estomàtica sinó també per les reaccions fotosintètiques. A més, els valors baixos de la δ2H a l’espiga comparats amb els dels grans donen suport al paper fotosintètic de l’espiga, el que recolza els resultats obtinguts en els Capítols 1, 2 i 3.This Thesis has studied the isotope composition on its natural abundance of carbon (δ13C), oxygen (δ18O) and hydrogen (δ2H) as phenotypic traits for cereal breeding and crop adaptation to optimal and limited agronomic conditions. Regarding the δ13C, only mature grains showed consistent phenotypic correlations (negative) against grain yield in durum wheat, especially under moderate stress conditions. In addition δ13C is also proposed as a tool to quantify the relative contribution of different plant organs to grain filling. In durum wheat and bread wheat δ13C approach assigned a higher role to the ear (both whole body and awns) compared to the flag leaf and peduncle (which integrates the assimilates produced by photosynthetic organs below the ear), regardless of growing conditions. Finally, δ13C approach based on the different plant parts was compared with other conventional approaches, such as shading or herbicide DCMU application, which assigned on average a comparable contribution to the ear than the culm. This thesis also studied the δ18O in maize and durum wheat. In both crops, phenotypic correlations between δ18O and grain yield were marginal. Only δ18O of leaf water in durum wheat was strongly correlated with GY when combining two water regimes. The absence of such correlations will eventually help to understand the use of δ18O as a genotype selection tool for the adaptation of maize and other crops to drought. Finally the δ13C and δ18O were compared with δ2H in durum wheat. δ2H performed better than the other two isotopes predicting grain yield and nitrogen content under water stress but contrasting nitrogen regimes. Besides, genotypic correlations between δ2H in the ear water-soluble fraction and grain yield were observed. In addition, δ2H in the water soluble fraction of leaves was better correlated against δ13C than with δ18O, suggesting that δ2H of leaf photo-assimilated is affected not only by transpiration and stomatal conductance but also by the photosynthetic reactions. In addition, the low values observed in the δ2H in the ear compared to mature grains supported the photosynthetic role of the ear, which reinforced results obtained in other chapter of this Thesis.
Books on the topic "GPP photosynthesis by vegetation"
1
Hanisak, M. Dennis. Photosynthetically active radiation, water quality, and submerged aquatic vegetation in Indian River Lagoon. Fort Pierce, FL: Marine Botany Dept., Harbor Branch Oceanographic Institution, 2001.
Find full text
2
Gamon, John A. [Predicting photosynthetic fluxes from spectral reflectance of leaves and canopies]. [Washington, DC: National Aeronautics and Space Administration, 1997.
Find full text
3
Gamon, John A. [Predicting photosynthetic fluxes from spectral reflectance of leaves and canopies]. [Washington, DC: National Aeronautics and Space Administration, 1997.
Find full text
4
Pross, Derek D. A global scale analysis of the spatiotemporal distribution of foliar biomass for 1988. 1991.
Find full text
5
Wilsey, Brian J. Grasslands of the World. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198744511.003.0001.
Full textAbstract:
Grasslands are herbaceous dominated areas with very low abundance of trees and shrubs. They are found in areas with intermediate precipitation amounts (250–1000 mm) characterized by occasional droughts and are usually the most extensive in the interior of continents. Grasslands began to form 11–24 million years ago (MYA) when grasses invaded woodlands. Grasses initially all had C3 photosynthesis and were found in shaded conditions. However, grasses with C4 photosynthesis require full sun, and they increased in abundance during this time to achieve between 20–40 percent of the local vegetation. By around 6–8 MYA before present, C4 grasses were widespread on most continents that now have extensive grasslands. Grasslands can be classified by soil type or based on gradients of humidity-aridity and human impact (wild grasslands to improved pastures). African savanna grasslands are important because it is where Homo sapiens (humans) speciated and eventually spread to other continents.
Book chapters on the topic "GPP photosynthesis by vegetation"
1
Gu, Lianhong, Wilfred M. Post, Dennis Baldocchi, T. Andy Black, Shashi B. Verma, Timo Vesala, and Steve C. Wofsy. "Phenology of Vegetation Photosynthesis." In Phenology: An Integrative Environmental Science, 467–85. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-007-0632-3_29.
Full text
2
Oker-Blom, P., J. Lappi, and H. Smolander. "Radiation Regime and Photosynthesis of Coniferous Stands." In Photon-Vegetation Interactions, 469–99. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-75389-3_15.
Full text
3
Gutschick, V. P. "Joining Leaf Photosynthesis Models and Canopy Photon-Transport Models." In Photon-Vegetation Interactions, 501–35. Berlin, Heidelberg: Springer Berlin Heidelberg, 1991. http://dx.doi.org/10.1007/978-3-642-75389-3_16.
Full text
4
Søndergaard, Morten. "Photosynthesis of Aquatic Plants Under Natural Conditions." In Vegetation of inland waters, 63–111. Dordrecht: Springer Netherlands, 1988. http://dx.doi.org/10.1007/978-94-009-3087-2_3.
Full text
5
Körner, Ch. "Leaf Diffusive Conductances in the Major Vegetation Types of the Globe." In Ecophysiology of Photosynthesis, 463–90. Berlin, Heidelberg: Springer Berlin Heidelberg, 1995. http://dx.doi.org/10.1007/978-3-642-79354-7_22.
Full text
6
Disney, Mathias. "Remote Sensing of Vegetation: Potentials, Limitations, Developments and Applications." In Canopy Photosynthesis: From Basics to Applications, 289–331. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-7291-4_11.
Full text
7
Milovanović, Lj, S. Veljović-Jovanović, Lj Jovanović, and Ž. Vučinić. "Concomitant Measurements of Biomass Increase and Photosynthetic Activity of Maize During the Vegetation Period." In Photosynthesis: Mechanisms and Effects, 3801–4. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-3953-3_885.
Full text
8
Chao, Zhenhua, Mingliang Che, Zhanhuan Shang, and A. Allan Degen. "Tracking of Vegetation Carbon Dynamics from 2001 to 2016 by MODIS GPP in HKH Region." In Carbon Management for Promoting Local Livelihood in the Hindu Kush Himalayan (HKH) Region, 45–62. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20591-1_3.
Full text
9
Roberts, M. J., S. P. Long, L. L. Tieszen, and C. L. Beadle. "Measurement of plant biomass and net primary production of herbaceous vegetation." In Photosynthesis and Production in a Changing Environment, 1–21. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-010-9626-3_1.
Full text
10
Roberts, M. J., S. P. Long, L. L. Tieszen, and C. L. Beadle. "Measurement of plant biomass and net primary production of herbaceous vegetation." In Photosynthesis and Production in a Changing Environment, 1–21. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1566-7_1.
Full textConference papers on the topic "GPP photosynthesis by vegetation"
1
Josiclêda Domiciano Galvíncio, Bernardo Barbosa da Silva, Magna Soelma Beserra de Moura, Celia Cristina Clemente Machado, Hewerton Alves da Silva, and Tiago Henrique de Oliveira. "Relationship between Vegetation Indices and Canopy Chlorophyll in GPP Estimation." In 2012 Dallas, Texas, July 29 - August 1, 2012. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2012. http://dx.doi.org/10.13031/2013.41984.
Full text
2
Moreno, Jose F., Gregory P. Asner, Heike Bach, Tomas Belenguer, Andrew Bell, Claus Buschmann, Alfonso Calera, et al. "FLuorescence EXplorer (FLEX): an optimised payload to map vegetation photosynthesis from space." In 57th International Astronautical Congress. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.iac-06-b1.3.04.
Full text
3
Moreno, Jose, Roberto Colombo, Alexander Damm, Yves Goulas, Elizabeth Middleton, Franco Miglietta, Gina Mohammed, et al. "Quantitative global mapping of terrestrial vegetation photosynthesis: The Fluorescence Explorer (FLEX) mission." In 2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). IEEE, 2017. http://dx.doi.org/10.1109/igarss.2017.8126987.
Full text
4
VAGUSEVICIENĖ, Ilona, Sonata KAZLAUSKAITĖ, Aiste JUCHNEVICIENĖ, Asta BYLAITE, and Audrone ŽEBRAUSKIENĖ. "COMPARISON OF PHOTOSYNTHETIC PARAMETERS IN DIFFERENT WHEAT (TRITICUM AESTIVUM L.) VARIETIES." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.064.
Full textAbstract:
Dynamics of photosynthesis pigments in the leaves of different varieties of winter wheat during the vegetation period is analyzed in the paper. The accumulation of pigments in the plant depends on the physiological activity, growth and development of the plant, therefore the composition and content of photosynthesis pigments chlorophyll a, b and carotenoids reflect the general condition of the plant. The ratio of chlorophyll a / b for normal photosynthesis activity in the leaves of the plant should be at least 1:3. The object of the research is different varieties of winter wheat (Triticum aestivum L.) - 'Artist', 'Edvin', 'Skagen', 'Bertold' and 'Viola'. Field experiment was carried out at the Experimental Station of Aleksandras Stulginskis University in 2015-2016. Soil type was identified as IDg8 - k (LVg - p - w - cc) - shallow calcareous luvisol (Calc (ar) i - Epihypogleyic Luvisols). Agrochemical parameters of the soil were determined using accepted analytical methods. The content of photosynthesis pigments (chlorophyll a, b and carotenoids) in green leaf mass was determined in 96% ethyl alcohol extract applying spectrophotometric Wettstein method, “Genesys” 6 spectrophotometer. The photosynthesis productivity (Fpr) was calculated according to the formula: Fpr = 2 (M2-M1) / (L1 + L2) T. The accuracy of the data analysis was estimated according to the standard measurement deviation from the mean. The highest content of photosynthesis pigments has been accumulated by winter wheat variety 'Skagen'. The best result has been observed at the end of nodding stage. A lower content of photosynthesis pigments has been found in the leaves of 'Edvin', 'Viola' and 'Artist' varieties. The highest photosynthesis productivity of all winter wheat varieties has been recorded at the end of nodding stage, and decrease of photosynthesis productivity has been observed since milk maturity stage.
5
Wang, Ruijie, Zhihao Qin, Bin Xu, Xiaoyong Zhang, and Maofang Gao. "Using vegetation photosynthesis model to estimate net primary production of rangeland ecosystem in Inner Mongolia of China." In Geoinformatics 2007, edited by Jingming Chen and Yingxia Pu. SPIE, 2007. http://dx.doi.org/10.1117/12.761893.
Full text
6
Qi, Yangqian, and Zhao-Cheng Zeng. "Weak Response of Vegetation Photosynthesis to Meteorological Droughts in Southwest China: Insights from Gome-2 Solar-Induced Fluorescence." In IGARSS 2020 - 2020 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2020. http://dx.doi.org/10.1109/igarss39084.2020.9323788.
Full text
7
SASNAUSKIENĖ, Jurgita, Nomeda SABIENĖ, Vitas MAROZAS, Laima ČESONIENĖ, and Kristina LINGYTĖ. "SOIL RESPIRATION IN STANDS OF DIFFERENT TREE SPECIES." In RURAL DEVELOPMENT. Aleksandras Stulginskis University, 2018. http://dx.doi.org/10.15544/rd.2017.106.
Full textAbstract:
Forest ecosystems of different tree species participate actively in climatic and biotic processes, such as photosynthesis, plant and soil respiration, therefore knowledge of soil respiration, especially of CO2 emissions to the atmosphere is of great importance. The aim of the study was to determine soil respiration rate of stands of deciduous (Betula pubescens Ehrh., Quercus robur L.) and coniferous (Larix eurolepis Henry, Thuja occidentalis L.) tree species as well as impact of abiotic (soil temperature, humidity, electrical conductivity, pH) and biotic (abundance of undergrowth, shrub, herbs) factors. Measurements of CO2 emissions, temperature, moisture and electrical conductivity were performed in-situ in the stands of different tree species with portable ADC BioScientific LCpro+ system and digital electrochemical device “Wet” (Delta-T). Soil samples were collected for the physicochemical analysis simultaneously. Chemical analysis of soil samples was done at the lab of the Environmental Research of the Aleksandras Stulginskis University by standard methods. Soil respiration was highest in the stand of Thuja occidentalis and lowest in the stand of Betula pubescens. Soil respiration intensity of the tree stands increased as follow: Thuja˂ Quercus˂ Larix˂ Betula. In the coniferous tree stands, the soil respiration was lower on average 27% comparing to deciduous tree stands. Soil respiration rate increased with increase of herbaceous vegetation cover and temperature. Soil respiration rate was mostly influenced by abundance of herbaceous vegetation (r = 0.91) of all biotic factors investigated, while soil temperature (r = 0.75) of abiotic factors. 60 years old stands of different tree species formed specific conditions what influenced different soil respiration rates.
8
Alina-Nicoleta, Paraschiv, Dima Milica, Diaconu Aurelia, Enache Viorel, and Fătu Viorel. "PRELIMINARY RESULTS ON THE INFLUENCE OF THE F414 BIOLOGICAL PRODUCT ON SOME PHYSIOLOGICAL INDEXES FOR PEACHES GROWN UNDER THERMO-HYDRIC STRESS." In GEOLINKS Conference Proceedings. Saima Consult Ltd, 2021. http://dx.doi.org/10.32008/geolinks2021/b1/v3/39.
Full textAbstract:
On the peach species, Springold variety, research was conducted on the influence of the F414 biological product on some physiological indexes and processes carried out on the foliar level, the area of culture being characterized by an accentuated thermo-hydric stress during the summer. Photosynthetic gas exchange, foliar transpiration and stomatal conductance were determined with the portable LC PRO + apparatus, and the leaf water forms were determined gravimetrically, the results obtained being correlated with the meteorological data from the vegetation period. Applying the F414 to the Springold variety resulted in the formation of a pellicle on the surface of the leaves, which, together with the action of the thermo-hydric stress specific to the area, caused stomate closure, reduction of CO2 supply, photosynthesis values being considerably lower compared to the control variant. As for foliar transpiration, the F414 product had a positive effect, the pellicle formed on the surface of the leaves, reducing the amount of water lost to the foliage. The application of this product has positively influenced drought resistance of the Springold variety, the percentages of the bound water being higher (5.1%) compared to the control variant (3.96%).
9
Gulin, S. V., and A. G. Pirkin. "FEATURES OF BUSINESS-PROCESSES IN THE CREATION OF ELECTROTECHNOLOGICAL SYSTEMS FOR THE AGRICULTURAL INDUSTRIAL COMPLEX." In INNOVATIVE TECHNOLOGIES IN SCIENCE AND EDUCATION. DSTU-Print, 2020. http://dx.doi.org/10.23947/itno.2020.357-362.
Full textAbstract:
This article offers a universal methodology for the design, creation and operation of complex electrotechnological systems. This methodology is based on a system-process approach to business modeling. The article provides a detailed description of all private business processes that provide a full cycle of business engineering, and offers a General mathematical expression for a comprehensive assessment of the effectiveness of the business engineering process. The proposed methodology has been tested on the example of designing, creating and operating vegetation climate systems (VCS). This example shows that it is possible to conduct quite serious scientific research at the intersection of plant physiology and electric power engineering, which allows us to create modern self-adjusting systems for automatic microclimate control when growing plants. Application of engineering methods allows to increase the efficiency of development of information systems for automatic control of parameters of the most important physiological processes (photosynthesis, transpiration, etc.) in plants under the influence of environmental factors. The article outlines the prospects for the development of the subject area of engineering in the direction of solving specific problems to integrated energy engineering, and the energy business - from trading individual services to trading models and technologies.