Dissipation Of Solar Energy Research Articles

Synthesis and Functional Reconstitution of Light-Harvesting Complex II into Polymeric Membrane Architectures.

One of most important processes in nature is the harvesting and dissipation of solar energy with the help of light-harvesting complex II (LHCII). This protein, along with its associated pigments, is the main solar-energy collector in higher plants. We aimed to generate stable, highly controllable, and sustainable polymer-based membrane systems containing LHCII-pigment complexes ready for light harvesting. LHCII was produced by cell-free protein synthesis based on wheat-germ extract, and the successful integration of LHCII and its pigments into different membrane architectures was monitored. The unidirectionality of LHCII insertion was investigated by protease digestion assays. Fluorescence measurements indicated chlorophyll integration in the presence of LHCII in spherical as well as planar bilayer architectures. Surface plasmon enhanced fluorescence spectroscopy (SPFS) was used to reveal energy transfer from chlorophyll b to chlorophyll a, which indicates native folding of the LHCII proteins.

Function of vegetation in new landscape units after brown coal mining

The functions of vegetation cover in a landscape disturbed by opencast mining in West Bohemia were investigated. The aim of the restoration strategy was to achieve a functional landscape. We defined the functions of the landscape in terms of solar energy flow and ways of utilising it in the water cycle and flow of matter, which are inseparably interconnected. Vegetation plays an important role in effective dissipation of solar energy and is very important for the function of the ecosystem. The results show the positive efficiency of particular vegetation cover types in new landscape units, and their importance for restoring the short water cycle. Quite rapid functional stabilisation of permanent grass covers, including rapid development of their species diversity, appears to be a significant outcome.

Solar energy dissipation and temperature control by water and plants

Ecosystems use solar energy for self-organisation and cool themselves by exporting entropy to the atmosphere as heat. These energy transformations are achieved through evapotranspiration, with plants as 'heat valves'. In this study, the dissipative process is demonstrated at sites in the Czech Republic and Belgium, using landscape temperature data from thermovision and satellite images. While global warming is commonly attributed to atmospheric CO2, the research shows water vapour has a concentration two orders of magnitude higher than other greenhouse gases. It is critical that landscape management protects the hydrological cycle with its capacity for dissipation of incoming solar energy.

Evaluation of functional properties of various types of vegetation cover using remotely sensed data analysis

The dissipation of solar energy and consequently the formation of the hydrological cycle are largely dependent on the structural and optical characteristics of the land surface. In our study, we selected seven units with different types of vegetation in the Mlýnský and Horský catchments (South-Eastern part of the Šumava Mountains, Czech Republic) for the assessment of the differences in their functioning expressed through the surface temperature, humidity, and energy dissipation. For our analyses, we used Landsat 5 TM satellite data from June 25<SUP>th</SUP>, 2008. The results showed that the microclimatic characteristics and energy fluxes varied in different units according to their vegetation characteristics. A cluster analysis of the mean values was used to divide the vegetation units into groups according to their functional characteristics. The mown meadows were characterised by the highest surface temperature and sensible heat flux and the lowest humidity and latent heat flux. On the contrary, the lowest surface temperature and sensible heat flux and the highest humidity and latent heat flux were found in the forest. Our results showed that the climatic and energetic features of the land surface are related to the type of vegetation. We state that the spatial distribution of different vegetation units and the amount of biomass are crucial variables influencing the functioning of the landscape.

Influence of vegetation cover on air and soil temperatures in the Šumava Mts. (Czech Republic)

Air temperature at heights of 5 and 200 cm above soil surface, and soil temperature at depths of 15, 30 and 60 cm, were measured in the cold climatic zone at three localities (catchments) under different plant cover during the growing seasons 2002-2007. The catchments Kout (dead forest), Doupě (clearing) and Stolec (mature spruce forest) are situated in the National Park of the Šumava Mts. (Czech Republic) at an elevation of 1105-1330 m a. s. 1. This region is part of the metamorphic complex – Moldanubicum. It is formed mainly by metamorphosed rocks (paragneiss with smaller anomalies). The three catchments have very similar natural conditions, but differ significantly in vegetation cover. The catchments are covered with acid brown soil developed on paragneiss. The clearing and dead forest catchments both exist as small islands inside an extensive spruce forest. The following conclusions were obtained from the interpretation of measured data: (1) The air temperature of the catchment covered by the dead forest had a greater daily fluctuation compared to the stands covered by clearing or mature forest. (2) The air temperature of catchments covered by mature forest had the smallest daily fluctuations. (3) The more extreme air temperatures in the dead forest caused the systematic raising of the soil temperature at a depth of 15 cm compared to soil in the clearing and mature forest. These conclusions are valid for a cold climatic zone during a vegetation season in which plant transpiration plays a governing role in solar energy dissipation.

Biophysical and morphological leaf adaptations to drought and salinity in salt marsh grasses

Leaf energy budgets were constructed for 13 species of estuarine C 4 grasses (Poaceae) to elucidate the biophysical effects of drought and salinity on the interception and dissipation of solar energy. Spartina alterniflora, S. anglica, S. argentinensis, S. bakeri, S. cynosuroides, S. densiflora, S. foliosa, S. foliosa × S. alterniflora hybrids, S. gracilis, S. patens, S. pectinata, S. spartinae, and Distichlis spicata plants were grown under controlled soil water potential gradients in a greenhouse. Species were grouped into four major ecological functional types, based on elevational zonation ranges: low marsh species, middle marsh species, high marsh species, and freshwater species. Different functional types are adapted to different environmental conditions, and responded differently to reduced water potentials. Latent heat flux decreased similarly across species in response to decreasing water potential. Latent heat loss was found to decrease by as much as 65% under decreasing water potential, leading to an increase in leaf temperature of up to 4 °C. Consequently, radiative and sensible heat losses increased under decreasing water potential. Sensible heat flux increased as much as 336% under decreasing water potential. Latent heat loss appeared to be an important mode of temperature regulation in all species, and sensible heat loss appeared to be more important in high marsh species compared to low marsh species. High marsh species are characterized by narrower leaves than middle and low marsh species, leading to a smaller boundary layer, and providing higher conductance to sensible heat loss. This may be an adaptation for high marsh species to regulate leaf temperature without access to large amounts of water for transpirational cooling. Stomatal conductance decreased with decreasing water potential across species: leaf conductances to water vapor and CO 2 decreased as much as 69% under decreasing water potential. Additionally, oxidative stress appeared to increase in these plants during times of drought or salinity stress. Ascorbate peroxidase activities increased with decreasing soil water potential, indicating increased cellular reactive oxygen species. High marsh species had higher ascorbate peroxidase activities compared to low marsh species, indicating higher tolerance to drought- or salinity-induced stresses. It was concluded that different species of marsh grasses are adapted for growth in different zones of salt marshes. Adaptations include biophysical, biochemical, and morphological traits that optimize heat exchange with the environment.

Dissipation of solar energy in landscape—controlled by management of water and vegetation

Man (farmers, forest managers) by dealing with water and vegetation changes substantially the distribution of solar energy. Differences in sensible heat (warming) and latent heat (cooling by evapotranspiration) on drained and wetland areas, and the air conditioning effect of a single tree are demonstrated. It is shown that the energy produced in all power stations of the Czech Republic is several orders of magnitude lower than the sensible heat released from the drained and urban areas of the country. A single tree transpiring about 400 l of water a day has an air-conditioning efficiency of about 20 kW. Whereas photosynthesis (biomass production) uses less than 1% of incoming solar energy, by evapotranspiration (latent heat) more than 50% can be used in water saturated vegetation. Distribution of temperatures (heat potentials) in large areas is shown on satellite pictures. Land managers influence local climate and their important role should be considered in policy-making decisions.