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Souhrnná výzkumná zpráva Aalto 1903
Hanuš, Jan ; Fabiánek, Tomáš ; Fajmon, Lukáš
Within the airborne hyperspectral campaign for a Finnish university Aalto University were scanned two locations - Hyytiälä (FI) - Järvselja (EST). The scanned processed data is used for other scientific purposes.\nAbstrakt: V rámci letecké hyperspektrální kampaňe pro Finskou univerzitu Aalto-yliopisto byly nasnímány dvě lokality - Hyytiälä (FI) - Järvselja (EST). Předaná zpracovaná data jsou používány pro další vědecké účely.
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Approaching dangerous impacts of global climate change
Ač, Alexander
Current global policy efforts are focused on limiting the global rise in mean temperature to well below a 2 K\nwarming compared to the pre-industrial temperature. It is questionable if achieving such goal is still feasible.\nHere, I review published works that suggesting that to keep global warming below or at a 2 K level cannot\nbe considered as safe, as is often assumed. A large body of studies have emerged recently investigating\nthe impacts of global climate change (GCC) at a 1.5 K or 2 K warming. The impacts range from changes in\nthe hydrological cycle, increasing frequency and intensity of extreme weather events, triggering of change\nfeedback processes at various spatio-temporal scales, affecting biological processes from the molecular to\necosystem levels, and to disrupting socio-economic conditions. In this short review, I present the latest scientific\nknowledge regarding some of the most important impacts of GCC on natural ecosystems, humanmade\nsystems, and societies.
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Modulation of ozone flux in a mountain spruce forest under different cloud cover
Juráň, Stanislav ; Fares, S. ; Urban, Otmar
Ozone (O3) fluxes were modelled from a concentration gradient in a Norway spruce forest at the Bílý Kříž experimental station for years 2012–2016. Daily and seasonal O3 depositions were calculated separately for days with cloudy, partly cloudy, and clear sky conditions. The hypothesis that overcast conditions modulate O3 flux in the forest ecosystem via controlled stomatal conductance is tested. Indeed, the highest stomatal conductance followed by the highest O3 deposition was found during partly cloudy and cloudy sky conditions in all seasons.
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Effect of elevated CO2 on morphological and photosynthetic parameters in two understory grass species in Beskydy Mountains
Holub, Petr ; Klem, Karel ; Urban, Otmar
We transplanted two grass species, Calamagrostis arundinacea and Luzula sylvatica, to the understory of\na 10-year-old experimental mixed forest exposed to ambient (385 μmol CO2 mol–1, AC) and elevated (700\nμmol CO2 mol–1, EC) atmospheric CO2 concentration using a glass dome facility. Effects of EC on plant\nmorphology and photosynthesis were examined after three years of treatment. We tested the hypotheses\nthat shade-tolerant species can profit from EC even at low light conditions and that relatively low accumulation\nof assimilates at such light conditions will not cause CO2-induced down-regulation of photosynthesis.\nWe expected that EC can substitute insufficient light intensities under the tree canopy and lead to both\nhigher biomass production and survival of plants in deep forest understories. The typical shade-tolerant\nspecies L. sylvatica exhibited positive acclimation under EC allowing higher light use efficiency under subsaturating\nlight intensities as compared to plants grown under AC. In contrast, C. arundinacea showed\nhigher stimulation of growth and photosynthetic rates by EC mainly under saturating light intensities at\nthe beginning of the growing season, when the forest leaf area is not fully developed and the open canopy\nallows a greater proportion of incident light to reach the understory. Our data indicate that growth and\nphysiological responses of EC plants in forest understories are species specific, differ from responses of\nsun-exposed plants, and depend on degree of shading.
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Interactive effect of UV radiation and CO2 treatment on extractable volatile organic compounds from European beech leaves
Večeřová, Kristýna ; Pernicová, N. ; Klem, Karel ; Urban, Otmar
The main objective of this experiment was to investigate the combined effect of different UV treatments\nand elevated CO2 concentration on monoterpene and methyl salicylate (MES) content in leaves of\nEuropean beech during the growing season. Plants were grown under ambient (AC, 400 μmol mol–1) and\nelevated (EC, 700 μmol mol–1) CO2 concentrations and three UV radiation treatments (ambient – UVamb,\nexcluded – UV-, and enhanced – UV+). Leaves collected from July to September were extracted in cold\nheptane to determine volatile organic compounds content using gas chromatography. Our results show\nthat AC plants had higher total content of extractable monoterpenes and MES than did EC plants over\nthe whole growing season and irrespective of UV treatment. Limonene, 2-bornene, and ester MES were\nthe most abundant volatile compounds in beech leaves. The highest contents of 2-bornene and MES were\nfound under the UV- treatment and AC. Contents of α-pinene, β-pinene, and carene decreased during the\ngrowing season while the content of limonene increased.
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