Climate Change Accelerates Recovery of the Tatra Mountain Lakes from Acidification and Increases Their Nutrient and Chlorophyll a Concentrations

We evaluated changes in the concentration of cations, anions, nutrients (dissolved organic carbon, DOC; phosphorus, P; and nitrogen forms including nitrate, NO3− and total organic nitrogen, TON), and chlorophyll a (Chl-a) in 31 Tatra Mountain lakes in Slovakia and Poland during their recovery from acidic deposition (1992–2018). Typical effects of decreasing acidic deposition on the lakes’ water composition, such as decreasing base cation concentrations, were confounded by climate change and catchment characteristics, including areal proportions of well-developed soils and scree. A climate-related increase in physical erosion provided freshly exposed unweathered granodiorite (the dominant bedrock) to chemical weathering. Dissolution of accessory calcite in the granodiorite increased the in-lake Ca2+ and HCO3− concentrations and reversed the Ca2+ trends, which originally decreased in parallel with strong acid anions. These changes were most pronounced in steep, scree-rich areas, which are most sensitive to physical weathering. Fresh apatite [Ca5(PO4)3(F, Cl, OH)] in the crushed granodiorite acts as a P source at soil pH’s between 4 and 5 and in the presence of chelating organic acids within soils. These conditions enhance apatite solubility, which in part explains increasing P in lakes with scree-dominated catchments. Soil recovery from acidification due to decreasing acidic deposition and the neutralizing effect of weathering of erosion-derived accessory calcite were the most likely causes of elevated DOC and P export from soils. Their elevated leaching was accompanied by increasing in-lake concentrations of Chl-a and TON. The increasing TON concentrations were, as for Ca2+, most pronounced in the scree-rich catchments, and represented the most sensitive indicator of the changes in the lake water nutrient composition

Factors affecting the leaching of dissolved organic carbon after tree dieback in an unmanaged European mountain forest

Forest disturbances affect ecosystem biogeochemistry, water quality, and carbon cycling. We analyzed water chemistry before, during, and after a dieback event at a headwater catchment in the Bohemian Forest (central Europe) together with an un-impacted reference catchment, focusing on drivers and responses of dissolved organic carbon (DOC) leaching. We analyzed data regarding carbon input to the forest floor via litter and throughfall, changes in soil moisture and composition, streamwater chemistry, discharge, and temperature. We observed three key points. (i) In the first 3 years following dieback, DOC production from dead biomass led to increased concentrations in soil, but DOC leaching did not increase due to chemical suppression of its solubility by elevated concentrations of protons and polyvalent cations and elevated microbial demand for DOC associated with high ammonium (NH4+) concentrations. (ii) DOC leaching remained low during the next 2 years because its availability in soils declined, which also left more NH4+ available for nitrifiers, increasing NO3– and proton production that further increased the chemical suppression of DOC mobility. (iii) After 5 years, DOC leaching started to increase as concentrations of NO3–, protons, and polyvalent cations started to decrease in soil water. Our data suggest that disturbance-induced changes in N cycling strongly influence DOC leaching via both chemical and biological mechanisms and that the magnitude of DOC leaching may vary over periods following disturbance. Our study adds insights as to why the impacts of forest disturbances are sometime observed at the local soil scale but not simultaneously on the larger catchment scale

Effects of bark beetle disturbance on soil nutrient retention and lake chemistry in glacial catchment

Forest ecosystems worldwide are subjected to human-induced stressors, including eutrophication and acidification, and to natural disturbances (for example, insect infestation, windstorms, fires). The occurrence of the later is expected to increase due to the ongoing climate change. These multi-stressor forcings modify ecosystem biogeochemistry, including the retention of limiting nutrients, with implications for terrestrial and aquatic biodiversity. Here we present whole ecosystem nutrient (N, Ca, Mg, K) mass balances in the forested catchment of Plešné Lake, CZ, which has undergone transient changes linked to the recovery from anthropogenic acidification and to the forest disturbances caused by severe infestations by the bark beetle (Ips typographus). Measured fluxes and storage of nutrients in the lake-catchment ecosystem were used to constrain the processoriented biogeochemical model MAGIC (Model of Acidification of Groundwater In Catchments). Simulated lake water chemistry and changes in soil nutrient pools fitted observed data and revealed that (1) the ecosystem N retention declined, thus nitrate leaching increased for 10 years following the bark beetle disturbance, with transient adverse effects on the acid–base status of lake water, (2) the kinetics of nutrient mineralisation from decaying biomass coupled with nutrient immobilisation in regrowing vegetation constrained the magnitude and duration of ecosystem losses of N, Ca and Mg, (3) the excess of mineralised base cations from decomposing biomass replenished the soil cation exchange matrix, which led to increased soil base saturation, and (4) the improvement of the catchment soil acid–base status led to an increase of lake water pH and acid neutralising capacity. Forested ecosystems underlain by nutrient-poor soils and bedrock are prone to human-induced damages caused by acidification and eutrophication, and any natural disturbance may further lead to nutrient imbalances. We demonstrated that in this natural forest ecosystem protected from human intervention, disturbances together with natural post-disturbance vegetation recovery have temporally positive effects on the nutrient stores in the soil

Photosynthesis in Chromera velia Represents a Simple System with High Efficiency

Chromera velia (Alveolata) is a close relative to apicomplexan parasites with a functional photosynthetic plastid. Even though C. velia has a primitive complement of pigments (lacks chlorophyll c) and uses an ancient type II form of RuBISCO, we found that its photosynthesis is very efficient with the ability to acclimate to a wide range of irradiances. C. velia maintain similar maximal photosynthetic rates when grown under continual light-limited (low light) or light-saturated (high light) conditions. This flexible acclimation to continuous light is provided by an increase of the chlorophyll content and photosystem II connectivity under light limited conditions and by an increase in the content of protective carotenoids together with stimulation of effective non-photochemical quenching under high light. C. velia is able to significantly increase photosynthetic rates when grown under a light-dark cycle with sinusoidal changes in light intensity. Photosynthetic activities were nonlinearly related to light intensity, with maximum performance measured at mid-morning. C. velia efficiently acclimates to changing irradiance by stimulation of photorespiration and non-photochemical quenching, thus avoiding any measurable photoinhibition. We suggest that the very high CO(2) assimilation rates under sinusoidal light regime are allowed by activation of the oxygen consuming process (possibly chlororespiration) that maintains high efficiency of RuBISCO (type II). Despite the overall simplicity of the C. velia photosynthetic system, it operates with great efficiency

The Impact of Load Folowing in Providing System Services of the Selected Dukovany Power Plant Unit on the Parameters of the Core

To operate safely and reliably, the power grid needs power sources that are capable of providing flexibility. In the scenario that emission-free sources dominate the energy mix, the provision of these services will largely be the responsibility of nuclear power plants. Changing the output of a nuclear power plant is burdened with a number of specificities that need to be respected compared to the output changes of thermal power plants. This thesis explores the possibilities of using the reactor at the Dukovany power plant to provide load-following. From a theoretical point of view, it presents information on the needs of the power system, the general possibilities and limitations of using nuclear power plants for load-following and presents the historical context of this practice. After applying different scenarios of load-following, the simulation results are assessed from safety, operational and economic points of view

Licence contract for industrial property rights under conditions of international trade

The diploma thesis deals with licence contract for industrial property rights under conditions of international trade. The first part describes basics of the discipline called intellectual property rights and mutual relation to industrial property rights. Furthermore the thesis includes relation between licence contract for industrial property rights and other contracts governed by private law. The second part is concerned with licence contract itself, including relation to licence governed by copyright law. Last but not least it deals with option contract and so called know how licence

Electricity balance in a typologically local system of an energy community with electricity production

The European trend of increasing the share of renewables and decentralizing energetics is leading to an enthusiastic debate over local energy communities. Mass support for this arrangement may seem to solve many of today's energetics problems, but at the same time we need to keep in mind the problematic aspects of the energy communities themselves. In particular, there is a need to resolve the economic and legal relations of the members of the community and to ensure the technical feasibility of such a transformation. This work summarizes the existing knowledge about the idea of energy communities, presents a summary of the most important information from a technical, economic and legal point of view in the context of the European and Czech environment and draws attention to the most pressing issues. Furthermore, the creation of a model of electricity consumption, photovoltaic production and metrics for measuring electricity with respect to the actual properties of the modeled systems is presented. In the final phase, a simulation of energy flows is performed on a model of an energy community with a specific topology with evaluation of the results