Jiří Kaňa

Chemical and Biochemical Characteristics of Alpine Soils in the Tatra Mountains and their Correlation with Lake Water Quality

AbstractSoils and lakes were sampled in fifteen catchments in the alpinezone of the Tatra Mountains (Slovak-Polish border) to evaluate the dependence of lake water chemistry on soil properties. The amount of soil in alpine meadows varied from 38 to 255 kg m-2 (dry weight soil <2 mm; average of 121 kg m-2). The average cation exchange capacity (CEC) was 12 eq m-2, average base saturation was 12%, and average

Effects of acidic deposition on in-lake phosphorus availability: a lesson from lakes recovering from acidification.

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Changes in surface water chemistry caused by natural forest dieback in an unmanaged mountain catchment

was 4.0. Moraine areas had, on average, 13 kg m-2 of <2 mm soil in small deposits between stones. Their chemical properties were similar to mineral horizons of alpine soils but had higher concentrations of P forms. Soil composition was spatially uniform, having coefficientsof variation of all parameters between 5 and 115%, and did not exhibit significant differences between the catchments or along the elevation gradient. Variation in pools of soil constituents was ∼2-fold higher. Soil organic matter concentration was theparameter that most strongly and positively correlated with N, P, S, CEC, exchangeable base cations, exchangeable acidity, and all biochemical parameters (C, N, and P in microbial biomass and C and N mineralisation rates). Lake water concentrations of organic C, N, and total P were positively correlated (P < 0.01) with the pool of soil organic matter in the catchments, while NO3- concentrations were negatively correlated (P < 0.001). No correlations were found between C, N, and P concentrations in lakes and soil chemistry, indicating the dominant role of soil quantity over quality for surface water composition in the Tatra lakes. Relatively high concentrations of Ca2+, Na+, SO42-, reactive Si, and acid neutralising capacity in some lakes were not explained by soil characteristics, and were more probably related to bedrock composition and structure.

Catchment biogeochemistry modifies long-term effects of acidic deposition on chemistry of mountain lakes

We reconstructed the history of terrestrial export of aluminium (Al) to Plesné Lake (Czech Republic) since the lake origin approximately 12,600 year BC, and predicted Al export for 2010-2050 on the basis of previously published and new data on mass budget studies, palaeolimnological data, and MAGIC modelling. We focused on three major Al forms; ionic Al (Al(i)), organically-bound Al (Al(o)), and particulate Al hydroxide [Al(OH)(3)]. In early post-glacial time, Plesné Lake received high terrestrial export of Al, but with a minor proportion of Al(OH)(3) (4-25 microM), and concentrations of Al(i) and Al(o) were negligible. Since the forest and soil development ( approximately 9900-9000 year BC), erosion has declined and soil organic acids increased export of Al(o) from soils. The terrestrial Al(o) leaching ( approximately 7.5 microM) persisted throughout the Holocene until the industrial period. Then, Al(i) concentrations continuously increased (up to 28 microM in the mid-1980s) due to atmospheric acidification; the Al(i) leaching was mostly associated with sulphate. The proportion of Al(i) associated with nitrate has been increasing since the beginning of lake recovery from acidification after approximately 1990 due to reduction in sulphur deposition and nitrogen-saturation of the catchment, leading to persistent nitrate leaching. Currently, nitrate has become the dominant strong acid anion and the major Al(i) carrier. Al(o) (5.5 microM) is predicted to dominate Al concentrations around 2050, but the predicted Al(i) concentrations ( approximately 4 microM) are uncertain because of uncertainty associated with the future nitrate leaching and its effect on soils.

Climate Change Increasing Calcium and Magnesium Leaching from Granitic Alpine Catchments

Lake water concentrations of phosphorus (P) recently increased in some mountain areas due to elevated atmospheric input of P rich dust. We show that increasing P concentrations also occur during stable atmospheric P inputs in central European alpine lakes recovering from atmospheric acidification. The elevated P availability in the lakes results from (1) increasing terrestrial export of P accompanying elevated leaching of dissolved organic carbon and decreasing phosphate-adsorption ability of soils due to their increasing pH, and (2) decreasing in-lake P immobilization by aluminum (Al) hydroxide due to decreasing leaching of ionic Al from the recovering soils. The P availability in the recovering lakes is modified by the extent of soil acidification, soil composition, and proportion of till and meadow soils in the catchment. These mechanisms explain several conflicting observations of the acid rain effects on surface water P concentrations.

Measurement of in situ Phosphorus Availability in Acidified Soils using Iron-Infused Resin

Mountain forests in National park Bohemian Forest (Czech Republic) were affected by bark beetle attack and windthrows in 2004–2008, followed by an extensive tree dieback. We evaluated changes in the biochemistry of the uppermost soil horizons with the emphasis on carbon (C) and nitrogen (N) cycling in a near-natural spruce (Picea abies) mountain forest after the forest dieback, and compared it with an undisturbed control plot of similar age, climate, elevation, deposition, N-saturation level, and land use history. We hypothesised that the high litter input after forest dieback at the disturbed plot and its consequent decomposition might influence the availability of C for microorganisms, and consequently, N transformations in the soil. The concentrations of dissolved organic C (DOC) and N (DON) in soil water extracts rapidly increased at the disturbed plot for 3 yeas and then continually decreased. Net ammonification exhibited a similar trend as DOC and DON, indicating elevated mineralization. Despite the high ammonium concentrations found after the forest dieback (an increase from 0.5 mmol kg-1 to 2–3 mmol kg-1), net nitrification was stable and low during these 3 years. After the DOC depletion and decrease in microbial biomass 5 years after the forest dieback, net nitrification started to rise, and nitrate concentrations increased from 0.2–1 mmol kg-1 to 2–3 mmol kg-1. Our results emphasize the key role of the availability of organic C in microbial N transformations, which probably promoted microbial heterotrophic activity at the expense of slow-growing nitrifiers.

Factors Affecting the Leaching of Dissolved Organic Carbon after Tree Dieback in an Unmanaged European Mountain Forest

Ionic and nutrient compositions of throughfall, tributaries and lake outlet were analysed in the Plešné catchment-lake system (an unmanaged mountain forest in Central Europe) from 1997 to 2016. The aim was to evaluate changes in surface water chemistry after natural forest dieback. In the 2004-2008, 93% of the Norway spruce trees were killed by bark beetle outbreak, and all dead biomass remained in the catchment. Forest dieback changed the chemistry of all water fluxes, and the magnitude, timing, and duration of these changes differed for individual water constituents. The most pronounced decreases in throughfall concentrations occurred for K+, dissolved organic carbon (DOC), Ca2+ and Mg2+, i.e. elements mostly originating from canopy leaching, while concentrations of NH4+ and soluble reactive phosphorus (SRP) remained almost unaffected. In tributaries, the most rapid changes were increases in NO3-, K+, H+ and ionic aluminium (Ali) concentrations, while terrestrial export of DOC and P forms started more slowly. Immediately after the forest dieback, increase in NO3- concentrations was delayed by elevated DOC availability in soils. NO3- became the dominant anion, with maximum concentrations up to 346μeqL-1 within 5-7years after the bark beetle outbreak, and then started to decrease. Terrestrial exports of Ali, K+, H+, Mg2+, and Ca2+ accompanied NO3- leaching, but their trends differed due to their different sources. Elevated losses of SRP, DOC, and dissolved organic nitrogen continued until the end of the study. In the lake, microbial processes significantly decreased concentrations of NO3-, organic acid anions, H+ and Ali, and confounded the chemical trends observed in tributaries. Our results suggest that terrestrial losses of elements and the deterioration of waters after forest dieback are less pronounced in unmanaged than managed (clear-cut) catchments.

Stability of mercury concentration measurements in archived soil and peat samples

Abstract Using relationships between the composition of precipitation and emission rates of sulphur and nitrogen compounds and dust from 1978 to 2012, we modelled concentrations of sulphate, nitrate, ammonium, chloride, and base cations and pH of precipitation in the Tatra Mountains (central Europe) back to 1900. The modelled precipitation chemistry exhibited a high degree of temporal coherence with the lake water chemistry in 1937 and during the period 1984–2014. The ionic composition of lake water reflected progress in their acidification until the late 1980s, and then a rapid recovery. The response of lake water chemistry to changes in precipitation chemistry differed for individual ions, nutrients, and among lakes, predominantly reflecting the proportions of soil in their catchments. Important differences occurred in nutrient concentrations. In-lake concentrations of dissolved organic carbon (DOC) and total organic nitrogen (TON) exhibited inverse patterns to nitrate. DOC and TON were higher in lakes with a higher proportion of soil in the catchments, and increased in many lakes during recovery from acidification, while nitrate concentrations were higher and decreased most steeply in the catchments with sparse soils. Lake water concentrations of total phosphorus (TP) were spatially similar to that of DOC and TON, but increased most steeply during recovery in lakes with a high proportion of till soils. Our results indicate that chemical recovery of mountain ecosystems is seriously modified by catchment biogeochemistry and may result not only in elevated DOC leaching, but also in an increase of terrestrial export of TON and TP to the receiving surface waters.