Marian Kazda

Nitrogen-induced nutritional imbalances — a contributing factor to Norway spruce decline in the Bohemian forest (Austria)

Abstract Studies of forest-decline symptoms in the Bohemian Forest of Austria showed significant effects of topography on forest conditions. Needle loss, as a measure of the tree vigour, was more severe in higher elevations and on west slopes which face the prevailing winds. Drought periods seem to enhance needle loss on temporarily waterlogged sites. Nutritional imbalances, especially low magnesium and calcium contents in the foliage and wide nitrogen-to-magnesium ratios were correlated with increased needle loss. Measurements of element fluxes at ground level have shown that nitrogen flux with throughfall was 30–70% higher and sulphur flux about 50% higher on a southwest slope and hilltop as compared with a northeast slope. Deposition rates in the open did not differ significantly between sites. Cloud- and fogwater deposition was the main source of higher inputs at the exposed sites. On the southwest slope, nitrogen losses via seepage were of the same magnitude as gains from atmospheric deposition, an indication of nitrogen saturation. On the northeast slope, nitrogen inputs could still be stored in soil and vegetation. This study shows that pollutant deposition, in particular nitrogen deposition, exceeds the buffering capacity of forest ecosystems on shallow, acidic soils of exposed west slopes. This leads to nutritional imbalances.

Effects of Carex rostrata on soil oxygen in relation to soil moisture

Many wetland plants are faced with severe edaphic problems. Long term flooding effects a sequence of chemical processes that result in soil anoxia and production of several phytotoxic compounds. In order to maintain an aerobic root respiration wetland plants produce aerenchyms that enable oxygen conduction through the plant body to underground organs. Moreover wetland plants are able to release oxygen into the soil. This aeration effect of wetland plants in turn can influence soil chemistry considerably and protects roots by an aerobic rhizosphere. Oxygen release by underground organs of aerenchymous plants has been well documented in laboratory investigations but not under field conditions. In this study, dynamics of oxygen saturation were measured together with soil water content and microclimatic parameters. Measurements were carried out on some lowland peat covered by Carex rostrata Stokes from July to October 2001. Oxygen saturation was quantified using novel optical sensors (microoptrodes). The presence of C. rostrata significantly increased oxygen content in the soil. Mean oxygen saturation under Carex rostrata (56.0%) was significantly higher than in a control plot without vegetation (26.6%). Due to fluctuating water content, oxygen saturation in both plots was characterized by pronounced time variation. Increasing soil water content caused an extreme decline of oxygen saturation in both plots and led to anoxia in the control plot. In the presence of C.rostrata, the decline in soil oxygen took place at significantly higher water content (68.5% compared to 67.5% in the control plot) which is substantial as the mean water contents varied between 67 and 69% during the measurement period.

Priority assessment for conversion of Norway spruce forests through introduction of broadleaf species

Serious damage to Norway spruce (Picea abies L. Karst) in Central and Western Europe together with increasing preference for forests with natural species composition emphasise the necessity to convert Norway spruce plantations on unsuitable sites and outside of its natural distribution. Site related priority assessment of Norway spruce replacement by Fagus sylvatica L., Quercus robur L., Acer pseudoplatanus L. and Fraxinus excelsior L., respectively, was calculated using a geographical information system for a management unit of 1248 ha in Upper Austria. Three matrix overlays combining soil depth with soil skeleton and vegetation type with gleyification resulted in different risk categories for Norway spruce. Further matrix overlay with Norway spruce stocking indicated sites with high conversion priority. Suitability indices of broadleaf species were evaluated using indexing overlay, allowing to weight map attributes of seven site parameters. This calculation was done separately for each species studied. Combination of these suitability indices with the conversion priority of Norway spruce led to site-related introduction priorities. The largest areas were found for Q. robur, followed by F. sylvatica. The higher suitability of Q. robur compared to F. sylvatica was explained by its superior adaptation to the acidic, shallow and partially gleyic soils in the area. The introduction of F. excelsior was generally not found advisable. The advantage of this method over the use of classic site classification was seen in the direct implementation of current stand characteristics into the decision rules.

Indications of unbalanced nitrogen nutrition of Norway spruce stands.

Differences in nitrogen cycling and in the nutrition of trees are significantly coupled to the levels of nitrogen input and to the nitrate levels in the soil solution. Relatively high nitrogen supply can cause unbalanced nutrition on sites which contain either low or moderate amounts of other nutrients. This is indicated by low cation/nitrogen ratios in foliage and also by the S/N ratio falling temporarily below 0.030.

Stability of a biogas-producing bacterial, archaeal and fungal community degrading food residues

The resident microbiota was analyzed in a mesophilic, continuously operating biogas plant predominantly utilizing food residues, stale bread, and other waste cosubstrates together with pig manure and maize silage. The dominating bacterial, archaeal, and eukaryotic community members were characterized by two different 16S/18S rRNA gene culture-independent approaches. Prokaryotic 16S rRNA gene and eukaryotic 18S rRNA gene clone libraries were constructed and further analyzed by restriction fragment length polymorphism (RFLP), 16S/18S rRNA gene sequencing, and phylogenetic tree reconstruction. The most dominant bacteria belonged to the phyla Bacteriodetes, Chloroflexus, and Firmicutes. On the family level, the bacterial composition confirmed high differences among biogas plants studied so fare. In contrast, the methanogenic archaeal community was similar to that of other studied biogas plants. Furthermore, it was possible to identify fungi at the genus level, namely Saccharomyces and Mucor. Both genera, which are important for microbial degradation of complex compounds, were up to now not found in biogas plants. The results revealed their long-term presence as indicated by denaturating gradient gel electrophoresis (DGGE). The DGGE method confirmed that the main members of the microbial community were constantly present over more than one-year period.

Fungi open new possibilities for anaerobic fermentation of organic residues

BackgroundLarge amounts of fibre-rich organic waste material from public green and private gardens have to be treated environmentally friendly; however, this fibre-rich biomass has low biogas yields. This study investigated the presence of fungi in full-scale biogas plants as well as in laboratory reactors and elucidated the importance of fungi for the biogas process.MethodsThe dominating members of the eukaryotic community were identified by analyzing 18S rRNA gene and internal transcribed spacer 1 (ITS1) region fragments of clone libraries. These identifications were accompanied by diverse microscopic techniques such as fluorescence microscopy and conventional scanning electron microscopy.ResultsCells of presumably fungal origin were characterized by intensive fluorescence and were about 1 order of magnitude larger than prokaryotic cells. Molecular techniques enabled to identify fungi from the subphyla Agaricomycotina, Mucoromycotina, Pezizomycotina, Pucciniomycotina and Saccharomycotina and from the class Neocallimastigomycetes. Members of these groups can be important for microbial degradation of complex compounds, due to the ability to penetrate cell walls, and thus open the cells for the influx of bacteria, further enhancing degradation.ConclusionsOptimal treatment of biowaste depends on the amount of lignocelluloses. Targeted application of fungi to the biogas process will open wider possibilities for anaerobic treatment of fibre-rich biomass and can result in better biomass utilization as a renewable energy resource. Due to higher temperature optima of fungal cellulolytic enzymes, the thermophilic process is suggested for anaerobic degradation of fibre-rich biomass.

Fine root dynamics of mature European beech (Fagus sylvatica L.) as influenced by elevated ozone concentrations

Fine root dynamics (diameter < 1 mm) in mature Fagus sylvatica, with the canopies exposed to ambient or twice-ambient ozone concentrations, were investigated throughout 2004. The focus was on the seasonal timing and extent of fine root dynamics (growth, mortality) in relation to the soil environment (water content, temperature). Under ambient ozone concentrations, a significant relationship was found between fine root turnover and soil environmental changes indicating accelerated fine root turnover under favourable soil conditions. In contrast, under elevated ozone, this relationship vanished as the result of an altered temporal pattern of fine root growth. Fine root survival and turnover rate did not differ significantly between the different ozone regimes, although a delay in current-year fine root shedding was found under the elevated ozone concentrations. The data indicate that increasing tropospheric ozone levels can alter the timing of fine root turnover in mature F. sylvatica but do not affect the turnover rate.

Functionally redundant but dissimilar microbial communities within biogas reactors treating maize silage in co-fermentation with sugar beet silage.

Numerous observations indicate a high flexibility of microbial communities in different biogas reactors during anaerobic digestion. Here, we describe the functional redundancy and structural changes of involved microbial communities in four lab‐scale continuously stirred tank reactors (CSTRs, 39°C, 12 L volume) supplied with different mixtures of maize silage (MS) and sugar beet silage (SBS) over 80 days. Continuously stirred tank reactors were fed with mixtures of MS and SBS in volatile solid ratios of 1:0 (Continuous Fermenter (CF) 1), 6:1 (CF2), 3:1 (CF3), 1:3 (CF4) with equal organic loading rates (OLR 1.25 kgVS m−3 d−1) and showed similar biogas production rates in all reactors. The compositions of bacterial and archaeal communities were analysed by 454 amplicon sequencing approach based on 16S rRNA genes. Both bacterial and archaeal communities shifted with increasing amounts of SBS. Especially pronounced were changes in the archaeal composition towards Methanosarcina with increasing proportion of SBS, while Methanosaeta declined simultaneously. Compositional shifts within the microbial communities did not influence the respective biogas production rates indicating that these communities adapted to environmental conditions induced by different feedstock mixtures. The diverse microbial communities optimized their metabolism in a way that ensured efficient biogas production.

Factors influencing the soil solution chemistry in Norway spruce stands in the Bohemian Forest, Austria

Abstract Weakly measurements of soil solution composition were performed in three stands of Norway spruce in the Bohemian Forest, Upper Austria from April to November during 1986, 1987 and 1988. Though these stands are only a few kilometres apart from each other, significant differences in the soil solution chemistry were found. Low calcium and magnesium concentrations in one of the stands were not only the result of atmospheric input, but the consequence of previous land use and nutrient accumulation in standing biomass and litter layer. Nitrate concentrations in the soil solution are related to atmospheric nitrogen deposition on the plots. The highest nitrate concentrations were found in the stand with the highest nitrogen input. There, excessive nitrification in a warm and dry period during late summer 1986 caused high nitrate concentrations in the soil solution. The results indicate that three major factors influence the chemistry of the soil solution in forest stands: (1) management of forest sites; (2) atmospheric deposition; (3) short-term climatic effects. All these factors can simultaneously impair the nutrition of recent stands and can increase their susceptibility to the impact of additional stress.

Analysis of Spatial Point Patterns in Microscopic and Macroscopic Biological Image Data

Point process characteristics like for example Ripley’s K-function, the L-function or Baddeley’s J-function are especially useful for cases of data with significant differences with respect to intensities. We will discuss two examples in the fields of cell biology and ecology were these methods can be applied. They have been chosen, because they demonstrate the wide range of applications for the described techniques and because both examples have specific interest- ing properties. While the point patterns regarded in the first application are three dimensional, the second application reveals planar point patterns having a vertically inhomogeneous structure.