Papers by Christian Huber
Journal of Environment Quality, 2005
During the past decade bark beetle (Ips typographus) attacks killed are usually enhanced after cu... more During the past decade bark beetle (Ips typographus) attacks killed are usually enhanced after cutting and cause "excess nearly all of the Norway spruce [Picea abies (L.) Karst.] stands in the unmanaged zone in the highlands of the Bavarian Forest National nitrification" (Dahlgren and Driscoll, 1994). The herba-Park. This study was conducted to predict if and how long the cata-ceous vegetation and regenerating trees may reduce soil strophic event might cause elevated nitrate (NO 3 Ϫ) concentration in solution NO 3 Ϫ in disturbed ecosystems (Stevens and seepage water, and if the presence of ground vegetation may reduce
Biogeochemistry, 2010
Ion concentrations and fluxes in seepage water (below the main rooting zone) were compared before... more Ion concentrations and fluxes in seepage water (below the main rooting zone) were compared before and after clear cutting at two similar long-term experimental Norway spruce forest plots. While Ballyhooly (Ireland) was influenced by sea salt deposition, Höglwald (Germany) received high nitrogen (N) deposition. These differences were reflected in seepage water concentrations with sodium (Na+) and chloride (Cl–) dominating at
Annals of Forest Science, 2006
From 1982 to 2004 the elemental concentrations of current, current+1, and current+2 year old need... more From 1982 to 2004 the elemental concentrations of current, current+1, and current+2 year old needles of a mature spruce stand were investigated at the N-saturated, acidified, but healthy Höglwald site. The control was compared with a liming, experimental acid irrigation, acid irrigation + liming, normal irrigation, and normal irrigation + liming treatment. Liming was performed in 1984, and irrigation from 1984-1990. High year to year variations were found for most of the elements in all treatments, especially for K ("deficient" to "high"). Despite the N saturation of the ecosystem, needles showed no N-overfeeding of the trees. N, Mg, K, Fe concentrations showed no clear treatment effects. Twenty years after liming a lowered P availability is indicated, which was more pronounced in older needles. Ca concentrations increased after liming, while Al decreased. The elemental concentrations of the acid irrigated treatment did not differ significantly from the normal irrigated or control treatment. liming / long term study / soil acidification / spruce / tree nutrition Résumé-Modifications de la nutrition forestière par acidification expérimentale et chaulage dans le site du Höglwald (Allemagne) entre 1982 et 2004. Les concentrations en éléments minéraux des aiguilles de l'année, et celles âgées d'un an et de deux ans ont été mesurées entre 1982 et 2004 dans un peuplement d'épicéa adulte, saturé en azote et acidifié, mais sain, du site de Höglwald. Ce témoin a été comparé avec les traitements suivants : chaulage, irrigation acide expérimentale, irrigation acide + chaulage, irrigation normale, irrigation normale + chaulage. de fortes variations interannuelles ont été observées pour tous les éléments et tous les traitements, particulièrement pour K (teneurs déficientes à élevées). Malgré la saturation en azote de l'écosystème, les aiguilles n'indiquaient pas d'excès de nutrition azotée. Les concentrations en N, Mg, K et Fe n'ont pas été affectées par les traitements. Vingt années après le chaulage, une plus faible disponibilité en P est indiquée, spécialement par les aiguilles agées. Les concentrations en Ca des aiguilles augmentent après chaulage, et celles en al baissent. Les concentrations mesurées dans le traitement d'irrigation acide ne diffèrent pas de celle des traitements irrigation normale ou du témoin. chaulage / étude à long terme / acidification des sols / épicéa / nutrition forestière
Water, Air, & Soil Pollution: Focus, 2007
In order to test the hypothesis of aluminium toxicity induced by acid deposition, an experimental... more In order to test the hypothesis of aluminium toxicity induced by acid deposition, an experimental acid irrigation was carried out in a mature Norway spruce stand in Southern Germany (Höglwald). The experiment comprised three plots: no irrigation, irrigation (170 mm a −1 ), and acid irrigation with diluted sulphuric acid (pH of 2.6-2.8). During the seven years of acid irrigation (1984)(1985)(1986)(1987)(1988)(1989)(1990) water containing 0.43 mol c m −2 a −1 of protons and sulphate was added with a mean pH of 3.2 (throughfall+acid irrigation water) compared to 4.9 (throughfall) on both control plots. Most of the additional proton input was consumed in the organic layer and the upper mineral soil. Acid irrigation resulted in a long lasting elevation of sulphate concentrations in the seepage water. Together with sulphate both aluminium and appreciable amounts of base cations were leached from the main rooting zone. The ratio between base cations (Ca+ Mg+K) and aluminium was 0.79 during acid irrigation and 0.92 on the control. Neither tree growth and nutrition nor the pool of exchangeable cations were affected significantly. We conclude that at this site protection mechanisms against aluminium toxicity exist and that additional base cation runoff can still be compensated without further reduction of the supply of exchangeable base cations in the upper mineral soil.
Plant and Soil, 2004
The chemistry of seepage water was studied before and after small scale clear-cutting and femel c... more The chemistry of seepage water was studied before and after small scale clear-cutting and femel cutting (removing 20% of the trees) between 1999 and 2002 at the Höglwald site in southern Bavaria. The interventions were performed in February 2000 on mature, N-saturated Norway spruce (Picea abies (L.) Karst.) stands with high NO − 3 concentrations before felling. Seepage water was collected with suction cups at 40 cm soil depth in the following treatments: (I) a mature stand (control), (II) a femel-cut, and (III) a clear-cut. In the femel cut subvariants were created with suction cups (plots) at varying distances from pre-selected spruce, which were later removed. The femel treatment was replanted with beech (Fagus sylvatica L.) saplings. On the clear-cut, subvariants of planted beech (close to the stem, interstem area), planted spruce (interstem), or natural spruce regeneration were investigated. Clear-cutting caused high NO − 3 peaks (average values up to 2750 µM) during 2000 and 2001 in all planted tree subvariants during times of comparatively low water fluxes. In contrast to peak concentrations, flux weighted yearly average concentrations showed different trends. In 2000, flux weighted yearly average NO − 3 concentrations were significantly elevated, but only on the subvariants of the interstem area, which covered in the clear-cut plot ca. 62% of the area. However, the subvariant close to the stem (31% of clear-cut area), or the natural spruce regeneration subvariant (6% of clear-cut area) exhibited no significant felling effect. With respect to the whole treatment area, this resulted in no significant felling effect as compared with the control. In the next year (2001), flux weighted yearly average NO − 3 concentrations were not significantly affected by clear-cutting, while the concentrations were even reduced for all of the clear-cut subvariants in 2002. On the subvariant natural spruce regeneration, NO − 3 concentrations remained below the European limit of drinking water (806 µM) during almost the whole investigation period. Selective cutting resulted in slightly reduced NO − 3 concentrations in 2000 and 2001 on the femel treatment. However, no significant effect could be detected for any subvariant in the femel-cut, even not for the subvariant with suction cups closest to the felled spruce. In contrast to many other investigations, clearcutting did not increase the NO − 3 problem on the treatment to a relevant extend. Quite contrary, a decline in NO − 3
Spatial and temporal variability of nitrate concentration in seepage water under a mature Norway spruce [Picea abies (L.) Karst] stand before and after clear cut
Plant and Soil, 2009
The spatial and temporal variability of the nitrate (NO3 −) concentration in seepage water below ... more The spatial and temporal variability of the nitrate (NO3 −) concentration in seepage water below the main rooting zone of a mature spruce forest was investigated using 121 suction cups which were implemented in a 2 × 2 m grid at 40 cm depth in the mineral soil. Seepage was collected at least monthly during the vegetation period in 2005. In January 2006 a
Forest Ecology and Management, 2006
In 1984, a liming experiment with a surface application of 4 t ha À1 of dolomitic limestone was s... more In 1984, a liming experiment with a surface application of 4 t ha À1 of dolomitic limestone was started at the acidic N-saturated Norway spruce forest ''Höglwald'' in southern Germany and monitored until 2004. The decay of surface humus due to the accelerated mineralisation accounted for 18.5 AE 2.7 t ha À1 C or 50% of the initial pool and 721.6 AE 115.0 kg ha À1 N or 46% for N. Due to some translocation of organic material to the mineral soil the values to 40 cm depth are slightly lower (13.5 AE 4.4 t ha À1 C or 15% of the initial pool and 631.6 AE 192.8 kg ha À1 N or 13% for N). In the control plot NO 3 À concentrations at 40 cm depth were above the European level of drinking water (0.8 mmolc l À1 or 50 mg NO 3 À l À1 ) for nearly the whole investigation period. Liming increased NO 3 À concentrations in seepage water for approximately 15 years, and accelerated leaching losses by 396.2 NO 3 À -N kg ha À1 from 1984 to 2003. The increase in pH of the soil matrix was more or less restricted to the humus layer and the upper 5 cm of the mineral soil during the whole time span, while the base cations Ca and Mg reached deeper horizons with seepage water. From 1984 to 2003, an amount that nearly equalled the applied Mg, was leached out of the main rooting zone, while most of the applied Ca was retained. The time series of the elemental concentrations in needles showed minor changes. Ca concentrations in needles increased with liming, while Mg remained nearly unchanged, and P decreased in older needles. #
European Journal of Forest Research, 2009
Twenty years after the application of dolomitic limestone to a well growing, mature Norway spruce... more Twenty years after the application of dolomitic limestone to a well growing, mature Norway spruce stand at Höglwald, Southern Germany an amount of magnesium equal to the input by liming has left the rooting zone. However, 80% of the applied calcium was retained by the ecosystem. A detailed biomass investigation was carried out in order to elaborate whether the stand shows any nutritional beneWts and if the aboveground tree biomass represents a sink for calcium and magnesium after liming. Stem wood, bark, branches, twigs, and needles were analysed for the major nutrients. Needles showed higher calcium and magnesium concentrations and signiWcantly lower potassium concentrations on the limed plot. Surprisingly, limed trees had signiWcantly lower magnesium concentrations in the bark but higher concentrations in twigs and needles than unlimed trees. In addition, signiWcantly lower concentrations for potassium, sulphur, and phosphorus were measured in the bark of limed trees, whereas the element concentrations in the wood were rather similar between the two treatments. The low potassium concentrations in bark and needles indicate an impeded potassium uptake after liming presumably due to a calcium potassium antagonism. Magnesium is probably used to compensate the relative lack of potassium. The small diVerences in the calculated nutrient storage of limed and unlimed trees, however, suggest that the aboveground biomass can be excluded as a relevant sink for the applied calcium and magnesium at the Höglwald site.
Method and apparatus for separating polynucleotides using monolithic capillary columns
Nucleic acid separation on alkylated nonporous polymer beads
This chapter discusses different stationary phase matrices and functionalities available for the ... more This chapter discusses different stationary phase matrices and functionalities available for the high-performance liquid chromatography (HPLC) separation of carbohydrates. Carbohydrates play an important role in many different research and industrial domains, such as biochemistry, clinical chemistry, biology, pharmacy, biotechnology, and food chemistry. Automated chromatographic analysis of carbohydrates is most frequently performed on ion-exchange stationary phases. The ion-exclusion phenomenon can be explained as the repulsion of ions with equidirectional charges. Spectrophotometric postcolumn labeling has played an important role in monitoring carbohydrates in borate complex anion-exchange chromatography because carbohydrates have no characteristic absorption in the ultraviolet (UV)-visible range. Measurement of the refractive index is insensitive and is prone to baseline drift because of temperature instability or changes in mobile-phase composition. The increase in retention times with increasing alkyl chain length as observed with linear acids, aldehydes, and alcohols is mainly caused by a reversed-phase mechanism. The elution of oligomeric analytes occurs in order of decreasing size. If there are no additional interactions between the analytes and the stationary phase, a linear correlation between the elution volume and the logarithm of molecular weight can be obtained.
Reactions of a cobalt-tin complex in zeolite Y
Luminescence indicator including ionophoric moiety
OPTICAL-CHEMICAL SENSOR FOR DETECTING CHLORIDE
HPLC of carbohydrates with cation- and anion-exchange silica and resin-based stationary phases
Journal of Chromatography Library, 2002
... 147 CHAPTER 4 HPLC o Carbohydrates with Cation-and f Anion=ExchangeSilica and Resin=Based Sta... more ... 147 CHAPTER 4 HPLC o Carbohydrates with Cation-and f Anion=ExchangeSilica and Resin=Based Stationary Phases CHRISTIAN G. HUBER and GUNTHER K. BONN ' ' Institute ofAnalytical Chemistry and Radiochemistry, Leopold-Framens-University, A-6020 lnnsbruck ...
Method for sequencing nucleic acids
Journal of the Chemical Society, Chemical Communications, 1994
A highly thermostable tin-molybdenum complex is encapsulated into the hexagonal mesoporous channe... more A highly thermostable tin-molybdenum complex is encapsulated into the hexagonal mesoporous channel host MCM-41 and thermally transformed into supported metal clusters.
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Papers by Christian Huber