Kirsti Derome

Simple procedure for ion chromatographic determination of anions and cations at trace levels in ice core samples

Several suppressed and non-suppressed ion chromatography (IC) elution systems were compared for the determination of ng ml ˇ1 levels of major cations and anions, including formate and methyl sulphonate, in ice core samples using a small (0.2‐ 0.8 ml) sample volume. The use of a suppression unit considerably enhanced the sensitivity of the anion determinations, but had no remarkable effect on the sensitivity of the cation determinations. Optimized analytical conditions were further validated in terms of accuracy, precision and total uncertainty and the results showed the reliability of the IC methods. In addition, contamination problems associated with handling the ice core were investigated, and a simple and almost contamination free ice handling procedure is presented. # 1999 Elsevier Science B.V. All rights reserved.

The Weathering of Mineral Soil by Natural Soil Solutions

Chemical weathering is an important neutralisation process and sourceof cations in forest soil. The presence of dissolved organic matter in the soil solution can have a considerable influence on weathering release. The aim of this study is to compare the weathering potentialof natural soil solutions, collected from Norway spruce, Scots pine and birch sites, to release Al, Ca, Mg, K, Na, and Si from the fine fraction in the C horizon of a podzol. Residual organic matter in the mineral soil was removed with H2O2. The <0.06 mm fraction of the mineral soil was suspended in soil solution, collected from the three sites, for 11 days with continuous agitation. Ultrapure water was used as a control. The pH of the suspensions was maintained at 5.4 by bubbling with CO2. The initial mean DOC concentrations in the soil solutions were 65, 56 and 40 mg L-1 for the spruce, pine and birch sites, respectively. The presence of DOM in the soil solution did not significantly enhance the capacity to weather mineral soil material, and no systematic differences were found between the three sites. However, Al release from the mineral soil was slightly higher in the soil solutions containing DOM compared to the control solution with no DOM. The proportions of DOM fractions capable of enhancing weathering were comparable with those reported in earlier studies. The weathering of metals was found to be primarily due to pH-driven processes. The lack of considerable weathering enhancement by DOM could be due to the fact that the cation-binding sites of the organic ligands were already saturated by e.g. Al and Fe in the soil solution derived from these podzolic, Al- and Fe-rich soils.

Geographical variations in seed oils from Rubus chamaemorus and Empetrum nigrum

Abstract Seeds of cloudberry ( Rubus chamaemorus ) and crowberry ( Empetrum nigrum ) growing wild in Finland between latitudes 60.5 and 69.5° were studied. Seed size, seed oil content and the composition of seed oil triacylglycerols were determined for berries collected from 14 areas. The weight of 100 seeds varied between 0.6 and 0.9 g in cloudberries and between 0.09 and 0.13 in crowberries. Cloudberry seeds collected in southern Finland were heavier ( P P P r = −0.61). The M r distribution of triacylglycerols showed no differences between cloudberry samples from south and north Finland. The seed oil of crowberry from the north contained more triacylglycerols of 52 acyl carbons (8 mole%) and less of those of 54 acyl carbons (87 mole%) than the corresponding sample from the south (6 and 90 mole%, respectively). The most abundant fatty acids were linoleic, α-linolenic, oleic and palmitic, which constituted over 95% of all fatty acids in both berry species. Latitudinal differences existed in the fatty acid compositions; for example, the proportion of linoleic acid was highest ( P P P P

Exceedance of critical loads and of critical limits impacts tree nutrition across Europe

Key messageExceedance of critical limits in soil solution samples was more frequent in intensively monitored forest plots across Europe with critical loads for acidity and eutrophication exceeded compared to other plots from the same network. Elevated inorganic nitrogen concentrations in soil solution tended to be related to less favourable nutritional status.ContextForests have been exposed to elevated atmospheric deposition of acidifying and eutrophying sulphur and nitrogen compounds for decades. Critical loads have been identified, below which damage due to acidification and eutrophication are not expected to occur.AimsWe explored the relationship between the exceedance of critical loads and inorganic nitrogen concentration, the base cation to aluminium ratio in soil solutions, as well as the nutritional status of trees.MethodsWe used recent data describing deposition, elemental concentrations in soil solution and foliage, as well as the level of damage to foliage recorded at forest plots of the ICP Forests intensive monitoring network across Europe.ResultsCritical loads for inorganic nitrogen deposition were exceeded on about a third to half of the forest plots. Elevated inorganic nitrogen concentrations in soil solution occurred more frequently among these plots. Indications of nutrient imbalances, such as low magnesium concentration in foliage or discolouration of needles and leaves, were seldom but appeared more frequently on plots where the critical limits for soil solution were exceeded.ConclusionThe findings support the hypothesis that elevated nitrogen and sulphur deposition can lead to imbalances in tree nutrition.

Nitrate reductase activity in some subarctic species and UV influence in the foliage of Betula pendula Roth. seedlings

Nitrate reductase (NR) activity was studied in the foliage of five subarctic species: mature trees of European white birch (Betula pubescens Erch. S.S.), Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies L. Karst), Ericaceous shrub bilberry (Vaccinium myrtillus L.), naturally growing in a forest, and seed-grown silver birch (Betula pendula Roth.) seedlings in an ultraviolet (UV) exclusion field experiment at the Pallas-Ounastunturi National Park in Finnish Lapland (68 degrees N). Mean NR activity ranged from 0 in bilberry to 1477 (S.D. = 277.7) and 1910 (S.D. = 785.4) nmol g(-1) DW h(-1) in mature trees of European white birch and silver birch seedlings, respectively. Significant differences due to UV exclosure treatments were determined for the NR activity of silver birch seedlings (F = 3.62, P= 0.025*) after three growing seasons (191 days) of UV exclusion. The ambient and control silver birch seedlings had or tended to have higher NR activity than those grown under UV exclusion. No relationship was found between the foliage NR activity and total nitrogen content, which ranged from 0.61 to 1.35% per seedling. The present study suggests large differences in NR activity between the species and the induction of NR activity in silver birch seedlings due to ambient UV radiation.

Techniques for preserving and determining aluminium fractions in soil solution from podzolic forest soils

Abstract The purpose of the study was 1) to determine techniques for minimising the effects of transportation and storage on the concentrations of different A1 fractions in soil solution samples, and 2) to determine a suitable method for analysing monomeric A1 concentrations in water samples from humus-rich podzolic soils. Aluminium fractionation was performed on a cation exchange column and the fractions were analysed by ICP/AES and FIA. A time lag of a few hours to two days between sampling and pretreatment appeared to have no effect on total A1 concentrations, even though the samples were not preserved with acid. Freezing the samples was not an appropriate storage technique because it resulted in a strong decrease in total A1 concentrations. Storage (+4°C) had a detrimental effect on the proportion of exchangeable monomeric A1, but this problem was overcome by fractionating the samples immediately on arrival at the laboratory. Adjustment of sample pH to

Data Quality in Laboratories: Methods and Results for Soil, Foliar, and Water Chemical Analyses

Abstract Chemical analyses are an essential part of forest ecosystem monitoring activities. Harmonized, well-defined, and documented analytical methods are an important part of a laboratory Quality Control program and are essential to maximize spatial and temporal comparability of monitoring data. Different quality and data consistency checks, plausible ranges for analytical results, use of reference materials, and control charts are described for internal laboratory Quality Control. On the other side, coordinated ring tests among participating laboratories are an integral part of external Quality Control. Organization of ring tests, evaluation, and the benchmark with tolerable limits are described and specified. Results for water, foliage, and soil ring tests and the evaluation of quality indicators within the European forest ecosystem monitoring program are reported.Chemical analyses are an essential part of forest ecosystem monitoring activities. Harmonized, well-defined, and documented analytical methods are an important part of a laboratory Quality Control program and are essential to maximize spatial and temporal comparability of monitoring data. Different quality and data consistency checks, plausible ranges for analytical results, use of reference materials, and control charts are described for internal laboratory Quality Control. On the other side, coordinated ring tests among participating laboratories are an integral part of external Quality Control. Organization of ring tests, evaluation, and the benchmark with tolerable limits are described and specified. Results for water, foliage, and soil ring tests and the evaluation of quality indicators within the European forest ecosystem monitoring program are reported.

Soil Solution: Sampling and Chemical Analyses

Abstract Chemical content of soil solution is varying in time and space and is dependent on the sampling and measurement techniques in use. It is a valuable indicator for effects of stress factors on both forests and the surrounding water ecosystems. A continuous standardized methodology for soil solution collection and analysis is of ultimate importance. Methods for harmonized collection and analysis of soil solution on a Europe-wide scale are presented with a special emphasis on sampling and measurement techniques, Quality Assurance, and laboratory analyses. Results based on data produced by the harmonized soil solution monitoring under ICP Forests are presented. They show regular exceedances of critical limits for nitrogen concentrations in soil solution on the majority of the examined sites.