Soil microbial effects of a Cu-Ni smelter in southwestern Finland

Summary The influence of a Cu-Ni smelter on the soil microbial parameters: physiological groups of bacteria, soil respiration, fungal hyphal length, and green-needle litter decomposition, were investigated. The microbial parameters were reduced and this was significantly explained (P<0.01) by the supplied environmental variables: exchangeable Ca, Mg, K, Mn, Cu, Ni, Cd, Zn, soil moisture, pH, and organic C as loss on ignition (Canoco, RDA-analysis). The importance of measuring exchangeable cations for major and trace elements appeared to be a relevant factor that must be considered when establishing relationships between microbial populations, their activity and the effect of heavy metals.     

Temperature sensitivity of soil organic matter decomposition in southern and northern areas of the boreal forest zone

Much effort has been made to improve understanding of factors controlling the temperature dependence of soil organic matter (SOM) decomposition. The question of how soils formed in different geographical locations and conditions respond to temperature changes is still open. In addition to climate, residence times of soil organic matter are controlled by its decomposability and microbial community. In this work we hypothesized that the decomposition of SOM is adapted to the prevailing SOM quality and climatic conditions. This should result in different temperature vs. decomposition curves for northern and southern soils. We studied short-term temperature dependence of SOM decomposition near the northern and southern borders of the boreal forest zone using a Gaussian model. As carbon mineralization rate is driven by microbial activity, we focused on organic carbon fractions available to microbes and the size, composition and functioning of microbial communities in the soil. Despite differences in microbial community structure and behavior, similar amounts and qualities of the microbially available carbon led to similar temperature dependences of carbon mineralization in the north and south. The overall soil respiration rate level was higher in spruce forest sites than in pine forest sites irrespective of climate conditions. Our results do not mean that there is no risk of carbon losses from northern soils due to warming climate conditions. As temperature sensitivity of the decomposition increases with decreasing temperature regime, the proportional increase in the decomposition rate in northern latitudes might lead to significant carbon losses from the soils.     

Effect of processing and storage on the stability of flaxseed lignan added to bakery products

The study focused on the effects of processing and storage on the stability of flaxseed-derived secoisolariciresinol diglucoside (SDG) added to various bakery products. The SDG concentration of doughs, baked rye breads, graham buns, and muffins was analyzed by high-performance liquid chromatography-diode array detection; the baked products were analyzed immediately after baking and upon storage at room temperature for 1 week and at -25 degrees C for 1 and 2 months, respectively. Added SDG was found to withstand normal baking temperatures in all bakery products. SDG also was a relatively stable compound during storage. Similarly, the content of SDG in flax buns containing fat-free flaxseed meal was unaffected by storage. We conclude that cereal-based bakery products can be supplemented with flaxseed-derived SDG.     

Effect of processing and storage on the stability of flaxseed lignan added to dairy products

This study investigated the effects of processing and storage on the stability of purified, flaxseed-derived secoisolariciresinol diglucoside (SDG) added to milk prior to the manufacture of different dairy products. We analyzed the effect of high-temperature pasteurization, fermentation, and milk renneting as well as storage on the stability of SDG added to milk, yogurt, and cheese. Also, the stability of SDG in whey-based drinks was studied. Added SDG was found to withstand the studied processes well. In edam cheese manufacture, most of the added SDG was retained in the whey fraction and 6% was found in the cheese curd. SDG was also relatively stable in edam cheese during ripening of 6 weeks at 9 degrees C and in yogurt during storage of 21 days at 4 degrees C. Up to 25% of added SDG was lost in whey-based drinks during storage of 6 months at 8 degrees C. We conclude that SDG can be successfully supplemented in dairy-based products.     

Comparing regional forest policy scenarios in terms of predicted suitable habitats for the Siberian flying squirrel (Pteromys volans)

Forecasting the potential impacts of forest policies on species of special conservation value is a prerequisite for safeguarding forest biodiversity. In this study, regional forest policy scenarios were compared in terms of predicted habitats suitable for the Siberian flying squirrel (Pteromys volans). To derive both patch- and landscape-scale models to predict species presence in a forest stand, species occurrence data from a systematic field survey covering the whole distribution area of the flying squirrel in Finland and Multi-Source National Forest Inventory data were combined. Then, the Finnish forestry model MELA and the derived occupancy models were applied to predict the quantity of suitable habitats for flying squirrels in three different 50-year policy scenarios. The results confirm that increasing the utilization of felling potential from the level of business-as-usual to the level stated as policy targets in regional forest programs decreases the amount of suitable habitat in the future. However, regional forest programs had a less drastic impact on habitats than maximum sustainable removal, except in two regions. It should be noted that the occupancy models seemed to fail on sites that experts deem to be most suitable for the species. Obviously, there are other factors than forest management affecting presence.     

Oat Bran Fermentation by Rye Sourdough

Hydration of oat bran including fermentation by rye sourdough was studied. Three types of oat bran suspensions were prepared (a control, one with whole meal rye flour added, and one with rye starter added). The suspensions were incubated for 1, 2, 3 and 4 hr. β‐Glucan content and solubilities of protein and β‐glucan were analyzed. Viscosity of the supernatants of oat bran suspensions was determined. Neither the rye sourdough nor the rye flour alone had a significant effect on the total β‐glucan content of oat bran suspensions. However, the addition of rye, either as whole meal rye flour or as sourdough starter, markedly increased the solubility of β‐glucan and proteins and simultaneously decreased the viscosity of the water‐soluble fraction of oat bran suspension. This suggests that a hydrolysis of β‐glucan had occurred that could change the rheological properties of oat bran in baking and the physiological potential of oat bran in nutrition.