Search results for "ravinteet"
showing 10 items of 26 documents
Grazing decreases N partitioning among coexisting plant species
2017
Herbivores play a key role in shaping ecosystem structure and functions by influencing plant and microbial community composition and nutrient cycling. This study investigated the long‐term effects of herbivores on plant resource acquisition. We explored differences in the natural δ15N signatures in plant, microbial and soil N pools, and examined mycorrhizal colonization in two tundra sites that have been either lightly or heavily grazed by reindeer for more than 50 years. The study examined changes in nutrient acquisition in five common tundra plants with contrasting traits and mycorrhiza status; the mycorrhizal dwarf shrubs, Betula nana, Vaccinium myrtillus and Empetrum hermaphroditum; a m…
Disparities in nutritional adequacy of diets between different socioeconomic groups of Finnish adults
2022
Information on dietary adequacy is needed to assess food and nutrition security in a modern society, especially in the transition towards climate-friendly food systems. In this study, differences in the nutritional adequacy of diets among Finnish adults were evaluated in population groups of different education, income and urbanisation levels. The study used data from the FinDiet 2017 Survey (n = 1655, 18–74 years). Modelled usual intakes of foods and nutrients were evaluated relative to food-based dietary guidelines issued by the National Nutrition Council of Finland (FNNC) and with respect to nutrient adequacy following the Nordic Nutrition Recommendations and FNNC. For about half of the …
Elevated nutrient concentrations in headwaters affected by drained peatland
2018
Abstract Nutrient export from drained peatland has significant impacts on aquatic environments in Nordic catchments. Spatial information on variations in nutrient concentrations across different landscapes and land uses is needed to design measures for achieving the good ecological status of the EU Water Framework Directive. In this study we determined background concentrations in natural peatland-dominated streams and examined effects of peatland use practices on water quality in headwater catchments. We quantified sources for different elements by joint analysis of water chemistry, isotopes, and hydrology for 62 small catchments in North Ostrobothnia, Finland. Concentrations of nutrients …
Upwelled plankton community modulates surface bloom succession and nutrient availability in a natural plankton assemblage
2022
Upwelling of nutrient-rich waters into the sunlit surface layer of the ocean supports high primary productivity in eastern boundary upwelling systems (EBUSs). However, subsurface waters contain not only macronutrients (N, P, Si) but also micronutrients, organic matter and seed microbial communities that may modify the response to macronutrient inputs via upwelling. These additional factors are often neglected when investigating upwelling impacts on surface ocean productivity. Here, we investigated how different components of upwelled water (macronutrients, organic nutrients and seed communities) drive the response of surface plankton communities to upwelling in the Peruvian coastal zone. Re…
The reduction of selenium(IV) by boreal Pseudomonas sp. strain T5-6-I – Effects on selenium(IV) uptake in Brassica oleracea
2019
Selenium (Se) is an essential micronutrient but toxic when taken in excessive amounts. Therefore, understanding the metabolic processes related to selenium uptake and bacteria-plant interactions coupled with selenium metabolism are of high importance. We cultivated Brassica oleracea with the previously isolated heterotrophic aerobic Se(IV)-reducing Pseudomonas sp. T5-6-I strain to better understand the phenomena of bacteria-mediated Se(IV) reduction on selenium availability to the plants. B. oleracea grown on Murashige and Skoog medium (MS-salt agar) with and without of Pseudomonas sp. were amended with Se(IV)/75Se(IV), and selenium transfer into plants was studied using autoradiography and…
Screening of microalgae and LED grow light spectra for effective removal of dissolved nutrients from cold-water recirculating aquaculture system (RAS…
2019
Popularity of recirculating aquaculture systems (RAS) is increasing. Because of the high water recirculation rate, dissolved nutrients originating from fish feed are concentrated enough in RAS wastewater (WW) to enable growth of primary producers, e.g. microalgae. This study evaluated nitrate-nitrogen (NO3-N) and phosphate-phosphorus (PO4-P) removal efficiency of ten temperate zone freshwater microalgae species during their exponential growth phase in unfiltered RAS WW at 17 ± 0.5 °C. Growth and nutrient uptake efficiency of six green and four non-green microalgae strains were compared between WW and reference growth medium in batch monocultures. The effect of three different LED grow light…
Effect of macro and micro nutrients addition during anaerobic mono-digestion of grass silage in leach-bed reactors
2019
The effect of macro- (NH4Cl) (set I) and micro-nutrients (Fe, Ni, Co and Mo) (set II) addition on chemical oxygen demand (COD) solubilisation during anaerobic mono-digestion of grass silage was investigated in two sets of leach bed reactor experiments at 35°C. Results showed that addition of NH4Cl and micro-nutrients improved COD solubilisation by 18% (0.56 g SCOD g−1 volatile solids) and 7% (0.45 g SCOD g−1 VS), respectively than control. About 20–50% of the added micro-nutrients were bioavailable in the produced leachates, while the rest (50–80%) were adsorbed onto the grass silage. Results of biological methane potential assays showed that, specific methane yields of grass silage were im…
Fish Diets in Aquaponics
2019
AbstractFish and feed waste provide most of the nutrients required by the plants in aquaponics if the optimum ratio between daily fish feed inputs and the plant growing area is sustained. Thus, the fish feed needs to fulfil both the fish’s and plant’s nutritional requirements in an aquaponic system. A controlled fish waste production strategy where the nitrogen, phosphorus and mineral contents of fish diets are manipulated and used provides a way of influencing the rates of accumulation of nutrients, thereby reducing the need for the additional supplementation of nutrients. To optimize the performance and cost-effectiveness of aquaponic production, fish diets and feeding schedules should be…