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Inorganic phosphorus released from littoral bottom sediments plays significant role in phosphorus budget of a whole ecosystem. An aim of the study was to assess a role of small invertebrates in phosphorus remineralization in hydroarenal (See Fig.1 in Preface). Hydropsammon organisms (i.e. bacteria, algae, ciliates, rotifers and crustaceans) living in a layer of submerged sands along the edge of a lake (=hydroarenal) were studied in psammolittoral of the deep, eutrophic Lake Mikołajskie (North-eastern Poland) in 2005. Sampling cores were taken at a station 1.5 m from water’s edge once or twice a month since April until October 2005. Each time three samples were taken: 5-cm thick water layer (AWL – adjacent water layer), 0.5-cm thick layer of water and sand from the transitory level (EPIH – epihydroarenal) and 2-cm thick slice of sand (ENDOH – endohydroarenal). The rate of phosphorus excretion was calculated using the appropriate regression equations expressing the relation between individual weight of organism and P excretion adjusted to the ambient temperature. Phosphorus remineralization by the psammon community (calculated for all ciliates, rotifers and crustaceans) was ca. 10 times higher than the maximum rate noted in lake pelagial. The most important role in the process was played by small ciliates, and in periods of high remineralization rate – by small cladocerans. Omnivores, feeding mostly on bacteria and small algae, played the most important role in all three studied layers, especially in periods of the highest rate of P remineralization, thus all kinds of food were used and mineralized. Predators do not seem to play significant role in P remineralization. In hydroarenal significant role seems to be played by processes involved in microbial loop. This suggestion is supported by strong domination of ciliates, main consumers of nanoflagellates, in the process of P remineralization. It seems that phytopsammon and psammic bacteria demands for phosphorus cannot be satisfied merely through the in situ remineralization by microinvertebrates.
Studies concerned a glassy fertilizer obtained at the Department Materials the University of Mining and Metallurgy in Krakow. The fertilizer is able to supply plants with a wide range of macro- and microelements. The present study is aimed to define the possibility of increasing the utilization rate of phosphorus contained in glasses by introducing into the soil the phosphorus bacteria Bacillus megaterium var. phospateum that had been isolated from the soil in which the experiment was carried out and grown on a mineral medium. The results showed an increased level of phosphorus in the soil of the treatments. By using the results obtained in the present and previous studies it is possible to determine the soil conditions to plants. It is worth mentioning that the residues of the glassy fertilizer from which nutrients have been leached are compatible with skeletal parts of soil and thus do not pollute the environment.
Soil phosphorus (P) availability and fractions are influenced to a large extent by land use and cover changes. Inorganic P (IP) and organic P (OP) fractions in surface soils (0–20 cm) under typical vegetation types, including subalpine coniferous forests, alpine shrubs, and alpine shrub-meadows, near the alpine timberline of the eastern Tibetan Plateau of China, were measured by a modified Hedley fraction method. The results showed that OP is the dominant soil P fraction and the main source of available P in alpine soils near the timberline. Soil organic carbon, total nitrogen, and total P contents were higher in subalpine coniferous forests than in alpine shrubs and alpine shrub-meadows. Concentrations of soil labile P (the sums of Resin–IP, NaHCO3–IP, and NaHCO3–OP) were higher in subalpine coniferous forests than in alpine shrubs and alpine shrub-meadows, an observation that may be partially ascribed to the presence of deep litter layers generated by trees. Concentrations of soil labile and moderately organic P (NaHCO3–OP and NaOH–OP) in subalpine coniferous forests were also greater than in alpine shrubs and alpine shrub-meadows. Greater amounts of soil stable OP (extracted by concentrated HCl and cHCl–OP) were accumulated in alpine shrub-meadows compared to alpine shrubs or subalpine coniferous forests. The reduced availability of OP may be attributed mainly to increasing recalcitrant soil organic matter input in alpine shrub-meadows and alpine shrubs. Concentrations of IP associated with Ca minerals and parent materials (extracted by diluted HCl and HCl–IP, and extracted by concentrated HCl and cHCl–IP, respectively) were lower in subalpine coniferous forests, indicating that coniferous forests are more likely to use recalcitrant IP than alpine shrubs and alpine shrub-meadows. In this alpine region, land cover changes from subalpine coniferous forests to alpine shrubs and alpine shrub-meadows near the alpine timberline could decrease soil P conservation, availability, and supplementation.
Male Wistar rats were given nickel (II) chloride (NiCl2 • 6 H2O) with drinking water (300 or 1200 ppm Ni for 90 days). Urine volume and nickel, zinc, copper, calcium and inorganic phosphorus were measured in 24 h urine after 45 and 90 days of exposure. The results demonstrate that relatively low-level oral ex­posure (300 ppm Ni) induces an increase of urinary Ni excretion (p < 0.001), but no significant changes in other elements. The higher Ni dose (1200 ppm) caused elevation of this metal in urine (p < 0.001), as well as significant changes of urinary volume, and zinc, copper and inorganic phosphorus concentration.
Celem przeprowadzonych badań było porównanie stosowanych do oznaczania zawartości fosforu ogólnego, nieorganicznego i organicznego w glebie trzech metod: Brogowskiego, Black’a i Olsena oraz Golachowskiej. Podczas badań analizowano również zmiany zawartości fosforu ogólnego, nieorganicznego, organicznego i przyswajalnego w glebach inkubowanych. Do doświadczenia użyto trzech gleb lekkich o składzie granulometrycznym piasku słabogliniastego. W drugiej części badań przeprowadzono inkubację dwóch gleb: piasku słabogliniastego i piasku gliniastego lekkiego przez okres 60 dni. Stosując metodykę proponowaną przez Black’a i Olsena oznaczono największe ilości fosforu ogólnego, nieorganicznego i organicznego. Trwająca 60 dni inkubacja piasku słabogliniastego i piasku gliniastego lekkiego nie wpłynęła na zmianę rozdziału fosforu glebowego pomiędzy część organiczną i nieorganiczną.
Niniejszy artykuł zawiera charakterystykę podstawowych organicznych i nieorganicznych związków fosforu występujących w glebach. Jednocześnie omawia w sposób chronologiczny rozwój metod mających na celu określenie ilości tych związków w glebach. Omawiane metody oparte są ekstrakcji gleby roztworami różnych związków chemicznych. Ponadto w artykule przedstawiono opis podstawowych zasad dotyczących metod oznaczania zawartości fosforu przyswajalnego w glebach. Omawiane metody to metody: biologiczne, biologiczno-chemiczne i chemiczne. Odnośnie metod chemicznych przedstawiono przydatność stosowanych roztworów ekstrakcyjnych w porównaniu do warunków istniejących podczas pobierania przez rośliny fosforu z gleby.
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