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  • paleolimnology  (54)
  • Phosphorus  (26)
  • Springer  (80)
  • 1980-1984  (80)
  • 1925-1929
  • 1983  (80)
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  • Springer  (80)
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  • 1980-1984  (80)
  • 1925-1929
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  • 1
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    Calcified tissue international 35 (1983), S. 773-777 
    ISSN: 1432-0827
    Keywords: 1,25-(OH)2-D3 ; Hypophysectomy ; Growth hormone ; Phosphorus ; 31P NMR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In order to evaluate a possible role for tissue phosphate or phosphorylated compounds in mediating the increase in plasma 1,25-(OH)2-D3 levels during dietary phosphate deprivation, measurements of total and acid-soluble renal cortical phosphate content have been made in both intact and hypophysectomized (hypox) rats eating a normal diet and also after four days of dietary phosphate deprivation. Similar measurements were also made in phosphate-deprived hypophysectomized rats replaced with growth hormone (GH). Total and acid-soluble renal cortical phosphate content averaged 81±8 µmol/g and 4.1±0.6 µmol/g, respectively, in intact rats eating the normal diet and were not significantly altered after phosphate deprivation despite a fall in plasma phosphate of about 40% and a fourfold increase in plasma 1,25-(OH)2-D3 levels. Total and acid-soluble renal cortical phosphate content levels were higher in hypox rats, averaging 92±8 µmol/g and 4.9±0.7 µmol/g, respectively, but also did not change after phosphate deprivation. Replacement of phosphate-deprived hypox rats with GH resulted in a further fall in plasma phosphate and a significant increase in plasma 1,25-(OH)2-D3 levels, but there was no change in either total or acid-soluble renal cortical phosphate content. The distribution of organophosphorus compounds in the acid-soluble phosphate fraction in these experiments was also evaluated using31P NMR spectroscopy. Although there appeared to be an increase in the total concentration of organophosphorus compounds after phosphate deprivation, this effect was not altered by hypophysectomy or by replacement of phosphate-deprived hypox rats with GH. These data suggest that unless phosphate deprivation affects only a small or specific cellular phosphate pool, some factor other than renal cell inorganic phosphate content must initiate the increase in renal 1,25-(OH)2-D3 synthesis that occurs during phosphate deprivation.
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  • 2
    ISSN: 1432-0827
    Keywords: 1,25(OH)2D ; Hypophysectomy ; GH ; T3 ; Phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Hypophysectomy abolishes the four- to fivefold increase in plasma 1,25(OH)2D levels that normally accompanies dietary phosphate deprivation in rats despite a smaller but significant decrease in plasma phosphate in these animals. This effect appears within 1 week of hypophysectomy and may be the result of a lack of GH, T3, or some other pituitary hormone. In hypothyroid rats (2 weeks after TPTX) not given replacement T3, plasma 1,25(OH)2D levels rose threefold from 148±57 pmol/l to 402±96 pmol/l (mean±SD) after 4 days of dietary phosphate deprivation. However, in hypophysectomized animals given replacement T3 alone, plasma 1,25(OH)2D levels rose fourfold from 82±13 to 333±230 pmol/l after 4 days of phosphate deprivation. In addition, in hypophysectomized animals replaced with GH alone, plasma 1,25(OH)2D levels rose from 243±86 to 525±85 pmol/l during phosphate deprivation. These results would suggest that both GH and T3 must be absent to prevent enhanced renal 1,25(OH)2D synthesis during phosphate deprivation. GH and T3 appear to play a permissive role since plasma levels of these hormones do not increase when intact rats are deprived of phosphate. Furthermore, bioassayable somatomedin levels are also not increased in intact rats during phosphate deprivation as well as plasma levels of prolactin. As observed previously, plasma 1,25(OH)2D levels were inversely correlated to plasma phosphate concentrations (r=0.46,P〈0.025), despite the inclusion of data points for unreplaced hypophysectomized animals who were hypophosphatemic but showed no increase in plasma 1,25(OH)2D. Thus the possibility remains that GH and T3 may exert their effect by permitting the renal 25OHD-1α-hydroxylase to respond to a change in phosphate concentrations during dietary phosphate deprivation, that, in turn, may ultimately increase renal 1,25(OH)2D synthesis and plasma levels of this hormone.
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  • 3
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    Calcified tissue international 35 (1983), S. 284-286 
    ISSN: 1432-0827
    Keywords: Phosphorus ; NMR ; Precipitation ; Nucleation ; Phosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary High-resolution31P NMR spectroscopy is shown to be a potentially valuable new method for monitoring the spontaneous precipitation of calcium phosphates from metastable supersaturated solutions. An apparatus capable of pH-statting the sample in a spinning 20 mm NMR sample tube is briefly described. The spontaneous precipitation of dicalcium phosphate dihydrate, CaHPO4· 2H2O, pH-statted at pH 5, is characterized by a base-uptake curve which follows the decrease in the intensity of the solution31P resonance. The precipitation of amorphous calcium phosphate at neutral pH, which exhibited an induction period of ∼ 10 min, was also studied. No evidence of NMR peaks from transient clusters or the initial colloidal solid phase has been seen.
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  • 4
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    Hydrobiologia 98 (1983), S. 223-235 
    ISSN: 1573-5117
    Keywords: diatoms ; paleolimnology ; lakes ; Minnesota ; sediments ; microfossils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fossil diatom assemblages from the sediment/water interface in 105 Minnesota lakes were compared with measurements of alkalinity, sulphate, total phosphorus, transparency, and water depth at the sample site. Similar assemblages were placed together using cluster analysis and comparisons of environmental variables between diatom clusters were made using an analysis of variance. Total alkalinity and transparency showed the greatest difference among clusters. Samples from shallow eutrophic prairie lakes were dominated by Melosira granulata, Stephanodiscus niagarae and, occasionally, by Stephanodiscus hantzschii. Deep oligotrophic lakes had modest percentages of Cyclotella comta. Dilute acid lakes were dominated either by Melosira distans and M. italica or by Tabellaria fenestrata, Cyclotella stelligera, and in some cases C. glomerata. Assemblages with Cyclotella glomerata and Synedra nana were found in naturally meromictic lakes. Stephanodiscus hantzschii showed a preference for extremely eutrophic lakes. The relationships between recently deposited diatom assemblages and the lake environmental conditions studied here can be used to evaluate the extent of past environmental change in lakes.
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  • 5
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    Plant and soil 70 (1983), S. 391-402 
    ISSN: 1573-5036
    Keywords: Intercropping Lupins ; Lupinus albus ; Manganese ; Nitrogen ; Phosphorus ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Significant interactions between wheat and lupins occur below ground and wheat intercropped with lupins has access to a larger pool of available P, Mn and N than has wheat grown in monoculture. This suggests that the wheat is able to take up nutrients produced or made available by lupins grown in association with it.
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  • 6
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    Plant and soil 70 (1983), S. 403-413 
    ISSN: 1573-5036
    Keywords: Buffer power ; Diffusion ; Nutrient influx ; Phosphorus ; Root hair density ; Root hair length ; Soil solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Root hairs increase phosphorus, P, uptake over that due to the plant root alone. A mechanistic model using 16 parameters was developed to describe this process. The model was verified with an experiment using six species that varied widely in root hair length, density and radius. A sensitivity analysis was conducted and the results are included to illustrate the situations where root hairs contribute significantly to P uptake. Length of root hair, root hair density and root hair radius all influenced predicted P uptake with root hair length being particularily significant.
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  • 7
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    Plant and soil 70 (1983), S. 211-217 
    ISSN: 1573-5036
    Keywords: Endomycorrhizae ; Fumigation ; Methyl bromide ; Phosphorus ; VAM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A greenhouse experiment was carried out comparing the growth of various plant species in non-fumigated, fumigated, and fumigated-inoculated soils. The soil used contained numerous pieces of root of Broom-Corn Millet (Panicum miliaceum L.) that were found intensely colonized by indigenous endomycorrhizal fungi. The soil was fumigated with methyl bromide and the inoculum used was a mixture of VA mycorrhizal root fragment from plants grown in the field from which the soil was collected. Plants used were cabbage (Brassica oleracea L. var Copenhagen Market), carrot (Daucus carota L. var. Nantaise), leek (Allium porrum L. var. American Flag), marigold (Tagetes patulus L. var. Golden Boy), tomato (Lycopersicum esculentum Mill. var. Michigan Ohio), sweet corn (Zea mays L. var. Span Cross) and wheat (Triticum aestivum L. var. Glenlea). No phosphorus was added to the soil which contained 93 μg/g of available P (bray II). All plants tested formed mycorrhizae except cabbage. Generally, values of the root endomycorrhizal colonization (REC) index were higher in fumigated-inoculated soil than in non-fumigated soil. Cabbage grew equally well in fumigated and fumigated-inoculated soil, but better than in non-fumigated soil. Cabbage did not form VA mycorrhizae and its better growth in fumigated soil was tentatively attributed to the destruction of soil-borne pathogens and the absence of competition. Wheat grew equally well in the three treatments, because 93 μg/g of available P is sufficient for wheat growth and thus the mycorrhizae were not efficient. The five other plant species used were severely stunted in fumigated soil and the inoculation permitted the reestablishment of normal growth as in non-fumigated soil. Growth stimulation is attributed to the efficiency of VA mycorrhizae since these plants were mycorrhizal in non-fumigated soil and in fumigated-inoculated soil. Stunting of these plants in fumigated soil was due to the destruction of VA mycorrhizae since results show that this stunting cannot be attributed to methylbromide residues in the soil. Moreover soil pH and nutrient content were not markedly changed after fumigation.
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  • 8
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    Plant and soil 71 (1983), S. 371-380 
    ISSN: 1573-5036
    Keywords: Apple ; Calcium ; Copper ; Iron ; Irradiance ; Magnesium ; Manganese ; Nitrogen ; Nutrient uptake rate ; Phosphorus ; Potassium ; Scion effects ; Season ; Source of nitrogen ; Temperature ; Tissue nutrient level ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The rates of uptake of nutrients from solution by apple roots were measured (a) in a root laboratory, using intact roots of mature trees growing under field conditions and (b) in controlled environment using young trees. Maximum nitrate inflows into Discovery/M.9 roots under field conditions were only slightly lower than those into roots of the same genotype in controlled environment, but up to 80 times lower than those into roots of Worcester Pearmain seedlings. At any given external P concentration, P inflows into roots of field-grown trees were about 2.5-times lower than those into the roots of young trees in controlled environment. Nitrate inflows were constant above a solution concentration of 20 mmol m−3 in both field-grown and small trees. In both cases, phosphate inflows increased linearly with solution concentration up to 10 mmol m−3. Among the various plant and environmental factors influencing nutrient uptake characteristics of apple roots were: the scion genotype, tissue nutrient levels, root origin, the form in which N is supplied, level of irradiance of the shoot, root temperature and the season of the year. The effects of these factors are illustrated with examples.
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  • 9
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    Plant and soil 71 (1983), S. 381-385 
    ISSN: 1573-5036
    Keywords: Apple tree ; Drip irrigation ; Phosphorus ; Soil physical properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary P absorption by apple tree roots (Golden delicious/M2) is studied using carrier-free32P. A qualitative model of the influence of some physical properties of the soil is proposed combining individual tree responses to32P injection.
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  • 10
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    Plant and soil 71 (1983), S. 455-462 
    ISSN: 1573-5036
    Keywords: Birch ; Mycorrhizas ; Phosphorus ; Pine ; Saprophytes enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Sheathing mycorrhizal fungi have been shown to possess phosphatase enzymes which can hydrolyse inositol hexaphosphate. In a range of mycorrhizal fungi, this activity was often greater than in two common decomposer basidiomycetes. Mycorrhizal birch and pine roots both produce phosphatases. In birch production is inversely related to the inorganic phosphorus concentration in the growth medium. Mycorrhizas reduce phosphatase activity compared with non-mycorrhizal plants. Phosphatase production by basidiomycete fungi in liquid culture is independent of P in the medium. Saprophytic basidiomycetes tend to incorporate hydrolysed phosphate into their biomass. In contrast mycorrhizal fungi release more into solution than they absorb. The significance of this difference in relation to the supply of nutrients to plants is discussed.
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  • 11
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    Plant and soil 70 (1983), S. 309-316 
    ISSN: 1573-5036
    Keywords: Calcium ; Ionic interaction ; Magnesium ; Nutrient solution ; Oryza sativa L. ; Phosphorus ; Potassium ; Rice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Ionic interactions may occur as cation-cation interactions, anion-anion interactions, or cation-anion interactions. Greater knowledge of this subject is warranted, due to the intensification of agriculture, in devising efficient fertilization systems. The present study was undertaken to elucidate the interaction among P, K, Ca and Mg absorption by the intact rice (Oryza sativa L.) plants from dilute solutions. The uptake of P was independent of Ca concentrations up-to 250 μM Ca but-there was a small decrease at the higher concentrations. Absorption of K and Mg was stimulated in the presence of Ca ions at low concentrations. But K and Mg absorption was decreased at higher Ca concentrations. Increasing concentrations of K in the nutrient solution depressed P and Ca uptake. Magnesium uptake was stimulated at lower concentrations of K, but at higher concentrations it was also decreased. Similarly, absorption of K and Ca was also decreased with increasing concentrations of Mg. Magnesium at lower concentrations stimulated P uptake but at higher concentraions it was decreased. In the present study maximum growth of rice plants was achieved at about 250μM Ca, 260 μM K, and 33μM Mg in the nutrient solution.
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  • 12
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    Plant and soil 71 (1983), S. 23-35 
    ISSN: 1573-5036
    Keywords: Apple ; Mycorrhizas ; Phosphorus ; Root activity ; Root growth ; Water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The paper reviews information, much of it obtained from studies using the East Malling root observation laboratories, on the growth and development of the fruit tree root system. The production of new white root varies from year-to-year, generally being highest in the early years. As trees age, woody roots constitute an increasing fraction of total root length although the contribution made by new root growth to the total root length of established trees is also affected by soil management, being higher for trees under grass than under herbicide. Soil management also affects the balance of short (lateral) to long (extension) roots; under grass there are more lateral roots. Calculation of the rate of water uptake per unit root length needed at various times in the year to meet transpirational demand, suggests that woody roots, which recent experimental work has shown to be capable of absorbing water, must be responsible for much of total water supply. Measurements of VA mycorrhizal infection in field-grown trees indicated, for part of the season, higher per cent infection in trees grown under irrigated grass than under herbicide management. It is suggested that this, which is associated with raised leaf phosphorus levels, may be due at least partly to higher numbers of lateral roots, the root type which becomes infected. The growth and functioning of the root system under field conditions depend upon the production and integration of a range of root types.
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  • 13
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    Plant and soil 72 (1983), S. 85-90 
    ISSN: 1573-5036
    Keywords: Chickpea ; Manganese ; Phosphorus ; Yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Phosphorus and Mn relationship was studied in chickpea at two stages of growth in pot culture using 0, 7.5, 15 and 30 ppm P and 0, 5, 10 and 15 ppm Mn. The dry matter yield increased with P at both stages of growth. Manganese improved the yield only in the first stage. Initial levels of Mn enhanced while higher levels had a depressing effect on tissue P. Addition of 7.5 ppm P enhanced Mn concentration at first stage and at higher levels a marked reduction in Mn content was observed at both the stages.
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  • 14
    ISSN: 1573-5036
    Keywords: Boron ; Calcium ; Copper ; Genotypic differences ; Iron ; Magnesium ; Manganese ; Mineral nutrition ; Molybdenum ; Nitrogen ; Phosphorus ; Plant adaptation ; Plant breeding ; Potassium ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant genotypes differ in their uptake, translocation, accumulation, and use of mineral elements. Examples of genotype differences to iron, nitrogen, phosphorus, potassium, calcium, magnesium, manganese, boron, copper, zinc, and molybdenum are discussed. Current knowledge is sufficient to indicate that many crop plants can be improved for the efficient use of mineral elements and better adaptation to mineral stress conditions.
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  • 15
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    Plant and soil 72 (1983), S. 225-230 
    ISSN: 1573-5036
    Keywords: Barley ; Kinetic parameters ; Phosphorus ; Varietal effects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Barley cultivars grown under field conditions of moderate deficiency of phosphorus (P) had great differences in P uptake and grain yields. As the rate determining step in P uptake under these conditions is located in the root net influx of P (ĪnL*) per g of dry matter of the plant can be expressed by $$\bar I_n L^* = \bar I_{max} L^* \frac{{c - c_{min} }}{{c - c_{min} + K_m }}$$ where Īn, L*, Īmax, c, cmin and Km denote mean net influx per unit length of the root, root length per unit weight of the plant, maximal mean net influx per unit length of the root, P concentration at the root surface, minimum concentration in solution of which net influx appears to be zero and Michaelis-Menten factor of P uptake, respectively. Studies of P uptake kinetics in water culture showed that the values of L*, Īmax, Km and cmin of P uptake varied considerably between barley cultivars. Furthermore, agreement was found between P uptake in the field and P uptake predicted from Īmax-, Km-, cmin- and L*-values observed in water culture experiments. The data thus indicate that it should be possible to improve the efficiency by which plants utilize soil as a source of P by selecting and/or developing genotypes of barley with a smaller cmin and/or Km and a greater Īmax and/or L* during the main period of growth. The results suggest therefore that it should be feasible to adapt plants to a considerably lower soil P level.
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  • 16
    ISSN: 1573-5036
    Keywords: Corn ; Nitrogen ; Phosphorus ; Potassium ; Sugarbeet ; Sunflower
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A three-year experiment was conducted in natural conditions on chernozem soil to examine the efficiency of nitrogen, phosphorus, and potassium use by corn (C4 type), sunflower and sugarbeet (C3 type) grown in optimum conditions of mineral nutrition (N100P100K100 kg/ha). Plant materials were analysed for the concentration of nitrogen, phosphorus, and potassium and dry matter mass per individual plant parts and the whole plant. Leaves of different age, of all three plant species, were analysed to find eventual differences in the efficiency of use of nitrogen, phosphorus, and potassium in the synthesis of organic matter depending on leaf age. It was found that corn had the lowest concentration of the elements studied but the highest dry matter mass. In other words, corn was more efficient than sunflower or sugarbeet in the use of these elements for the synthesis of an organic matter unit. Such results were arrived at in both sets of analyses, i.e., the analyses of leaves performed in the course of ontogenetic plant development as well as the analyses of leaves of different age.
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  • 17
    ISSN: 1573-5036
    Keywords: Calcium ; Nutrient stress ; Phosphorus ; Potassium ; Root growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Techniques developed to measure growth of tomatoes and beans under limiting amounts of either P, K or Ca in solution culture reveal differences among strains. Genetic analysis permits estimates of gene action for control of efficiency and the isolation of improved segregants. The genetic isolates have value in studying mechanisms contributing to uptake, transport and utilization processes.
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  • 18
    ISSN: 1573-5036
    Keywords: Neem cake coated urea ; Nitrogen ; Phosphorus ; Potassium ; Rice ; Rice-wheat ; Sulphur coated urea ; Urea ; Urea briquette
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Removal of NPK in the rice-wheat double cropping system was studied in a field experiment conducted for two crop years (1977–79) at the Indian Agricultural Research Institute, New Delhi. The double cropping system producing 8×103 kg/ha/yr grain (4.5×103 kg rice and 3.5×103 kg wheat) removed 166 kg N, 35 kg P and 174 kg K per hectare per year. Thus the rice-wheat double cropping system heavily depletes the soils of their NPK content and calls for balanced fertilization for continued high production. NPK removal was higher when a 135-day duration rice variety was grown than when a 105-day duration variety was grown, because the former resulted in overall (rice + wheat) more grains and straw. Similarly grain and straw yield and NPK removal was more with transplanted rice than when sprouted rice seeds were sown on puddled seedbed; the latter method was in turn superior to direct drilling. Use of urea briquette, neem cake coated urea and sulphur coated urea gave higher yields and resulted in removal of more NPK than prilled urea.
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  • 19
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    Plant and soil 70 (1983), S. 199-209 
    ISSN: 1573-5036
    Keywords: Endomycorrhizae ; Fumigation ; Methyl bromide ; Mycorrhizal dependency ; Phosphorus ; VAM
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The growth of twenty plant species was compared under field conditions in a methyl bromide fumigated and non-fumigated soil. The non-fumigated soil had a wild endomycorrhizal flora and contained 100 μg/g of available phosphorus. No phosphorus was added to the soil but both fumigated and non-fumigated plots received a basal fertilization of 100 kg/ha N−NH4NO3 and 100 kg/ha K−KCl. Based on plant growth responses, three groups of plants were distinguishable. Plants from group I were mycorrhizal and had better growth in non-fumigated than in the fumigated soil. This group was the most important, including sixteen plant species. Stunting of plants from group I following soil fumigation was mainly attribuable to the destruction of mycorrhizae. Plants from group II (oat and wheat) grew equally well in non-fumigated and fumigated soils. For these plants which were mycorrhizal in the non-fumigated plots, the P-content of the soil was sufficient for growth and therefore no stunting was observed in the absence of mycorrhizae. Plants from group III (cabbage and garden beet) grew better in fumigated than in non-fumigated soil. Their better growth in fumigated soil was tentatively attributed to the destruction of soil-borne pathogens. They did not form mycorrhizae in non-fumigated soil. A new method of calculating mycorrhizal dependency is proposed, and the value calculated was named relative field mycorrhizal dependency (RFMD) index. It is also proposed that the acronym RFMD receive a superscript representing in μg/g the quantity of available P in the soil. Carrot with its characteristic root systems had the highest RFMD100 index (99.2%), but other plants with high phosphorus requirements for normal growth had a wide range of RFMD100 index values.
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  • 20
    ISSN: 1573-5036
    Keywords: Ammonification ; Eh ; Flooded soils ; Iron ; Manganese ; Nitrate reduction ; Phosphorus ; pH ; Salinity and extractable cations ; Zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The electro-chemical and chemical kinetics of six California rice soils were significantly influenced by the presence of salts up to an EC of 9 mmhos/cm in saturation extract (ECe). Subsamples of each soil salinity treatment were incubated for periods up to 10 weeks after flooding. Most of the changes in Eh and pH values took place in the first 3–4 weeks after submergence. Salinity decreased pH values, but slightly increased the redox-potential. Both ammonification and nitrate reduction were significantly decreased, by increasing soil salinity. Salinity up to 9 mmhos/cm did not affect levels of Bray and Kurtz extractable P, but increased the water extractable Ca, Mg, K and Mn. In DTPA extract, salinity in incubated soils had no effect on Zn in 4 soils, but it decreased Fe in acid and neutral soils. Possible explanations for the electro-chemical and chemical kinetic changes due to flooding and salinity are discussed.
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  • 21
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    Plant and soil 70 (1983), S. 107-124 
    ISSN: 1573-5036
    Keywords: Citrate ; Iron ; Lupins ; Lupinus albus L. ; Phosphorus ; Polymers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Large quantities of citrate ions have been shown to be secreted by the roots ofLupinus albus. It is postulated that these react in the soil to form ferric hydroxy phosphate polymers which diffuse to the root surface where they are degraded by the action of reducing agents in the presence of an Fe II uptake mechanism balanced by hydrogen ion secretion. Some known chemical behaviour of Fe III and citrate which supports this postulate is reviewed. Evidence is also presented which suggests that much of the Fe absorbed circulates within the root system and is subsequently precipitated.
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  • 22
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    Plant and soil 71 (1983), S. 415-431 
    ISSN: 1573-5036
    Keywords: Carbon allocation ; Light Mycorrhizas ; Nitrogen ; Phosphorus ; Photosynthesis ; Pinus contorta ; Pinus taeda ; Pisolithus tinctorius ; Respiration ; Source-sink ; Suillus granulatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Studies examined net photosynthesis (Pn) and dry matter production of mycorrhizal and nonmycorrhizalPinus taeda at 6 intervals over a 10-month period. Pn rates of mycorrhizal plants were consistently greater than nonmycorrhizal plants, and at 10 months were 2.1-fold greater. Partitioning of current photosynthate was examined by pulse-labelling with14CO2 at each of the six time intervals. Mycorrhizal plants assimilated more14CO2, allocated a greater percentage of assimilated14C to the root systems, and lost a greater percentage of14C by root respiration than did nonmycorrhizal plants. At 10 months, the quantity of14CO2 respired by roots per unit root weight was 3.6-fold greater by mycorrhizal than nonmycorrhizal plants. Although the stimulation of photosynthesis and translocation of current photosynthate to the root system by mycorrhiza formation was consistent with the source-sink concept of sink demand, foliar N and P concentrations were also greater in mycorrhizal plants. Further studies examined Pn and dry matter production ofPinus contorta in response to various combinations of N fertilization (3, 62, 248 ppm), irradiance and mycorrhizal fungi inoculation. At 16 weeks of age, 6 weeks following inoculation with eitherPisolithus tinctorius orSuillus granulatus, Pn rates and biomass were significantly greater in mycorrhizal than nonmycorrhizal plants. Mycorrhizal plants had significantly greater foliar %P, but not %N, than did nonmycorrhizal plants. Fertilization with 62 ppm N resulted in greater mycorrhiza formation than either 3 or 248 ppm. Increased irradiance resulted in increased mycorrhiza formation.
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    Plant and soil 71 (1983), S. 463-467 
    ISSN: 1573-5036
    Keywords: Anion uptake ; Barley ; Hordeum vulgare ; Mycorrhiza ; Phosphorus ; pH Rhizosphere ; Triticum aestivum ; Wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In two field experiments sown in 1982 to test the effect of vesicular-arbuscular mycorrhizas (VAM) on growth and phosphorus nutrition of (i) spring wheat and spring barley, (ii) winter wheat and winter barley, we measured the concentrations of the major cation (K+, Ca2+, Mg2+ and Na+) and anions (Cl−, SO4 2−, H2PO4 − and NO3 −) in shoot tissue. In all cases the sum of the anion concentrations (ΣA) was increased strongly by mycorrhizal infection but not by P additions, confirming earlier observations2 on spring wheat. The concentration of total cations (ΣA) was generally reduced by P additions, hence P and VAM both reduced the cation excess (ΣC−ΣA) but by different mechanisms. These results suggest that increased uptake of anions by plants with VAM may be a general phenomenom which would have important implications for the elemental composition of crops. The effect may also be manifested by other types of mycorrhizal association.
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    Plant and soil 72 (1983), S. 351-364 
    ISSN: 1573-5036
    Keywords: Acid soils ; Cation exchange capacity ; Fertilizer use ; Nitrogen ; Phaseolus vulgaris ; Phosphorus ; Selection ; Soil stresses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Genetic effects are obtainable for any aspect of transport, accumulation, and efficiency of nutrient use by plants, and for virtually any element. Some of the important characters are: tolerance to acid soils (18% of soils or 2.4 billion ha), tolerance to high pH induced Fe-chlorosis, and tolerance to salinity (about 1,000 m ha). Genotypes which made better use of N and P would be the means of saving fertilizers, especially important to developing countries. A 10% economy of fertilizer use represents a minimum world saving of US$6 billion annually. Phaseolus vulgaris is taken as a model to show that although we know quite a lot about the extent of its nutritional variation, e.g. adaptability to acid soils, and the crop's utilization of N and P, we are handicapped in exploiting this because of lack of genetic information. This in turn depends on knowledge of specific mechanisms, and investigating these must be a priority.
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  • 25
    ISSN: 1573-5036
    Keywords: Glomus fasciculatum ; Iron hydroxide ; Lolium rigidum ; Phosphorus ; Response equation ; Ryegrass ; Sigmoidal response ; Subsoil ; Subterranean clover ; Trifolium subterraneum ; Vesicular arbuscular mycorrhiza
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary In a series of glasshouse experiments, plants were grown in pots and their response to applied phosphate was measured. In the experiments we measured the response of subterranean clover and ryegrass to applied phosphate in surface soil and subsoil, with and without inoculation with vesicular-arbuscular (VA) mycorrhizal fungi, and with different levels of added iron hydroxide. For subterranean clover, there was often a clearly marked threshold level of phosphate application below which the plants took up little P and grew poorly. This threshold effect led to the sigmoidal response curves. It occurred when plants were grown in subsoil and in surface soil when iron hydroxide was added. However, it only occurred when the plants were non-mycorrhizal. Inoculation with a VA mycorrhizal fungi (Glomus fasciculatum) eliminated the threshold even when large amounts of iron hydroxide were present. For ryegrass, no threshold was observed and the response curve was never sigmoidal. Thus sigmoidal response curves to applied phosphate were only observed when a coarse-rooted plant species (subterranean clover) was grown in soils with large adsorption capacities for phosphate, and when roots were not mycorrhizal. Sigmoidal response to applied phosphate may occur because there is a threshold concentration of P in soil solution for adsorption by plant roots, for movement to plant roots or for desorption of adsorbed phosphate from the soil particles.
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    Plant and soil 72 (1983), S. 379-383 
    ISSN: 1573-5036
    Keywords: Clover ; Phosphorus ; Populations ; Root ; Shoot ; Trifolium repens ; White clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Eight semi-natural white clover populations and two cultivars were grown in culture solutions containing 10 ppm and 0.01 ppm phosphorus (P). The rate of P uptake by the intact plants was then measured in solutions containing 10 ppm P. Phosphorus uptake per unit root length was twice as great by plants previously grown at 0.01 ppm P than those grown at 10 ppm P. Large differences in total P uptake were found among populations regardless of the pretreatment; most of this variation was accounted for by differences in root length. Only small differences were found between populations for P uptake per unit root length, and then only after pretreatment with 10 ppm P; this variation was largely accounted for by relative growth rate and shoot %P.
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    Plant and soil 74 (1983), S. 211-222 
    ISSN: 1573-5036
    Keywords: Availability ; Cropping system ; Fertilizer response ; Phosphorus ; Rice-wheat rotation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary To work out efficient utilization and to standardize P requirement of rice-wheat rotation, a field experiment is in progress on Fatehpur loamy sand (Typic, Ustochrepts) soil at PAU Farm Ludhiana, since summer 1977. Soil of the experimental site was non-saline, alkaline, low in available P, N and oxidizable organic matter and medium in available K. Three years' yield data revealed that only wheat responded to fertilizer P in the rotation indicating thereby that 26 kg P ha−1 applied to wheat only, in rice-wheat rotation, was sufficient to meet P requirement of both crops. This suggested that for efficient use and economic returns from fertilizer input, the fertilizer schedule should be worked out in the cropping system rather than on a single-crop basis. To explain the differential response, of rice and wheat to P application, an incubation study under simulated moisture and temperature conditions of the two crop cultures was carried out in the laboratory. Results indicated that high temperature (33±2°C) in combination with high soil moisture content (150 per cent of saturation capacity) representing growth conditions of rice culture increased P availability significantly as compared to its content at low temperature (13±2°C) and soil moisture content of about field capacity (50 per cent of saturation capacity) representing conditions of wheat culture. Application of FYM increased available P under both the situations, however, its impact was more pronounced under conditions of rice culture. But effect of N (urea) application on the P availability of soil under the given situations was not significant.
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    Hydrobiologia 103 (1983), S. 65-69 
    ISSN: 1573-5117
    Keywords: paleolimnology ; X-ray radiography of sediment cores ; sedimentary properties ; sediment accumulation
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    Topics: Biology
    Notes: Abstract X-ray radiographs of unextruded sediment cores are used for the documentation and the interpretation of primary and secondary sedimentary structures, and for the correlation of synchronous laminations between different cores. The vertical variation in bulk density, water content and void ratio, and the increase of solids with increasing sediment depth are calculated from the recorded film density along the radiographs. The X-ray radiographic technique for the study of sedimentary properties is fast and non-destructive. The technique is especially valuable when studying the uppermost part of the sediment cover and the processes of sediment redistribution and sediment accumulation. Studies are being undertaken in several Swedish lakes and coastal bays, where mono- and stereoradiographs are being used to classify bottom and sediment types, to interpret changes in the depositional environment, and to calculate past and present rates of sediment accumulation.
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    Hydrobiologia 103 (1983), S. 75-79 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Dead Sea climate ; pore-waters ; diffusion ; sediments ; salinity ; porosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The salinity of lakes is subject to variations imposed by climatic changes. These variations are recorded in the salinity profile of pore waters. Meromictic lakes, such as the Dead Sea, are a special case where waters which underlie the mixolimnion reflect salinity variations. In a sediment core from Dead Sea shallow waters, the salinity profile exhibited a minimum at about 1.9 m depth. It is shown by a diffusion model that this minimum can be attributed to lower salinities which prevailed at the sediment water interface for several decades around the turn of this century. No such minimum was observed in a sediment core from the deepest part of the lake where, during the last two centuries, the overlying brines had a constant salinity.
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    Hydrobiologia 103 (1983), S. 81-84 
    ISSN: 1573-5117
    Keywords: paleolimnology ; geochemistry ; trace elements
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    Topics: Biology
    Notes: Abstract A geochemical study of lacustrine sediments was undertaken as part of a major paleolimnological project concerned with the impact of man on lakes. Factor analysis was applied to the geochemical data obtained from a core from one lake. Three principal factors which explained most of the variance of the initial data were identified. Factor I is related to the organic:mineral component ratio of the sediment, and can be considered as an indirect index of change in lake trophic status through time. Factor II is related to the granulometric composition of the sediment and matches evidence for changes in the hydrological regime of the lake. Factor III reflects changes in redox potential and is more closely related to processes occurring within the lake than other factors. Specific geochemical associations of elements are connected with each factor and are the factor indicators. The correlation of these associations are analyzed as geochemical indices of the variability of sediment accumulation conditions in time.
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    Hydrobiologia 103 (1983), S. 85-90 
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; East Africa ; transfer functions ; pH-indicators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our purpose is to establish the quantitative relationship between recent diatom floras and ecological parameters, in order to extrapolate the results to the past. The parameter pH is here considered as an example. This work is based on the study of about I60 diatom samples from East Africa and of their corresponding biotopes. We propose some statistical methods to interpret the data. Correspondence analysis allows us to define the pH-indicator species. The regression calculations allow pH values to be calculated using the percentage of the diatom species in a sample.
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  • 32
    ISSN: 1573-5117
    Keywords: paleolimnology ; caesium-137 ; perched lake ; meromictic ; diffusion ; bioconcentration ; sediment accumulation
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    Topics: Biology
    Notes: Abstract Hidden Lake is a perched, brown-water lake located in the centre of Great Sandy Island (Fraser Is.), S.E. Queensland. It is highly acid (pH 4.0), oligotrophic and is thermally and chemically stratified for most of the year. The sediments revealed a 137Cs profile which departed from the temporal pattern of 137Cs fallout in Brisbane and was represented by an exponential increase of 137Cs towards the surface sediments from ca. 32 cm depth. The possible causes of the divergent profile are discussed, including physical and biological mixing, lag in the transport of catchment material to the sedimentary basin, diffusion, recycling and biological concentration. It is hypothesised that a combination of the last four processes, with diffusion facilitated by the highly acid conditions, are the major causes of the observed 137Cs profile. Possible recycling and bioconcentration of 137Cs raises questions as to the validity of this method of dating in similar environmental conditions, and as to the interpretation of other palaeochemical data. These hypotheses are to be tested against profiles obtained from 14C, 210Pb, 239/240Pu analyses of the sediment, and the measurement of 137Cs activity in the water and biota of the lake.
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    Hydrobiologia 103 (1983), S. 45-51 
    ISSN: 1573-5117
    Keywords: paleolimnology ; magnetism ; dating ; Australia ; North America ; Japan ; Europe ; Near East
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paleolimnomagnetic records from five regions of the world have been combined with historical magnetic field observations in order to produce regional geomagnetic master curves.
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    Hydrobiologia 103 (1983), S. 37-44 
    ISSN: 1573-5117
    Keywords: paleolimnology ; magnetic minerals ; sediment sources
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    Topics: Biology
    Notes: Abstract This review outlines the origin and environmental significance of magnetic minerals in lake sediments. Attention is drawn to situations where the patterns of mineral magnetic variation is a reflection of processes other than changing erosion rates and fire incidence. The use of mineral magnetic techniques in sediment source tracing, palaeoclimatic studies and the reconstruction of particulate pollution history is illustrated by means of case studies from Britain and N. America. The value of magnetic susceptibility as an on-site core logging technique is shown by reference to data from Lake Washington.
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    Hydrobiologia 103 (1983), S. 53-58 
    ISSN: 1573-5117
    Keywords: paleolimnology ; secondary ferrimagnetic oxides ; S.I.R.M. ; magnetic susceptibility ; laminated sediments
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    Topics: Biology
    Notes: Abstract The magnetic parameters S.I.R.M. and magnetic susceptibility have been used to try and establish the fire histories of lake drainage basins. The technique is demonstrated using sediments from three lakes: Llyn Bychan (N. Wales), a lake with a recently burnt catchment, Lake Biscarrosse (S. W. France), a lake with a well documented fire history, and Lake Laukunlampi (E. Finland), a lake with laminated sediments and a long, but unknown fire history.
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    Hydrobiologia 103 (1983), S. 141-146 
    ISSN: 1573-5117
    Keywords: paleolimnology ; lakes ; sediments ; eutrophication ; Cladocera ; Switzerland
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    Topics: Biology
    Notes: Abstract Species composition and density of cladoceran populations changed in Lakes Zürich, St. Mortiz and Baldegg as human populations increased in these watersheds. Lake Zürich sediments became annually laminated in the 1890's as a result of increased organic input as the size of the cities surrounding the lake grew. At the same time, the Bosmina species changed from a oligotrophic form (longispina) to a eutrophic form (longirostris). An increase in Daphnia spp. populations also occurred at this time in the lake's history. Bosmina longispina reappeared in the lake in 1965 as the lake's trophic status changed from eutrophic to mesotrophic due to effective sewage treatment facilities. Annual laminations appear in the Lake St. Moritz sediments about 1910. Shortly thereafter, a shift from B. longispina to B. longirostris occurred. This change in trophic status is associated with increased tourism in the area. Lake Baldegg sediments also show annual laminations beginning in 1885 and a similar shift in the Bosmina species. Other cladoceran remains were too scarce to be useful in interpreting the histories of these lakes.
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    Hydrobiologia 103 (1983), S. 59-64 
    ISSN: 1573-5117
    Keywords: paleolimnology ; sedimentation pattern ; magnetic susceptibility ; Scanian lakes ; palaeomagnetism
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    Topics: Biology
    Notes: Abstract Magnetic susceptibility measurements have been used to correlate synchronous depths in ca. 50 l m. cores of recent sediment from a small lake (area ca. 55 ha) in Scania, southern Sweden. The three-dimensional picture of sediment accumulation which emerges provides a basis for studying sediment deposition patterns through time. Using a palaeomagnetic chronology, the results show that the pattern and rate of accumulation have dramatically altered during the past 350 years, thus making semiquantitative studies of downcore sediment properties in a single core problematical. Possible reasons for these phenomena are briefly discussed.
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  • 38
    ISSN: 1573-5117
    Keywords: paleolimnology ; sediment core positioning ; hydrographic survey ; computer contouring ; morphometric calculation
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    Notes: Abstract Automated techniques for sediment core site positioning, hydrographic survey, and contour mapping are described. The computer contouring system can be extended to calculate values for morphometric variables such as maximum length (1max), maximum width (wmax), lake perimeter (10), lake area (A) and lake volume (V). The techniques are exemplified using results from Augher Lough, Northern Ireland.
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  • 39
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; salinity ecology ; annual lamination ; sulphide mud ; meromixis ; Baltic
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    Topics: Biology
    Notes: Abstract Diatoms have been studied in an annually laminated sulphide mud which was deposited after the impoundment of the sea-bay of Gennarbyviken. It was possible to follow how the measured decrease in salinity in the basin was reflected by the diatom flora of the sediment which had been deposited concurrently
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    Hydrobiologia 103 (1983), S. 153-158 
    ISSN: 1573-5117
    Keywords: paleolimnology ; eutrophication ; reservoirs ; Bosmina ; Chironomidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eutrophication of reservoirs can be detected by changes in the abundance of insect and crustacean remains in the sediments. In recently constructed reservoirs, the time of impoundment can be determined through the presence of chironomid head capsules. The initial phase is characterised by highly enriched water as can be seen by the abundance of Bosmina remains. If further nutrient input into the reservoir remains low, the upper part of the sediment column is almost completely lacking in invertebrate remains.
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    Hydrobiologia 103 (1983), S. 159-163 
    ISSN: 1573-5117
    Keywords: paleolimnology ; marine/brackish-freshwater ; transition basin ; wildfowl ; gregarious waterfowl ; allochthonous nutrients ; seasonal eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A new and very special course of events starts in a freshwater basin, just isolated from the sea. In NW Europe this is mainly caused by land uplift in Holocene times or by regression of the sea. It has been thoroughly documented by the gradual change in the composition of the fossil diatom floras. Attention is drawn to the possible impact of migrating birds, especially wildfowl, breeding, resting and moulting in those often shallow, sheltered lakes along the Scandinavian coastlines. The gregarious wildfowl species might seasonally increase the allochthonous input of nutrients in the lake ecosystems and cause marked changes in biotic interactions. A working hypothesis is suggested, that the wildfowl species in question were appreciably more numerous before the arrival of man. Consequently, their effect on seasonal eutrophication cannot be neglected in the paleolimnological context.
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  • 42
    ISSN: 1573-5117
    Keywords: paleolimnology ; lakes ; eutrophication
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    Notes: Abstract Problems relating to the disappearance and eutrophication of lakes as a result of human activity are presented. A study area was selected located in an agricultural/forest region where human influence on lakes used to be minimal. In the past 25 years a number of lakes have completely disappeared and others have become rapidly enriched. Human interference has included: the pulling down of water mills, drainage and river canalisation, construction of holiday resorts, development of intensive farming, increased mineral fertilization, and the extension of roads and road traffic.
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    Hydrobiologia 103 (1983), S. 177-179 
    ISSN: 1573-5117
    Keywords: paleolimnology ; sediment chemistry ; heavy metals ; ATP
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    Topics: Biology
    Notes: Abstract This investigation is concerned with the impact of industrial and municipal waste discharge on lakes near the city of Tampere, Finland. The record of P, Zn and ATP in the recent sediments of Vanajavesi I, a polluted lake, and Mallasvesi, a largely unpolluted lake, are compared.
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    Hydrobiologia 103 (1983), S. 247-250 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Pannonian lakes ; infilling process ; environmental change ; hydrosere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data on the stratigraphy and development of a former lake near the town of Vracov, SE Moravia, Czechoslovakia, are presented. The infilling process and vegetation succession are described. An attempt to reconstruct changes in habitat conditions during the last ca. 13 000 years has been made.
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    Hydrobiologia 103 (1983), S. 241-245 
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatom succession ; lake development
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    Topics: Biology
    Notes: Abstract The Late-glacial and Postglacial sediments of the former Komořany Lake in North-West Bohemia were studied by means of diatom analysis to trace the pattern of past environmental change in the lake. Several phases of lake development could be distinguished. Originally the Komořany Lake was a eutrophic shallow water basin. The diatom succession in the early Postglacial sediment indicates alternating alkaliphilic, epiphytic and planktonic diatom communities associated with changes in water level in the basin. At the beginning of the Subatlantic period the water level began to rise and the development of planktonic diatoms, typical of small eutrophic lakes, occurred. Later, the basin became shallow again and the number of indifferent and acidophilous diatoms increased. This is typical for the final phase of the infilling process of a lake before its transformation to peatland
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    Hydrobiologia 103 (1983), S. 257-260 
    ISSN: 1573-5117
    Keywords: paleolimnology ; palynology ; bacteriology
    Source: Springer Online Journal Archives 1860-2000
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    Notes: Abstract There are many lake basins in the Soviet Union, both in the humid and the arid regions, including lowland and alpine, and shallow and deep-water lakes. Lithological, geochemical, radiological and paleobiological methods have been utilized in studying the history of these lakes. Lake Zaisan in Kazakhstan is described as an example of lake development in the arid zone, whilst the lake systems of the Pribaltica, where human influence on the environment is clearly recorded, exemplifies the humid zone.
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    ISSN: 1573-5117
    Keywords: paleolimnology ; diatom flora ; sediments ; Vistula Lagoon ; Poland
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    Notes: Abstract The variability of Actinocyclus kuetzingii (A.S.) Sim. in the Littorina deposits of the Vistula Lagoon and Lake Druzno were studied. During the time of the Littorina Lake Druzno was a part of the Vistula Lagoon. In the different parts of the Lagoon both the abundance of A. kuetzingii and the diameter of its valves change in a manner associated with phases of the Littorina transgression. Coscinodiscus (Actinocyclus) kuetzingii fo. subsalsa Brockmann is probably an ecotype of A. kuetzingii (A.S.) Sim.
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    Hydrobiologia 103 (1983), S. 281-285 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Lake Baikal ; Pliocene ; Pleistocene ; pollen ; diatoms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The following stages in the formation of sediments in Lake Baikal have been distinguished. In the Middle Miocene lacustrine deposits accumulated in the southern depression. In Early and Middle Pliocene, as well as in Early-Middle Pleistocene the bottom of the southern and middle Baikal depressions was occupied by large lakes, but the northern basin was mainly dry with a system of small lakes, streams and rivers. This accounts for the great facies variety and the genetic heterogeneity of sediments in the northern depression. At the end of Middle and in the Late Pleistocene an abrupt warping of the depression took place, and a shore-line similar to the present one was formed. Sands in the upper part of the sediments are considered to be the product of intensive erosion which probably occurred in the pluvial epoch in the Late Pleistocene period.
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    Hydrobiologia 103 (1983), S. 287-293 
    ISSN: 1573-5117
    Keywords: paleolimnology ; sedimentation ; sediment laminations ; diatom microstratigraphy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Laminated sediment is deposited in the deep areas (〉 30 m) of Lake Pääjärvi. In the diatom microstratigraphy a regular alteration of planktonic and littoral floras, which goes in pace with the visual structure, reflects the yearly cycle of sedimentation. Considerable variation in sedimentation was found to have occurred during the past two decades. A sequence, dated to the early 1960's, in which the organic content was exceptionally high, could be identified in the sediment at 6–14 cm depth even in shallower areas where laminations are not formed. This level was used as a marker horizon when determining the recent distribution of sediment by means of 19 cores taken from different parts of the lake. The average annual sediment accumulation in the profundal zone of the lake is 340 g m−2a−1 dry weight, of which 25 g m−2 a−1 (1100 kJ m−2 a−1) is organic carbon.
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    Hydrobiologia 103 (1983), S. 303-308 
    ISSN: 1573-5117
    Keywords: paleolimnology ; acid waste-water ; liming ; diatoms ; heavy metals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Sysmäjärvi is located inside the municipal boundary of Outokumpu in North Karelia, Finland. Since 1928 metalliferous, and at a later stage highly acid waste-water, has been discharged into the lake. Neutralization of the lake water by liming was introduced, and by the end of 1966 the pH of the water had become neutral to alkaline. Two sediment cores (0.5 m and 5 m long, respectively) were analyzed for pollen, diatoms, loss-on-ignition, organic carbon, Fe, Cu, Ni, Pb, Zn and Hg. The maximum concentrations of organic matter and heavy metal content occur 30 cm below the sediment surface. Evidence of the liming and of accelerated eutrophication appear close to the surface of the sediment (0–10 cm), indicated by an increase in Nitzschia plana.
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    Hydrobiologia 103 (1983), S. 295-301 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Flandrian biostratigraphy ; Tabellaria binalis
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    Topics: Biology
    Notes: Abstract The Early and Middle Flandrian geological development and paleolimnology of Lake Spitaalijärvi was studied using pollen, diatom and cladoceran analysis and 14C dating. Spitaalijärvi was isolated from the Ancylus Lake about 9000 B.P., at which time birch and pine and plants typical of open habitat communities grew on the solitary island. The rational limits for Alnus and Picea were ca. 8300 B.P. and 3700 B.P., respectively. During the first few hundred years after isolation Spitaalijärvi was probably fairly eutrophic, with a low water level. Water level began to rise before the Alnus rise (A°) and the lake became oligotrophic. After another transgression, which started before the Picea rise (P°), Tabellaria binalis and Semiorbis hemicyclus appear in the diatom stratigraphy indicating ultra-oligotrophic conditions. The main reason for the ultra-oligotrophy of Lake Spitaalijärvi is the character of the parent material in the catchment, consisting of glacial and littoral deposits derived from the local quartz sandstone of highly siliceous nature.
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    Hydrobiologia 103 (1983), S. 309-318 
    ISSN: 1573-5117
    Keywords: paleolimnology ; heavy metals ; polluted lake ; sedimentary chemistry
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    Topics: Biology
    Notes: Abstract Macro nutrients N, P, K, Ca, Mg, Na and S as well as heavy metals Pb, Cu, Zn, Co, Cr, Ni, Fe and Mn were analysed from a sediment core representing a 7000-year long history of a lake including the preceding brackish (Litorina Sea) and freshwater (Ancylus Lake) stages. Sediments were also analysed for sedimentary pigments, algal growth potential (AGP) of the interstitial water, phosphorus fractions, pH, specific conductivity and redox potential. The annual accumulation values of several chemical elements were interpreted in light of other paleolimnological data from the same core. In the uppermost sediment stratum the influence of sewage pollution is clearly reflected by increases in total electrolyte content, pH, AGP and sedimentary pigments including myxoxanthophyll. Nickel, copper and manganese only slightly increase in the recent sediment, whilst other heavy metals (especially Cr and Zn) and sulphur, phosphorus, nitrogen and total organic matter are heavily concentrasted in the polluted surface sediment. The interpretation of the chemostratigraphy of the lake accords with evidence of lake development based on biological analyses.
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    Hydrobiologia 103 (1983), S. 15-19 
    ISSN: 1573-5117
    Keywords: paleolimnology ; dating ; radioactive fallout ; sediment ; 137Cs ; 239,240Pu ; varves
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    Topics: Biology
    Notes: Abstract The distribution of 137Cs and 239,240Pu in sediment core samples of the Finnish lakes Laukunlampi, Lovojärvi and Pääjärvi were determined. The sediment samples were collected using dry ice and liquid nitrogen freezing methods. The sediments of these lakes are annually laminated. A clear maximum concentration of 137Cs and 239,240Pu was found in sediment layers formed during 1962–1964, the years of maximum fallout, and the middle of the 1950's can be estimated from the 137Cs and 239,240Pu profiles. The highest concentrations, 11 500 and 820 pCi kg−1 dry wt for 137Cs and 239,240Pu, respectively, were found in the sediment of Laukunlampi. The vertical distribution was similar for 137Cs and 239,240Pu in the lakes investigated. A slight migration of 239,240Pu and 137Cs was found and the migration of 137Cs seems to be higher than that of 239,240Pu. The advantages of 137Cs dating method are rapidity and simplicity. 239,240Pu is preferable when the sample size is small. The agreement found between 137Cs and 239,240Pu dates and the annual laminae show that these fallout radio isotopes can be used for dating sediments formed during the past 25 years.
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  • 54
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    Keywords: Chrysophycea ; cultural eutrophication ; paleolimnology ; resting cyst ; statospore ; stratigraphy
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    Topics: Biology
    Notes: Abstract The recent sediments of Frains Lake, Michigan contain a rich and well preserved association of chrysophycean cysts. Forty one forms are revealed by scanning electron microscopy (SEM) and light microscopy (LM). Taxonomic descriptions. and SEM micrographs are provided for the dominant forms. The three dominant taxa throughout the sediments, Cysta minima, C. modica and C. subbavaricum, do not show significant shifts in proportional abundance associated with European settlement and the onset of cultural eutrophication. However, certain subdominant taxa do show clear trends. Density counts indicate a dramatic decline in cyst concentration (by volume and by dry mass) and a sharp increase in absolute accumulation (net annual influx) following settlement. The Frains Lake profile of chrysophycean cysts is compared to sequences of other North American and European temperate lakes. The utility of chrysophycean cysts as paleoenvironmental indicators is considered on the basis of these results.
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    Hydrobiologia 103 (1983), S. 91-97 
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; assemblage indicators ; Finland
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    Topics: Biology
    Notes: Abstract Diatom assemblages from the topmost sediment of 49 lakes were ordinated by means of a program for detrended correspondence analysis and reciprocal averaging (Decorana). Five lake groups were separated, each having more or less characteristic diatom assemblages and water quality. Shifts from one group to another caused by factors such as acidification, artificial drainage, diffuse nutrient loading and sewage are discussed.
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    Hydrobiologia 103 (1983), S. 99-102 
    ISSN: 1573-5117
    Keywords: paleolimnology ; organic matter ; bacteria ; aerobic decomposition ; oxygen consumption
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    Notes: Abstract The investigations were carried out in lakes situated in the forest zone (Karelian Isthmus, Baltic zone, South Ural) and in the forest-steppe (South Ural) of the USSR. The lakes differ in their bioproductivity and in the intensity of their human influence. The amount of organic matter accumulating in the sediments is closely related to production and decomposition processes in the trophogenic layer. Processes of organic matter transformation were found to be most active in the uppermost sediment. The quantity of bacteria shows no correlation with the organic matter content of the sediment. Increase in organic matter, up to 70–80% of dry weight, is often accompanied by a decrease in bottom bacteria. The intensity of aerobic decomposition of the labile organic matter can be judged from the oxygen demand of the sediments. However, it is important to differentiate between chemical and biological oxidation processes. The quantity of bottom bacteria correlates closely with the value of oxygen consumption only in cases of high sediment redox potentials.
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    Keywords: paleolimnology ; sedimentary pigments ; primary production ; core analyses
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    Notes: Abstract A statistically significant correlation of the type y = axb between sedimentary plant pigments and contemporary algal primary production has been found in a study of the recent trophic evolution of twelve Italian lakes. The equation is used to assess baseline production levels in periods (50–70 years ago) when human influence was low.
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    Hydrobiologia 103 (1983), S. 107-111 
    ISSN: 1573-5117
    Keywords: paleolimnology ; lake ontogeny ; lake succession ; eutrophication
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    Topics: Biology
    Notes: Abstract Paleolimnologists frequently invoke the term ‘eutrophication’ for describing apparent enrichment phases in the history of a lake. I argue that this term is often used incorrectly and that alternative explanations can serve as more accurate descriptions. Increased organic content in the sedimentary record may result from increased nutrient availability (eutrophication), but it can also reflect decreased residence time of water, or changes in biotic interactions, or changes in lake morphometry. Additionally, I argue that ‘eutrophication’ is an inappropriate term for describing the aging process of lakes. Lake ontogeny is the preferred term, as it does not imply directional changes in nutrients, nor in community structure.
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    Hydrobiologia 103 (1983), S. 125-130 
    ISSN: 1573-5117
    Keywords: paleolimnology ; pollen ; diatoms ; Synuraceae ; Chrysophyta ; meromixis ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The recent history of Little Round Lake, a small meromictic lake in southeastern Ontario, is considered. Pollen analyses were used to identify past changes in terrestrial vegetation, whilst limnological conditions were interpreted on the basis of diatom and chrysophyte microfossils. Contemporaneous with the arrival of European settlers (ca. A. D. 1850), the predisturbance assemblage of oligotrophic Cyclotella diatoms was replaced by Synedra spp., which then succeeded to a eutrophic flora dominated by Stephanodiscus hantzschii. Meanwhile, synuracean algae were almost completely excluded. Over the last 30 years, the algal microfossils indicate that the lake underwent a marked return to oligotrophy. Evidence is presented which suggests that this shift was related to the cultural enhancement of meromixis by the seepage of road salt.
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  • 60
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    Keywords: paleolimnology ; acidic precipitation ; lake acidification ; heavy metal pollution ; diatoms ; cladocerans
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    Topics: Biology
    Notes: Abstract Sediment cores from nine lakes in southern Norway (N) and six in northern New England (NE) were dated by 137Cs, 210Pb and in NE also by pollen, and were analyzed geochemically and for diatoms. Cores from two N and three NE lakes were analyzed for cladocerans. 137Cs dating is unreliable in these lakes, probably due to mobility of Cs in the sediment. In Holmvatn sediment, an up-core increase in Fe, starting ca. 1900, correlates with geochemical indications of decreasing mechanical erosion of soils. Diatoms indicate a lake acidification starting in the 1920's. We propose that soil Fe was mobilized and runoff acidified by acidic precipitation and/or by soil acidification resulting from vegetational succession following reduced grazing. Even minor land use changes or disturbances in lake watersheds introduce ambiguity to the sedimentary evidence relating to atmospheric influences. Diatom counts from surface sediments in 36 N and 31 NE lakes were regressed against contemporary water pH to obtain coefficients for computing past pH from subsurface counts. Computed decreases of 0.3–0.8 pH units start between I890 and I930 in N lakes already acidic (pH 5.0–5.5) before the decrease. These and lesser decreases in other lakes start decades to over a century after the first sedimentary indications of atmospheric heavy metal pollution. It is proposed that the acidification of precipitation accompanied the metal pollution. The delays in lake acidification may be due to buffering by the lakes and watersheds. The magnitude of acidification and heavy metal loading of the lakes parallels air pollution gradients. Shift in cladoceran remains are contemporary with acidification, preceding elimination of fishes.
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    Hydrobiologia 103 (1983), S. 131-133 
    ISSN: 1573-5117
    Keywords: paleolimnology ; recent sediments ; diatoms ; chrysophytes ; 210lead
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    Topics: Biology
    Notes: Abstract Diatom and chrysophyte remains in recent sediments have been examined. The upper stratigraphy is dated by reference to phytoplankton records whilst the lower depends on dates from 210Pb analysis, which shows some unexplained variation. Recent changes, due to farming and domestic drainage, form part of the long term response of the lake to events upon the catchment.
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    Hydrobiologia 103 (1983), S. 135-139 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Traunsee ; artificial meromixis ; ostracods
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    Topics: Biology
    Notes: Abstract Traunsee is the deepest (189 m) lake in Austria and has been holomictic until the beginning of industrial discharges from the alkali works in Ebensee. The input of soluble compounds such as CaCl2 and NaCl have produced meromictic conditions. The relatively high oxygen content of the monimolimnion is due to water movements promoted by the large inflow and wind-action. The industrial discharges have caused both meromictic conditions and the deposition of highly alkaline sediment in the southern portion of the profundal zone. The effect of the discharges on the benthic fauna was evaluated by comparing the subfossil benthic fauna of four cores taken inside and outside the affected area. The ostracod fauna resembles that of other large lakes in the Salzkammergut, but also includes groundwater species such as Kovalevskiella and Cypridopsis subterranea. Leucocythere mirabilis has been found for the first time in an Austrian lake. Ostracods and other benthic organisms such as Testacea were not apparently influenced by the meromictic condition. They are, however, missing in all areas covered by the alkaline sludge.
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    Hydrobiologia 103 (1983), S. 169-175 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Chironomidae ; subfossil remains ; shallow lake ; eutrophication ; Lake Balaton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Balaton, the largest shallow lake in Central Europe, is about 20 000 years old. An enormous increase in tourism and the disproportionate building development of the last few decades has resulted in the acceleration of eutrophication in the lake. Widespread research to reveal the causes of water-quality deterioration and possible ways of protection against it have recently started. The investigation of the larvae of non-biting midges (Diptera: Chironomidae) in the sediment of the open-water zone has also begun. The contemporary faunal composition strongly correlates with the trophic gradient along the longitudinal axis of the lake. We therefore supposed that the eutrophication process should be identifiable from the analysis of subfossil chironomid head capsules from the upper (15 cm thick) layer of the sediment. We found that quantitative results could only be obtained when fragments as well as relatively intact head capsules are considered. Our data verify that the originally oligo-mesotrophic community has been gradually replaced by eutrophic species in a west to east direction. Large-bodied larvae belonging to the Chironomus plumosus group mix the sediment down to 15 cm as they build their tubes and consequently alter the original proportions of head capsules at the different levels. So the sequence of communities through the sediment-layers is not quite reliable.
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    Hydrobiologia 103 (1983), S. 181-184 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Clostridium perfringens ; sewage pollution ; eutrophication
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    Topics: Biology
    Notes: Abstract The horizontal and vertical distribution of the gram-positive, non-motile, spore-forming and rod-shaped bacterium Clostridium perfringens Holland was studied. The aim of the study was to estimate the quantity of C. perfringens at different depths of the sediment and evaluate the effect of human effluent which the lake received between 1940 and 1956. C. perfringens lives in the colon of man. Because it is spore forming and cannot multiply under a temperature of 20 °C and, according to the studies of Seppänen et al. (1979) it can be at least 300 years old, it may be a suitable paleolimnological indicator of pollution by human effluent. The results showed that the amounts of Clostridium increased at the same level where redox potential decreased in the sediment due to the beginning of effluent disposal at a depth of 40 mm. The maximum number of Clostridium colonies occurred between 0–30 mm depth.
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    Hydrobiologia 103 (1983), S. 193-198 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Lake Michigan ; geochemistry ; stratigraphy ; Quaternary ; trace elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The stresses placed on Lake Michigan since the advent of industrialization require knowledge of the sedimentology of the whole lake in order to make informed decisions for environmental planning. Sediment accumulation rates are low: areas of the lake receiving the most sediment average only 1 mm a−1; deep-water basins average 0.1 to 0.5 mm a−1; and large areas are not receiving any sediment. Sediment was deposited rapidly (typically 5 mm a−1), in the form of rock flour, during the deglaciation of both Lake Michigan and Lake Superior Basins. Then the rate of accumulation decreased by 80–90% and has remained relatively constant since final deglaciation. Because active sedimentation occurs mostly in the deep water areas of the lake, the sediment remains undisturbed and contains a record of the chemical history of the lake.
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  • 66
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    Keywords: paleolimnology ; annual laminations ; magnetism ; sediment influx ; sediment chemistry ; eutrophication
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    Topics: Biology
    Notes: Abstract The sediments of Loe Pool, a eutrophic coastal lake in south west England, consist largely of laminated clays and clay-gyttjas. Studies of the diatom microstratigraphy of frozen sediment cores from the Pool indicate that the laminations are annual, and that they contain pairs of light and dark bands formed by seasonal variations in the supply of sediment to the Pool from its catchment. Analysis of the magnetic properties of individual laminations demonstrates the presence of physical and mineralogical microstratigraphic variations, which may also be related to seasonality. A varve chronology, which is confirmed by 137Cs analysis and historical records, has been used to provide a timescale for the interpretation of data from other paleolimnological studies. A close agreement between variations in the abundance of sedimentary Sn, and the history of mining in the catchment, has been found. Similarly, analysis of total organic matter, total phosphorus, sedimentary chlorophyll a, sterols, diatoms and Cladocera in the uppermost sediments all indicate eutrophication of the Pool in the period AD 1940 to the present.
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    Hydrobiologia 103 (1983), S. 199-203 
    ISSN: 1573-5117
    Keywords: paleolimnology ; clay ; cultural disturbance ; erosion ; Guatemala ; Mayan archaeology ; silt ; particle-size analysis ; tropical lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Long-term changes of sedimentary particle-size distribution in two tropical lowland lakes were compared with changes of human population sizes, estimated archaeologically, in the drainage basins. Mean particle size of silt and clay fractions (〈64 µm) varied between 3 and 15 µm. High positive skewness and kurtosis of the distributions were associated with smaller particle sizes; hence small mean size resulted from greater influx of small particles while influx of larger particles was probably constant. An inverse correlation between mean particle size and human population size is interpreted to mean that disturbance-induced erosion results in delivery of very fine inorganic particles at higher rates. Within any one basin, particle-size stratigraphy is more precisely related to archaeological time periods than is pollen stratigraphy. An absolute chronology still eludes us, owing to the failure of 14C dating of calcareous, colluvial sediments, but our relative chronology is now more precise than before. If certain assumptions about past hydrologic relations can be met, particle-size analysis is a way of comparing the histories of geographically very different lakes, including lakes from tropical, temperate, and arctic regions.
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    Hydrobiologia 103 (1983), S. 217-224 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Greenland ; Holocene ; oligotrophication ; pollen analysis ; macrofossils ; arctic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During the Holocene most West Greenland lakes passed from an early eutrophic stage, rich in both flora and fauna, through a mesotrophic to an oligotrophic stage with very low productivity. Temperature conditions were limiting factors only in the very beginning, whereas chemical factors alone were decisive later on.
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    Hydrobiologia 103 (1983), S. 205-210 
    ISSN: 1573-5117
    Keywords: paleolimnology ; colluvium ; soil chemistry ; clay ; phosphorus loading ; tropical lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The long-term impact of Maya culture on a lowland tropical watershed is assessed, using data from a 9.2 m sediment core taken from deep water (28 m) in Lake Quexil. Human population growth, estimated by the 1980 archaeological survey, is associated with a shift in the composition of the sediment to a dominance by inorganic material, the Maya clay formation, beginning ca. 3500 B.P. Increasing settlement densities are correlated with accelerated influxes of phosphorus, carbonates, and siliceous sediment. However, chemical data do not track short-term population fluctuations closely. Because much of the sediment is delivered as colluvium, and not by running water, there is a lag between terrestrial disturbance and impact on the aquatic system. As an indication of this lag, contemporary high sedimentation rates are a residual of Maya activity that virtually ceased some 300–400 years B.P. Comparison of the deep-water core with a shallow-water (7 m) section, based on palynological correlation, reveals only minor differences in proximate chemical composition. Chemical influxes are much higher at the deep-water site, however, as a consequence of sediment focusing in this hyperconical basin. Chemical analyses of soil samples from 21 test pits in the Quexil basin support the principal conclusion that bulk soil movement was the mode of nutrient transfer to the lake, following forest clearance by the Maya.
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    Hydrobiologia 103 (1983), S. 211-216 
    ISSN: 1573-5117
    Keywords: paleolimnology ; Pleistocene aridity ; calcite ; dolomite ; gypsum ; laminated gyttja
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The transition from an arid, glacial Late Pleistocene to an early Holocene (Gamblian ‘pluvial’) moist period has not been documented in Central America. Finding accessible volcanic lakes too youthful, and knowing that most Florida and Yucatan lakes were dry during glacial ages, we sought appropriate deposits lying deeper than 40 m in the deeper karst lakes of the Peten, in northern Guatemala. The bottom half of a 19.7 m core from Lake Quexil, and the bottom third of a 15 m core from Lake Salpeten, appear to be of Pleistocene age. The sediments contain lacustrine shells, sponge spicules, and Pinus pollen, and include several bands of humified gyttja with fragments of wood, but are dominantly montmorillonitic and mixed-layer clays and may be in part colluvial, like the later Holocene Maya clay. Calcite, gypsum, and (in presently saline Lake Salpeten only) dolomite indicate shallow, closed, moderately saline lakes 30–40 m lower than at present. In both cores a layer of inorganic sediment with gypsum dominant, perhaps recording the most arid phase of the glacial Late Pleistocene, overlies a similar clay layer with calcite dominant. As calcite and dolomite occur throughout the section(s), both minerals are believed to be detrital, but one source of calcite is algal crusts, formed and exposed today in the littoral and supralittoral zones. The early Holocene rise of lake levels formed several meters of fossiliferous gyttja with pollen of mesic tropical forest, now assigned to the pan-tropical Gamblian moist episode. Where deposited in oligomictic or meromictic lakes 〉 30 m deep, Gamblian gyttja of pollen zone Pl is finely laminated, the dark layers being richer in Ptot and Stot and poorer in Fe, Mn, Mg, and K than the light (clay) layers, but we cannot yet say that the laminae are annual.
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    Hydrobiologia 103 (1983), S. 225-230 
    ISSN: 1573-5117
    Keywords: paleolimnology ; pollen analysis ; sediment accumulation rate ; vegetation history ; Holstein ; Postglacial
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pollen analysis was carried out on the sediments of 10 lakes in eastern Holstein. Sediment accumulation rates varied considerably both from lake to lake and also between respective periods. Increases in sediment accumulation rate often coincide with the Neolithic settlement periods. Faunal remains have been examined from two of these lakes (cf. Günther 1983; Hofmann 1983).
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    Hydrobiologia 103 (1983), S. 235-239 
    ISSN: 1573-5117
    Keywords: paleolimnology ; cladoceran analysis ; chironomid analysis ; successions ; lake development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the subfossil assemblages of chironomids and cladocerans significant changes were found during the late-glacial and postglacial development of a small, shallow North German lake. The successions observed were obviously not related to eutrophication but to factors such as climatic conditions and lake siltation. The absence of species of the subgenus Eubosmina during postglacial times as well as the predominance of Alonella species among the chydorids was due to the small dimensions of the water body.
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    Hydrobiologia 103 (1983), S. 231-234 
    ISSN: 1573-5117
    Keywords: paleolimnology ; lake development ; trophic status ; Chironomidae ; Cladocera ; Ostracoda
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Microfossil analysis was carried out on 90 samples of a sediment core from Grossensee. The diversity of subfossil Cladocera, Chironomidae, Chaoborus, and Ostracoda reflects at least five different stages of development. Three extended cycles correspond to different climatic periods in the first 10 000 years of the lake's history, while during the last 2 000 years, two shorter cycles can be identified which correlate with proofs or even historical events for human activity in the catchment area. During this time the profundal fauna changed from stenoxibiontic to euryoxibiontic species. In the planktonic fauna a succession of three Eubosmina types, B. longispina, B. coregoni kessleri, and B. coregoni coregoni, was observed. The chydorid and ostracod assembly of the littoral showed no clear change.
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    Hydrobiologia 103 (1983), S. 261-263 
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; eutrophication ; Ladoga
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Combined paleolimnological investigations of a 1.8 m sediment core from the deepest north-western part of Lake Ladoga show stratigraphic changes in granulometric and chemical composition, organic matter content, diatom species composition and chlorophyll ‘a’ concentration. The sediment accumulation rate was calculated and 5 stages of lake history over the last 4 000 years were described. Changes in lake environment were mainly caused by changes in climate and lake water balance. Human impact on the lake was also traced.
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    Hydrobiologia 103 (1983), S. 265-268 
    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; plankton ; eutrophication ; sediment accumulation rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Species composition, quantity and distribution of diatoms in both the plankton and the surface sediments (0–30 cm) of mesotrophic Lake Krasnoye and eutrophic Lake Vishnevskoye (Karelian Isthmus) were studied. In the mesotrophic lake the composition of dominant diatoms (mainly Melosira) corresponded to those in the plankton. The Araphidineae/Centrales (A/C) ratio was 0.2–0.3%, increasing in the upper layers to 7%. Alkaliphilous and alkalibiontic forms constituted 60% of the total. In the eutrophic lake diatoms with thin valves (mainly Synedra) predominated in the plankton but their quantity in the sediments was insignificant in comparison with other plankton. Nevertheless, the A/C ratio was much higher, 17–35%. Alkaliphilous and alkalibiontic forms accounted for 78–90% of the total number of valves. In both lakes the highest number of diatom valves was registered in the upper layer of the sediments. From the ratio of the total number of diatoms in the upper 5 cm layer to their annual flux to the sediment from the plankton the approximate sediment accumulation rate was calculated to be 1.9 mm a−1 for the mesotrophic lake and 2.5 mm a−1 for the eutrophic one.
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  • 76
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    Hydrobiologia 103 (1983), S. 275-279 
    ISSN: 1573-5117
    Keywords: paleolimnology ; freshwater diatoms ; Middle-Valdaj
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This paper presents results of diatom analyses of dated Upper-Pleistocene lacustrine deposits from the Shapkina river in the Bolshezemelskaja tundra of the USSR. Both diatom systematics and palaeoecology have been studied. A marine diatom assemblage was found in the lower part of the sedimentary sequence and a rich freshwater assemblage, including more than 200 taxa, was found in the upper part. Some of the characteristic diatoms are typical of standing or slowly-moving waters of more southern and western districts but are not found in the Bolshezemelskaja tundra lakes today. According to 14C dating, the age of the deposit is about 40 000 years, and represents the Middle-Valdaj (Middle-Weichselian). Palynological and diatom analysis suggest that the climate was similar to the present, that of an interglacial.
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  • 77
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    Hydrobiologia 103 (1983), S. 269-273 
    ISSN: 1573-5117
    Keywords: paleolimnology ; palynology ; pollen diagram ; Holocene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the last decade palynological investigations of the sediments of large lakes in the USSR (Ladoga, Onega, Kubenskoye, Vozhe, Lacha, Beloye) and the Baltic Sea have been carried out. Limnic and marine sediments are notable for their high pollen and spore concentrations and pollen diagrams from these deposits have a regional significance. The diagrams from Lakes Onega and Ladoga belong to the Kola-Karelian type while the sediments of Lacha, Vozhe, Kubenskoye and Beloye belong to the North-Russian type (Neustadt 1957). Three types of Holocene pollen diagrams are registered for the Baltic Sea. Modern and fossil pollen spectra reflect the composition of the zonal vegetation. Late-glacial sediments are found in several profiles of lake and sea deposits. Holocene deposits are divided into eight stratigraphic zones: Late-glacial sediments (DR2-Al-DR3) and Post-glacial sediments (PB, BO, AT, SB, SA). The zonations of lake and sea sediments can be clearly correlated.
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  • 78
    ISSN: 1573-5117
    Keywords: paleolimnology ; pollen analysis ; land drainage ; sediment accumulation ; 210Pb dating ; 14C reservoir effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Previous measurements of the 14C activity of lake sediments and Potamogeton plants from Säynäjälampi, collected in 1970, indicated a severe hard-water effect (Donner et al. 1971). Samples from new cores, collected in 1977, were sliced into thin sections down to 18 cm. The 14C concentration in samples down to 7 cm was similar to that obtained by the Helsinki Laboratory. The corresponding apparent 14C age is almost 2 000 years. Light-coloured layers, apparently due to catchment drainage, were used together with density diagrams to correlate the cores. The drainage history gives a time-scale showing that the lowest samples dated to correlate the cores. The drainage history gives a time-scale showing that the lowest samples dated were just old enough to be pre-bomb sediments. Three samples of submerged plants were also examined, indicating some exchange with the air and an appreciable reservoir age. The activity of the plants was significantly lower in 1978 than in 1970. One sample, well below the lowest drainage stratum, indicates a reservoir age of ca. 1 100 years. This sample yielded an apparent age of the INS fraction which was significantly different from that of the SOL fraction. The difference was determined to ca. 600 years. Total 210Pb was determined via 210Po using isotope dilution while 226Ra was measured with the help of radon emanation. The 226Ra was used to estimate the supported 210Pb. The unsupported 210Pb showed a higher sediment accumulation rate for the top nine cm of one core (the length investigated was 16.5 cm). The varying accumulation rate was explained by human activities, as could be seen from the heterogenous sediment composition of the cores. Recent vegetational change is described from direct observations since 1957. Pollen analysis does not give any reliable indication of agriculture.
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  • 79
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    Hydrobiologia 103 (1983), S. 29-35 
    ISSN: 1573-5117
    Keywords: paleolimnology ; 210Pb ; sediment accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The last few years have seen a dramatic growth in the use of 210Pb sediment dating. Despite this, considerable doubt still surrounds the nature of the processes by which 210Pb is deposited in lake sediments, and this has lead to a situation where there is a choice of dating models offering different interpretations of 210Pb data. In assessing 210Pb data it is therefore essential to first of all determine whether data is consistent with the assumptions of the dating model, and to then compare the 210Pb chronology with independent dating evidence. We have tested 210Pb data from a wide variety of sites, and our calculations indicate that the crs (constant rate of 210Pb supply) model provides a reasonably accurate chronology when the total 210Pb contents of cores from neighbouring locations are comparable.
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  • 80
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    Hydrobiologia 106 (1983), S. 43-57 
    ISSN: 1573-5117
    Keywords: eutrophication ; paleolimnology ; diatoms ; sediment chemistry ; peatland management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stratigraphy of diatoms and chemistry in the surface sediment deposited at 35 m depth in Lake Polvijärvi was studied. The existence of annual laminations or varves in the sediment allowed a precise dating of the profile. Diatoms were analysed in 0.5 cm sequences; from 0 to 16.0 cm continuously and then intermittently every fourth 0.5 cm down to 44.0 cm. Sediment chemistry (loss-on-ignition, C, N, Fe, Mn, Mg, P, chlorophyll and carotenoids) was analysed from sediment surface down to 10.5 cm of altogether 33 subsamples, each containing 1–3 varves, and spanning the period 1921–1980. From 4.5 cm depth upwards the diatom concentration strongly increases, and the plankton diatom succession from Tabellaria flocculosa through Asterionella formosa to Melosira ambigua and Fragilaria crotonensis reflects a marked eutrophication of the lake. This algal succession occurs in pace with an increase in sediment accumulation rate and changes in sediment chemistry, which indicate increased allochthonous inputs and enhanced algal production in the lake. The change of the lake ecosystem is contemporaneous with extensive peatland draining and fertilizing that was carried out on its watershed during the past two decades. Existing chemical data from a number of lakes situated within the drainage area prove that at present the treated peatlands are the main source of nutrient loading of Lake Polvijärvi. A former period with indications of slightly increased productivity of the lake was dated by varve counting to AD 1690–1910 (35–12 cm). This period (characterised by Asterionella formosa) may coincide with that of the slash-and-burn cultivation in the area.
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