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  • Articles  (75)
  • Nitrification  (49)
  • sediments  (26)
  • Springer  (75)
  • 1990-1994  (46)
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  • Springer  (75)
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  • 1
    Electronic Resource
    Electronic Resource
    Effect of bamboo harvest on dynamics of nutrient pools, N mineralization, and microbial biomass in soil (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 137-142 
    Details
    ISSN: 1432-0789
    Keywords: Microbial biomass ; Bamboo savanna ; N mineralization ; Nutrient pools ; Temporal variations ; Nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of harvesting bamboo savanna on the dynamics of soil nutrient pools, N mineralization, and microbial biomass was examined. In the unharvested bamboo site NO inf3 sup- -N in soil ranged from 0.37 to 3.11 mg kg-1 soil and in the harvested site from 0.43 to 3.67 mg kg-1. NaHCO3-extractable inorganic P ranged from 0.55 to 3.58 mg kg-1 in the unharvested site and from 1.01 to 4.22 mg kg-1 in the harvested site. Over two annual cycles, the N mineralization range in the unharvested and harvested sites was 0–19.28 and 0–24.0 mg kg-1 soil month-1, respectively. The microbial C, N, and P ranges were 278–587, 28–64, and 12–26 mg kg-1 soil, respectively, with the harvested site exhibiting higher values. Bamboo harvesting depleted soil organic C by 13% and total N by 20%. Harvesting increased N mineralization, resulting in 10 kg ha-1 additional mineral N in the first 1st year and 5 kg ha-1 in the 2nd year following the harvest. Microbial biomass C, N and P increased respectively by 10, 18, and 5% as a result of bamboo harvesting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336460
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  • 2
    Electronic Resource
    Electronic Resource
    Palaeolimnological studies of the eutrophication of volcanic Lake Albano (Central Italy) (1994)
    Springer
    Journal of paleolimnology 10 (1994), S. 181-197 
    Details
    ISSN: 1573-0417
    Keywords: palaeolimnology ; eutrophication ; core analysis ; sediments ; algal pigment ; bacterial pigments ; chironomids ; volcanic lake ; Italy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract We use palaeolimnological techniques to reconstruct the eutrophication history of a volcanic lake (Lake Albano, central Italy) over the past three centuries. The presence of annual varves down to the bottom of the core (c. 1700 A.D.) indicated the lack of bioturbation and likely long-term meromixis. Sedimentation rates were estimated by varve counts (calcite/diatom couplets), indicating a mean rate of 0.15 cm yr−1. The reconstruction of eutrophication was traced using past populations of algal and photosynthetic bacteria (through their fossil pigment), and geochemistry, as well as fossil remains of chironomids. Phaeophorbidea and the red carotenoid astaxanthin were used to detect past zooplankton development. The first sign of trophic change related to human activities is datedc. 1870 A.D. From that period onward a sharp increase of authigenic CaCO3, nitrogen, N:P ratio, and dinoxanthin, a characteristic carotenoid of Chrysophyceae and Dinophyceae, is observed. Chironomid analyses showed the near absence of a deep water fauna throughout the core length. The populations of chironomid larvae are restricted to oxygenated littoral zones. In fact, the few fossil remains found are primarily of littoral origin, representing shallow water midges that were transported to profundal waters. The reduction of total chironomid in the uppermost layers of the core is to be related to human land uses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00684032
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  • 3
    Electronic Resource
    Electronic Resource
    A Holocene paleoenvironmental history of Lake Alexandria, South Australia (1994)
    Springer
    Journal of paleolimnology 12 (1994), S. 259-268 
    Details
    ISSN: 1573-0417
    Keywords: sediments ; 14C ; 210Pb ; diatoms ; geochemical analyses ; coastal paleoenvironments ; paleolimnology ; Nodularia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract An investigation of Holocene sediments within Lake Alexandrina, a shallow coastal lake at the mouth of the Murray River, South Australia, is presented based on a multidisciplinary approach.14C and210Pb radiometric dating methods are used to establish a geochronological framework for the last 7000 yr BP, and diatoms, sand-siltclay ratios, organic carbon, phosphorus and copper concentrations are used to infer paleoenvironmental changes. The diatom assemblages indicate a change from marine-brackish to oligosaline-freshwater conditions between 7000 and 6000 yr BP, with sea-level stabilisation and continuous barrier formation across the Murray mouth. Sand pulses after 2300 yr BP document sand spit formation in the lake and the commencement of extensive lacustrine sedimentation. In the past 100 years which include the advent of European settlement in the region, the short-term210Pb-based mass accumulation rate of 0.063 g cm−2 yr−1 is greater than that of the longer-term mean14C-based rate (0.023 g cm−2 yr−1), and high concentrations of phosphorus and copper correspond to historical records of blue-green algal blooms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00678024
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  • 4
    Electronic Resource
    Electronic Resource
    A note on further refinements to a procedure for the extraction of carbonaceous fly-ash particles from sediments (1994)
    Springer
    Journal of paleolimnology 11 (1994), S. 201-204 
    Details
    ISSN: 1573-0417
    Keywords: atmospheric pollutants ; sediments ; fossil-fuels ; carbonaceous particulates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract This paper describes improvements to a previously published technique for the extraction of carbonaceous fly-ash particles from sediments. By using test-tubes in a water-bath rather than beakers on a hot-plate, the number of simultaneous preparations that can be done is increased and the length of time spent on the preparations and the amounts of hazardous chemicals used is reduced. As the digestion vessel remains the same throughout the procedure, potential loss of particles due to transfer of material between vessels is also minimised, whilst keeping sensitivity, accuracy and detection limit the same.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686866
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  • 5
    Electronic Resource
    Electronic Resource
    Effect of Baythroid on nitrogen transformations in soil (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 173-176 
    Details
    ISSN: 1432-0789
    Keywords: Ammonification ; Cyfluthrin ; Nitrification ; Nitrogen ; N mineralization ; N transformations ; Pesticides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Laboratory incubation experiments were conducted in soil to study the influence of the insecticide Baythroid on immobilization-remineralization of added inorganic N, mineralization of organic N, and nitrification of added NH inf4 su+ -N. Baythroid was applied at 0, 0.4, 0.8, 1.6, 3.2, and 6.4 μg g-1 soil (active ingredient basis). The treated soils were incubated at 30°C for different time intervals depending upon the experiment. The immobilization and mineralization of N were significantly increased in the presence of Baythroid, the effect being greater with higher doses of the insecticide. Conversely, nitrification was retarded at lower doses of Baythroid and significantly inhibited at higher doses. The results of these studies suggest that excessive amonts of insecticide residues affect different microbial populations differently, leading to changes in nutrient cycling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336318
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of preemergence and postemergence herbicides on urea hydrolysis and nitrification of urea nitrogen in soil (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 309-313 
    Details
    ISSN: 1432-0789
    Keywords: Herbicides ; Urea hydrolysis ; Nitrification ; Ammonia toxicity ; Nitrification inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The influence of 5 and 50 mg active ingredient kg-1 soil of nine preemergence and nine postemergence herbicides on transformations of urea N in soil was studied in samples of two coarse-textured and two fine-textured soils incubated aerobically at 20°C. The effects of each herbicide on soil urea transformations was measured by determining the amounts of urea hydrolyzed and the amounts of NO inf3 sup- and NO inf2 sup- produced at various times after treatment with urea. Applied at the rate of 5 mg active ingredient kg-1 soil, none of the herbicides retarded urea hydrolysis in the four soils used, but four of the postemergence herbicides (acifluorfen, diclofop methyl, fenoxaprop ethyl) retarded urea hydrolysis in the two coarse-textured soils. All the herbicides tested except siduron retarded nitrification in the two coarse-textured soils when applied at 50 mg of urea N active ingredient kg-1 soil, and fenoxaprop ethyl and tridiphane markedly retarded nitrification of urea N in all four of the soils when applied at this rate. One-way analysis of variance and correlation analyses indicated that the inhibitory effects of the 18 herbicides tested on nitrification of urea N in soil increased with a decrease in the organic-matter content and an increase in the sand content of the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00383987
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  • 7
    Electronic Resource
    Electronic Resource
    Increase in nitrous oxide production in soil induced by ammonium and organic carbon (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 1-6 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium ; Denitrification ; Nitrification ; Nitrous oxide ; Organic carbon ; Acetylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We observed that soil cores collected in the field containing relatively high NH inf4 sup+ and C substrate levels produced relatively large quantities of N2O. A series of laboratory experiments confirmed that the addition of NH inf4 sup+ and glucose to soil increase N2O production under aerobic conditions. Denitrifying enzyme activity was also increased by the addition of NH inf4 sup+ and glucose. Furthermore, NH inf4 sup+ and glocose additions increased the production of N2O in the presence of C2H2. Therefore, we concluded that denitrification was the most likely source of N2O production. Denitrification was not, however, directly affected by NH inf4 sup+ in anaerobic soil slurries, although the use of C substrate increased. In the presence of a high substrate C concentration, N2O production by denitrifiers may be affected by NO inf3 sup- supplied from NH inf4 sup+ through nitrification. Alternatively, N2O may be produced during mixotrophic and heterotrophic growth of nitrifiers. The results indicated that the NH inf4 sup+ concentration, in addition to NO inf3 sup- , C substrate, and O2 concentrations, is important for predicting N2O production and denitrification under field conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336436
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  • 8
    Electronic Resource
    Electronic Resource
    Wood-ash fertilization and fire treatments in a Scots pine forest stand: Effects on the organic layer, microbial biomass, and microbial activity (1994)
    Springer
    Biology and fertility of soils 17 (1994), S. 57-63 
    Details
    ISSN: 1432-0789
    Keywords: Coniferous humus ; Ergosterol ; Soil respiration ; Substrate induced respiration ; Metabolic quotient ; Nitrification ; Pinus sylvestris
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We studied the reactions of humus layer (F/H) microbial respiratory activity, microbial biomass C, and the fungal biomass, measured as the soil ergosterol content, to the application of three levels of wood ash (1000, 2500, and 5000 kg ha-1) and to fire treatment in a Scots pine (Pinus sylvestris L.) stand. Physicochemical measurements (pH, organic matter content, extractable and total C content, NH 4 + and total N content, cation-exchange capacity, base saturation) showed similarity between the fire-treated plots and those treated with the lowest dose of wood ash (1000 kg ha-1). The ash application did not change the level of microbial biomass C or fungal ergosterol when compared to the control, being around 7500 and 350 μg g-1 organic matter for the biomass C and ergosterol, respectively. The fire treatment lowered the values of both biomass measurements to about half that of the control values. The fire treatment caused a sevenfold fall in the respiration rate of fieldmoist soil to 1.8 μl h-1 g-1 organic matter compared to the values of the control or ash treatments. However, in the same soils adjusted to a water-holding capacity of 60%, the differences between the fire treatment and the control were diminished, and the ash-fertilized plots were characterized by a higher respiration rate compared to the control plots. The glucose-induced respiration reacted in the same way as the water-adjusted soil respiration. The metabolic quotient, qCO2, gradually increased from the control level with increasing applications of ash, reaching a maximum in the fire treatment. Nitrification was not observed in the treatment plots.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00418673
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of long-term field exposure of soil to acetylene on nitrification, denitrification, and acetylene consumption (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 42-48 
    Details
    ISSN: 1432-0789
    Keywords: N2O ; Coated Calcium Carbide ; Acetylene ; Nitrification ; Denitrification ; Soil respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Coated CaC2 is a newly developed product which can supply nitrification-inhibiting quantities of C2H2 (1–10 Pa) to the soil, throughout a cropping season. This method of applying C2H2 to the soil maintains C2H2 in the soil continuously for several months. It is not know whether these low C2H2 concentrations alter soil microbial processes. A field study was initiated to determine the effect of supplying C2H2 to a clay soil, using coated CaC2, on soil respiration, denitrification, nitrification, and C2H2 consumption. The C2H2 consumption rate increased with length of soil exposure to C2H2 (r 2=0.59). The rates of CO2 production (r 2=0.88) and denitrification (r 2=0.86) were both highly correlated with the C2H2 consumption rates. The nitrifier potential decreased to a minimum of 21% of the control after 3 months of C2H2 treatment. After this time, nitrifier activity increased to 41% of the control after 11 months of treatment. This increase was due to increased C2H2 consumption in the soil. After 3 months of continuous application of C2H2 to the soil, the C2H2 concentrations were generally below that necessary to inhibit nitrification. No adaptation to the C2H2 by nitrifiers was found. Repeating these measurements 1 year later showed that soils previously exposed to C2H2 retained their enhanced C2H2 oxidation capacity and the capacity to use C2H2 to increase denitrification. Nitrification potentials remained about 50% lower in soils exposed to C2H2 a year earlier compared to soils not previously exposed to C2H2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00336443
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  • 10
    Electronic Resource
    Electronic Resource
    Notes on growth faults and sedimentary bed motions (1994)
    Springer
    Mathematical geology 26 (1994), S. 677-715 
    Details
    ISSN: 1573-8868
    Keywords: sediments ; faults ; mapping ; paleo-evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Mathematics
    Notes: Abstract The behavior of sediments in response to faults, and the corresponding influence of the sediments on the faults, are problems that control or modify substantially the evolution of sedimentary structures, fluid migration pathways, and the later deposition of post-fault sedimentary units. The self-consistent evolution of faults and sedimentary beds, including both footwall and hanging-wall motion of the beds, is investigated here using a novel inverse procedure which is guaranteed to honor present-day data on fault and bed positions. Paleo-evolution of both the faults and sediments is handled through constraint criteria such as conserved sediment area, bed-length, desired depositional and/or boundary conditions, or prescribed throw of sediments along a fault curve with time, etc. A procedure is given for using the constraint criteria either individually or collectively, with or without relative weighting conditions. In addition, for the cases of observed multiple faults, which either overlap laterally in a section or which are separated with no lateral overlap, a mapping procedure is given for transforming all such faults to a much simpler coordinate frame in which all the faults are (a) vertical, (b) of constant length, (c) do not overlap. The mapping procedure is shown to be universally valid for all times, so that the faults stay fixed and the sedimentary beds move through the new coordinate frame with time. Growth and arcuate faults are accommodated by the mapping procedure, as are flower and inverted flower arrangements of faults. The constraint criteria controlling paleo-evolution are also shown to be mappable to the new coordinate frame, so that desired paleo-evolutionary constraints can be easily accommodated through time-dependence of the mapping functions. The general mapping procedure, and the inverse method given for obtaining those parameters which describe paleo-evolution of faults and sediments in a self-consistent manner, are of use in addressing a wide variety of evolving fault/sediment interactions with a guarantee that the control criteria imposed will automatically honor present-day observations of both the faults and the sedimentary beds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02086867
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  • 11
    Electronic Resource
    Electronic Resource
    Resin diterpenoids as tracers for biomass combustion aerosols (1994)
    Springer
    Journal of atmospheric chemistry 18 (1994), S. 1-15 
    Details
    ISSN: 1573-0662
    Keywords: Diterpenoids ; resin components ; biomass burning ; thermal alteration ; atmospheric particles ; transport ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Diterpenoids present in atmospheric particles produced by slash burns were analyzed by capillary gas chromatography-mass spectrometry. This suite of compounds, originating in the resinous higher plants which were combusted, was comprised of reaction intermediates in the thermal transformation sequence of components such as abietic acid and dehydroabietin to retene. This sequence parallels the diagenetic alteration/decomposition processes noted in sedimentary records. Since global transport of combustion aerosols has been well documented, it is likely that the thermally-altered diterpenoids elucidated in this study can be deposited directly to sedimentary sinks.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00694371
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  • 12
    Electronic Resource
    Electronic Resource
    Ammonium sorption to channel and riparian sediments: A transient storage pool for dissolved inorganic nitrogen (1994)
    Springer
    Biogeochemistry 26 (1994), S. 67-83 
    Details
    ISSN: 1573-515X
    Keywords: ammonium ; riparian ; sediments ; sorption ; storage ; streams
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Sediment (0.5 mm–2.0 mm grain size) was incubated in nylon bags (200 μm mesh) below the water table in the channel and in two transects of shallow wells perpendicular to the banks (to 18 m) of a third-order stream during August, 1987. One transect of wells drained steep old-growth forest, and the other a steep 23 year-old clear-cut partially regenerated in alder. At approximately 6-week intervals between October, 1987, and June, 1988, bags were retrieved. Total exchangeable ammonium was determined on sediment, and dissolved oxygen, nitrate and ammonium were determined in stream and well water. Exchangeable ammonium ranged from 10 μeq/100 g of sediment in the stream where nitrification potential and subsurface exchange with stream water were high, to 115 μeq/100 g sediment 18 m inland where channel water-groundwater mixing and nitrification potential were both low. Sorbed ammonium was highest during summer/autumn base flow and lowest during winter storm flow. Both channel and well water contained measurable dissolved oxygen at all times. Ammonium concentration was typically 〈 10 μg-N/L in channel water, increased with distance inland, but did not exceed 365 μg-N/L at any site. Nitrate concentration was typically higher in well water than channel water. Nitrate levels increased dramatically in wells at the base of the clear-cut following the onset of autumn rains. The results indicate a potential for temporary storage of ammonium on riparian sediments which may influence biotic nitrogen cycling, and alter the timing and form of dissolved inorganic nitrogen transport from the watershed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02182880
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  • 13
    Electronic Resource
    Electronic Resource
    Historical loading record of sulfur in an Adirondack Lake (1993)
    Springer
    Journal of paleolimnology 9 (1993), S. 243-256 
    Details
    ISSN: 1573-0417
    Keywords: sulfur ; sediments ; mathematical model ; paleolimnology ; non steady-state diagenesis ; Adirondack
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A model for the distribution of sulfur in the sediments of a lake in the Adirondack Mountains, New York, is developed to gain insight into the timing and magnitude of anthropogenic increases in sulfur loading. Surficial sulfur concentrations are about 3500 µg g−1, increase to 6000–7000 µg g−1 at a depth of about 6 cm, and then decrease downcore to background levels of about 2500 µg g−1. Sulfate concentrations are about 60–80 µM in the overlying water and decrease rapidly below the sediment-water interface. This reflects assimilatory reduction and/or dissimilatory reduction of sulfate and incorporation into the inorganic and/or organic solid-phase fractions of the sediment. A mathematical model is constructed assuming sulfur is incorporated into sediments by burial of detrital organic matter and by diffusion of sulfate from the overlying water with subsequent fixation in the sediment. Several historical scenarios of atmospheric sulfate loading rates were examined as model boundary conditions. Model results are compared with observed sedimentary sulfur profiles. The observed sediment sulfur profiles are best described using model boundary conditions showing increases in lake water sulfate concentrations since about 1940. Assuming as much as a decade of retention of sulfate within the terrestrial portion of the ecosystem, this suggests that significant increases in sulfate deposition rates began sometime after 1930 in this relatively remote area.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00677216
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  • 14
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    Paleohydrology and paleoclimate records in a saline prairie lake core: mineral, isotope and organic indicators (1993)
    Springer
    Journal of paleolimnology 8 (1993), S. 135-147 
    Details
    ISSN: 1573-0417
    Keywords: sediments ; paleohumidity ; paleosalinity ; aragonite ; lake level ; pigments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract This pilot study examines the potential of obtaining a sedimentary record of paleoenvironmental/climatic/hydrologic conditions for saline Redberry Lake in southern Saskatchewan, Canada. The tools are mineralogy, stable isotopes and pigments. The upper meter of an offshore sediment core contains 10 to 20% by weight aragonite (CaCO3), which apparently precipitated in the water column. The δ18O and δ13C of the bulk aragonite (corrected for content of detrital calcite) vary by 4 to 5‰. Enrichment in 18O in aragonite is significantly correlated with pigment concentrations (chlorophyll a, phaeophytin). The δ18O and pigment data provide evidence for relatively dry and/or warm conditions and high limnetic productivity for the period 2500 to 1500 yrs B.P. After 1500 B.P., the climate was apparently similar to the present, with two episodes of relatively enhanced productivity, dryness and/or warmth, at around 1000 to 900 and 500 to 200 B.P. During the past century, Redberry Lake has decreased approximately 8 m in depth and its salinity has doubled. No clear sedimentary signal was observed in response to these recent hydrologic trends. These changes have not been associated with a significant climate trend in the region, but may have been induced by land use changes in the catchment.
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    URL: http://dx.doi.org/10.1007/BF00119786
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  • 15
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    Temperature dependence of nitrification, denitrification, and turnover of nitric oxide in different soils (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 21-27 
    Details
    ISSN: 1432-0789
    Keywords: NO production ; NO consumption ; Chemodenitrification ; Nitrification ; Denitrification ; Activation energy ; Temperature optimum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The temperature dependence of the NO production rate and the NO consumption rate constant was measured in an Egyptian soil, a soil from the Bavarian Forest, and a soil from the Donau valley, together with the temperature dependence of the potential rates of ammonium oxidation, nitrite oxidation, and denitrification, and the temperature dependence of the growth of NH inf4 sup+ -oxidizing, NO inf2 sup- -oxidizing, and NO inf3 sup- -reducing bacteria in most probable number assays. In the acidic Bavarian Forest soil, NO production was only stimulated by the addition of NO inf3 sup- but not NH inf4 sup+ . However, NO production showed no temperature optimum, indicating that it was due to chemical processes. Most probable numbers and potential activities of nitrifiers were very low. NO consumption, in contrast, showed a temperature optimum at 25°C, demonstrating that consumption and production of NO were regulated individually by the soil temperature. In the neutral, subtropical Egyptian soil, NO production was stimulated only by the addition of NH inf4 sup+ but not NO inf3 sup- . All activities and most probable numbers showed a temperature optimum at 25° or 30°C and exhibited apparent activation energies between 61 and 202 kJ mol-1. However, a few nitrifiers and denitrifiers were also able to grow at 8° or 50°C. Similar temperature characteristics were observed in the Donau valley soil, although it originated from a temperate region. In this soil NO production was stimulated by the addition of NH inf4 sup+ or of NO inf3 sup- . Both NO production and consumption were stimulated by drying and rewetting.
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    URL: http://dx.doi.org/10.1007/BF00336283
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  • 16
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    Seasonal nitrification measurements with different species of forest litter applied to granite-sand-filled lysimeters in the field (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 28-34 
    Details
    ISSN: 1432-0789
    Keywords: Plant forest litters ; Biodegradation ; Nitrification ; Nitrogen mineralization ; Litter decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The biodegradation of litter from Festuca silvatica, Abies pectinata, Fagus silvatica, Calluna vulgaris, Picea abies associated with forest brown acid soils or with podzolic soils was studied in field lysimeters filled with granite sand. Analysis of the leachates collected during 2 years made it possible to determine NO inf3 sup- , NH inf4 sup+ , and soluble organic N production in order to investigate the specific influence of the different species of litter on the mineralization of organic N and the variations in nitrification. With Festuca silvatica (grass), active nitrification was observed after the addition of fresh litter in autumn (fall of leaves). Nitrification remained significant in winter, reached a maximum in spring until early summer, and then decreased after mineralization of the easily mineralizable organic N. Nitrification was the major N transformation process in this litter. The addition of fresh litter of Abies pectinata (fir), Fagus silvatica (beech), Calluna vulgaris (heather), and Picea abies (spruce) in autumn induced an inhibition of nitrification during winter and spring. With these litter species, nitrification started again by the end of spring and was at a maximum in summer and autumn until leaf fall. By comparison with Festuca, inhibition observed in winter and spring with the other litter species was definitely due to the chemical composition of the leaves. Simultaneously, a lower C mineralization of these plant material occured. These litter species, in particular Calluna and Picea released leachates containing significant amounts of soluble organic N that were only slightly decomposed. We conclude that NO inf3 sup- production outside of the plant growth period can definitely be involved in soil acidification and weathering processes.
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    URL: http://dx.doi.org/10.1007/BF00336284
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  • 17
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    Nitrification and nitrifying potential of tropical and subtropical soils (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 87-90 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; Tropical soil ; Subtropical soil ; Nitrifying population
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nitrification was measured in five different soils (slate alluvial soil, sandstone shale alluvial soil, sandstone shale and slate alluvial soil, red soil, and Taiwan clay). In these soils different lag periods were recorded before the onset of nitrification. Nitrifying activity was highest in sandstone shale alluvial soil and the lowest in acidic red soil. A part from those in the red soil, the numbers of nitrifying bacteria detected were all higher than numbers reported in temperate soils. However, there were no clear relationships between the numbers of nitrifying bacteria and the rate of nitrification in these soils. When soil cores were incubated for 3 weeks, no NO inf2 sup- or NO inf3 sup- was defected in the slate alluvial soil. This was ascribed to denitrification.
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    URL: http://dx.doi.org/10.1007/BF00336423
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    In situ net N transformations in pine, fir, and oak stands of different ages on acid sandy soil, 3 years after liming (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 120-126 
    Details
    ISSN: 1432-0789
    Keywords: Lime ; Forest soil ; Nitrification ; N mineralization ; Nitrate leaching ; Pinus sylvestris ; Pseudotsuga menziesii ; Quercus robur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of liming on in-situ N transformations was studied in two stands of different ages of each of Scots pine (Pinus sylvestris L.), Douglas fir [Pseudotsuga menziesii (Mirb.) Franco], and common oak (Quercus robur L.). The stands were located on acid sandy soils in an area with high atmospheric N input. The organic matter of the upper 10-cm layer of the soil, including the forest floor, had a relatively high N content (C: N ratio 〈25) in all stands. Using a sequential core technique, N transformations were measured in both control plots and plots that had been limed 3 years previously with 3 t ha-1 of dolomitic lime. Limed plots had a higher net NO inf3 sup- production and a higher potential for NO inf3 sup- leaching than the controls in all stands except that of the younger oak. Net N mineralization did not differ significantly between limed and control plots in oak stands and younger coniferous stands but was significantly lower in the limed plots of the older coniferous stands. It is concluded that long-term measurements of net N mineralization in limed forest soils are needed to evaluate the effect of liming with respect to the risk of groundwater pollution.
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    URL: http://dx.doi.org/10.1007/BF00336429
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    Mineralization of nitrogen in fertilizer-acidified lime-amended soils (1993)
    Springer
    Biology and fertility of soils 15 (1993), S. 249-252 
    Details
    ISSN: 1432-0789
    Keywords: N fertilizer requirement ; Nitrification ; Zea mays ; N mineralization ; Lime ; Soil pH ; Nitrate-N
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The application of NH inf4 su+ -based fertilizers to soils slowly lowers soil pH, which in turn decreases nitrification rates. Under these conditions nitrification and N mineralization may be reduced. We therefore investigated the impact of liming fertilizer-acidified soils on nitrification and N mineralization. Soil samples were collected in the spring of 1987 from a field experiment, initiated in 1980, investigating N, tillage, and residue management under continuous corn (Zea mays L.). The pH values (CaCl2) in the surface soil originally ranged from 6.0 to 6.5. After 6 years the N fertilizer and tillage treatments had reduced the soil pH to values that ranged between 3.7 and 6.2. Incubation treatments included two liming rates (unlimed or SMP-determined lime requirement), two 15N-labeled fertilizer rates (0 or 20 g N m-2), and three replicates. Field-moist soil was mixed with lime and packed by original depth into columns. Labeled-15N ammonium sulfate in solution was surface-applied and columns were leached with 1.5 pore volumes of deionized water every 7 days over a 70-day period. Nitrification occurred in all pH treatments, suggesting that a ferilizer-acidified soil must contain a low-pH tolerant nitrifier population. Liming increased soil pH values (CaCl2) from 3.7 to 6.2, and increased by 10% (1.5 g N m-2) the amount of soil-derived NO3 --N that moved through the columns. This increase was the result of enhanced movement of soil-derived NO3 --N through the columns during the first 14 days of incubation. After the initial 14-day period, the limed and unlimed treatments had similar amounts of soil N leaching through the soil columns. Lime increased the nitrification rates and stimulated the early movement of fertilizer-derived NO3 --N through the soil.
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    URL: http://dx.doi.org/10.1007/BF00337208
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    Phosphorus and nitrogen dynamics during field incubations in forest and fallow subarctic soils (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 243-248 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Mineralization ; Immobilization ; Forest floor ; Subarctic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A knowledge of the nutrient dynamics that occur with land use changes, e.g., in clearing forests for farmland, is useful in choosing the most efficient soil and fertilizer management practices. To determine net in situ P and N mineralization and nitrification rates of forest floor materials and their nutrient value for agricultural crops, plastic bags containing different materials (moss, O horizon, and A horizon) collected from a subarctic black spruce (Picea mariana Mill.) forest were incubated for 2 years in their respective forest horizons and at 7.5 cm depth in a nearby fallow field. Net amounts of P and N mineralized were highest in moss and were similar in forest and field when the temperature and moisture content were similar, but smaller in forest when the water content was higher. Net nitrification was negligible in O and A horizon material but significant in moss during the 2nd year, occurring sooner and producing higher NO inf3 sup- levels in the field (171 mg ha-1) than in the forest (13 mg ha-1). Moss P and N mineralization rates were correlated in the fallow field. Temperature, moisture content, and substrate quality were important factors controlling P and N dynamics of forest floor materials in a subarctic fallow field and native forest. In subarctic regions, incorporation and mineralization of forest floor materials could provide an early source of N and P (70 and 17 kg ha-1, respectively) for succeeding agricultural crops.
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    URL: http://dx.doi.org/10.1007/BF00369299
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    Effect of cattle slurry in grassland on microbial biomass and on activities of various enzymes (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 249-254 
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    ISSN: 1432-0789
    Keywords: Microbial biomass ; Soil enzymes ; Nitrification ; Cattle slurry ; Grassland soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We examined the long-term effects of cattle slurry, applied at high rates, on microbial biomass, respiration, the microbial quotient (qCO2) and various soil enzyme activities. In March, June, July, and October 1991, slurry-amended grassland soils (0–10 cm) contained significantly higher levels of microbial biomass, N mineralization and enzyme activities involved in N, P, and C cycling. With microbial biomass as the relative value, the results revealed that the slurry treatment influenced enzyme production by the microbial biomass. High levels of urease activity were the result not only of a larger microbial biomass, but also of higher levels of enzmye production by this microbial biomass. The ratio of alkaline phosphatase and xylanase to microbial biomass was nearly constant in the different treatments. The metabolic quotient (qCO2) declined with increased levels of slurry application. Therefore it appears that microorganisms in slurry-amended soils require less C and energy if there is no competition for nutrients. The results of this study suggest that urease activity, nitrification, and respiration (metabolic quotient) can be used as indicators of environmental stress, produced by heavy applications of cattle slurry.
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    Effect of wax-coated calcium carbide and nitrapyrin on nitrogen loss and methane emission from dry-seeded flooded rice (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 71-75 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; Denitrification ; Nitrification inhibitors ; 15N balance ; Nitrous oxide ; Greenhouse gases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effectiveness of wax-coated calcium carbide (as a slow-release source of acetylene) and nitrapyrin in inhibiting nitrification and emission of the greenhouse gases N2O and CH4 was evaluated in a microplot study with dry-seeded flooded rice grown on a grey clay near Griffith, NSW, Australia. The treatments consisted of factorial combinations of N levels with nitrification inhibitors (control, wax-coated calcium carbide, and nitrapyrin). The rate of nitrification was slowed considerably by the addition of wax-coated calcium carbide, but it was inhibited only slightly by the addition of nitrapyrin. As a result, the emission of N2O was markedly reduced by the application of wax-coated calcium carbide, whereas there was no significant difference in rates of N2O emission between the control and nitrapyrin treatments. Both nitrification inhibitors significantly reduced CH4 emission, but the lowest emission rates were observed in the wax-coated calcium carbide treatment. At the end of the experiment 84% of the applied N was recovered from the wax-coated calcium carbide treatment compared with ∼ 43% for the nitrapyrin and control treatments.
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    URL: http://dx.doi.org/10.1007/BF00336519
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    Effect of acetylene provided by wax-coated calcium carbide on transformations of urea nitrogen applied to an irrigated wheat crop (1993)
    Springer
    Biology and fertility of soils 16 (1993), S. 86-92 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen immobilization ; Mineralization ; Nitrification ; Nitrification inhibitor ; Acetylene ; CaC2 ; 15N enrichment ; Urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of acetylene (provided by wax-coated calcium carbide, CaC2) on N transformations in a red-brown earth was measured in a field experiment with irrigated wheat by determining the change in the concentration and 15N enrichment of the organic N and mineral N pools with time. The study was conducted in the Goulburn-Murray Irrigation region of south-eastern Australia using 0.3 m by 0.3 m microplots fertilized with 15N-labelled urea (10 g N m-2; 5 atom% 15N). Acetylene was effective in slowing the nitrification of both unlabelled and labelled N. Nitrate derived from the added fertilizer reached a maximum 19 days after sowing in the treatment without CaC2, whereas little nitrate accumulated in the 8 g CaC2 m-2 treatment. There was significant immobilization of the urea N by 19 days after sowing in all treatments, but the extent of immobilization was not affected by the acetylene. The addition of acetylene slowed net mineralization of labelled and unlabelled N from the organic N pool, and resulted in increased accumulation of both unlabelled and labelled N in wheat tops.
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    URL: http://dx.doi.org/10.1007/BF00369408
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    Atmospheric loading of Zn, Cu, Ni, Cr, and Pb to lake sediments: The role of catchment, lake morphometry, and physico-chemical properties of the elements (1993)
    Springer
    Biogeochemistry 23 (1993), S. 1-22 
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    ISSN: 1573-515X
    Keywords: catchment export ; catchment retention ; metals ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Although catchments have been implicated as an important source of metals to lakes, the catchment contribution of different metals is poorly known, and the anthropogenic contribution is not known at all. We determine the anthropogenic lake sediment burdens of Zn, Cu, Ni, Cr, and Pb for several Quebec and Ontario lakes, not subject to point source loading, to obtain estimates of atmospheric loading and inputs from terrestrial sources. To do this, we first collected multiple cores across 11 lake basins to estimate the whole-lake Pb burdens. As the whole-lake Pb burdens did not differ among lakes that spanned over two orders of magnitude in drainage ratios (drainage basin area/lake area), we conclude that catchment retention of anthropogenic Pb is complete. The anthropogenic Pb burdens were then used as a correction for focusing for the other metals. Among the metals, Cr and Ni were the most readily exported from drainage basins, followed by Cu. Zn showed no increase with drainage ratio, indicating Zn to be effectively retained by catchments. The export coefficients of the Pb corrected metals correlate well with ocean residence time, revealing a similar metal sorption/precipitation sequence in both soils and oceans. Sediment metal burdens provide a relatively easy way to obtain not only metal export coefficients from drainage basins, but also the atmospheric deposition of anthropogenic metals (e.g. Pb: S.E. Quebec, 950 mg*m−2: Laurentians, north of Montreal, 420 mg*m−2). The export coefficients are not only simpler to obtain than by mass balance measurements, but, in addition, identify the anthropogenic component.
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    URL: http://dx.doi.org/10.1007/BF00002920
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    A simple, inexpensive piston corer for collecting undisturbed sediment/water interface profiles (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 157-161 
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    ISSN: 1573-0417
    Keywords: coring device ; paleolimnology ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
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    URL: http://dx.doi.org/10.1007/BF00196870
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    Simple gravity corer suitable for educators (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 253-255 
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    ISSN: 1573-0417
    Keywords: paleolimnology ; paleoecology ; limnology ; coring ; sediments ; education
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Instructions for construction and use of a simple and inexpensive sediment coring device are presented. The sampler is suitable for use in high school and undergraduate science courses.
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    URL: http://dx.doi.org/10.1007/BF00181717
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    A new method for processing clay-rich unconsolidated sediments for paleoecological investigations (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 95-101 
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    ISSN: 1573-0417
    Keywords: sediments ; soft sediments ; loose sediments ; sampling ; subsampling ; cysts ; dinoflagellates ; freeze coring ; Twin 80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A method is described for processing flocculated clay-rich sediments which avoids acetolysis and heavy liquid separation. Twin 80 (Merck index 1983) is used for deflocculation. Microsieves separate the recovered organisms according to size. Taxonomic identification and quantitative evaluation of the organisms can be performed in counting chambers or on permanent slides. Algae, cysts and exospores of dinoflagellates, pollen grains and zooplankton remains can be recovered.
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    URL: http://dx.doi.org/10.1007/BF00197033
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    Fossil diatoms and the mid to late holocene paleolimnology of Lake Turkana, Kenya: a reconnaissance study (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 23-35 
    Details
    ISSN: 1573-0417
    Keywords: diatoms ; paleolimnology ; paleoclimatology ; sediments ; radiocarbon chronology ; East Africa (Kenya)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract A 12 m sediment core recovered from the south basin of Lake Turkana, northwestern Kenya, reveals four major diatom assemblages that span approximately 5450 to 1070 years BP based on AMS radiocarbon analyses. The oldest assemblage, Zone D (5450 to 4850 yr BP), is dominated by Melosira nyassensis and Stephanodiscus spp. and is interpreted to reflect higher lake levels, fresher water and more variable seasonal mixing of the water column than the modern lake. Melosira dominates the assemblage in Zone C (4850 to 3900 yr BP) with some Surirella engleri and Stephanodiscus. This assemblage indicates a continuation of relatively high lake levels and seasonal mixing of a stratified lake. The brief peak of Surirella, interpreted as benthic, suggests an episode of slightly lower lake level. Thalassiosira rudolfi and Surirella predominate since the beginning of Zone B (3900 to 1900 yr BP), reflecting a decrease in lake level and increase in water column salinity. Increasing dominance of Surirella in Zone A (1900 to 1070 yr BP) may suggest that the lake continued to decrease in depth. Salinity probably rose to levels comparable with the modern lake. These results are consistent with paleoclimatic interpretations based on carbonate abundance, lamination thickness, oxygen isotope and bulk geochemistry profiles from this core and cores recovered from the north basin. It extends the known paleolimnology beyond 4000 yr BP of the earlier research to 5450 yr BP and into the early to mid Holocene pluvial phase in northern intertropical east Africa.
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    Spatial and temporal distribution of diatoms in sediments of Lake Malawi, Central Africa, and ecological implications (1992)
    Springer
    Journal of paleolimnology 7 (1992), S. 55-71 
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    ISSN: 1573-0417
    Keywords: Malawi ; sediments ; diatom ; paleolimnology ; paleoecology ; nutrients
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Lake Malawi lies in a major rift valley in Central Africa that is some 700 m deep and 550 km long. A total of 242 cores and 111 grab samples were recovered between 1984 and 1989 and form the data base for a study of diatom distribution in this lake basin. The sediments consist of homogeneous diatomites, pelagic diatomaceous muds, varved diatomite-mud couplets, turbidites, littoral sand sheets and extensive deposits of ferro-manganous nodules. Fossil diatoms show major temporal and regional contrasts between the southern, central and northern areas of the lake. A wide variety of Aulacoseira species occur in the southern lake sediments. To the north, the Nkhotakota region is generally characterised by Stephanodiscus and Aulacoseira, with occasional diatomite laminae composed of Aulacoseira or Nitzschia. The central parts of the lake show the greatest variation, with Stephanodiscus, Nitzschia and Aulacoseira all being prominent. The northern region is dominated by Aulacoseira nyassensis throughout most core sequences. Variability in these assemblages appears to be controlled by Si:P ratios, Si concentrations, turbulence and light penetration. These factors themselves are influenced by differences in the depth and duration of lake mixing due to variations in wind strength, seiches and bottom topography among different regions of the lake and from lakewide circulation patterns.
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    Carbon and nitrogen mineralization and ammonia volatilization from fresh, aerobically and anaerobically treated pig manure during incubation with soil (1992)
    Springer
    Biology and fertility of soils 13 (1992), S. 135-141 
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    ISSN: 1432-0789
    Keywords: Ammonia loss ; CO2-C evolution ; Combined first- and zero-order kinetics ; N-immobilization ; Nitrification ; Non-linear regression ; Priming effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We studied the decomposition of aerobically and anaerobically treated pig manure during a 2-month incubation with soil. The manure samples had not been in contact with straw or with animal urine. The aerobically decomposed manure proved to be the most stable (23% C mineralization), followed by fresh (75%) and anaerobically treated manure (105%, priming effect). The course of mineralization fitted combined first- and zeroorder kinetics. In the anaerobically treated manure, 76% of NH 4 + -N was immobilized during the initial incubation phase, followed by a slow linear mineralization. In the aerobically treated manure there was a slow linear mineralization after 5 days, and in the fresh material, a slightly faster linear mineralization after 6 days. Total mineralized N was very similar after 2 months (12%) in all treatments. Total NH3 losses were highest from the anaerobically treated manure (14%), reflecting a higher NH 4 + content with N mineralization following first-order kinetics. Relating NH3 losses to the initial NH 4 + content showed that all NH3 in the aerobically treated manure was volatilized, whereas only 28% was volatilized from the fresh and the anaerobically treated manure.
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    Effects of long-term 2,4-D application on microbial populations and biochemical processes in cultivated soil (1992)
    Springer
    Biology and fertility of soils 13 (1992), S. 187-191 
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    ISSN: 1432-0789
    Keywords: Dehydrogenase activity ; DHA ; Microbial biomass ; Microbial populations ; 2,4-D ; Nitrification ; Soil respiration ; Urease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of 15 years of field applications of 2,4-dichlorophenoxy acetate (2,4-D) on soil microbial population and biochemical processes were studied in a field cropped with maize followed by potatoes. Amine or ester formulations at the rate of 0.95 kg 2,4-D per hectare applied in May and October every year. Fungal, bacterial, and actinomycete populations, and microbial biomass C and N were reduced by the 2,4-D treatment, the reduction being more marked where the ester was used. N mineralization, nitrification, and potentially mineralizable N were reduced by the 2,4-D ester only, while urease activity was depressed by both formulations. Dehydrogenase activity and soil microbial respiration tended to be temporarily increased by the amine, but were reduced substantially by the ester, indicating that the ester probably interfered with nutrient cycling.
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    Nitrogen turnover rates in a riparian fen determined by 15N dilution (1992)
    Springer
    Biology and fertility of soils 14 (1992), S. 230-236 
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    ISSN: 1432-0789
    Keywords: N mineralization ; Assimilation ; Nitrification ; NO in3 sup- reduction ; Riparian fen ; 15N substrates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Gross rates of N mineralization, assimilation, nitrification, and NO in3 sup- reduction were determined in soil from a wet riparian fen by 1-day incubations of soil cores and slurries with 15N-labelled substrates. N mineralization transformed 0.1% of the total organic N pool daily in the soil cores, of which 25% was oxidized through autotrophic nitrification and 53%–70% was incorporated into microorganisms. N mineralization and nitrification were markedly inhibited below 5 cm in soil depth. At least 80% of the NO in3 sup- reduction in aerated cores occurred through dissimilatory processes. Dissimilatory reduction to NH in4 sup+ (DNRA) occurred only below 5 cm in depth. The results show that NH in4 sup+ oxidation was limited by available substrate and was itself a strong regulator of NO in3 sup- -reducing activity. NO in3 sup- reduction was significantly increased when the soil was suspended under anaerobiosis; adding glucose to the soil slurries increased NO in3 sup- reduction by 2.4–3.7 times. Between 3% and 9% (net) of the added NO in3 sup- was reduced through DNRA in the soil slurries. The highest percentage was observed in soil samples from deeper layers that were pre-incubated anaerobically.
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    Fatty acid oxidation in anoxic marine sediments: the importance of hydrogen sensitive reactions (1992)
    Springer
    Biogeochemistry 17 (1992), S. 23-47 
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    ISSN: 1573-515X
    Keywords: anaerobic food chain ; fatty acids ; hydrogen ; inhibitors ; sediments ; sulfate reduction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract In anoxic marine sediments fatty acids may be oxidized directly by sulfate reducing bacteria, or may be oxidized by pathways which result in hydrogen production. Some of these latter reactions are quite sensitive to hydrogen concentrations ... in other words if hydrogen concentrations become elevated, fatty acid oxidation will cease. Thus sulfate reducers may actually play two important roles in the metabolism of fatty acids in marine sediments. The sulfate reducers both can utilize fatty acids directly, and also can oxidize hydrogen and thus control hydrogen partial pressures in the sediments. Therefore sulfate reducers may act indirectly to facilitate fatty acid oxidation by hydrogen-producing pathways. We carried out a series of incubations of slurried salt marsh sediment under high and low hydrogen partial pressures and in the presence and absence of molybdate to investigate the relative importance of sulfate reducers and other bacteria mediating hydrogen-sensitive reactions. Our results suggest that both classes of bacteria contribute significantly to fatty acid turnover in marine sediments. Studies of low molecular weight fatty acid turnover in sediment must explicitly recognize that manipulation of sediment (including addition of molydbate to inhibit sulfate reducers) may have a large impact on hydrogen partial pressures in sediment, and may thus significantly alter the pathways and/or rates of fatty acid turnover.
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    Decomposition of sawdust and bark treated with cellulose-decomposing microorganisms (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 105-110 
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    ISSN: 1432-0789
    Keywords: Compost ; Sawdust ; Bark ; Cellulolysis ; Ammonification ; Nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The decomposition of coniferous sawdust and bark with added N and P was studied in relation to its capacity to serve as a substrate for plant growth. With sawdust as a substrate, there was more microbial biomass, greater CO2 evolution, more ammonification and more actinomycetes but less nitrification and less fungi compared with bark. All groups and activities were greater in sawdust and bark compared with soil used as the substrate. Inoculation with cellulolytic strains of Bacillus sp. Cephalosporium sp. and Streptomyces sp. sometimes increased these activities but only marginally. The derived sawdust and bark composts increased the yields of tomato compared with soil to which the same nutrients had been added.
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    Variations in the rates of nitrification and denitrification during the growth of potatoes (Solanum tuberosum L.) in soil with different carbon inputs and the effect of these inputs on soil nitrogen and plant yield (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 157-162 
    Details
    ISSN: 1432-0789
    Keywords: Carbon ; Denitrification ; Immobilisation ; Mineralisation ; Nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A potato crop (Solanum tuberosum L. cv. Maris piper) was grown in a soil to which N was added, as NH4NO3, with or without added C, as sucrose or straw. Shortly after amendment the soil, in all treatments, contained only relatively low levels of mineral N. However, these levels increased later. The increase, which was greatest in the absence of added C and least with added sucrose, occurred before the emergence of the plant canopy. The addition of C to the soil had no effect on plant yield, measured either as dry matter or total N content. The potential nitrification rate was high early in the season, and decreased significantly as the plants developed. The potential denitrification rate showed two significant peaks in activity, possibly related to plant development, the first to the development of new roots and the second to root senescence. It seems probable that the amount of C released by the potato plants was only about one-quarter of that required for the maximum microbial activity.
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    Inhibition of nitrification in soil by gaseous hydrocarbons (1991)
    Springer
    Biology and fertility of soils 11 (1991), S. 231-233 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Hydrocarbons ; Methane ; Ethane ; Ethylene ; Acetylene ; Nitrosomonas europaea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Recent work has shown that gaseous hydrocarbons such as methane, ethane, and ethylene are competitive inhibitors of the monooxygenase enzyme responsible for oxidation of ammonia by chemoautotrophic nitrifying microorganisms such as Nitrosomonas europaea. Because methane, ethane, and ethylene are produced by microbial activity in soil, we studied the possibility that they may inhibit oxidation of ammonia by the nitrifying soil microorganisms. We found that all three of these gaseous hydrocarbons inhibited nitrification in soil and that their ability to inhibit nitrification decreased in the order: ethylene 〉 ethane 〉 methane. Ethylene was much more effective than ethane or methane for inhibiting nitrification of ammonium in soil, but it was much less effective than acetylene, and it seems unlikely that the amounts of ethylene produced in soils will be sufficient to cause significant inhibition of nitrification by soil microorganisms.
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    A simple gas chromatographic approach to evaluate CO2 release, N2O evolution, and O2 uptake from soil (1991)
    Springer
    Biology and fertility of soils 12 (1991), S. 1-4 
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    ISSN: 1432-0789
    Keywords: Microbial activity ; Gas chromatographic analysis ; Soil atmosphere ; N2O release ; CO2 evolution ; O2 uptake ; Denitrification ; Nitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary We have developed a simple method for the determination of gaseous compounds that reflect microbial activity in soil, as affected by factors such as the presence of an organic amendment (peat) or a variation in soil moisture. The method is based on a gas chromatographic analysis of the headspace of vials containing the soil under examination. A single gas chromatograph can detect up to 10 different gases. As expected, after peat was added to the soil, CO2 evolution and O2 uptake increased significantly. Positive relationships were found between the evolution of N2O, and soil moisture and the amount of peat added to the soil. Both the these variables influenced the CO2:O2 ratio. The results given by this method show high reproducibility.
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    Coupled nitrification-denitrification associated with liquid manure in a gel-stabilized model system (1991)
    Springer
    Biology and fertility of soils 12 (1991), S. 19-27 
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    ISSN: 1432-0789
    Keywords: Manure ; Nitrification ; Denitrification ; Silica gel ; Phospholipids ; Microbial biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Following the application of liquid manure to soil, the development of the two processes, nitrification and denitrification, was studied in a two-phase model system. A saturated mixture of manure and soil, stabilized with silica gel, was overlain by an aerobic soil phase. Profiles of the redox potential pH, inorganic N, dissolved organic C, nitrification and denitrification potentials, and phospholipid concentrations for an estimate of microbial biomass were measured during a 20-day period. NH 4 + diffusing into the aerobic soil was oxidized within 10 mm of the interface, but with only a small accumulation of NO 2 - and NO 3 - . It was estimated that N equivalent to approximately 70% of the NH 4 + originally present in the manure was lost through coupled nitrification-denitrification. The potentials for nitrification and denitrification increased 40-and 20-fold, respectively, around the interface. Maximum values were recorded after 14 days. Within 0–5 mm of the anaerobic zone, apparent generation times for NH 4 + -oxidizing bacteria of 1.1–1.8 days were estimated between day 1 and day 7. The phospholipid concentration profiles suggested that the biomass within 2 mm on either side of the interface was stimulated throughout the 20-day period.
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    Effects of organic manure on nitrification in arable soils (1991)
    Springer
    Biology and fertility of soils 12 (1991), S. 147-153 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Integrated farming ; Conventional farming ; Ammonification ; Fluorescence antibody microscopy ; Nitrobacter spp.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The production of nitrate by the process of nitrification is highly dependent on other N-transforming processes in the soil. Hence, changes in the type of N compound applied to enrich agricultural soils may affect the production of nitrate. The size and activity of the chemolithotrophic bacterial community were studied in an integrated farming system, with increased inputs of organic manure and reduced inputs of mineral nitrogenous fertilizer, versus conventional farming. The integrated farming had a positive effect on potential nitrifying activity, but not on the numbers of chemolithotrophic nitrifying bacteria as determined by a most probable number technique or by fluorescence antibody microscopy. Cells of the recently described nitrite-oxidizing species Nitrobacter hamburgensis and Nitrobacter vulgaris were just as common as the cells of the well known species Nitrobacter winogradskyi. It was concluded that nitrification is stimulated by integrated farming, presumably by an increased mineralization of ammonium which is not immediately consumed by the crop or immobilized in the heterotrophic microflora of the soil. Since nitrifying bacteria are involved in the production of NO and N2O, integrated farming with the application of manure may favour the production of noxious N-oxides.
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    URL: http://dx.doi.org/10.1007/BF00341492
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    Heavy metal surveys in sediments of five important Cuban bays (1991)
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    Biogeochemistry 14 (1991), S. 113-128 
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    ISSN: 1573-515X
    Keywords: Bays ; Cuba ; estuaries ; heavy metals ; pollution ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract This paper presents data obtained between 1983 and 1989 on concentration of heavy metals in sediments of five Cuban bays having different physical and geographical characteristics and differing degrees of anthropogenic activities. Data are normalized with respect to Al, Fe, and organic content and processed through statistical techniques of multivariate analysis. The degree of heavy metal pollution among the harbors decreases in the following order: Havana, Santiago de Cuba, Cienfuegos ≈ Matanzas, Cárdenas
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    URL: http://dx.doi.org/10.1007/BF00002901
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    Urea losses in flooded soils with established oxidized and reduced soil layers (1990)
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    Biology and fertility of soils 9 (1990), S. 283-287 
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    ISSN: 1432-0789
    Keywords: Nitrogen transformations ; Flooded soil ; Nitrogen loss ; Nitrification ; Dentitrification ; Urea ; NH3 volatilization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Laboratory batch incubation experiments were conducted to determine in fate of urea-15N applied to floodwater of four rice soils with established oxidized and reduced soil layers. Diffusion-dependent urea hydrolysis was rapid in all soils, with rates ranging from 0.0107 to 0.0159 h-1 and a mean rate of 0.0131 h-1. Rapid loss of 53%–65% applied urea-15N occurred during the first 8 days after application, primarily by NH3 volatilization. At the end of 70 days, an additional 20%–30% of applied urea-15N was lost, primarily through nitrification-denitrification processes. The soil types showed significant differences in total applied urea-15 recovery. Conversion of urea-15N to N2-15N provided direct evidence of urea hydrolysis followed by nitrification-denitrification in flooded soils.
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    Holocene paleoclimatic evidence and sedimentation rates from a core in southwestern Lake Michigan (1990)
    Springer
    Journal of paleolimnology 4 (1990), S. 269-284 
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    ISSN: 1573-0417
    Keywords: Lake Michigan ; paleolimnology ; radiocarbon ; stable isotopes ; ostracodes ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Preliminary results of a multidisciplinary study of cores in southwestern Lake Michigan suggest that the materials in these cores can be interpreted in terms of both isostatically and climatically induced changes in lake level. Ostracodes and mollusks are well preserved in the Holocene sediments, and they provide paleolimnologic and paleoclimatic data, as well as biogenic carbonate for stable-isotope studies and radiocarbon dating. Pollen and diatom preservation in the cores is poor, which prevents comparison with regional vegetation records. New accelerator-mass spectrometer 14C ages, from both carbon and carbonate fractions, provide basin-wide correlations and appear to resolve the longstanding problem of anomalously old ages that result from detrital organic matter in Great Lakes sediments. Several cores contain a distinct unconformity associated with the abrupt fall in lake level that occurred about 10.3 ka when the isostatically depressed North Bay outlet was uncovered by the retreating Laurentide Ice Sheet. Below the unconformity, ostracode assemblages imply deep, cold water with very low total dissolved solids (TDS), and bivalves have δ 18O (PDB) values as light as — 10 per mil. Samples from just above the unconformity contain littoral to sublittoral ostracode species that imply warmer, higher-TDS (though still dilute) water than that inferred below the unconformity. Above this zone, another interval with δ 18O values more negative than — 10 occurs. The isotopic data suggest that two influxes of cold, isotopically light meltwater from Laurentide ice entered the lake, one shortly before 10.3 ka and the other about 9 ka. These influxes were separated by a period during which the lake was warmer, shallower, but still very low in dissolved solids. One or both of the meltwater influxes may be related to discharge from Lake Agassiz into the Great Lakes. Sedimentation rates appear to have been constant from about 10 ka to 5 ka. Bivalve shells formed between about 8 and 5 ka have δ 18O values that range from-2.3 to-3.3 per mil and appear to decrease toward the end of the interval. The ostracode assemblages and the stable isotopes suggest changes that are climatically controlled, including fluctuating water levels and increasing dissolved solids, although the water remained relatively dilute (TDS 〈 300 mg/l). A dramatic decrease in sedimentation rates occurred at about 5 ka, about the time of the peak of the Nippissing high lake stage. This decrease in sedimentation rate may be associated with a large increase in effective wave base as the lake approached its present size and fetch. A dramatic reduction in ostracode and mollusk abundances during the late Holocene is probably due to this decrease in sedimentation rates, which would result in increased carbonate dissolution. Ostracode productivity may also have declined due to a reduction in bottom-water oxygen caused by increased epilimnion algal productivity.
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    Comparison of industrial and high-resolution thermal data in a sedimentary basin (1990)
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    Pure and applied geophysics 133 (1990), S. 251-267 
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    ISSN: 1420-9136
    Keywords: Heat flow ; sediments ; temperature ; gradients ; conductivity ; industrial data ; scientific data ; hydrodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Temperature, temperature gradient and heat flow, derived from four wells in the Western Canada Sedimentary Basin have been compared with similar quantities derived from maps constructed from industrial data. Individual industrial temperature data may differ from the high-resolution temperature log by up to 30 K, but linear regression of the collected data agrees within 10 K at all points observed. Some evidence suggests that measured conductivities, using drill-cuttings, are biased toward average values. Derived heat flows show agreement of heat flow within 10% within the Mesozoic section. In the Paleozoic section differences are greater, and more varied, with insufficient data for general conclusions. Both styles of measurement provide opportunities for interpretation, each contributing to thermal analysis of sedimentary basins.
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    Potential variation of nitrogen transformations in pinyon-juniper ecosystems resulting from burning (1990)
    Springer
    Biology and fertility of soils 10 (1990), S. 35-44 
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    ISSN: 1432-0789
    Keywords: Pinus edulis ; Juniperus osteosperma ; Carbon ; Nitrogen ; Nitrification ; Microbial N ; N immobilization ; Fire ecology ; Nitrifying bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest floor litter, duff, and underlying soils were assembled in laboratory microcosms representing pinyon, juniper, and interspace field conditions. Burning removed more than 95% of both N and C from the litter, with losses from the duff dependent on soil moisture conditions. No significant changes in total N or C were noted in the soil. Immediate increases were observed in soil NH inf4 sup+ , decreasing with depth and related to soil heating. The greatest increases were noted in both the pinyon and juniper soils that were dry at the time of the burn, with interspace soils exhibiting the least changes. Soil NH inf4 sup+ closely approximated the controls on day 90 after the burns in all treatments. Ninety days after the burn microbial biomass N was highest in the controls, followed by the wet and then the dry-burned soils, in both the pinyon and juniper microcosms. This was inversely related to the levels of accumulated NO inf3 sup- . Nitrifying bacteria populations were indirectly correlated to soil temperatures during the burn. Population levels 90 days after the burn showed increases in both the wet- and the dry-burn treatments, with those in the pinyon treatments exceeding those found in the nitial controls of pinyon soils.
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    Can acidification associated with nitrification increase available soil phosphate or reduce the rate of phosphate fixation? (1990)
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    Biology and fertility of soils 10 (1990), S. 145-151 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Soil acidification ; Carbonate dissolution ; Available P ; Phosphate precipitation ; Intensive agriculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary It is often proposed that soil acidification by microorganisms dissolves unavailable soil phosphates, especially crystalline Ca phosphates. Unavailable phosphates, it is suggested, could thus become available to crops. Microorganisms that oxidize one ammonium ion to one nitrate ion excrete two protons into the soil solution. In the present study, this universal biological process of soil acidification was used to measure, in neutral and calcareous soils, the effect of acidification on available soil phosphate and on the rate of phosphate fixation when water-soluble phosphate fertilizers are added to soils. During nitrification the Ca2+ and Mg2+ ion concentrations in soil solutions increase but the phosphate ion concentration remains constant. The excreted protons preferentially dissolve soil Ca and Mg carbonates. Soil Ca phosphates are not dissolved; they remain unavailable. When P fertilizers were applied, the rate of fixation of phosphate ions was not slowed down by acidification associated with nitrification. This biological acidification may have a long term effect, over many years, on the slow accumulation of available phosphate in soils under native grasslands, but it cannot have a significant effect on the availability of soil P under intensive agricultural practices.
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    Influence of pH on the release of NO and N2O from fertilized and unfertilized soil (1990)
    Springer
    Biology and fertility of soils 10 (1990), S. 139-144 
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    ISSN: 1432-0789
    Keywords: Denitrification ; Nitrification ; Chemodenitrification ; Ammonium ; Nitrite ; Nitrate ; Nitric oxide ; Nitrous oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary NO and N2O release rates were measured in an acidic forest soil (pH 4.0) and a slightly alkaline agricultural soil (pH 7.8) after the pH was adjusted to values ranging from pH 4.0 to 7.8. The total release of NO and N2O during 20 h of incubation was determined together with the net changes in the concentrations of NH 4 + , NO 2 − and NO 3 − in the soil. The release of NO and N2O increased after fertilization with NH 4 + and/or NO 3 − ; it strongly decreased with increasing pH in the acidic forest soil; and it increased when the pH of the alkaline agricultural soil was decreased to pH 6.5. However, there was no simple correlation between NO and N2O release or between these compounds and activities such as the NO 2 − accumulation, NO 3 − reduction, or NH 4 + oxidation. We suggest that soil pH exerts complex controls, e.g., on microbial populations or enzyme activities involved in nitrification and denitrification.
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    Detection of nitrification in a stagnohumic-gley soil (1989)
    Springer
    Biology and fertility of soils 8 (1989), S. 335-338 
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    ISSN: 1432-0789
    Keywords: Autotrophy ; Lime ; Lolium perenne ; Nitrate reductase ; Nitrification ; Stagnohumic gley
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Three different nitrification assays (short-term nitrifier activity, assimilatory nitrate reductase activity of Lolium perenne, and nitrate accumulation in the absence of plants) were performed either on soil from a naturally acidic stagnohumic-gley or on leaves from L. perenne grown in this soil. Before the investigation the soil was limed and fertilised in a manner consistent with established agricultural pasture improvement strategies. Short-term nitrifier activity was only detected in soils above pH 5.6. However, nitrate reductase activity and nitrate accumulation both showed a near linear increase between soil pH 3.8 and 6.8. These findings are attributed to the nature of the assays, each of which considers a different component of the soil nitrifier population.
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    Abiotic factors regulating nitrification in a Swedish arable soil (1989)
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    Biology and fertility of soils 8 (1989), S. 247-254 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Abiotic factors ; Ammonium concentration ; Vmax of nitrification ; Michaelis-Menten constant for ammonium oxidation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of temperature, water potential and ammonium concentrations were studied in field and laboratory experiments on arable soil. The two field experiments used different sampling intervals, one at daily (short-term) and the other at monthly (long-term) intervals. In the short-term field experiment, the numbers and activities of nitrifiers were assessed before and after natural rain or irrigation. The nitrifiers were apparently outcompeted by heterotrophs during the first days after wetting the soil. Potential nitrification was affected only slightly by changes in water potential, whereas the numbers of ammonium and nitrite oxidizers appeared more sensitive to these changes. The numbers of ammonium and nitrite oxidizers correlated strongly during the daily samplings. The potential nitrite-oxidation rates correlated with water potentials whereas the potential ammonium oxidation rates did not. Extractable ammonium decreased in proportion to increasing nitrate concentrations in both the rain-fed and the irrigated plots. In the long-term field experiments, the numbers of ammonium oxidizers correlated with water potentials but not with in situ temperature or with ammonium concentrations. The potential ammonium-oxidation rates correlated with water potentials and with ammonium-oxidizer numbers. The potential nitrite-oxidation rates correlated strongly with the potential ammonium-oxidation rates. The field experiments implied that nitrite oxidizers obtained substrate from ammonium oxidizers but also from nitrate reduction. In laboratory experiments nitrate accumulated at a Q 10 of about 2 and the V max for nitrification was observed at a water potential of −0.11 MPa (65% of water-holding capacity). The K m for ammonium oxidation at pH 8.2 was 1.72 mg l−1 soil water.
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    Long-term effects of different inorganic pollutants on nitrogen transformations in a sandy cambisol (1989)
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    Biology and fertility of soils 7 (1989), S. 254-258 
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    ISSN: 1432-0789
    Keywords: N-mineralisation ; Nitrification ; Arginine ammonification ; Inorganic pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Long-term effects of 12 inorganic pollutants on N transformations were studied in a sandy cambisol. As, Be, Br, Cd, Cr, F, Pb, Hg, Se, Sn, and V were added to the soil as inorganic salts in 1975 and 1976. Soil samples were taken in 1984 to determine total N mineralisation and nitrification. All pollutants except Se and Sn inhibited N mineralisation. The most toxic elements under investigation were Be and Hg. Nitrification was reduced to a lower degree than total N mineralisation. As, Be, Cd, Cr, F, Pb, Se, and Sn failed to inhibit this process at all. It is assumed that nitrifying bacteria became adapted to these pollutants in the course of time. The arginine-ammonification method was less sensitive in detecting the effects of pollutants on N transformation than the N mineralisation test.
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    Inhibition of nitrification in soil by heterocyclic nitrogen compounds (1989)
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    Biology and fertility of soils 8 (1989), S. 204-211 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Heterocyclic N compounds ; Pyrazoles ; Triazoles ; Pyridines ; Thiadiazoles ; 2-Ethynylpyridine ; Nitrapyrin ; Etridiazole
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The relationship between the structures of diverse heterocyclic nitrogen (N) compounds and the effectiveness of these compounds for the inhibition of nitrification in soil was studied by determining the effects of different amounts of 12 unsubstituted and 33 substituted heterocyclic N compounds on the production of (NO 2 − +NO 3 − )-N in soils incubated at 25 °C for 21 days after treatment with ammonium sulfate. The results showed that unsubstituted heterocyclic N compounds containing two adjacent ring N atoms inhibit nitrification in soil and that two of these compounds, pyrazole and 1,2,4-triazole, are potent inhibitors. They also showed that several substituted pyrazoles and thiadiazoles are good inhibitors of nitrification in soil (e.g., 3-methylpyrazole and 3,4-dichloro-1,2,5-thiadiazole).
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    Morphological variation of Stephanodiscus niagarae Ehrenb. (Bacillariophyta) in a Lake Ontario sediment core (1989)
    Springer
    Journal of paleolimnology 2 (1989), S. 227-236 
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    ISSN: 1573-0417
    Keywords: Stephanodiscus ; diatom ; eutrophication ; morphology ; core ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Stephanodiscus niagarae populations in a core from Lake Ontario show systematic variation in radial puncta number and mean valve diameter. Puncta number is stable in specimens from samples deposited between 1720 and 1844. Puncta number gradually increases in samples deposited between 1860 and 1947, then increases rapidly to high numbers in samples deposited after 1964. Mean valve diameter is relatively high in specimens from samples deposited between 1720 and 1959. Diameter of specimens deposited during this period fluctuates around a mean of 63.2 μm. Mean diameter of specimens deposited from 1959 to 1980 is only 42.5 μm. We conclude that the trend in puncta number reflects the time course of eutrophication in Lake Ontario. We interpret the precipitous decline in mean diameter as an indication that conditions in the lake after the late 1950's did not permit sexual reproduction in this species.
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    The sedimentary flux of nutrients at a Delaware salt marsh site: A geochemical perspective (1989)
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    Biogeochemistry 7 (1989), S. 55-75 
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    ISSN: 1573-515X
    Keywords: salt marsh ; nutrients ; sediments ; diffusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A basic geochemical approach has been used to study the diagenetic cycling and sediment-water exchange rates of essential nutrients at a site in a Delaware salt marsh. The pore water nutrients Si (OH)4, NH4 +, PO4 −3, and NO3 − were analyzed and compared seasonally, and potential diffusive fluxes were calculated from the corresponding pore water concentration gradients. Concurrent direct flux measurements were also made using closed chambers deployed on the salt marsh surface under ambient and controlled conditions. The differences in these two approaches allows for estimation of nutrient production and consumption in the root zone and at the salt marsh surface. Silicate and phosphate appear to be primarily geochemically controlled, while the nitrogen species undergo dynamic seasonal redox fluctuations resulting from microbial mediation (e.g., nitrification and denitrification). Specifically: silicate behaves rather conservatively according to silica solubility phosphate flux is controlled by the corresponding sequestering or reductive remobilization of surface iron oxides, and ammonium has a strong upward flux which appears to undergo quantitative nitrification in spring. None of the measured flux rates would have a major impact on the nutrient budget for the local estuary, Delaware Bay.
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    Carbon and nitrogen mineralization in subarctic agricultural and forest soils (1988)
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    Biology and fertility of soils 6 (1988), S. 33-38 
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    ISSN: 1432-0789
    Keywords: Microbial activity ; Nitrification ; Taiga ; Tillage system ; Crop residue management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary C and N mineralization potentials were determined, in a 12-week laboratory incubation study, on soil samples obtained from recently cleared land which had been cropped to barley for 4 years (field soils) and from nearby undisturbed taiga (forest soils). Treatments for the cropped soils were conventional and no-tillage with and without crop residues removed. An average of about 3% of the total C was evolved as CO2 from the field soils compared with 〉 10% and 4% for the upper (Oie) and lower (Oa) forest-floor horizons, respectively. Significantly more C was mineralized from the Ap of the no-till treatment with residue left on the surface than from the other field Ap horizons. Both forest-floor horizons showed rather long lag periods for net mineralization compared with the field soils, but at the end of the incubation, more mineral N was recovered from the forest Oie despite a rather wide C:N ratio, than from the field soils. After 12 weeks about 115, 200 and 20 μg mineral N/g soil were recovered from the field Ap, the forest Oie and the forest Oa horizons, respectively. Very little C or N was mineralized from the B horizon of the forest or the field soils. Nitrification was rapid and virtually complete for the field soils but was negligible for both forest-floor O horizons.
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    URL: http://dx.doi.org/10.1007/BF00257917
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    The effect of fertilisation on soil nitrifier activity in experimental grassland plots (1988)
    Springer
    Biology and fertility of soils 5 (1988), S. 344-349 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; Deamination ; Grassland ; N fertilisers ; pH ; Denitrification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soil nitrification was compared in soils from 89-year-old grassland experimental plots with diverse chemical characteristics. Measurements of NaClO3-inhibited short-term nitrifier activity (SNA) and deamination of 1,2-diamino-4-nitrobenzene were used to study nitrification and deamination activities, respectively, in soil from each of 12 plots. Using multiple regression analysis, an expression for the relationship between SNA, soil pH and fertiliser N additions was derived which indicated that both the frequency and the quantity of farmyard manure additions were important in determining the rate of nitrification. SNA was greatest where there were large and frequent additions of farmyard manure. In soil with pH below 5.2 SNA was very low or insignificant. The effect of (NH4)2SO4 additions could not be assessed because they acidified the soil. We suggest that additions of farmyard manure increase the potential for NO3 − leaching or for denitrification. Deaminase assays indicated that soils with a higher pH showed greater N mineralisation than soils with a lower pH, except at the low extreme. There was no obvious relationship between SNA and deaminase activity at higher levels of pH.
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    URL: http://dx.doi.org/10.1007/BF00262144
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    Seasonal, annual, and treatment-induced variation in available nitrogen pools and nitrogen-cycling processes in soils of two Douglas-fir stands (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 93-99 
    Details
    ISSN: 1432-0789
    Keywords: Ammonium ; Nitrate ; N-mineralization ; Nitrification ; Fertilization ; Irrigation ; Forest ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest-floor and 0–10 cm depth mineral soil horizons in two stands of Douglas fir were sampled for available NH4 +-N and NO3 −-N, N-mineralization potentials, and nitrification potentials for 2 years. The plots in each stand were sampled for 1 year, treated with either ammonium sulfate, carbohydrate (sawdust-sucrose), irrigation, carbohydrate plus irrigation, or no treatment (control), and then sampled for 1 year following treatment. In general, the direction of change following the treatments was the same for both the forest-floor and the mineral soils. Fertilization increased the NH4 +-N and NO3 −-N pools, nitrification potential, and N-mineralization potential, while treatment with carbohydrate decreased all of these characteristics. Irrigation generally increased NH4 +-N pools, nitrification potential, and N-mineralization potential, but decreased these characteristics in the soil at one site. Irrigation plus carbohydrate gave similar results to those of carbohydrate alone. Treatments altered pool sizes and/or potentials, but did not reduce within-year variance in any of these characteristics. Distinct seasonal patterns occurred in all measurements, suggesting that control of short-term variation in N-transformation processes is by factors which are dynamic in nature.
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    URL: http://dx.doi.org/10.1007/BF00257656
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    Relationships between soil moisture content and nitrous oxide production during nitrification and denitrification (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 106-111 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; Denitrification ; Soil water content ; N2O production ; Acetylene ; Ammonium fixation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect of soil water content [60%–100% water-holding capacity (WHC)] on N2O production during autotrophic nitrification and denitrification in a loam soil was studied in a laboratory experiment by selectively inhibiting nitrification with a low C2H2 concentration (2.1 Pa). Nitrifiers usually produced more N2O than denitrifiers. During an initial experimental period of 0–6 days the nitrifiers produced more N2O than the denitrifiers by a factor ranging from 1.4 to 16.5, depending on the water content and length of incubation. The highest N2O production rate by nitrifiers was observed at 90% WHC, when the soil had become partly anaerobic, as indicated by the high denitrification rate. At 100% WHC there were large gaseous losses from denitrification, while nitrification losses were smaller except for the first period of measurement, when there was still some O2 remaining in the soil. The use of 10 kPa C2H2 to inhibit reduction of N2O to N2 stimulated the denitrification process during prolonged incubation over several days; thus the method is unsuitable for long-term studies.
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    URL: http://dx.doi.org/10.1007/BF00257658
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    A method of selective inhibition to distinguish between nitrification and denitrification as sources of nitrous oxide in soil (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 112-119 
    Details
    ISSN: 1432-0789
    Keywords: Denitrification ; Nitrification ; Selective inhibitors ; Nitrapyrin ; Acetylene ; Nitrous oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nitrapyrin and C2H2 were evaluated as nitrification inhibitors in soil to determine the relative contributions of denitrification and nitrification to total N2O production. In laboratory experiments nitrapyrin, or its solvent xylene, stimulated denitrification directly or indirectly and was therefore considered unsuitable. Low partial pressures of C2H2 (2.5–5.0 Pa) inhibited nitrification and had only a small effect on denitrification, which made it possible to estimate the contribution of denitrification. The contribution of nitrification was estimated by subtracting the denitrification value from total N2O production (samples without C2H2). The critical C2H2 concentrations needed to achieve inhibition of nitrification, without affecting the N2O reductase in denitrifiers, must be individually determined for each set of experimental conditions.
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    URL: http://dx.doi.org/10.1007/BF00257659
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    Carbon and nitrogen accretion and dynamics in volcanic ash deposits from different subarctic habitats (1988)
    Springer
    Biology and fertility of soils 7 (1988), S. 79-87 
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    ISSN: 1432-0789
    Keywords: Microbial biomass ; Mineralization ; Nitrification ; Subarctic ; Volcanic ash
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary C and N pool sizes and rates of mineralization were studied in volcanic-ash deposits found in different subarctic habitats in southwestern Alaska. Surface ash samples were taken from white-spruce, alder, and moist- and dry-tundra habitats and were analysed for total and microbial C and N. C and N dynamics were studied using a 28-day aerobic laboratory incubation, with weekly measurement of evolved CO2 and determination of inorganic-N pools initially and after 10 and 28 days. Total and microbial C and N and cumulative respired CO2 all followed a similar pattern among the different habitats, with the moist-tundra habitat having the highest values and the spruce site the lowest. The size of the microbial biomass C and N pool in the spruce habitat was among the lowest reported for any ecosystem. Little net N mineralization occurred in the spruce-forest and dry-tundra ash over 28 days. Ash from the moist-tundra habitat immobilized a significant amount of N during the first 10 days of incubation, yet showed a large net release of N after 28 days. In contrast, the ash from the alder site exhibited net mineralization after both periods, with N production after 28 days being about 3.5 times that after 10 days. In addition, the alder-habitat ash was the only soil that showed net nitrification. Rates of total C and N accretion in the tundra and alder habitats were rapid relative to rates found for primary successions. The results of this study show that habitat has a profound effect on C and N cycling in subarctic environments.
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    URL: http://dx.doi.org/10.1007/BF00260737
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    Influence of smoke exposure on soil enzyme activities and nitrification (1988)
    Springer
    Biology and fertility of soils 6 (1988), S. 341-346 
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    ISSN: 1432-0789
    Keywords: Nitrification ; Phosphatase ; Dehydrogenase ; Aerosol ; Soil thickness ; Soil enzymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Soil was exposed to red phosphorous/butyl rubber (RP/BR) aerosols at various relative humidities in a recirculating environmental wind tunnel. Soil microbial and enzymatic activities were measured immediately after exposure and periodically thereafter for 56 days. The nitrification potential was significantly reduced in soil amended with ammonium sulfate and exposed to RP/BR smoke, and could be related to a decline in soil pH. The rate of nitrate formation in unamended soil with time was also reduced, but by 57 days postexposure, concentrations were similat to those of unexposed controls in all but the thinnest soil lense. Soil dehydrogenase and phosphatase enzyme activities were sensitive to RP/BR smoke and in some treatments no activity was detected. The measured activities did not recover within the 56-day postexposure period and in some cases declined. Soil lense thickness was the greatest factor controlling the degree of RP/BR effects, indicating that injury to soil microbial and enzymatic activities may be surficial. Deposition of smoke particles increased with increasing relative humidity, which had a significant impact on the activities measured.
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    URL: http://dx.doi.org/10.1007/BF00261024
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    Retention of mercury in sediments of the Baltic Sea near Oulu, Finland (1988)
    Springer
    Journal of paleolimnology 1 (1988), S. 133-140 
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    ISSN: 1573-0417
    Keywords: mercury ; sediments ; waste waters ; dated cores ; Baltic Sea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Several cores were compared to elucidate the grade of mercury retention in sediments of the Baltic Sea near Oulu, Finland. The known history of the mercury discharge to waste water from a chlor-alkali plant, the primary pollution source, was compared to that in the sedimentary record. One core was dated by lead-210 and varve counts. During the past thirty years, the rate of sedimentation was up to 10 mm per year corresponding to a dry matter accumulation rate of about 3 kg m−2a−1. Under these conditions, most of the mercury reaching the sediment was retained. Correspondingly, the mercury levels in fish were considerably lower, with a delay of some five years. The present mercury content of the upper layers is some 1/4 or 1/5 that of the late 1970's, but it is still some twentyfold compared to levels at the beginning of the century. The extent to which the present mercury level in the sediment represents the various phases of industrial emission remains unsolved due to the origin of mercury in this sea area from several other sources and due to difficulties in exact core correlations from different years.
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    URL: http://dx.doi.org/10.1007/BF00196069
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    Biogenic silica as an estimate of siliceous microfossil abundance in Great Lakes sediments (1988)
    Springer
    Biogeochemistry 6 (1988), S. 161-179 
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    ISSN: 1573-515X
    Keywords: biogenic silica ; diatoms ; Great Lakes ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Biogenic silica concentration (BSi) in sediment cores from the Great Lakes is evaluated as an estimate of siliceous microfossil abundance. A significant linear relationship was found between measured BSi and diatom valve abundance for sediment cores from the Bay of Quinte, Lake Ontario, Lake Erie, Lake Michigan and Lake Superior and between measured BSi and diatom biovolume for Lake Erie, Lake Michigan, and Lake Superior but not for Lake Ontario. Diatom silica predicted from diatom species abundance and an estimated silica content per cell in the Lake Erie cores accounted for 117% and 103% of measured BSi, respectively. By contrast, predicted diatom silica could only account for 28% of measured BSi in the Lake Michigan core and only 25% in the Lake Superior core. A few large diatoms with a large silica content per cell comprised a major portion of predicted diatom silica in all cores. The discrepancy between chemically measured BSi and the silica predicted from diatoms in the Lake Michigan and Lake Superior cores was partially due to the inability of the regression model, used to estimate diatom silica content, to account for different degrees of silicification in the diatom asemblages from the more dissolved silica rich Lake Michigan and Lake Superior.
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    URL: http://dx.doi.org/10.1007/BF02182994
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    Factors controlling nitrogen mineralization and nitrification in forest ecosystems in New Mexico (1987)
    Springer
    Biology and fertility of soils 5 (1987), S. 195-202 
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    ISSN: 1432-0789
    Keywords: Nitrogen mineralization ; Nitrification ; Organic quality ; New Mexico
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Forest floor and mineral soil from ponderosa-pine, Douglas-fir, aspen and spruce-fir ecosystems located along a rising gradient in New Mexico were tested with laboratory assays for factors controlling N mineralization and nitrification. We concluded that low pH in combination with factors associated with organic quality controlled N mineralization and almost completely limited nitrification in spruce-fir soils, while N mineralization in the forest floor of ponderosa-pine was limited by low nutrient availability (other than N). Organic quality of the substrate and temporal changes in organic quality appeared to control N-mineralization and nitrification processes in forest-floor and mineral soils from all other sites.
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    URL: http://dx.doi.org/10.1007/BF00256900
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    Active methanotrophs suppress nitrification in a humisol (1987)
    Springer
    Biology and fertility of soils 4 (1987), S. 205-212 
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    ISSN: 1432-0789
    Keywords: Nitrate production ; Nitrification ; Humisol ; Methane oxidation ; Methanotrophs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The coexistence of chemoautotrophic nitrifiers and methanotrophs in a cultivated humisol was investigated. Under laboratory conditions which supported the growth and activity of methanotrophs, the nitrifiers were partially or completely inhibited. The inhibition was related to a competition for available oxygen and a high assimilatory requirement for inorganic nitrogen by the Methanotrophs. Dissolved methane concentrations as high as 250 μM had no direct effect on the oxidation of ammonium. Simultaneous nitrification and methane oxidation was observed only if relatively high levels of ammonium and oxygen were maintained. Coupled nitrification-assimilatory/dissimilatory nitrate reduction resulted from the high oxygen demand of the actively growing methanotrophs. This study suggests that the potential competitive effects of methanotrophs may influence nitrification by chemoautotrophic nitrifiers in certain environmental systems.
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    URL: http://dx.doi.org/10.1007/BF00270942
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    Chesapeake Bay nutrient budgets — a reassessment (1987)
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    Biogeochemistry 4 (1987), S. 77-90 
    Details
    ISSN: 1573-515X
    Keywords: Chesapeake Bay ; nutrients ; eutrophication ; estuary ; nitrogen ; phosphorus ; silicon ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Recently published annual mass balances or budgets for nitrogen, phosphorus, and silicon in Chesapeake Bay have pictured the estuary as retaining a very large fraction, perhaps all, of the nutrients that enter from land drainage, the atmosphere, and anthropogenic discharges. However, these budgets have been based on estimates of the net exchanges of nutrients at the mouth of the bay or on the rates of accumulation of nutrients and sediments calculated from the distributions of various geochemical tracers in the sediments. While conceptually straightforward, the first approach is subject to large errors because it requires the determination of a small "signal" against a large background of tidal "noise". The second approach has led to overestimates of the nutrient trapping efficiency of the bay because tracer-derived sediment deposition rates have been multiplied by the surface area of the whole bay or various parts of the bay rather than by the smaller area of active sediment deposition. This approach is also incorrect because the average, long-term rates of sediment deposition measured by the geochemical tracers, including major floods, have been compared to shorter-term records of nutrient input. The more appropriate calculation of nutrient retention based on contemporaneous measurements of nutrient and sediment input and the chemical compositon of sediments accumulated in the estuary shows that Chesapeake Bay retains only some 3–6% of the nitrogen, 11–17% of the phosphorus and 33–83% of the silicon brought into its waters during a year in which no major flood occurred. This behavior suggests that current problems of estuarine eutrophication are more a consequence of present nutrient inputs than an inevitable or inescapable legacy of past enrichment. It also follows that the management or manipulation of nutrient loadings to esturies may lead to a more rapid response in environmental quality than previously predicted.
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    Lacustrine sediment/groundwater nutrient dynamics (1987)
    Springer
    Biogeochemistry 4 (1987), S. 3-14 
    Details
    ISSN: 1573-515X
    Keywords: nutrient dynamics ; sediments ; ground water ; phosphorus ; nitrogen ; organic matter
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract A small pond in southwestern peninsular Florida was sampled to determine the areal and depth distribution of total phosphorus, total nitrogen, and organic matter. Concentrations of these constituents decreased from the center to the edge of the pond and from the top to the bottom of the sediments. At the center of the pond total phosphorus showed a secondary concentration peak at a depth of 20 to 40 cm in the sediments indicative of the downward transfer of soluble phosphorus during times of low water. A system of monitoring wells was installed at the pond to measure groundwater input and output nutrient concentrations. There was no difference in total groundwater nitrogen concentration across the pond but the mean increase in total phosphorus concentration between input and output wells, ca. 200 μg1−1, was statistically highly significant. The results suggest that whereas nitrogen is recycled from sediments to the pond and the atmosphere, the pond-sediment system loses some phosphorus to groundwater throughflow.
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    URL: http://dx.doi.org/10.1007/BF02187358
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    The biogeochemistry of nitrogen in freshwater wetlands (1987)
    Springer
    Biogeochemistry 4 (1987), S. 313-348 
    Details
    ISSN: 1573-515X
    Keywords: nitrogen cycling ; marshes ; bogs ; fens ; swamps ; mires ; sediments ; vegetation ; microbiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The biogeochemistry of N in freshwater wetlands is complicated by vegetation characteristics that range from annual herbs to perennial woodlands; by hydrologic characteristics that range from closed, precipitation-driven to tidal, riverine wetlands; and by the diversity of the nitrogen cycle itself. It is clear that sediments are the single largest pool of nitrogen in wetland ecosystems (100's to 1000's g N m-2) followed in rough order-of-magnitude decreases by plants and available inorganic nitrogen. Precipitation inputs (〈 1–2 g N m-2 yr-1) are well known but other atmospheric inputs, e.g. dry deposition, are essentially unknown and could be as large or larger than wet deposition. Nitrogen fixation (acetylene reduction) is an important supplementary input in some wetlands (〈 〈 1–3 g N m-2 yr-1) but is probably limited by the excess of fixed nitrogen usually present in wetland sediments. Plant uptake normally ranges from a few g N m-2 yr-1 to ∼ 35 g N m-2 yr-1 with extreme values of up to ∼ 100g N m-2 yr-1 Results of translocation experiments done to date may be misleading and may call for a reassessment of the magnitude of both plant uptake and leaching rates. Interactions between plant litter and decomposer microorganisms tend, over the short-term, to conserve nitrogen within the system in immobile forms. Later, decomposers release this nitrogen in forms and at rates that plants can efficiently reassimilate. The NO3 formed by nitrification (〈 0.1 to 10 g N m-2 yr-1 has several fates which may tend to either conserve nitrogen (uptake and dissimilatory reduction to ammonium) or lead to its loss (denitrification). Both nitrification and denitrification operate at rates far below their potential and under proper conditions (e.g. draining or fluctuating water levels) may accelerate. However, virtually all estimates of denitrification rates in freshwater wetlands are based on measurements of potential denitrification, not actual denitrification and, as a consequence, the importance of denitrification in these ecosystems may have been greatly over estimated. In general, larger amounts of nitrogen cycle within freshwater wetlands than flow in or out. Except for closed, ombrotrophic systems this might seem an unusual characteristic for ecosystems that are dominated by the flux of water, however, two factors limit the opportunity for N loss. At any given time the fraction of nitrogen in wetlands that could be lost by hydrologic export is probably a small fraction of the potentially mineralizable nitrogen and is certainly a negligible fraction of the total nitrogen in the system. Second, in some cases freshwater wetlands may be hydrologically isolated so that the bulk of upland water flow may pass under (in the case of floating mats) or by (in the case of riparian systems) the biotically active components of the wetland. This may explain the rather limited range of N loading rates real wetlands can accept in comparison to, for example, percolation columns or engineered marshes.
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    Gaseous nitrogen losses from fertilized soil during nitrification and denitrification using the acetylene blockage technique (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 65-70 
    Details
    ISSN: 1432-0789
    Keywords: Fertilized soil ; Nitrification ; Denitrification ; N2O production ; C2H2 blockage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary A sandy soil amended with different forms and amounts of fertilizer nitrogen (urea, ammonium sulphate and potassium nitrate) was investigated in model experiments for N2O emission, which may be evolved during both oxidation of ammonia to nitrate and anaerobic respiration of nitrate. Since C2H2 inhibits both nitrification and the reduction of N2O to N2 during denitrification, the amount of N2O evolved in the presence and absence of C2H2 represents the nitrogen released through nitrification and denitrification. Results show that amounts of N2O-N lost from soils incubated anaerobically with 0.1% C2H2 and treated with potassium nitrate (23.1 µg N-NO 3 − /g dry soil) exceeded those from soils incubated in the presence of 20% oxygen and treated with even larger amounts of nitrogen as urea and ammonium sulphate. This indicates that nitrogen losses by denitrification may potentially be higher than those occurring through nitrification.
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    Nitrogen availability in some Wisconsin forests: comparisons of resin bags and on-site incubations (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 77-82 
    Details
    ISSN: 1432-0789
    Keywords: Ecosystem production ; Mineralization ; Nitrification ; Ion exchange resin bag method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Estimates of ammonium and nitrate availability in conifer and hardwood forests using an ion exchange resin (IER) bag method and with on-site incubations of soil cores in buried bags were compared. Correlations between the two methods were generally high. Correlation coefficients (r) between IER nitrate and buried-bag mineralized nitrate ranged from 0.87 to 0.92. Both methods also correlated well with aboveground net primary production, litter fall N content, and fine root biomass. The major differences between the methods related to the relative importances of ammonium and nitrate forms of available N. The IER method indicated that both ammonium and nitrate were important on all sites, with nitrate predominating in most soils. The buried-bag results indicated that available N was primarily in the form of nitrate (all ammonium was oxidized), but that nitrate was insignificant on infertile sites.
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    URL: http://dx.doi.org/10.1007/BF00257583
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    Volatile and water-soluble inhibitors of nitrogen mineralization and nitrification in a ponderosa pine ecosystem (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 97-104 
    Details
    ISSN: 1432-0789
    Keywords: Nitrogen mineralization ; Nitrification ; Water-soluble inhibitors ; Allelochemic control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Bioassay experiments were performed to test for inhibition of the processes of nitrogen mineralization and nitrification by organics in the forest floor of a ponderosa pine ecosystem. Water-extractable organics in the forest floor were tested by applying filtered extracts to the assay soil. The extract decreased nitrate production by 17.0% and decreased net mineralization by 4.1%. Inhibition by volatile organics was tested by placing vials containing forest floor or selected terpenoids of ponderosa pine in sealed jars containing the assay soil. Nitrate production was inhibited by 87.4% and 100%, and net nitrogen mineralization was inhibited by 73.3% and 67.7% in the jars with forest floor and terpenoids, respectively. Organics which are partially water-soluble and are volatile (such as terpenoids) would be very effective inhibitors of nitrogen cycling processes.
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    URL: http://dx.doi.org/10.1007/BF00257586
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    Effects of prescribed fire on rates of decomposition and nitrogen mineralization in a ponderosa pine ecosystem (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 87-95 
    Details
    ISSN: 1432-0789
    Keywords: Fire effects on mineralization ; Ammonification ; Nitrification ; Ponderosa pine soils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effects of a prescribed fire in a ponderosa pine ecosystem on the rates of decomposition and nitrogen mineralization (including ammonification and nitrification) in the forest floor and mineral soil horizons were evaluated. The prescribed fire immediately increased the rates of nitrogen mineralization and nitrification in the forest floor of all burned plots and in the mineral soil of one plot. The rates of decomposition, as measured by CO2 evolution, in both the forest floor and mineral soil were not significantly different immediately after the burn when expressed on an organic matter basis. The rates of nitrogen mineralization in the forest floor and mineral soil were higher 6 and 10 months after the burn. The rate of decomposition (as measured by respiration) was lower in the forest floor but not in the mineral soil 6 and 10 months after the burn. Volatile organics that may inhibit rates of nitrogen mineralization may have been consumed by prescribed fire.
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    URL: http://dx.doi.org/10.1007/BF00257585
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  • 71
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    Electronic Resource
    Effects of rate and depth of fertilizer application on emission of nitrous oxide from soil fertilized with anhydrous ammonia (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 201-204 
    Details
    ISSN: 1432-0789
    Keywords: Fertilizer ; Nitrification ; Denitrification ; N2O emission ; Anhydrous ammonia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Field studies to determine the effect of different rates of fertilization on emission of nitrous oxide (N2O) from soil fertilized with anhydrous ammonia showed that the fertilizer-induced emission of N2O-N in 116 days increased from 1.22 to 4.09 kg ha−1 as the rate of anhydrous ammonia N application was increased from 75 to 450 kg ha−1. When expressed as a percentage of the N applied, the fertilizer-induced emission of N2O-N in 116 days decreased from 1.6% to 0.9% as the rate of fertilizer N application was increased from 75 to 450 kg N ha−1. The data obtained showed that a 100% increase in the rate of application of anhydrous ammonia led to about a 60% increase in the fertilizer-induced emission of N2O. Field studies to determine the effect of depth of fertilizer injection on emission of N2O from soil fertilized with anhydrous ammonia showed that the emission of N2O-N in 156 days induced by injection of 112 kg anhydrous ammonia N ha−1 at a depth of 30 cm was 107% and 21 % greater than those induced by injection of the same amount of N at depths of 10 cm and 20 cm, respectively. The effect of depth of application of anhydrous ammonia on emission of N2O was less when this fertilizer was applied at a rate of 225 kg N ha−1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260844
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  • 72
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    Electronic Resource
    Effects of various nitrogen fertilizers on emission of nitrous oxide from soils (1986)
    Springer
    Biology and fertility of soils 2 (1986), S. 195-199 
    Details
    ISSN: 1432-0789
    Keywords: Fertilizer N ; Nitrification ; Denitrification ; N2O emission ; Anhydrous ammonia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Field studies of the effects of different N fertilizers on emission of nitrous oxide (N20) from three Iowa soils showed that the N2O emissions induced by application of 180 kg ha−1 fertilizer N as anhydrous ammonia greatly exceeded those induced by application of the same amount of fertilizer N as aqueous ammonia or urea. On average, the emission of N2O-N induced by anhydrous ammonia was more than 13 times that induced by aqueous ammonia or urea and represented 1.2% of the anhydrous ammonia N applied. Experiments with one soil showed that the N2O emission induced by anhydrous ammonia was more than 17 times that induced by the same amount of N as calcium nitrate. These findings confirm indications from previous work that anhydrous ammonia has a much greater effect on emission of N2O from soils than do other commonly used N fertilizers and merits special attention in research relating to the potential adverse climatic effect of N fertilization of soils. Laboratory studies of the effect of different amounts of NH4OH on emission of N2O from Webster soil showed that the emission of N2O-N induced by addition of 100 μg NH4OH-N g−1 soil represented only 0.18% of the N applied, whereas the emissions induced by additions of 500 and 1 000 μg NH4OH-N g−1 soil represented 1.15% and 1.19%, respectively, of the N applied. This suggests that the exceptionally large emissions of N2O induced by anhydrous ammonia fertilization are due, at least in part, to the fact that the customary method of applying this fertilizer by injection into soil produces highly alkaline soil zones of high ammonium-N concentration that do not occur when urea or aqueous ammonia fertilizers are broadcast and incorporated into soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00260843
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  • 73
    Electronic Resource
    Electronic Resource
    Site of nitrous oxide production in field soils (1985)
    Springer
    Biology and fertility of soils 1 (1985), S. 3-7 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; Denitrification ; Soil profile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Nitrous oxide (N2O) fluxes at the soil surface and concentrations at 0.1, 0.2, and 0.3 m were determined in a 40-year-old planted tallgrass (XXX) prairie, a 40-year-old white pine (Pinus strobus) plantation, and field plots treated annually for 18 years either with 33 metric tons of manure ha−1 (330 kg N ha−1) and NH4NO3 (80 kg N ha−1) or with only NH4NO3 (control). Nitrous oxide fluxes from the prairie, forest, manure-amended, and control sites from 13 May to 10 November 1980 ranged from 0.2 to 1.3, 3.5 to 19.5, 3.7 to 79.0, and 1.7 to 24.8 ng N2O-N m−2s−1, respectively. We observed periods when there was no apparent relationship between the N2O flux from the surface and N2O concentrations in the soil profile. This was generally the case in the prairie and in the field sites following the application of N fertilizer. The N2O concentrations in the soil profile increased markedly and coincided with increased soil water content following periods of heavy rainfall for all sites except the prairie. Nitrous oxide concentration gradients indicate that following heavy rainfalls the site of N2O production was moved from the surface deeper into the soil profile. We suggest that the source of N2O production near the surface is nitrification and that N2O is produced by denitrification of NO3 leached into the soil following heavy rainfall.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00710964
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  • 74
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    Electronic Resource
    Ammonium oxidizer numbers, potential and actual oxidation rates in two swedish arable soils (1985)
    Springer
    Biology and fertility of soils 1 (1985), S. 131-140 
    Details
    ISSN: 1432-0789
    Keywords: Nitrification ; MPN of ammonium oxidizers ; Chlorate inhibition ; Arable soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The number of ammonium-oxidizing bacteria was measured with the most probable number (MPN) method while potential ammonium oxidation rates were determined with a chlorate inhibition technique in two arable soils. A new method for measuring actual in situ ammonium oxidation in soil cores is presented. One soil was cropped for 4 years with one of four crop-fertilizer combinations: Unfertilized lucerne ley, unfertilized barley, nitrate-fertilized grass ley, or nitrate-fertilized barley. The highest ammonium oxidizer numbers and potential rates were found in the grass ley. The unfertilized barley had one-third the number and activity of the grass ley. Actual rates were in general 5–25 times lower than potential rates. The other soil was that undergoing a 27-year-old field trial with a fallow and four different cropping treatments: No addition, nitrate, nitrate + straw, or manure. Ammonium oxidizer numbers were highest in the manure and straw treatments. MPN numbers and potential rates were lowest in the fallow treatment. Typical specific potential rates were 30 ng N oxidized cell−1 h−1. Actual rates were in general 40 times lower than potential rates. Actual ammonium oxidation measurements seem to correspond to actual in situ activity at the moment of sampling, whereas the MPN technique and the potential measurements reflect events that occurred weeks to months before the sampling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00301780
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  • 75
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    Electronic Resource
    The effects of heat and stannous chloride addition on the active distillation of acid volatile sulfide from pyrite-rich marine sediment samples (1985)
    Springer
    Biogeochemistry 1 (1985), S. 375-382 
    Details
    ISSN: 1573-515X
    Keywords: iron monosulfide ; acid volatile sulfide ; pyrite ; stannous chloride ; sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Iron monosulfides are important intermediates in pyrite formation, and are operationally defined as sulfides soluble in concentrated hydrochloric acid. A number of variations are currently employed in their isolation and quantification. In this study, the active distillation of acid volatile sulfide from sediment samples was studied to determine the effects of stannous chloride and heat. The addition of SnCl2 caused recovery of sulfide to increase by 20% during distillations performed at room temperature. If distillations with SnCl2 were then heated and boiled, recovery increased by up to 100%. Tests with 98% pure pyrite and elemental sulfur showed that these compounds were reduced to sulfide in solutions of 15% and 20% SnCI2 in boiling 6N HCI, and that these reactions were grain size dependent. The compounds were not significantly reduced by solutions of SnCI2 at room temperature, or by boiling 6N HCl not containing SnCl2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187379
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