Precipitation Chemistry and Chemical Limnology of Fertilized and Natural Lakes at Saqvaqjuac, N.W.T.

1986 ◽  
Vol 43 (6) ◽  
pp. 1104-1134 ◽  
Author(s):  
Harold E. Welch ◽  
John A. Legault
Keyword(s):  
Late Summer ◽  
Precipitation Chemistry ◽  
Lower Latitude ◽  
Hudson Bay ◽  
Total N ◽  
Isostatic Rebound ◽  
Natural Lakes ◽  
Spring Lake ◽  
High Concentrations ◽  
Rain Events

Precipitation at Saqvaqjuac (northwest coast of Hudson Bay, 60°39′N) had high concentrations of sea salts, was moderately acidic, and had less SO4 and total N than lower latitude precipitation, although SO4 sources were distant. Watershed retention was high for H+, but negative for other elements as a consequence of isostatic rebound. Annual element runoff was a function of the timing of melt runoff and summer rain events because of permafrost. Lake retention of Si was higher than P because of the different times of loading, late summer versus spring. Conservative element mass did not change overwinter except in low-elevation Spring Lake, where residual Cl, Na, and K diffused from the sediments. Phosphorus and N were the only elements incorporated into black ice. As a result of freezeout and incomplete meltwater mixing beneath lake ice, element concentrations were 1.6 times higher in lakes than inflows, and major ion turnover times were 1.5–2.0 times higher than water turnover times.

scholarly journals N Management of European Grasslands: Can the Exchange of Gaseous N Species Be Influenced at the Operational Level?

2001 ◽  
Vol 1 ◽  
pp. 652-657 ◽  
Author(s):  
P. Calanca ◽  
A. Neftel ◽  
J. Fuhrer
Keyword(s):  
Late Summer ◽  
Fertilizer Application ◽  
Effective Control ◽  
Management Options ◽  
Total N ◽  
Model Calculations ◽  
Weather Forecasts ◽  
Grassland Ecosystems ◽  
Order Of Magnitude ◽  
N Management

Grassland ecosystems can be regarded as biochemical reactors in which large amounts of organic nitrogen (N) are converted into inorganic N, and vice versa. If managed in a sustainable manner, grasslands should operate in a quasi steady state, characterized by an almost perfect balance between total N input and output. As a consequence, the exchange of gaseous N species (NH3, NO, NO2, N2O, and N2) between grasslands and the atmosphere is very small compared to the total N turnover. In this study, the effects of two management options (mowing and fertilization) on production and emission of nitrous oxide (N2O) from a grass/clover crop were examined on the basis of observations and model results referring to an experiment carried out on the Swiss Plateau in late summer of 2000. It was found that production and emission of N2O induced by mowing were of the same order of magnitude as those brought about by fertilization, suggesting a possible transfer of N from clover to the soil after defoliation. Emissions were strongly modulated by precipitation on time scales ranging from 1 day to 1 week. This indicates that effective control of N2O emissions through management on a day-to-day basis requires reliable medium-range weather forecasts. Model calculations were not able to reproduce essential characteristics of the emissions. The model slightly overestimated the background emissions, but severely underestimated the emission peaks following fertilizer application, and largely failed to reproduce emission induced by mowing. Shortfalls in the model used for this study were found in relation to the description of soil-water fluxes, soil organic matter, and the physiology of clover.

Growth and N status of Populus in mixture with red alder on recent volcanic mudflow from Mount Saint Helens

1990 ◽  
Vol 20 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Paul E. Heilman
Keyword(s):  
Late Summer ◽  
Height Growth ◽  
Phosphorus Fertilization ◽  
Cross Sectional ◽  
Red Alder ◽  
Total N ◽  
Foliar N ◽  
N Concentration ◽  
The Mean ◽  
Foliar N Concentration

Eleven months after the May 1980 eruption of Mount Saint Helens in southeastern Washington, United States, three Populus clones were planted in an experiment on the Toutle River mudflow deposit. The trees grew at an abnormally slow rate and by 3 years were overtopped by a dense stand (14 600 ± 3600 trees/ha) of red alder seeded naturally onto the site. Over the 6-year period of the study, the total N content of the soil increased an average of 56 kg•ha−1•year−1•. Foliar N concentration in Populus increased significantly from a mean late summer – early autumn value in the 2nd year (1982) of 0.69% N to a value of 2.06% N at the end of the seventh growing season. The mean annual height growth of the largest Populus averaged <0.5 m/year in the first 3 years, increasing to an average of over 1.0 m/year in the 5th and 6th years. Fertilizer treatments with N (as urea) and N + P (as urea plus treble superphosphate) placed in the soil near the individual Populus at a maximum rate of 5.3 g N/tree increased height growth in the year of fertilization (1982) and the following year (the response in height growth for the 2 years totaled 64%). After 1984, no significant effects of fertilizer on height growth, total height, or diameter were evident. Nitrogen fertilization significantly increased foliar N concentration (1.54% N with the highest N treatment vs. 0.69% N in the control) in the year of treatment only. Phosphorus fertilization had no significant effect on growth or foliar P concentration. At 6 years, only 2% of the Populustrichocarpa Torr. & Gray clone and 13% of the tallest Populus hybrid were equal to or above the mean height of alder dominants and codominants (6.2 m). Additionally, the diameter growth of Populus was severely limited: the trees had only 8% of the cross-sectional area of "normal" trees for their height. Results indicated that on sites of low N such as the mudflow, Populus may not compete satisfactorily in mixture with alder. Such behavior is in sharp contrast to sites of high N, where red alder cannot compete with Populus.

Holocene deltaic sedimentation along an emerging coast: Nastapoka River delta, eastern Hudson Bay, Quebec

2002 ◽  
Vol 39 (4) ◽  
pp. 505-518 ◽  
Author(s):  
Caroline Lavoie ◽  
Michel Allard ◽  
Philip R Hill
Keyword(s):  
River Delta ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Fluvial Erosion ◽  
Fine Grained ◽  
Isostatic Rebound ◽  
Geophysical Surveys ◽  
Deltaic Sedimentation ◽  
Forced Regression ◽  
Natural Laboratory

Eastern Hudson Bay is characterized by falling relative sea level as a result of post-glacial isostatic rebound, which makes the region a natural laboratory for rapid forced regression, where the evolution of deltaic systems and offshore sedimentation patterns can be studied. A multidisciplinary approach involving airphoto analysis, offshore geophysical surveys, sediment coring, and facies and diatom analyses was used in this study of the Nastapoka River delta. The delta has formed as a result of the fluvial erosion of emerged Quaternary sediments but is mainly subaqueous. Offshore, in the prodelta zone, the oldest deposits are glaciomarine, laid down when the ice front of the receding Laurentide ice sheet stood on the Nastapoka hills some 7700–6800 years BP. Lateral equivalents of this glaciomarine unit are presently exposed on land. The shallow-water platform of the delta shows a thin surficial unit of wave-worked sand that overlies fine-grained, deeper water deposits derived from erosion of clay soils in the river catchment a few centuries ago, probably during periods of intense thermokarst activity. As the isostatic uplift continues, the deltaic platform will gradually emerge and be incised by the river channel.

scholarly journals Structural Characterization of Dissolved Organic Matter in Permafrost Peatland Lakes

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3059
Author(s):  
Diogo Folhas ◽  
Armando C. Duarte ◽  
Martin Pilote ◽  
Warwick F. Vincent ◽  
Pedro Freitas ◽  
...  
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Complex Mixture ◽  
Resonance Spectroscopy ◽  
Hudson Bay ◽  
Microbial Decomposition ◽  
Thermokarst Lakes ◽  
Geochemical Properties ◽  
High Concentrations ◽  
Analytical Approaches

Thermokarst lakes result from the thawing of ice-rich permafrost and are widespread across northern landscapes. These waters are strong emitters of methane, especially in permafrost peatland regions, where they are stained black by high concentrations of dissolved organic matter (DOM). In the present study, we aimed to structurally characterize the DOM from a set of peatland thermokarst lakes that are known to be intense sites of microbial decomposition and methane emission. Samples were collected at different depths from three thermokarst lakes in the Sasapimakwananisikw (SAS) River valley near the eastern Hudson Bay community of Kuujjuarapik–Whapmagoostui (Nunavik, Canada). Samples were analyzed by spectrofluorometry, Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and elemental analysis. Fluorescence analyses indicated considerable amounts of autochthonous DOM in the surface waters of one of SAS 1A, indicating a strong bioavailability of labile DOM, and consequently a greater methanogenic potential. The three lakes differed in their chemical composition and diversity, suggesting various DOM transformations phenomena. The usefulness of complementary analytical approaches to characterize the complex mixture of DOM in permafrost peatland waters cannot be overlooked, representing a first step towards greater comprehension of the organic geochemical properties of these permafrost-derived systems.

Effects of age and state of incisor dentition on faecal output of dry matter and on faecal and urinary output of nitrogen and minerals, of sheep grazing hill pastures

1974 ◽  
Vol 83 (1) ◽  
pp. 151-160 ◽  
Author(s):  
A. C. Field ◽  
A. R. Sykes ◽  
R. G. Gunn
Keyword(s):  
Body Weight ◽  
Urine Volume ◽  
Late Summer ◽  
The Body ◽  
The Other ◽  
Urinary Output ◽  
Sheep Grazing ◽  
Total N ◽  
P Deficiency ◽  
Daily Intakes

SUMMARYExcretion of D.M., N, Ca, P and Mg in faeces, and N, P and Mg in urine were measured at intervals over 12 months in breeding Scottish Blackface sheep grazing hill pastures. These values were used with data on reproductive performance and body compositional changes, to calculate the energy, nitrogen and mineral balances. The sheep were: 11 6½-year-old with sound mouths (SM), 16 6½-year-old with broken mouths (BM), 16 5½-year-old with all permanent incisors clipped to gum level (CM) and 16 2½-year-old (Y). An energy supplement was given at the end of gestation and during early lactation. All faeces were collected and creatinine was used as an internal marker to estimate urine volume.Faecal D.M. output ranged from 443 to 662 g/day, with highest values in November and lowest in May. Average values for the BM sheep were lower than those for the other groups but when output was expressed as a power function of body weight, the values for the Y sheep were 15% higher than those for the other groups. Faecal excretions of Ca and P in January and February were very low and the values for P were half the expected endogenous faecal loss.Urinary output ofN ranged from 6·0 g/day in February to 22·2 g/day in August and the corresponding urinary urea N: total N ratios were 0·24 and 0·69. Urinary Mg output was highest in late summer and early winter but urinary P showed no consistent trends.The estimated daily intakes of DOM (g) were 936 in November 1969, 599 in January, 414 in February, 1075 in May, 1150 in August and 946 in November 1970.The loss of energy from the body between mating (November) and mid-lactation (June) ranged from 9·5 to 16·8% of the total calculated ME requirements in the Y and BM sheep, respectively. Maintenance requirements averaged 204 kJ/kg body weight/day and the value for the Y sheep was 12% higher than the mean for the older sheep.Nitrogen and mineral balances were calculated for February, May, August and November. The sheep were protein-deficient in winter, not from a shortage of crude protein in the diet but because of its low digestibility (34%). Intakes of Ca and P in winter were low and a real possibility of a P deficiency exists. Estimates of the concentrations of N and of minerals in the herbage consumed by the sheep were made and compared with those obtained for cut herbage from the same pastures. It would appear that the sheep selected herbage of a higher protein content than that of the cut herbage. Herbage selection was greatest in November.

Modelling the total ammonia impact of CSO and WWTP effluent on the receiving water

1998 ◽  
Vol 38 (10) ◽  
pp. 31-39 ◽  
Author(s):  
Peter Holzer ◽  
Peter Krebs
Keyword(s):  
Treatment Plant ◽  
Rain Event ◽  
Combined System ◽  
Sewer System ◽  
Wwtp Effluent ◽  
Fish Poison ◽  
Combined Sewer ◽  
Total Ammonia ◽  
High Concentrations ◽  
Rain Events

For 25 rain events test runs were performed on a catchment of a small town, where 40% of the person equivalents are connected to a separate sewer system and 60% to a combined one. We investigate the effects of rain events with regard to NH4-loads discharged by the wastewater treatment plant and by a combined sewer overflow. NH4-concentrations in the river caused by these loads are also discussed. NH4 is important as (i) it closely interrelates with NH3 – a fish poison – and (ii) it stands for dissolved compounds that mainly origin from the wastewater. The sewer system is simulated with three different options: with a combined water retention tank connected to the CSO structure, with a sewage retention tank at the interface between the separate and the combined system, and without any retention structure. While the sewage retention tank performs better concerning the integrated load discharged into the river, the combined sewer retention tank is more efficient in decreasing peak values and duration of high concentrations in the river. We also show that NH4 peak concentrations in the river are largely due to a wash-out effect in the main sewer at the beginning of a rain event.

RESPONSE OF ORCHARD GRASS TO MULTIPLE HARVESTS AND RATES OF NITROGEN IN POST-SEEDING YEARS

1977 ◽  
Vol 57 (3) ◽  
pp. 763-770
Author(s):  
H. T. KUNELIUS ◽  
MICHIO SUZUKI
Keyword(s):  
Dry Matter ◽  
Dactylis Glomerata ◽  
Late Summer ◽  
Total N ◽  
Orchard Grass ◽  
Nitrate N ◽  
Dactylis Glomerata L ◽  
N Rates

Frode orchard grass (Dactylis glomerata L.) was fertilized with 99–495 kg N/ha/yr in three equal applications and harvested three or four times per season over a 3-yr period to determine the productivity, quality of forage and persistence of stands. The application of N resulted in significant (P =.001) linear and quadratic increases in dry matter (DM) yields. Higher DM yields were obtained with the 3-harvest system while the yield distribution within the season was more uniform for the 4-harvest system. Total N concentrations of orchard grass increased linearly with the N rates. Total N yields were dependent on the rates of applied N with the recovery of applied N ranging from 39 to 70% at 99–297 kg N/ha/yr, respectively. The in vitro disappearance of DM was slightly reduced by the high N rates in the 1st and 2nd harvests. The nitrate-N concentrations were highest in the early and late summer ranging from.11 to.29% at 297–495 kg N/ha/yr, respectively. The persistence of orchard grass was better under the 4- than the 3- harvest system.

Collapse of the Hudson Bay ice center and glacio-isostatic rebound

Geology ◽  
1976 ◽  
Vol 4 (2) ◽  
pp. 73 ◽  
Author(s):  
J. T. Andrews ◽  
W. R. Peltier
Keyword(s):  
Hudson Bay ◽  
Isostatic Rebound

scholarly journals Surface albedo observations of Hudson Bay (Canada) landfast sea ice during the spring melt

2006 ◽  
Vol 44 ◽  
pp. 23-29 ◽  
Author(s):  
J.K. Ehn ◽  
M.A. Granskog ◽  
T. Papakyriakou ◽  
R. Galley ◽  
D.G. Barber
Keyword(s):  
Energy Balance ◽  
Surface Energy ◽  
Sea Ice ◽  
Surface Energy Balance ◽  
Spatial And Temporal Variability ◽  
Hudson Bay ◽  
Night Time ◽  
Thaw Cycle ◽  
Landfast Sea Ice ◽  
Rain Events

AbstractThe shortwave albedo is a major component in determining the surface energy balance and thus the evolution of the spring melt cycle. As the melt commences, the ice is partitioned into multiple surface types ranging from highly reflective white ice to absorptive blue ice. The reflectance from these surfaces shows significant spatial and temporal variability. Spectral albedo measurements were made at six different sites encompassing these two surface types, from 19 March to 3 May 2005, on 1.5 m thick landfast sea ice in southwestern Hudson Bay, Canada (58˚ N). Furthermore, the broadband albedo and the surface energy balance were continuously recorded at a nearby site during the 1 month period. Rapid changes in the albedo were found to relate to typical subarctic climate conditions, i.e. frequent incursions of southerly air, resulting snow and rain events and the generally high maximum solar insolation levels. Subsequently, diurnal variations in snow surface temperature were evident, often causing daytime melting and night-time refreezing resulting in the formation of ice lenses and superimposed ice. After rain events and extensive melting, the snowpack was transformed throughout into melt/freeze metamorphosed snow and superimposed ice. The integrated (350–1050 nm) albedo varied between 0.52 and 0.95 at the blue-ice sites, while it varied between 0.73 and 0.91 at white-ice sites. Variability on the order of ±10% in the white-ice broadband albedo resulted from the diurnal freeze–thaw cycle, but also synoptic weather events, such as snowfall and rain events, could rapidly change the surface conditions.

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