Response of Lake Ontario to Reductions in Phosphorus Load, 1967–82

1987 ◽  
Vol 44 (12) ◽  
pp. 2059-2068 ◽  
Author(s):  
R. J. J. Stevens ◽  
M. A. Neilson
Keyword(s):  
Response Time ◽  
Multiple Regression ◽  
Total Phosphorus ◽  
Algal Biomass ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
Multiple Regression Equation ◽  
Phosphorus Load ◽  
N:P Ratios ◽  
Reactive Phosphorus

Total phosphorus (TP) loading to Lake Ontario has declined from 14 600 t∙yr−1 in 1969 to 8900 t∙yr−1 in 1982. Midlake spring TP has responded rapidly to these reductions, decreasing at the rate of 1.09 μg∙L−1∙yr−1 from a maximum of 30.6 μg∙L−1 in 1973 to 12.8 μg∙L−1 in 1982. Spring soluble reactive phosphorus (SRP) exhibited a proportionally larger decrease than TP such that 1982 SRP was 33% of 1973 levels, compared with 42% for TP. A multiple regression equation indicated an 80% response time of spring TP within 2 yr and a 90% response time within 4 yr. Spring nitrate plus nitrite has increased since 1969 at the rate of 9.5 μg∙L−1∙yr−1 causing N:P ratios to increase from 10 to 32. Mean summer epilimnetic TP declined at the rate of only 0.3 μg∙L−1∙yr−1 from 1977 to 1982 so that mean summer TP levels now exceed spring TP by 1–2 μg∙L−1. This suggests that loading to the lake during the stratified period has not shown a similar decline and may be responsible for the lack of a trend in algal biomass indicators during this period.

scholarly journals Impacts of drying and reflooding on water quality of a tropical semi-arid reservoir during an extended drought event

2019 ◽  
Vol 31 ◽  
Author(s):  
Jéssica Nayara de Carvalho Leite ◽  
Vanessa Becker
Keyword(s):  
Water Quality ◽  
Electrical Conductivity ◽  
Chlorophyll A ◽  
Total Phosphorus ◽  
Algal Biomass ◽  
Soluble Reactive Phosphorus ◽  
Drought Event ◽  
Reactive Phosphorus ◽  
Semi Arid

Abstract Aim The aim of this study was to analyze the water quality of a tropical, semi-arid reservoir after a reflooding. In terms of impact on water quality after a drought event, it is expected that there will be improvements with the reflooding. Less algal biomass, increased water transparency, decreased turbidity and low nutrient concentration. Methods This study was performed in a tropical, semi-arid man-made lake (Dourado Reservoir), during an extended drought period. This study consisted of a comparison of three distinct periods determined by water accumulation. The limnological variables, including water transparency, turbidity, electrical conductivity, pH, total phosphorus, soluble reactive phosphorus, and chlorophyll-a were analyzed. A principal component analysis (PCA) was also performed to verify the patterns of the variables in relation to the sample units in the studied periods. Results After water renewal, there was an expressive reduction in chlorophyll-a. Electrical conductivity, pH, and turbidity variables also reduced after the reflooding, indicating an improvement in water quality. There was no reduction in total phosphorus and soluble reactive phosphorus after the reflooding compared to the previous periods. Conclusions The significant reduction in algal biomass after reflooding in Dourado indicates water quality improvement in terms of eutrophication due to the change of the trophic state from eutrophic to mesotrophic.

Changes in Nutrient Levels of Lake Water Stored at 4 °C

1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson
Keyword(s):  
Statistical Analysis ◽  
Lake Water ◽  
Water Samples ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
The Other ◽  
Nutrient Levels ◽  
Glass Bottles ◽  
Reactive Phosphorus

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.

Reduction of Cladophora Biomass and Tissue Phosphorus in Lake Ontario, 1972–83

1987 ◽  
Vol 44 (12) ◽  
pp. 2212-2215 ◽  
Author(s):  
D. S. Painter ◽  
G. Kamaitis
Keyword(s):  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
Sampling Period ◽  
Dry Weight ◽  
Weight Basis ◽  
Remote Site ◽  
Net Production ◽  
Control Programs ◽  
Reactive Phosphorus ◽  
Tissue Phosphorus

Cladophora biomass and tissue phosphorus concentrations at seven sites in Lake Ontario have decreased from 1972 to 1983 in response to phosphorus control programs introduced in the early 1970's. Biomass and tissue phosphorus were significantly different between 1972 and 1982–83 (ANOVA, P < 0.001) but not significantly different between 1982 and 1983. The lakewide average tissue phosphorus was 0.49% in 1972 but by 1982 and 1983 had dropped to 0.26 and 0.20%, respectively, on an ash-free dry weight basis. Tissue phosphorus concentrations did not limit growth in 1972 but in 1983 had begun to limit growth. Model-predicted net production for a 6-wk sampling period in 1983 was 1.7 times greater in the western end of the lake than at a remote site in eastern Lake Ontario due to higher soluble reactive phosphorus concentrations.

scholarly journals The Integrated Catchments model of Phosphorus dynamics (INCA-P), a new approach for multiple source assessment in heterogeneous river systems: model structure and equations

2002 ◽  
Vol 6 (3) ◽  
pp. 583-606 ◽  
Author(s):  
A. J. Wade ◽  
P. G. Whitehead ◽  
D. Butterfield
Keyword(s):  
Water Quality ◽  
Total Phosphorus ◽  
Management Practices ◽  
Soluble Reactive Phosphorus ◽  
Particulate Phosphorus ◽  
Model Structure ◽  
River Systems ◽  
Soil System ◽  
Phosphorus Dynamics ◽  
Reactive Phosphorus

Abstract. A new model has been developed for assessing the effects of multiple sources of phosphorus on the water quality and aquatic ecology in heterogeneous river systems. The Integrated Catchments model for Phosphorus (INCA-P) is a process-based, mass balance model that simulates the phosphorus dynamics in both the plant/soil system and the stream. The model simulates the spatial variations in phosphorus export from different land use types within a river system using a semi-distributed representation, thereby accounting for the impacts of different land management practices, such as organic and inorganic fertiliser and wastewater applications. The land phase of INCA-P includes a simplified representation of direct runoff, soilwater and groundwater flows, and the soil processes that involve phosphorus. In addition, the model includes a multi-reach in-stream component that routes water down the main river channel. It simulates Organic and Inorganic Phosphorus concentrations in the land phase, and Total Phosphorus (dissolved plus particulate phosphorus) concentrations in the in-stream phase. In-stream Soluble Reactive Phosphorus concentrations are determined from the Total Phosphorus concentrations and the macrophyte, epiphyte and algal biomasses are simulated also. This paper describes the model structure and equations, the limitations and the potential utility of the approach. Keywords: modelling, water quality, phosphorus, soluble reactive phosphorus, basin management

scholarly journals Tertiary phosphorus removal to extremely low levels by coagulation-flocculation and cloth-filtration

2020 ◽  
Vol 82 (1) ◽  
pp. 131-143 ◽  
Author(s):  
T. Fundneider ◽  
L. Alejo ◽  
S. Lackner
Keyword(s):  
Total Phosphorus ◽  
Phosphorus Removal ◽  
Membrane Filtration ◽  
Soluble Reactive Phosphorus ◽  
Organic Micropollutants ◽  
Synergy Effects ◽  
Coupled Process ◽  
Low Levels ◽  
Reactive Phosphorus ◽  
Solids Removal

Abstract Higher standards in the European Water Framework Directive and national directive demand advanced wastewater treatment for removal of nutrients and organic micropollutants before the discharge into water bodies. Systematic investigations regarding relative dosage and filtration processes for removal of flocculated solids are currently lacking. In this study, the performance of technologies for advanced removal of total phosphorus down to &lt;100 μg/L with pile cloth-filtration (CF) and membrane filtration was verified and synergy effects for the removal of other contaminants were identified. The results show that an over-stoichiometric addition of coagulants of &gt;5 mol Me3+/mol sRP was necessary to achieve soluble reactive phosphorus (sRP) concentrations of &lt;50 μg/L in the effluent. After the coupled process of tertiary phosphorus removal and solids removal, the soluble non-reactive phosphorus (sNRP) concentration regulates the lowest total phosphorus effluent concentration. sNRP is also partially, but not completely, removed by the use of coagulants. CF has proven to be an alternative technology for the removal of phosphorus and total suspended solids below the detection limit.

Effects of Large-Scale Metalimnetic Migration Events on Phosphorus Dynamics In a North-Temperate Reservoir

1990 ◽  
Vol 47 (1) ◽  
pp. 156-162 ◽  
Author(s):  
William F. James ◽  
Robert H. Kennedy ◽  
Robert F. Gaugush
Keyword(s):  
Total Phosphorus ◽  
Large Scale ◽  
Soluble Reactive Phosphorus ◽  
Phosphorus Loading ◽  
Sediment Surface ◽  
Anoxic Water ◽  
Oxidized Iron ◽  
Phosphorus Sedimentation ◽  
Reactive Phosphorus ◽  
Large Wind

In Eau Galle Reservoir, Wisconsin, early in the stratified period of 1982, hypolimnetic anoxia developed, soluble reactive phosphorus concentrations increased above the profundal sediment surface, and internal total phosphorus loading was high. Shortly thereafter, the passage of a cold front with high wind power resulted in mixing and a pronounced descent of the metalimnion. During this event, previously anoxic water within the metalimnion and upper hypolimnion became reoxygenated, internal total phosphorus loading declined to a minimum, and a loss of total phosphorus mass occurred from the metalimnion and hypolimnion. Total phosphorus mass in the epilimnion remained constant during this period. A similar pattern occurred during a large, wind-driven migration of the metalimnion in early August. During such events, phosphorus sedimentation rates increased in the hypolimnion, reflecting the loss of total phosphorus mass from the water column. In contrast, other investigations of lakes have reported that phosphorus is entrained into the epilimnion during metalimnetic migrations, rather than lost through sedimentation. Phosphorus sedimentation during large metalimnetic migration events in Eau Galle Reservoir may occur because previously anoxic water containing iron becomes reoxygenated, causing the coprecipitation and sedimentation of oxidized iron and phosphorus.

Spatial Heterogeneity of Nutrients and Organic Matter in Lake Ontario

1987 ◽  
Vol 44 (12) ◽  
pp. 2192-2203 ◽  
Author(s):  
M. A. Neilson ◽  
R. J. J. Stevens
Keyword(s):  
Organic Matter ◽  
Soluble Reactive Phosphorus ◽  
Lake Ontario ◽  
Nepheloid Layer ◽  
Niagara River ◽  
Water Column Stability ◽  
Phytoplankton Species Composition ◽  
Reactive Silica ◽  
Spring Lake ◽  
Reactive Phosphorus

During spring, Lake Ontario was vertically homogeneous except for the bottom 2 m where soluble reactive silica (SRS) and temperature (TEMP) were significantly (p < 0.05) elevated and dissolved oxygen was depleted. With stratification, soluble reactive phosphorus (SRP) and total filtered phosphorus, SRS, and nitrate-plus-nitrite were depleted in the epilimnion due to phytoplankton uptake. Total unfiltered phosphorus (TP) and ammonia (NH3) exhibited higher epilimnetic concentrations, the former being attributed to tributary inputs which were maintained throughout the stratified period, even though inputs from Niagara River served to dilute the epilimnion. Increased levels of TP, SRP, and SRS were also evident within the nepheloid layer. Horizontal distributions of TP and NH3 were governed by point-source inputs throughout the study period. Distributions of the soluble nutrients were governed by phytoplankton uptake in the spring, point/nonpoint inputs and upwelling in the summer, and differential breakdown of stratification in the fall. Spring distribution of particulate organic matter (POM) was strongly related to nutrient availability and water column stability, while phytoplankton species composition determined fall POM distribution. Significantly higher (p < 0.05) POM levels, detrital content, and productivity were observed nearshore of the thermal bar.

Longitudinal and seasonal development of planktonio chlorophyll a in the Rideau River, Ontario

1995 ◽  
Vol 52 (4) ◽  
pp. 804-815 ◽  
Author(s):  
B. K. Basu ◽  
F. R. Pick
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Soluble Reactive Phosphorus ◽  
Seasonal Development ◽  
Phosphorus Concentration ◽  
Total Phosphorus Concentration ◽  
Chlorophyll A Concentration ◽  
Chl A ◽  
Reactive Phosphorus ◽  
Rideau River

Planktonic chlorophyll a (chl-a) concentrations in the Rideau River, Ontario showed longitudinal and seasonal variation and ranged from 2 to 19 μg∙L−1. Chlorophyll a concentrations in the river were not simply a reflection of the concentrations in the headwaters. On movement from the lentic headwaters into the lotic river waters there was usually a significant decrease in chl-a concentration. Downstream there were reaches of net increase in chl-a (sources), reaches of no change in concentration, and reaches of net decrease (sinks). Increases in concentration only occurred over reaches with retention times of 72 h or longer. No increases in chl-a concentration occurred over a reach with a retention time less than 50 h. Chlorophyll a concentration was not significantly correlated with discharge. Chlorophyll a concentration was positively related to total phosphorus concentration (R2 = 0.15, p = 0.016). About 50% of the variation in chl-a concentration could be accounted for by a combination of total phosphorus, nitrate, and soluble reactive phosphorus concentrations.

Spatial and Temporal Water Quality Trends in Severn Sound, Georgian Bay, since the Introduction of Phosphorus Control Guidelines: Nutrients and Phytoplankton, 1973 to 1991

1995 ◽  
Vol 30 (4) ◽  
pp. 565-592 ◽  
Author(s):  
A.F. Gemza
Keyword(s):  
Total Phosphorus ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Soluble Reactive Phosphorus ◽  
Euphotic Zone ◽  
Water Clarity ◽  
Sewage Treatment Plants ◽  
Order Of Magnitude ◽  
Phosphorus Levels

Abstract Severn Sound continues to exhibit signs of eutrophication despite initial identification of the problem in 1969 and the construction of several sewage treatment plants since then. In general, improvements in trophic state indicators have been marginal, suggesting that the sewage treatment plants have had limited success in controlling phosphorus concentrations. These discharges likely contributed to the increased total phosphorus levels and consequently the higher phytoplankton densities of the nearshore waters. Phytoplankton biovolumes were on average one order of magnitude higher than in the open waters of Lake Huron with mean summer biovolumes as high as 8.0 mm/L. Algal biovolumes were most dense in Penetang Bay, which experienced limited exchange with the main waters of the sound. No significant long-term trends were observed. Water clarity was declining significantly, however, at a rate of -0.60 to -0.78 m/year throughout the sound except in Sturgeon Bay. Total phosphorus levels were highly variable from year to year; however, concentrations from a 20-year perspective were declining in the open waters at a rate of 0.70 µg/L/year, but response was limited in nearshore areas. In Sturgeon Bay, mean annual euphotic zone total phosphorus as well as soluble reactive phosphorus levels declined by as much as 50% following the construction of a sewage treatment plant with tertiary treatment. Phytoplankton genera typical of eutrophic waters continued to dominate the algal assemblage but members indicative of mesotrophic conditions have become apparent in some areas of the sound.

Differences between Nearshore and Offshore Phytoplankton Communities in Lake Ontario

1987 ◽  
Vol 44 (12) ◽  
pp. 2155-2163 ◽  
Author(s):  
I. M. Gray
Keyword(s):  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Algal Biomass ◽  
Phytoplankton Community ◽  
Seasonal Pattern ◽  
Principal Component ◽  
Lake Ontario ◽  
Dominant Group ◽  
Phytoplankton Communities ◽  
Eutrophic Species

Differences between nearshore and offshore phytoplankton biomass and composition were evident in Lake Ontario in 1982. Phytoplankton biomass was characterized by multiple peaks which ranged over three orders of magnitude. Perhaps as a consequence of the three times higher current velocities at the northshore station, phytoplankton biomass ranged from 0.09 to 9.00 g∙m−3 compared with 0.10 to 2.40 g∙m−3 for the midlake station. Bacillariophyceae was the dominant group at the northshore station until September when Cyanophyta contributed most to the biomass (83%). Although Bacillariophyceae was the principal component of the spring phytoplankton community at the midlake station, phytoflagellates (49%) and Chlorophyceae (25%) were responsible for summer biomass, with the Chlorophyceae expanding to 80% in the fall. The seasonal pattern of epilimnetic chlorophyll a correlated with temperature. While chlorophyll a concentrations were similar to values from 1970 and 1972, algal biomass had declined and a number of eutrophic species (Melosira binderana, Stephanodiscus tenuis, S. hantzschii var. pusilla, and S. alpinus) previously found were absent in 1982.

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