scholarly journals Effects of nutrient loading on the trophic state of Lake Brunner

2013 ◽  
Vol 64 (5) ◽  
pp. 436 ◽  
Author(s):  
P. Verburg ◽  
J. Horrox ◽  
E. Chaney ◽  
J. C. Rutherford ◽  
J. M. Quinn ◽  
...  
Keyword(s):  
Nutrient Loading ◽  
Urban Expansion ◽  
Secchi Depth ◽  
Oxygen Depletion ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
Nutrient Inputs ◽  
Hypolimnetic Oxygen ◽  
Algal Productivity ◽  
Nitrogen Phosphorus

Lake Brunner, an oligotrophic monomictic lake on the West Coast of the South Island of New Zealand, is under pressure from urban expansion and increased farming activity, which has led to concern for the effects on water quality in the lake. Epilimnetic nitrogen, phosphorus and chlorophyll a concentrations have increased since 1992, and Secchi depth decreased. This suggests an increased algal productivity caused by increased nutrient inputs, further supported by increased hypolimnetic oxygen depletion since 1992. These observations are likely to have resulted from enhancement of pasture drainage and effluent inputs from expanding dairy farms. The Vollenweider model predicted a mean phosphorus concentration in the lake close to that observed, from estimated catchment loading, suggesting that the Vollenweider model adequately estimated the retention of phosphorous. With the Vollenweider model the effects of potential future loading scenarios were explored. Modelling suggested that a 70% increase in phosphorus loading could turn the lake into a mesotrophic state. Trend analysis of total phosphorus suggests that, with present land uses in the catchment (intensive dairy farming) continuing to develop at the same rate using the same land management practises, this transition to a mesotrophic state will occur by 2040.

Phosphorus Input and Its Consequences for Phytoplankton Standing Crop and Production in the Experimental Lakes Area and in Similar Lakes

1978 ◽  
Vol 35 (2) ◽  
pp. 190-196 ◽  
Author(s):  
D. W. Schindler ◽  
E. J. Fee ◽  
T. Ruszczynski
Keyword(s):  
Lake Management ◽  
Phosphorus Loading ◽  
Phytoplankton Production ◽  
Phosphorus Concentration ◽  
Nutrient Inputs ◽  
Experimental Lakes Area ◽  
Total Phosphorus Concentration ◽  
Water Renewal ◽  
Rapid Changes ◽  
Shield Lakes

Correlation and regression analyses were used to assess several expressions for phosphorus loading, with and without corrections for water renewal and sedimentation, as predictors of total phosphorus concentration, chlorophyll, phytoplankton volume, and phytoplankton production in the Experimental Lakes Area (ELA) lakes. All expressions tested were good predictors, allowing predictions of the above parameters with 95% confidence intervals of 20–30% of the mean for any loading value. In general, correction for water renewal improved the fit of the expression, but correction for sedimentation did not. When the above strategy was applied to lakes outside ELA but with Shield or Shield-like drainage, good results were also obtained when expressions incorporating water renewal were used. If uncorrected for water renewal, loading was a poor predictor. Correction for sedimentation did not improve the expressions significantly. Correction for rapid changes in phosphorus input did not improve the predictability of equations, indicating that the equilibrium between ELA lakes and new loading conditions occurs very rapidly. Key words: Precambrian Shield lakes, eutrophication, lake management, nutrient inputs

Effects of hypolimnetic oxygenation on water quality in Amisk Lake, Alberta, a deep, eutrophic lake with high internal phosphorus loading rates

1997 ◽  
Vol 54 (9) ◽  
pp. 2111-2120 ◽  
Author(s):  
E E Prepas ◽  
J M Burke
Keyword(s):  
Nutrient Loading ◽  
Injection System ◽  
Pure Oxygen ◽  
Management Tool ◽  
Phosphorus Loading ◽  
Nutrient Concentrations ◽  
Oxygen Injection ◽  
Loading Rates ◽  
Hypolimnetic Oxygen ◽  
Injection Rates

Year-round injection of pure oxygen into the hypolimnion of one of two basins in Amisk Lake during 1988-1993 changed dissolved oxygen (DO) and nutrient concentrations in both lake basins without eliminating thermal stratification. Changes were greatest in the treated basin and during 1990-1993, when an upgraded injection system operated; injection rates of <<= 1.3 t · day-1 increased mean summer hypolimnetic DO concentrations from 1.0 (1980-1987) to 4.6 mg ·L-1 (1990-1993). Summer hypolimnetic DO depletion rates nearly doubled relative to the pretreatment period. Mean summer hypolimnetic total phosphorus (TP) concentrations decreased from 123 to 56 µg · L-1, despite low iron to phosphorus ratios near the sediments. Similarly, mean hypolimnetic ammonium concentrations declined from 120 to 42 µg ·L-1. Epilimnetic TP and chlorophyll a concentrations decreased to 87 and 45%, respectively, of pretreatment summer means. Oxygen consumption rates in the treated basin were lower in winter than in summer; injection rates of <<= 0.8 t ·d-1 increased mean winter deepwater DO concentrations from 2.5 to 7.2 mg ·L-1. In winter, mean deepwater TP concentrations decreased from 96 to 51 µg ·L-1. Oxygenation enhanced deepwater circulation in the treated basin in summer and winter. No changes were seen in two other reference basins during the study period. The hypolimnetic oxygen injection technology developed at Amisk Lake can be a cost-effective management tool for lakes with high hypolimnetic oxygen depletion rates related to high internal nutrient loading rates.

scholarly journals Simulating Nutrients and Phytoplankton Dynamics in Lakes: Model Development and Applications

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2088
Author(s):  
Bushra Tasnim ◽  
Xing Fang ◽  
Joel S. Hayworth ◽  
Di Tian
Keyword(s):  
Chlorophyll A ◽  
Nutrient Dynamics ◽  
Nutrient Loading ◽  
Phosphorus Release ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
Model Parameters ◽  
Quality Model ◽  
Demand Models ◽  
Mean Square Errors

Due to eutrophication, many lakes require periodic management and restoration, which becomes unpredictable due to internal nutrient loading. To provide better lake management and restoration strategies, a deterministic, one-dimensional water quality model MINLAKE2020 was modified from daily MINLAKE2012 by incorporating chlorophyll-a, nutrients, and biochemical oxygen demand models into the regional year-around temperature and dissolved oxygen (DO) model. MINLAKE2020 was applied to six lakes (varying depth and trophic status) in Minnesota focusing on studying the internal nutrient dynamics. The average root-mean-square errors (RMSEs) of simulated water temperature and DO in six lakes are 1.51 °C and 2.33 mg/L, respectively, when compared with profile data over 2–4 years. The average RMSE of DO simulation decreased by 24.2% when compared to the MINLAKE2012 model. The internal nutrient dynamics was studied by analyzing time series of phosphorus, chlorophyll-a, and DO over several years and by performing a sensitivity analysis of model parameters. A long-term simulation (20 years) of Lake Elmo shows that the simulated phosphorus release from sediment under the anoxic condition results in surface phosphorus increase, which matches with the observed trends. An average internal phosphorus loading increase of 92.3 kg/year increased the average daily phosphorus concentration by 0.0087 mg/L.

Prediction of Total Phosphorus Concentrations, Chlorophyll a, and Secchi Depths in Natural and Artificial Lakes

1981 ◽  
Vol 38 (4) ◽  
pp. 414-423 ◽  
Author(s):  
Daniel E. Canfield Jr. ◽  
Roger W. Bachmann
Keyword(s):  
Total Phosphorus ◽  
Environmental Protection Agency ◽  
Secchi Depth ◽  
Sedimentation Coefficient ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
Total Phosphorus Concentration ◽  
Artificial Lakes ◽  
Wide Range ◽  
Using Data

A model for the prediction of total phosphorus was developed and tested using data on 704 nautral and artificial lakes including 626 lakes in the U.S. Environmental Protection Agency (EPA) National Eutrophication Survey. A statistical analysis showed that the best estimate for the sedimentation coefficient (σ) in the Vollenweider equation was[Formula: see text]for artificial lakes where L is the areal phosphorus loading rate (mg∙m−2∙yr−1) and z is the mean depth (m). The model yields unbiased estimates of phosphorus concentrations over a wide range of lake types and has a 95% confidence interval of 31–288% of the calculated total phosphorus concentration. Other models are less precise. Though total phosphorus concentrations can be predicted equally well in natural and artificial lakes, predictions of algal densities and water transparency are less reliable in artificial lakes, as the phosphorus–chlorophyll and chlorophyll–Secchi depth relationships are less precise. This seems to be due to the influence of nonalgal particulate materials.Key words: phosphorus models, eutrophication, lake trophic state

scholarly journals Assessing Impacts of Changes in External Nutrient Loadings on a Temperate Chinese Drinking Water Reservoir

2021 ◽  
Vol 9 ◽  
Author(s):  
Qingchuan Chou ◽  
Anders Nielsen ◽  
Tobias K. Andersen ◽  
Fenjuan Hu ◽  
Weiyu Chen ◽  
...  
Keyword(s):  
Water Quality ◽  
Drinking Water ◽  
Nutrient Loading ◽  
Water Reservoir ◽  
Phosphorus Loading ◽  
Lake Ecosystem ◽  
Nutrient Load ◽  
Nutrient Inputs ◽  
Nutrient Loadings ◽  
External Nutrient

The safety of drinking water is constantly being evaluated. In the last few decades, however, many drinking waters sources in the world, including in China, have undergone serious eutrophication and consequently water quality deterioration due to anthropogenic induced stressors such as elevated external nutrient inputs. In this study, we used the state-of-the-art complex, dynamic, mechanistic model GOTM-FABM-PCLake (a coupled one-dimensional hydrodynamic-lake ecosystem model) to quantitatively assess the impacts of external nutrient loading on the temperate Jihongtan reservoir in Shandong Province, China. Simulated values of all variables targeted in calibration (water temperature, dissolved oxygen, total nitrogen, total phosphorus, and chlorophyll a) agreed well with observations throughout the entire calibration and validation period and generally mimicked seasonal dynamics and inter-annual variations as found in the monitoring data. A series of scenarios, representing changed external nutrient loadings (both increasing and decreasing compared to the current nutrient load), were set up to quantify the effects on the reservoir water quality. Changes relative to the current external nutrient load had a significant effect on the simulated TN and TP concentrations in the reservoir. Our impact assessment indicate that TN will meet the Chinese water quality requirements of the water source (Class III) when the external nitrogen load is reduced by 70%, whereas TP will meet the requirements even if the external phosphorus load is increased by 100% relative to current loads. The model predicts progressively higher summer and autumn phytoplankton biomasses in the scenarios with increasing external phosphorus loading and potential toxic cyanobacteria will become more dominant at the expense of diatoms and other algae. Strict control of the external nutrient loading is therefore needed to maintain good drinking water quality in the reservoir.

Long-Term (15 Years) Results of NPS Controls in an Agricultural Watershed upon a Receiving Lake's Water Quality

1993 ◽  
Vol 28 (3-5) ◽  
pp. 441-449 ◽  
Author(s):  
Paul J. Garrison ◽  
Timothy R. Asplund
Keyword(s):  
Water Quality ◽  
Structural Changes ◽  
Soil Phosphorus ◽  
Water Clarity ◽  
Management Control ◽  
Agricultural Watershed ◽  
Control Measures ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
White Clay

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.

Loading rates of nutrients discharging from a golf course and a neighboring forested basin

1999 ◽  
Vol 39 (12) ◽  
pp. 99-107 ◽  
Author(s):  
Takao Kunimatsu ◽  
Miki Sudo ◽  
Takeshi Kawachi
Keyword(s):  
Nutrient Loading ◽  
Chamaecyparis Obtusa ◽  
Phosphorus Loading ◽  
Golf Course ◽  
Nutrient Concentrations ◽  
Golf Courses ◽  
Japanese Cypress ◽  
Arithmetic Average ◽  
Loading Rates ◽  
Runoff Rate

In the last ten years, the number of golf courses has been increasing in some countries as the game gains popularity. This indicates, a need to estimate the nutrient loading from golf courses in order to prevent the eutrophication of water bodies. Nutrient concentrations and flow rates of a brook were measured once a week from 1989 to 1990 at two sites: Site A of a brook flowing out from D-golf course (53 ha) and Site B of the same brook discharging into the golf course from an upper forested basin (23 ha) covered mainly with planted Japanese cypress (Chamaecyparis obtusa SIEB. et ZUCC). The bedrock of the area was granite. The annual values of precipitation and mean temperature were 1947 mm and 13.5°C in 1989, respectively. The arithmetic average values of discharge from the forested basin and the golf course were 0.392 and 1.26 mg/l total nitrogen (TN), 0.0072 and 0.145 mg/l total phosphorus (TP), 0.82 and 3.53 mg/l potassium ion (K+, 5.92 and 8.24 mg/l sodium ion (Na+), 2.1 and 9.9 mg/l suspending solid (0.001–2.0 mm, SS), 0.087 and 0.147 mS/cm electric conductivity (EC), and 0.031 and 0.037 m3/km2•s specific discharge, respectively. The loading rates of the forested basin and the golf course were 5.42 and 13.5 TN, 0.133 and 3.04 TP, 8.84 and 33.9 K+, 55.0 and 73.0 Na+, and 54.3 and 118 SS in kg/ha•y. The leaching and runoff rate of nitrogen in the chemical fertilizers applied on the golf course was calculated as 32%. These results indicated the importance of controlling the phosphorus loading for the management of golf courses.

Phosphorus and land-use changes are significant drivers of cladoceran community composition and diversity: an analysis over spatial and temporal scales

2010 ◽  
Vol 67 (8) ◽  
pp. 1262-1273 ◽  
Author(s):  
Marc Richard Albert ◽  
Guangjie Chen ◽  
Graham K. MacDonald ◽  
Jesse C. Vermaire ◽  
Elena M. Bennett ◽  
...  
Keyword(s):  
Land Use ◽  
Community Composition ◽  
Time Series Data ◽  
Temporal Analysis ◽  
Phosphorus Loading ◽  
Series Data ◽  
Phosphorus Concentration ◽  
Total Phosphorus Concentration ◽  
Watershed Disturbance ◽  
Subfossil Cladoceran

We conducted paleolimnological studies over spatial and temporal gradients to define the responses of subfossil cladoceran community composition and diversity to changes in land use and phosphorus concentrations in shallow lakes. We predicted that watershed disturbance by humans, through its impact on water quality, would explain significant variation in cladoceran diversity and composition. Across lakes, water-column total phosphorus concentration was a significant (p < 0.05) predictor of the subfossil cladoceran community composition. Chydorid diversity was also found to be related significantly to phosphorus concentration (r = –0.55, p < 0.05) and the proportion of disturbed land in the watershed (r = –0.47, p < 0.05). However, net load of phosphorus to the watershed rather than proportion of watershed disturbance was a significant predictor of chydorid diversity (r = –0.86, p < 0.001) in our temporal analysis of an eutrophying lake. Given that phosphorus loading to surface waters is often related to phosphorus concentrations in soils, we suggest that the net phosphorus load to the watershed is a more sensitive metric of land-use change and necessary for detecting ecological responses in time series data.

scholarly journals Physico-Chemical Analysis of Mangrove Soil, Kundapura, Karnataka, India

2020 ◽  
Vol 15 (3) ◽  
pp. 624-631
Author(s):  
Vijaya Kumar Kallushettihalli Mallappa ◽  
Vijaya Kumara
Keyword(s):  
Electrical Conductivity ◽  
Soil Analysis ◽  
Periodic Variation ◽  
Soil Samples ◽  
Phosphorus Concentration ◽  
Available Phosphorus ◽  
Available Nitrogen ◽  
Mangrove Soil ◽  
Physico Chemical ◽  
Nitrogen Phosphorus

The present study was carried out to determine the periodic variation in physico-chemical characteristics of mangrove soil samples. The soil samples had been accrued from four distinctive places of Kundapura mangrove areas in three seasons, monsoon, pre-monsoon and post-monsoon. Soil analysis pertaining to various variables such as total Nitrogen, Phosphorus, Potassium, pH and Electrical conductivity. Soil pH is assorted from 3.84 to 6.66. Electrical conductivity is assorted from 0.02 dSm-1 to 9.60 dSm-1. Available nitrogen is assorted from 30.7 kg/ha to 323 kg/ha. Available phosphorus concentration has ranged between 1.37 kg/ha and 47.27 kg/ha. Available potassium is differed from 117.43 kg/ha to 537.63 kg/ha. The results confirmed variations in all of the analyzed parameters of the soils amassed from four stations.

Kinetic modelling of microalgal growth and fucoxanthin synthesis in photobioreactor

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaojuan Zhang ◽  
Junru Zhao ◽  
Jie Zhang ◽  
Shijing Su ◽  
Luqiang Huang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Kinetic Parameters ◽  
Kinetic Modelling ◽  
Inhibitory Effect ◽  
Rate Equations ◽  
Phosphorus Concentration ◽  
Model Output ◽  
Nitrogen And Phosphorus ◽  
Nitrogen Phosphorus

Abstract This paper presented a mathematical model to describe the production of fucoxanthin by alga Thalassiosira weissflogi ND-8 in photobioreactor. Our interest was focused on characterizing the effects of nitrogen and phosphorus on the growth of microalgae and on the synthesis of fucoxanthin. The rate equations of microalgal growth, fucoxanthin synthesis and substrate consumptions were formulated. Kinetic parameters of the model and their sensitivities with respect to model output were estimated. The predicted results were compared with experimental data, which showed that this model closely agrees with actual experiment and is able to reflect the growth and metabolism characteristics of microalgae. Our results also indicated that nitrogen plays a major role in the synthesis of fucoxanthin, and the synthesis of fucoxanthin is partially linearly related to the consumption of nitrogen. Phosphorus is primarily consumed in the growth and metabolism of microalgal cells, while excessive phosphorus concentration has an inhibitory effect on the growth of microalgae.

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