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

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.


1985 ◽  
Vol 42 (4) ◽  
pp. 831-835 ◽  
Author(s):  
E. T. Riley ◽  
E. E. Prepas

Data from the literature were used to calculate separate regressions of summer chlorophyll a concentration ([Chl a]) on spring total phosphorus concentration ([TP]) for lakes that remain thermally stratified during the summer and lakes that mix intermittently during the summer. Significant differences were found in the spring [TP] – summer [Chl a] relationships for the two lake types (P < 0.05). The mean ratios of summer [TP] to spring [TP] were also significantly different in stratified and mixed lakes (P < 0.001); this difference is the explanation offered for why the spring [TP] – summer [Chl a] relationships were different in stratified and mixed lakes.



2019 ◽  
Vol 31 ◽  
Author(s):  
Jéssica Nayara de Carvalho Leite ◽  
Vanessa Becker

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.





1975 ◽  
Vol 32 (9) ◽  
pp. 1519-1531 ◽  
Author(s):  
P. J. Dillon ◽  
F. H. Rigler

A general technique is presented for calculating the capacity of a lake for development based on quantifiable relationships between nutrient inputs and water quality parameters reflecting lake trophic status. Use of the technique for southern Ontario lakes is described. From the land use and geological formations prevalent in a lake’s drainage basin, the phosphorus exported to the lake in runoff water can be calculated, which, when combined with the input directly to the lake’s surface in precipitation and dry fallout, gives a measure of the natural total phosphorus load. From the population around the lake, the maximum artificial phosphorus load to the lake can be calculated and, if necessary, modified according to sewage disposal facilities used. The sum of the natural and artificial loads can be combined with a measure of the lake’s morphometry expressed as the mean depth, the lake’s water budget expressed as the lake’s flushing rate, and the phosphorus retention coefficient of the lake, a parameter dependent on both the lake’s morphometry and water budget, to predict springtime total phosphorus concentration in the lake. Long-term average runoff per unit of land area, precipitation, and lake evaporation data for Ontario provide a means of calculating the necessary water budget parameters without expensive and time-consuming field measurements. The predicted spring total phosphorus concentration can be used to predict the average chlorophyll a concentration in the lake in the summer, and this, in turn, can be used to estimate the Secchi disc transparency. Thus, the effects of an increase in development on a lake’s water quality can be predicted. Conversely, by setting limits for the "permissible" summer average chlorophyll a concentration or Secchi disc transparency, the "permissible" total phosphorus concentration at spring overturn can be calculated. This can be translated into "permissible" artificial load, which can then be expressed as total allowable development. This figure can be compared to the current quantity of development and recommendations made concerning the desirability of further development on the lake.



2000 ◽  
Vol 57 (S2) ◽  
pp. 73-81 ◽  
Author(s):  
P McEachern ◽  
E E Prepas ◽  
J J Gibson ◽  
W P Dinsmore

The biogeochemistry of 10 headwater lakes in burnt peatland-conifer catchments and 14 in unburnt catchments was evaluated throughout a summer 2 years following forest fire in a boreal subarctic region of northern Alberta. Cation exchange within burnt catchments resulted in proton flux and a 9% reduction in mean pH. Lakes in burnt catchments contained more than twofold higher (P << 0.01) mean concentrations of total, total dissolved, and soluble reactive phosphorus, 1.5-fold higher (P << 0.01) concentrations of dissolved organic carbon, and more than 1.2-fold higher (P < 0.05) concentrations of total and total dissolved nitrogen, nitrate + nitrite, and ammonium compared with reference lakes. Total phosphorus concentration explained 86% of the variance in reference lake chlorophyll concentration but was not related to chlorophyll concentration in burnt lakes. Analysis of chlorophyll - total phosphorus residuals suggested that algae in burn-impacted lakes were light limited. With the addition of five lakes burnt between 1961 and 1985, time since disturbance and percent disturbance combined explained 74% of the variance in total phosphorus among burnt lakes. Fire caused increased flux of materials to the study lakes with slow recovery over decades.



1984 ◽  
Vol 41 (3) ◽  
pp. 439-445 ◽  
Author(s):  
John Mark Hanson ◽  
Robert Henry Peters

We used data taken from the literature to develop and compare several estimators of crustacean zooplankton biomass (49 lakes) and profundal macrobenthos biomass (38 lakes). Both mean zooplankton biomass (r2 = 0.72, P < 0.001) and mean profundal macrobenthos biomass (r2 = 0.48, P < 0.001) correlated better with mean total phosphorus concentration than with Secchi depth, mean depth, maximum depth, or lake surface area. Mean total phosphorus concentration was also superior to mean chlorophyll a concentration (r2 = 0.57, P < 0.001) as an estimator of zooplankton biomass, but data were insufficient to evaluate chlorophyll a concentration as an estimator of macrobenthos biomass. Inclusion of maximum depth as a variable in a multiple regression resulted in a slight but significant (P < 0.030) improvement in the zooplankton–total phosphorus relationship (R2 = 0.75, P < 0.001). Inclusion of lake surface area as a variable in a multiple regression significantly (P < 0.001) improved the predictive power of the profundal macrobenthos–total phosphorus relationship (R2 = 0.59, P < 0.001).



1995 ◽  
Vol 52 (6) ◽  
pp. 1202-1209 ◽  
Author(s):  
Ruth E. Holland ◽  
Thomas H. Johengen ◽  
Alfred M. Beeton

Concentrations of soluble reactive phosphorus, ammonium-nitrogen, nitrate-nitrogen, silica, and chloride have all increased since the establishment of the zebra mussel (Dreissena polymorpha) in Hatchery Bay, western Lake Erie, in 1988. Total phosphorus concentrations have changed little. These results are from 188 samples collected weekly and year round before the establishment of Dreissena (1984–1987) and 192 samples post-Dreissena (1990–1993). The mean annual total phosphorus concentration for the three complete post-Dreissena years was 35 μg∙L−1 strikingly similar to the concentration of 36 μg∙L−1, which in 1959 helped to define the waters of Lake Erie as eutrophic. The relative steadiness in total phosphorus may reflect sediment reflux, because Hatchery Bay is a polymictic system. The slight increase in the biologically conservative ion, chloride, in the 1990s, is probably due to the increased precipitation and runoff in the western Lake Erie watershed. Decreased phytoplankton and associated increased water clarity caused by efficient filtering by D. polymorpha, have lessened symptoms of eutrophication and produced a situation where nutrients are not fully utilized, i.e., biological oligotrophy.



2000 ◽  
Vol 51 (1) ◽  
pp. 91 ◽  
Author(s):  
Simon A. Townsend

Manton River Reservoir (MRR) and Darwin River Reservoir (DRR) are two small impoundments in the Australian wet/dry tropics. Over an eight-year period, chlorophyll a concentrations in the mixed layer averaged 3.6 µg L−1 in DRR, and 7.1 µg L−1 in MRR. The seasonal pattern of chlorophyll a at MRR was influenced by wet season wash-out (February average 4.8 µg L−1 ), and dry season destratification and nutrient enrichment of the surface waters (July average 8.4 mg L−1 ). In contrast, DRR exhibited near uniform chlorophyll a concentrations over the year. The seasonal patterns of DRR and MRR chlorophyll a are typical of tropical water bodies which tend to have a smaller annual range than temperate lakes, though this can be modified by significant wash-out. Empirical evidence suggests that the phytoplankton biomass of each reservoir is phosphorus limited, relative to the potential provided by other nutrients and light energy. This conclusion is based on a regression of total phosphorus and chlorophyll a concentrations of pooled DRR and MRR data (P < 0.001; r2 = 0.90), and the high total-nitrogen to total-phosphorus concentration ratios (by weight) of 50 and 37 in DRR and MRR, respectively. Annual chlorophyll a and total phosphorus concentrations for both reservoirs are in accord with the OECD regression for temperate lakes and reservoirs.



1978 ◽  
Vol 35 (3) ◽  
pp. 300-304 ◽  
Author(s):  
W. A. Scheider

Phosphorus and hydrological budgets were constructed for four small lakes with Precambrian drainage in Algonquin Park, Ontario. Lake outflow discharge ranged from 21.7 × 105 to 177 × 105 m3∙yr−1. Annual phosphorus input to the lakes from terrestrial drainage and precipitation totaled 36.3–188 kg∙yr−1. The lakes retained 16–41% of the annual input. These data were used to test a series of models that predict the spring total phosphorus concentration in lake water and the mean summer chlorophyll a. The predicted spring phosphorus concentration agreed well with measured values (within 1.3 mg∙m−3) except where human-associated phosphorus input may have contributed to the phosphorus budget of the lake. Agreement between predicted and measured chlorophyll a was not as close. A figure of 0.48 kg P∙capita−1∙yr−1 was calculated as the human-associated supply. Key words: phosphorus budget, chlorophyll a, predictive model, Precambrian lake



1992 ◽  
Vol 49 (5) ◽  
pp. 975-977 ◽  
Author(s):  
Robert L. France ◽  
Robert H. Peters

General relationships between means and variances can be used to determine requisite sample number for desired levels of precision but have not been developed for phosphorus, one of the best indicators of lake eutrophication. Data from 65 north-temperate lake-years are used to compare such relationships of temporal variance as functions of mean concentration for both total phosphorus (TP) and chlorophyll a (Chl a). We found TP to be less seasonally variable than Chl a, confirming several regional analyses and strengthening the established recommendations that variability in Chl a should dictate sampling program design.



Sign in / Sign up

Export Citation Format

Share Document