Temporal Variance Function for Total Phosphorus Concentration

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.


Author(s):  
F. A. J. Armstrong ◽  
H. W. Harvey

Determinations of total phosphorus in water samples have shown areas in the western English Channel with water containing as little as 10 mg. P/m.3, and other areas with double, and more than double, this concentration.The integral mean concentration of total P in the water column, 20 miles off-shore from Plymouth, has fluctuated between 10 and 16 mg. P/m.3 since June 1947.The changes which have taken place in this integral mean concentration are attributed to different water masses, of different total phosphorus concentration, passing through the area, rather than to a seasonal change in the total phosphorus content of a water mass. No marked deposition of phosphorus-containing detritus could be found.Changes in this integral mean were not coincident with changes in salinity. The geographical distribution of total phosphorus does not coincide with the geographical distribution of salinity.



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.



1999 ◽  
Vol 56 (4) ◽  
pp. 560-569 ◽  
Author(s):  
J Chételat ◽  
F R Pick ◽  
A Morin ◽  
P B Hamilton

Epilithic periphyton was investigated in riffle zones of 13 rivers in southern Ontario and western Quebec to describe how algal biomass and community composition vary with nutrient concentration and water velocity during summer. Algal biomass (milligrams chlorophyll a (Chl a) per square metre) was strongly correlated with total phosphorus concentration (r2 = 0.56, p < 0.001) and conductivity (r2 = 0.71, p < 0.001) of the overlying water but unrelated to water velocity over the range of 10-107 cm·s-1. Differences in periphyton Chl a were associated with changes in biomass of Chlorophyta (r2 = 0.51, p = 0.001) and Bacillariophyta (r2 = 0.64, p < 0.001) and were not related to Rhodophyta and Cyanophyta biomass (p > 0.10). The relative proportions of taxonomic divisions varied with total standing stock. Percent Chlorophyta biomass increased with periphyton Chl a and was the largest fraction at moderately eutrophic sites. Rhodophyta contributed the most biomass at sites with the lowest Chl a. Cladophora, Melosira, and Audouinella biomasses were positively correlated with total phosphorus concentration over the range of 6-82 µg·L-1 (r2 = 0.39-0.64, p < 0.005), and these genera were dominant at sites with the highest nutrient concentrations.



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.



1992 ◽  
Vol 27 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Sonia Paulino Mattos ◽  
Irene Guimarães Altafin ◽  
Hélio José de Freitas ◽  
Cristine Gobbato Brandão Cavalcanti ◽  
Vera Regina Estuqui Alves

Abstract Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.



2001 ◽  
Vol 58 (2) ◽  
pp. 421-436 ◽  
Author(s):  
E E Prepas ◽  
B Pinel-Alloul ◽  
D Planas ◽  
G Méthot ◽  
S Paquet ◽  
...  

Eleven headwater lakes in Alberta's Boreal Plain were monitored for nutrients and plankton 2 years before and 2 years after variable watershed harvesting (harvesting mean 15%, range 0-35%). After harvesting, variations in annual precipitation resulted in lake water residence times that differed by an order of magnitude from one year to the next. During the first posttreatment year, total phosphorus concentrations increased (overall 40%) in most lakes; however, response was most consistent in lakes that were shallow and the water column mixed or weakly thermally stratified. Chlorophyll a, cyanobacteria (Aphanizomenon-Anabaena), and cyanotoxins (microcystin-LR) increased after harvesting, primarily in shallow lakes. Zooplankton abundance and biomass decreased after harvesting, particularly in stratified lakes where edible phytoplankton biomass declined. In the weakly or nonstratified lakes, declines in zooplankton biomass were associated with higher cyanobacterial biomass and cyanotoxins. Posttreatment change in total phosphorus concentration was strongly related to weather (greatest response in a wet year) and relative drainage basin size (drainage basin area to lake volume, r2 = 0,78, P << 0,01). There was no evidence that buffer strip width (20, 100, and 200 m) influenced lake response. These results suggest that activities within the entire watershed should be the focus of catchment-lake interactions.



1989 ◽  
Vol 21 (2) ◽  
pp. 111-118 ◽  
Author(s):  
A. H. Arthington ◽  
G. J. Miller ◽  
P. M. Outridge

The water quality and trophic status of two Queensland dune lakes are compared in the context of assessing the impacts of recreational use and other human activities. Lake Freshwater, Cooloola, has a mean total phosphorus concentration of 12.1 ± 3.3 µg l−1 and is approaching mesotrophic status, whereas Blue Lagoon, Moreton Island, is oligotrophic. Natural loadings of total phosphorus, ranging from 0.2 to 0.35 g m−2 yr−1, are consistent with the progression of Lake Freshwater from oligotrophic to mesotrophic status. The phosphorus loadings predicted by Vollenweider's (1976) one-compartment model, for two values of mean lake depth, also indicate that Lake Freshwater is tending towards eutrophic conditions. The management implications of phosphorus loadings and budgets are discussed.





2019 ◽  
Vol 19 (5) ◽  
pp. 1500-1506 ◽  
Author(s):  
I. Melendez-Pastor ◽  
E. M. Isenstein ◽  
J. Navarro-Pedreño ◽  
M-H. Park

Abstract Cyanobacteria bloom events have been associated with eutrophication processes, along with hydrologic and climate factors. Missisquoi Bay is a portion of Lake Champlain (USA–Canada) that is highly eutrophic and prone to cyanobacteria blooms and cyanotoxins. This study assessed the spatial–temporal influence of nutrients, turbidity and temperature in cyanobacteria distributions during a bloom event in the summer of 2006. Correlations, generalized linear models (GLMs), geostatistics and local indications of spatial association (LISA) autocorrelation analysis tested the influence of nutrient and non-nutrient explanatory variables in cyanobacteria biovolume. Total phosphorus exhibited a high direct correlation with cyanobacteria biovolume. The best performing GLMs included total phosphorus, total nitrogen, Secchi depth (as turbidity) and temperature as explanatory variables of cyanobacteria biovolume. Variogram analysis of those variables resulted in a better understanding of the underlying spatial variation process of the cyanobacteria bloom event. The LISA test revealed a moderate but stable autocorrelation between cyanobacteria biovolume and total phosphorus from 180 to 1,000 m of weight distance, suggesting the possibility of up-scaling the current results to coarse-resolution satellite imagery for more frequent monitoring of bloom events. The LISA test also revealed the spatial–temporal dynamic (movement of cyanobacteria scums) of high cyanobacteria blooms with high total phosphorus concentration.



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