Effects of Changes in pH on Transparency and Thermal Regimes of Lohi Lake, near Sudbury, Ontario

1983 ◽  
Vol 40 (5) ◽  
pp. 621-626 ◽  
Author(s):  
Norman D. Yan
Keyword(s):  
Total Phosphorus ◽  
Phytoplankton Biomass ◽  
Secchi Depth ◽  
Thermocline Depth ◽  
Heating Rates ◽  
Thermal Regimes ◽  
Hypolimnetic Heating ◽  
Chlorophyll Concentrations

Changes in Secchi transparency (depth) and thermal regimes accompanying experimental neutralization and subsequent re-acidification of Lohi Lake, near Sudbury, Ontario are described. Secchi depth was not correlated with chlorophyll concentrations, phytoplankton biomass or total phosphorus, but it was negatively correlated with pH. Secchi depth was positively correlated with thermocline depth, epilimnetic thickness, and hypolimnetic heating rates suggesting that acidification should result in deeper mixing zones and warmer hypolimnia in lakes. Several possible implications of changes in transparency and thermal regimes produced by acidification are presented.

Spatial variability and temporal dynamics of cyanobacteria blooms and water quality parameters in Missisquoi Bay (Lake Champlain)

2019 ◽  
Vol 19 (5) ◽  
pp. 1500-1506 ◽  
Author(s):  
I. Melendez-Pastor ◽  
E. M. Isenstein ◽  
J. Navarro-Pedreño ◽  
M-H. Park
Keyword(s):  
Total Phosphorus ◽  
Temporal Dynamics ◽  
Secchi Depth ◽  
Spatial Association ◽  
Phosphorus Concentration ◽  
Lake Champlain ◽  
Total Phosphorus Concentration ◽  
Cyanobacteria Bloom ◽  
Explanatory Variables ◽  
Cyanobacteria Blooms

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.

scholarly journals Piscivores, Trophic Cascades, and Lake Management

2002 ◽  
Vol 2 ◽  
pp. 284-307 ◽  
Author(s):  
Ray W. Drenner ◽  
Ray K. David Hambright
Keyword(s):  
Total Phosphorus ◽  
Phytoplankton Biomass ◽  
Field Experiments ◽  
Experimental Testing ◽  
Management Strategies ◽  
Lake Management ◽  
Zooplankton Biomass ◽  
Phosphorus Concentration ◽  
Cascading Trophic Interactions ◽  
Lake Systems

The concept of cascading trophic interactions predicts that an increase in piscivore biomass in lakes will result in decreased planktivorous fish biomass, increased herbivorous zooplankton biomass, and decreased phytoplankton biomass. Though often accepted as a paradigm in the ecological literature and adopted by lake managers as a basis for lake management strategies, the trophic cascading interactions hypothesis has not received the unequivocal support (in the form of rigorous experimental testing) that might be expected of a paradigm. Here we review field experiments and surveys, testing the hypothesis that effects of increasing piscivore biomass will cascade down through the food web yielding a decline in phytoplankton biomass. We found 39 studies in the scientific literature examining piscivore effects on phytoplankton biomass. Of the studies, 22 were confounded by supplemental manipulations (e.g., simultaneous reduction of nutrients or removal of planktivores) and could not be used to assess piscivore effects. Of the 17 nonconfounded studies, most did not find piscivore effects on phytoplankton biomass and therefore did not support the trophic cascading interactions hypothesis. However, the trophic cascading interactions hypothesis also predicts that lake systems containing piscivores will have lower phytoplankton biomass for any given phosphorus concentration. Based on regression analyses of chlorophyll�total phosphorus relationships in the 17 nonconfounded piscivore studies, this aspect of the trophic cascading interactions hypothesis was supported. The slope of the chlorophyll vs. total phosphorus regression was lower in lakes with planktivores and piscivores compared with lakes containing only planktivores but no piscivores. We hypothesize that this slope can be used as an indicator of “functional piscivory” and that communities with extremes of functional piscivory (zero and very high) represent classical 3- and 4-trophic level food webs.

scholarly journals Synergistic effects between omnivorous filter-feeding fish and nutrient enrichment on algal biomass

2015 ◽  
Vol 27 (2) ◽  
pp. 223-227 ◽  
Author(s):  
Leonardo Henrique Teixeira ◽  
José Luiz Attayde
Keyword(s):  
Chlorophyll A ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Nutrient Enrichment ◽  
Phytoplankton Biomass ◽  
Nile Tilapia ◽  
Nutrient Addition ◽  
Northeastern Brazil ◽  
Filter Feeding ◽  
Positive Effect

Aim: The Nile tilapia - Oreochromis niloticus(Linnaeus 1758) - is an exotic omnivorous filter-feeding fish that has been stocked for three decades in man-made lakes of Northeastern Brazil. Most experiments manipulating omnivorous filter-feeding fish in eutrophic lakes and reservoirs shows that their presence tends to increase phytoplankton biomass and primary production. In this study, we tested the hypothesis that tilapia interact synergistically with nutrient enrichment so that the effects of omnivorous fish on phytoplankton biomass becomes more intense with increasing nutrient concentration.MethodsA field experiment with a 2×3 factorial design was performed during four weeks in twenty-four mesocosms (0.25 m3) to which six treatments were randomly allocated: fingerling addition (F), juvenile tilapia addition (J), nutrient addition (NP), nutrient and fingerling addition (NPF), nutrient and juvenile tilapia addition (NPJ) and a control treatment with no tilapia or nutrients addition (C). A two-way repeated measures ANOVA was done to test for time (t), tilapia and nutrients effects and their interaction on total phosphorus, total nitrogen and chlorophyll-a concentrations.ResultsThe results showed a positive effect of nutrient addition on total phosphorus, total nitrogen and chlorophyll-a concentrations and a positive effect of tilapia on the concentration of chlorophyll-a. As expected, we found a synergistic interaction between the positive effect of Nile tilapia and nutrient enrichment on phytoplankton biomass.ConclusionsThe above results suggest that controlling tilapia abundance through fisheries management is a potential tool to improve water quality and mitigate the effects of lake and reservoir eutrophication.

Seasonal pattern and inferred phosphorus limitation of phytoplankton biomass in two tropical reservoirs in northern Australia

2000 ◽  
Vol 51 (1) ◽  
pp. 91 ◽  
Author(s):  
Simon A. Townsend
Keyword(s):  
Chlorophyll A ◽  
Total Phosphorus ◽  
Phytoplankton Biomass ◽  
Seasonal Pattern ◽  
Phosphorus Concentration ◽  
Wet Season ◽  
Temperate Lakes ◽  
Total Phosphorus Concentration ◽  
River Reservoir ◽  
Annual Range

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.

scholarly journals ZOOPLANKTON OF TWO SHALLOW LAKES IN THE SOUTH OF MEAUCO FORMATION (LA PAMPA PROVINCE, ARGENTINA)

2020 ◽  
Vol 30 (2) ◽  
pp. 9-18
Author(s):  
Santiago Echaniz ◽  
◽  
Alicia Vignatti ◽  
Javier Schlegel ◽  
Nicolás Schiel ◽  
...  
Keyword(s):  
Shallow Lakes ◽  
Phytoplankton Biomass ◽  
Secchi Disk ◽  
Total Zooplankton ◽  
Secchi Disk Depth ◽  
The South ◽  
Physical Chemical ◽  
Zooplankton Density ◽  
The Mean ◽  
Chlorophyll Concentrations

The Meauco Formation, a dune region of the central Pampa province, has numerous shallow lakes. Although there is hydrological information about them, it is very scarce about their limnological characteristics. The objectives are to know the physical-chemical and zooplankton parameters of two nearby shallow lakes, with and without fishes: Santa Isabel I (SI I) and Santa Isabel II (I II) respectively, and determine the influence of zooplankton on phytoplankton biomass and transparency. It was sampled during 2018 and 2019. In both the mean salinity were less than 1g.L-1 and the Secchi disk depth was around 0.45m. The chlorophyll concentrations varied between 9.32 and 11.63 mg.m-3. Seven cladocerans, 4 copepods and 20 rotifers were recorded. Most of the taxa were shared by both lakes, however, 20 rotifers were recorded in SI I and 13 in SI II. The total zooplankton density did not differ, but SI I had greater abundance of rotifers (69% of total) and SI II of crustaceans (72%). The presence of fish influences the zooplankton composition but its small size, even in the absence of fish, makes it have little influence on the phytoplankton; therefore, no differences were found in the transparency and phytoplankton biomass of both lakes.

Limnological Effects of the Elimination of Phosphorus from the Wahnbach Reservoir

1982 ◽  
Vol 14 (4-5) ◽  
pp. 397-406 ◽  
Author(s):  
H Bernhardt ◽  
J Clasen
Keyword(s):  
Green Algae ◽  
Total Phosphorus ◽  
Secchi Depth ◽  
Algal Growth ◽  
Phosphorus Compounds ◽  
Phosphorus Concentration ◽  
Annual Average ◽  
Total Phosphorus Concentration ◽  
Blue Green Algae ◽  
N Concentration

The elimination of the phosphorus compounds from the River Wahnbach (100 - 150 µg/l Ptot) at the point where it flows into the Wahnbach Reservoir down to a figure of 5 µg/l Ptot has decreased the total phosphorus concentration in the Wahnbach Reservoir to 8 - 10 µg/l Ptot. As a result of this, the impoundment which had been in an eutrophic state became oligotrophic to mesotrophic within 3 years. The blue-green algae which had been predominant disappeared and diatoms grow again every spring. Algal growth has been reduced to such an extent that the transparency has gone up to a Secchi-depth of 10 m and was 6 m on an annual average. This was solely produced by eliminating phosphorus and without eliminating nitrogen at the same time (the annual average N-concentration of all tributaries was 5 mg/l).

scholarly journals The impacts of global and local change on a tropical lake over forty years

2020 ◽  
Author(s):  
Jemma M. Fadum ◽  
Ed K. Hall
Keyword(s):  
Total Phosphorus ◽  
Trophic State ◽  
Inorganic Nitrogen ◽  
Secchi Depth ◽  
Water Clarity ◽  
Physical Structure ◽  
Tropical Lake ◽  
Dissolved Inorganic Nitrogen ◽  
Lake Ecosystems ◽  
Algal Productivity

AbstractLakes across the world are experiencing novel trophic states, declining water quality, and altered biogeochemical cycling due to the synergistic impacts of global change and local anthropogenic stressors. In the tropics these changes can be difficult to assess due to a lack of continuous monitoring or documented legacy conditions to serve as a reference for the contemporary lake. Over the last forty years, Lake Yojoa, located in west central Honduras, has shifted from an oligotrophic to mesotrophic ecosystem as evidenced by a loss of water clarity. To assess the changes that have occurred in Lake Yojoa as well as putative drivers for those changes, we compared secchi depth, dissolved inorganic nitrogen, and total phosphorus concentrations between 1979-1983 and today (2018-2020). While we found little change in total phosphorus between legacy and contemporary data, we found concurrent changes to seasonal trends in secchi depth and dissolved inorganic nitrogen (DIN). Seasonal peaks in DIN coincident with mixus suggest that accumulation of ammonium in the hypolimnion during stratification, and release to the epilimnion with mixus maintains algal productivity in what was previously a nutrient-limited, clear water phase, driving a change in the overall trophic state of Lake Yojoa. This impact of seasonal dynamics on the trophic state of the lake illustrates a key distinction in how physical structure and nutrients interact differently in tropical and temperate lake ecosystems and highlights the importance of warm anoxic hypolimnions to the biogeochemistry that governs the trophic state of tropical lake ecosystems.

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

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