Monitoring and Modeling of Chlorophyll-a Dynamics in a Eutrophic Lake: M'koa Lake (Jacqueville, Ivory Coast)

AIM: The main objective of this work is to describe the changes in water characteristics of a shallow subtropical lake, in periods with and without growing of macrophytes, related to periods of clear-macrophyte dominance and turbid-phytoplankton dominance states. METHODS: The study was conducted in Biguás Lake, in the south coastal plain of Brazil (32° 04' 43" S and 52° 10' 03" W). Samplings were carried out monthly between October 2000 and November 2013. The limnological variables measured in the water column were dissolved oxygen (DO), water temperature, pH, electrical conductivity (EC), chlorophyll-a, total nitrogen (TN), total phosphorous (TP) and suspended material (SM). Data were grouped according to periods with macrophyte growth dominance (MD) and without macrophytes, with phytoplankton dominance (PD), and applied t- tests among TP, TN, Chlorophyll-a and SM. During macrophyte growth we estimated the coverage (%) and biomass variation of plants. RESULTS: Over the 13 years, the lake was well oxygenated, alkaline, and with a temperature variation according to subtropical seasonality. The lower values of all of the limnological variables were verified during periods of macrophyte growth, characterizing periods of clear and turbid waters. CONCLUSIONS: The influence of aquatic macrophytes in improving water quality in this shallow lake during the studied period, reducing nutrient concentrations, chlorophyll-a and suspended material in water, favoring the maintenance of a clear water state, was verified.

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Estimation of Chlorophyll-a Concentrations in a Highly Turbid Eutrophic Lake Using a Classification-Based MODIS Land-Band Algorithm

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing ◽

10.1109/jstars.2019.2936403 ◽

2019 ◽

Vol 12 (10) ◽

pp. 3769-3783 ◽

Cited By ~ 2

Author(s):

Junsheng Li ◽

Min Gao ◽

Lian Feng ◽

Hongli Zhao ◽

Qian Shen ◽

...

Keyword(s):

Chlorophyll A ◽

Eutrophic Lake

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Temperature Dependence of Freshwater Phytoplankton Growth Rates and Zooplankton Grazing Rates

Water ◽

10.3390/w13111591 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1591

Author(s):

Jennifer Pulsifer ◽

Edward Laws

Keyword(s):

Temperature Dependence ◽

Chlorophyll A ◽

Growth Rates ◽

Eutrophic Lake ◽

Phytoplankton Growth ◽

Type I ◽

Zooplankton Grazing ◽

Temperature Range ◽

Freshwater Phytoplankton ◽

Louisiana State University

Phytoplankton growth rates and zooplankton grazing rates were estimated on 16 occasions over a period of 17 months in University Lake, a highly eutrophic lake on the campus of Louisiana State University. Phytoplankton growth rates and chlorophyll a concentrations averaged 1.0 ± 0.2 d−1 and 240 ± 120 mg m−3, respectively. Chlorophyll a concentrations were at or above the inflection point of the Holling type I curve that described the relationship between zooplankton grazing rates and chlorophyll a concentrations. In most cases, it was necessary to dilute lake water by more than a factor of 4 before zooplankton grazing rates became sensitive to chlorophyll a concentrations. Chlorophyll a concentrations were positively correlated with temperature and were roughly fourfold higher at 30 °C than at 15 °C. An analysis of the temperature dependence of the growth rates and grazing rates in this study and 87 other paired estimates of limnetic phytoplankton growth rates and zooplankton grazing rates revealed virtually identical temperature dependences of growth rates and grazing rates that were very similar to the temperature dependence predicted by the metabolic theory of ecology. Phytoplankton growth rates exceeded zooplankton grazing rates by 0.13 ± 0.05 d−1 at all temperatures over a temperature range of 8.5–31.5 °C. The Q10 for both phytoplankton growth rates and zooplankton grazing rates was 1.5 over that temperature range.

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Use of Lake Fossil Diatom Assemblages to Determine Historical Changes in Trophic Status

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f89-131 ◽

1989 ◽

Vol 46 (6) ◽

pp. 1013-1021 ◽

Cited By ~ 20

Author(s):

M. Agbeti ◽

M. Dickman

Keyword(s):

Chlorophyll A ◽

Total Phosphorus ◽

Trophic Status ◽

Eutrophic Lake ◽

Regression Analyses ◽

Diatom Assemblages ◽

Trophic Index ◽

Trophic Changes ◽

Classification Index ◽

Oligotrophic Condition

Based on the composition of surface sediment diatom assemblages of 30 lakes a classification index for lake trophic status was developed. The lakes were selected to represent a continuum ranging from oligotrophic to eutrophic lake types. A trophic index quotient was derived. The log diatom inferred trophic index (D.I.T.I.) was regressed against the trophic status of the lakes as determined by the log total phosphorus (r = 0.84) and log chlorophyll-a (r = 0.91). Multiple regression analyses showed significant correlations between log D.I.T.I. and the log percentage abundances of oligotrophic, mesotrophic, and eutrophic species (r = 0.89). The abundance of the trophic indicator diatom species depends not only on total phosphorus and chlorophyll-a, but possibly on the interaction of these with other factors. Using this approach, past trophic changes were inferred for oligotrophic Barbara Lake and eutrophic Chemung Lake. The study suggested that Barbara Lake had retained its present day oligotrophic condition over the last 200 yr, whereas major trophic changes have occurred in Chemung Lake.

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