Estimating the abundance of blue-green algae
Visual observations of the abundance of blue-green algae are classified into four categories:
No blue-green algae observable
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© Pirjo Ferin / Ympäristöhallinnon kuvapankki
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No blue-green algae observable on the water or along the shoreline. Water transparency normal Some algae observable
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© Seppo Knuuttila
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Blue-green algae observable as greenish flakes or specks in the water, and in water samples in transparent containers. Narrow streaks of washed up algae may form along the shoreline. Water transparency reduced by the algae. Algae abundant
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© The Finnish environment institute (SYKE)
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The water is obviously discoloured by algae; or small accumulations of algae have formed on the surface or drifted onto the shore. Algae very abundant
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© The Finnish environment institute (SYKE)
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© Seppo Knuuttila
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Algal blooms form extensive rafts, or have accumulated thickly on shores
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