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Pelican River at the Highway 20 Culvert Chlorophyll-a

explanation of Chlorophyll-a

Chlorophyll a is the pigment that makes plants and algae green. Chlorophyll a is tested in lakes to determine the algae concentration or how "green" the water is. Chlorophyll a concentrations greater than 10 ug/L are perceived as a mild algae bloom, while concentrations greater than 20 ug/L are perceived as a nuisance.

Algae grows better in calm water than flowing water, so the chlorophyll-a concentration in Pelican River is relatively low compared to Little Pelican Lake.

Chlorophyll-a is measured at the Hwy 20 culvert to get an idea of what is flowing into Little Pelican Lake from the Pelican River and Buck Lake upstream. The Chlorophyll-a at the Hwy 20 culvert usually remains below 10 ug/L, indicating no algae blooms. Chlorophyll-a concentrations only reached 20 ug/L on one date in 2003, indicating a nuisance algae bloom. Algae growth depends on the amount of nutrients and sunlight available.

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