Sources of blue-green algae

Blue-green algae (cyanobacteria) are naturally occurring, microscopic, photosynthetic organisms found in a wide range of aquatic environments. Here are the primary sources and typical habitats:

• Freshwater: Blue-green algae are commonly found in lakes, ponds, rivers, streams, and bays^{[1][2][3][4][5][6][7][8]}. They thrive in warm, nutrient-rich, and slow-moving or stagnant waters, especially during late spring to early fall when temperatures rise and sunlight is abundant^{[1][2][3][4][9][5]}.
• Marine and Brackish Waters: While most abundant in freshwater, some species also inhabit coastal and marine waters^[9][6].
• Favorable Conditions: Their growth is promoted by high levels of nutrients (especially phosphorus and nitrogen), abundant sunlight, and calm water conditions^{[1][2][3][9][5]}. Nutrient enrichment can result from natural sources or human activities such as agricultural runoff, sewage effluent, and urban stormwater^[2][3][9][5].
• Bloom Formation: Under ideal conditions, blue-green algae can rapidly multiply to form visible blooms or mats, often appearing as green, blue-green, brown, or even reddish scums on the water surface^{[1][2][3][4][9][5]}.

Key points:

• Blue-green algae are ubiquitous in natural surface waters.
• They are most often sourced from nutrient-rich, warm, and slow-moving or stagnant freshwater bodies^{[1][2][3][4][9][5][6][7][8]}.
• Human activity that increases nutrient levels in water (e.g., fertilizer use, septic leaks) can significantly boost their abundance^[2][3][9][5].

Caution: Some blue-green algae can produce toxins harmful to humans, animals, and pets, so always ensure any collected material is from a safe, uncontaminated source if considering use in gardening or other applications^{[1][2][4][9][5]}.

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• https://novascotia.ca/blue-green-algae/      
• http://www.ontario.ca/page/blue-green-algae        
• https://ncceh.ca/resources/subject-guides/cyanobacteria-freshwater       
• https://www2.gov.bc.ca/gov/content/environment/air-land-water/water/water-quality/algae-watch/what-are-algae/cyanobacteria     
• https://lakeheadca.com/watershed/blue-green-algae        
• https://www2.gnb.ca/content/gnb/en/corporate/promo/cyanobacteria.html   
• https://www.healthvermont.gov/environment/tracking/cyanobacteria-blue-green-algae-tracker  
• https://www.hkpr.on.ca/classes-clinics-and-supports/water-quality-and-testing/blue-green-algae/  
• https://www.daera-ni.gov.uk/articles/what-blue-green-algae