Algae get into water primarily through nutrient runoff and natural introduction.
Essentially, algae are naturally present in many aquatic environments. However, algal blooms, which are excessive growths of algae, occur when there's an overabundance of nutrients, primarily phosphorus and nitrogen, in the water. These nutrients act as fertilizer, promoting rapid algae growth.
Here's a breakdown of how algae and their triggering nutrients get into water:
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Natural Introduction: Algae spores are microscopic and can be transported by wind, rain, and animals to new bodies of water. These spores can lie dormant until conditions are favorable for growth.
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Nutrient Runoff: This is the most common cause of excessive algal growth. The main sources of these nutrients include:
- Fertilizers: Agricultural and residential fertilizers contain high concentrations of nitrogen and phosphorus. Rainwater washes these fertilizers into rivers, lakes, and oceans.
- Pet Waste: Pet waste, if not properly disposed of, can contribute significantly to nutrient pollution.
- Improperly Functioning Septic Tanks: Leaking septic tanks release untreated sewage containing nitrogen and phosphorus into groundwater, which can then seep into surface water.
- Yard Waste: Grass clippings, leaves, and other yard waste that end up in waterways decompose, releasing nutrients into the water.
- Industrial Discharge: Some industries release wastewater containing nutrients.
- Atmospheric Deposition: Nitrogen oxides from vehicle emissions and industrial processes can be deposited from the atmosphere into bodies of water.
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Water Currents and Mixing: Algae can be transported from one area to another by water currents and mixing of water layers.
Once algae are present and nutrient levels are high, they can multiply rapidly, leading to algal blooms. These blooms can have detrimental effects on aquatic ecosystems, including depleting oxygen levels, blocking sunlight, and producing toxins.
