While both pollen and harmful algal blooms (HABs) can create discolorations on the water’s surface, understanding their differences is crucial for protecting water quality and public health. Observing their color, texture, and behavior can help distinguish between them. When in doubt, it’s best to err on the side of caution and avoid contact with the water if you suspect a HAB.
How to Identify Pollen vs. HABs
- Pollen appears as a yellow-green film or powder floating on the surface. It may resemble “yellow paint”, especially in still water. Pollen is buoyant and tends to collect on the surface but may sink over time. While generally harmless, it can trigger allergies in sensitive individuals. It is most common in spring when trees and plants release large amounts of pollen.
- HABs, caused by cyanobacteria (blue-green algae), can look like thick paint, scum, or foam, with colors ranging from blue-green to brownish-red, pea green, or white. Some blooms make the water appear murky or like “pea soup.” HABs can form floating mats or scums that wash to the shoreline or remain suspended in the water, affecting clarity. Unlike pollen, HABs may drip off a stick like paint when disturbed.
Why HABs Are Dangerous
HABs can produce toxins harmful to humans, pets, and wildlife. Contact with or swallowing water containing HABs can cause skin irritation, nausea, diarrhea, vomiting, and respiratory issues. These blooms thrive in warm temperatures and nutrient-rich conditions, often in late summer.
Preventing and Reporting HABs
Climate change and excessive phosphorus and nitrogen contribute to HAB formation. The Upper Saranac Foundation is working to reduce nutrient pollution through watershed management efforts, including septic system maintenance, limiting lawn fertilizer use, and improving stormwater management
If you suspect a HAB, report it to the USF Lake Manager at: lakemanager@usfoundation.net
By recognizing and addressing HABs early, we can protect water quality and ensure safe recreational and drinking water sources. To learn more about HABs and prevention efforts, visit our web site.