High Sierra Topix

Harmful Algae Blooms detected in Deadman Creek, observed in Hummingbird and Odell Lakes

Recent testing yielded positive results for small amounts of toxic algae in Deadman Creek and visual observations made at Hummingbird and Odell Lakes in the 20 Lakes Basin may indicate toxic algae is also present in these two lakes. Toxic algae may exist in other sites on the forest.

Toxins are concentrated within the algal mats themselves and released episodically into the water when the algae dies or is disturbed.

For your safety, do not enter the water or drink in these areas. Filtering and/or boiling the water is not effective against this type of algae.

Prevent pets from drinking the water and eating or touching algae in the water and dried on the shore. In particular, prevent dogs from eating dried algal mats on shore.
Please report any large algal blooms and/or algae that is particularly bright, bubbly, strange-looking, or appears like a haze in the water.

Do not disturb algal mats in any way. Wading or swimming can cause toxins to be released into the water.

If you suspect a site has toxic algae, do not enter the water and do not drink water from the area. While some sites are signed based on testing results, it’s likely that algae exists in other parts of the forest. Don’t rely on signage alone.

According to the California Water Quality Monitoring Council, the following signs and symptoms may occur within 48 hours of exposure to a waterbody with a suspected or confirmed algal bloom:
• sore throat or congestion;
• coughing, wheezing, or difficulty breathing;
• red, or itchy skin, or a rash;
• skin blisters or hives;
• earache or irritated eyes;
• diarrhea or vomiting;
• agitation;
• headache; and/or,
• abdominal pain.

If people show symptoms of cyanotoxin and/or cyanobacteria exposure after contact with water, or with scums or mats of algae, they should receive immediate medical attention. Additional resources are available from the Centers for Disease Control and Prevention (CDC), and by contacting the California Poison Control Center (1-800-222-1222). See the HAB-related Illness Tracking webpage for information on previously reported human illnesses related to HABs in California.

Harmful Algal Blooms
Recent testing yielded positive results for small amounts of toxic algae above and below Rainbow Falls in Devils Postpile National Monument, and toxic algae may exist in other sites in the monument. Toxins are concentrated within the algal mats themselves and released episodically into the water when the algae dies or is disturbed.

What does this mean for me?

• For your safety, do not enter or drink in the area of Rainbow Falls.
• Filtering and/or boiling the water is not effective against this type of algae.
• Prevent pets from drinking the water and eating or touching algae in the water and dried on the shore. In particular, prevent dogs from eating dried algal mats on shore.
• Please report any large algal blooms and/or algae that is particularly bright, bubbly, strange-looking, or appears like a haze in the water.
• Do not disturb algal mats in any way. Wading or swimming can cause toxins to be released into the water.
• If you suspect a site has toxic algae, do not enter the water and do not drink water from the area. While some sites are signed based on testing results, it’s likely that algae exists in other parts of Devils Postpile. Don’t rely on signage alone.

Can I still swim in the river? Can I still filter or treat the water for drinking?
Water that is clear with no visible algae in the area presents a low risk. Even in areas with no visible algae, watch for isolated clumps of algae floating by.

If you think algae may be in the water:

• Do not enter the water.
• Do not drink the water, even if treated.
• Do not let pets into the water, allow them to drink the water, or eat algae on the shore.

What are the signs and symptoms of exposure to toxins from algae?
According to the California Water Quality Monitoring Council, the following signs and symptoms may occur within 48 hours of exposure to a waterbody with a suspected or confirmed algal bloom:

• sore throat or congestion;
• coughing, wheezing, or difficulty breathing;
• red, or itchy skin, or a rash;
• skin blisters or hives;
• earache or irritated eyes;
• diarrhea or vomiting;
• agitation;
• headache; and/or,
• abdominal pain.

If people show symptoms of cyanotoxin and/or cyanobacteria exposure after contact with water, or with scums or mats of algae, they should receive immediate medical attention. Additional resources are available from the Centers for Disease Control and Prevention (CDC), and by contacting the California Poison Control Center (1-800-222-1222). See the HAB-related Illness Tracking webpage for information on previously reported human illnesses related to HABs in California.

Is the National Park Service monitoring for harmful algal blooms?
The park continues monitoring for toxic algae and testing for toxins throughout the park. You can learn more about harmful algal blooms at https://mywaterquality.ca.gov/habs/.

Algae toxins are not removed by standard
water treatments. Disinfection using
chlorine, hypochlorate (bleach) or iodides
have no effect on algae produced toxins.
Backpack filters do not remove these toxins.
... Ultraviolet light has variable
effects, depending on the toxin.

Note: Confirmation of toxins and toxin levels within a bloom cannot be accomplished by visual inspections so samples must be sent to a lab for analysis.

Toxins from blue-green algae cannot be removed by boiling the water or treating it with chlorine or UV light.

What does a Harmful Algal Bloom (HAB) look like?
HABs can vary in colour and texture. They can also move up or down through the water column over the course of the day and appear on the surface of the water or below the surface of the water.

To spot a Harmful Algal Bloom, look for water that:

Resembles spilt paint
Is discoloured or has streaks of colour. Most HABs in Lake Erie appear greenish (e.g. green, olive-green, bright green, blue-green) or sometimes black but could also be blue, brown, white, black, red or purple in colour.
Looks slimy or woolly
Has mats, scums or films on the surface
Has clumps or globs floating below the surface

Note: Confirmation of toxins and toxin levels within a bloom cannot be accomplished by visual inspections so samples must be sent to a lab for analysis.

tweederjohnson wrote: ↑Thu Oct 07, 2021 11:39 am Anyone know if these algae blooms survive winter deep freezes in the mountain lakes/streams? I don't see much in the links that inform whether a generous winter would allow for a fresh, algae-free start in the spring.