Algae
& Microscopic Organisms
The lake may look sterile and devoid of life now that the Grass Carp have removed
much of the aquatic plant growth, but actually the lake is teeming with small
organisms. A good balance of these organisms is needed to provide food for larger
organisms, such as birds and fish. Viewing lake water under a microscope can
open up a whole new world of exploration. The Preservation Association of Devils
Lake invites the public to attend our annual meeting (usually in June) to learn
more.
What is the scum floating on the lake? It could be a blue-green algae bloom.
Algae blooms can occur when there are nutrients in the water column and the
temperature is warm. Winter storms and wave action from boats can stir up the
lake bottom, releasing nutrients into the water column. If other conditions
are right, an algae bloom can occur. Algae can be an indicator of limited water
quality (pollution). Anabaena is a type of blue-green algae that can discolor
the water and give off a putrid odor when the cells die off and decay. Devils
Lake has seen an increase in the frequency of algae blooms from undesirable
species, and a decrease in the diversity of desirable algae species. Algae in
the lake can affect water clarity. Secchi disks are round, black and white disks
that are lowered into the water from the surface. Clarity is gauged by how far
down the disks go into the water before disappearing. Report algae blooms to
the Devils Lake Water Improvement District (DLWID) at 541-994-5330.
Phytoplankton surveys from July 17, 1981 identified the following alga: Fragilaria
crotonensis, Cryptomonas erosa, Anabaena sp., Kephyrion spirale, Ankistrodesmus
falcatus, and four others.
Blue-green algal blooms - potential for toxins
North American Lake Management Society Blue-green algae page
http://nalms.org/Resources/BlueGreenInitiative
Blue-green algae blooms on Devils Lake can occur when conditions are right. Most
are non-toxic. However,
you
should
avoid
swimming
in
an
area
where
there
is
an
abundance of algae blooms. Some algae toxins can be harmful to pets, so keep
your pets
away from algae blooms.
The Oregon Department of Human Services has a download
pdf brochure, download
pdf flyer about algae,
and a web page at www.oregon.gov/DHS/ph/envtox/maadvisories.shtml You
can subscribe to receive blue-green algae advisories by email from the website. www.oregon.gov/DHS/ph/hab/advisories.shtml
• Washington
State Department of Health
www.doh.wa.gov -
Cyanobacteria were
previously grouped with algae but are now classified as bacteria after analysis
of cell
structure and cell division. They differ from other bacteria in that they contain
photosynthetic pigments similar to those found in algae and plants. Although
they are predominantly photosynthetic (light-dependent) organisms, they are
also capable of using organic compounds as a source of energy. Some cyanobacteria
have a specialized structure called a heterocyst that can fix molecular nitrogen.
The ability to fix nitrogen gives these species a competitive advantage over
other algae. Many cyanobacteria have gas vacuoles that allow them to remain
in suspension and migrate to surface waters where there is plenty of light
for photosynthesis. On the surface, colonies may clump together and form a
scum which can cause water quality problems in lakes.
Case
Studies of algal blooms Lost Creek Lake blue-green algae testing Great
quote from a news article after Diamond Lake was closed for 3 weeks
due to algal blooms. "The lake isn't meeting state water quality
standards. It isn't meeting the recreational and economic expectations
of Oregonians." |
Potential blue-green
algae toxin types:
1. Endotoxins - skin rashes, irritation of the eyes, and gastroenteritis
2. Neurotoxins - damage nerves and can cause muscle tremors, especially in
the muscles animals and people need to breath
3. Hepatotoxins - damage the liver
–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––
2008 Cyano-watch by the Devils Lake Water Improvement District (DLWID) - http://www.dlwid.org
• 9/24/08 - The RED Health Advisory posted August 14, 2008 remains in effect.