Samples of the species were examined under the microscope by Natural Resources Director Tom Leach and assistant Heinz Proft and it was attributed that nearly 100% of the sample was identified as the blue-green species. The anabaena may be toxic if ingested, so citizens are cautioned to keep pets away from drinking the water until the bloom runs its course. Neighbors might also expect a putrid odor and further discoloration of the water as the cells die-off. A similar bloom of anabaena was found on the reservoir in 1996 and 2001.
These blooms are abundant in ponds containing much organic matter. It resembles a string of beads with larger empty cells scattered along the filament.
More information from the web about anabaena (source Maryland Dept of Natural Resources website)
Anaebaena species and Aphanizomenon flos-aquae are frequently found in freshwaters. Their greatest abundances are usually observed during the summer. These are filamentous cyanobacteria, capable of nitrogen fixation. Anabaena is one of four genera of bluegreen algae capable of producing neurotoxins along with Oscillatoria, Lyngbya and Aphanizomenon. Anabaena flos-aqua is a major producer of neurotoxins (Carmichael 1997 Advances in Botanical Research Vol 27:211-256). The best way to minimize animal poisonings by these species that produce cyanotoxins is to recognize you are in the area of a bloom and keep animals away from the waters that may be toxic. No human deaths have been directly associated with these cyanotoxins however they may cause skin irritations or nausea.
Pets and farm animals have been killed by the toxins when the animals ingested waters containing toxic blooms of one or a combination of these algal species. Such poisonings typically occur when heavy surface growths or scums of the cyanobacteria have accumulated near the shoreline and animals have easy access to toxic levels of cells (W.W. Carmichael). This type of toxin has been shown to persist in water for a week or more after the bloom has disappeared. Not all cyanobacteria blooms are toxic, and even blooms caused by known toxin producers may not produce toxins or may produce toxins at undetectable levels. It is not know what triggers toxin production. Recent studies have shown the probability that an individual bloom containing Anabaena, Microcystis, and/or Aphanizomenon will be toxic could be between 45 and 75% (Toxic Cyanobacteria Blooms; A Field/Laboratory Guide, Dr. M. A. Crayton). The presence of Anabaena in a water body can contribute to poor water quality because it can impart noxious odors and disagreeable tastes to the water.
