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Species of toxigenic Lyngbya adapted to high salinity environments can
form benthic mats that expand over an area equivalent to a football field
within an hour, causing ecological damage and endangering human health
(Australian Environmental Protection Agency 2003).
Cyanotoxins also are found in terrestrial environments where they may
pose a risk to human and animal health. Surface waters are increasingly
used for field irrigation in agricultural production. Water drawn from
sources experiencing toxigenic CHABs is sprayed on crops, producing
cyanotoxin-containing aerosols that may be inhaled by humans and other
animals, and absorbed by crops. Cyanobacteria can form a symbiotic relationship
with terrestrial plants which may biomagnify cyanotoxins.
Cyanobacteria of the genus Nostoc form colonies on the roots of cycad
plants in Guam where for more than 30 years scientists have tried to unravel
the genesis of the mysterious neurodegenerative disease that afflicts
the native Chamorro population. An amino acid cyanotoxin produced by
Nostoc, beta methylamino-alanine (BMAA), accumulates in cycad seeds.
The seeds are eaten by a species of bat that accumulates high levels of
BMAA in its tissues. The bat is a traditional food source for the Chamorro.
Analyses detected BMAA in brain tissues of Chamorro victims, leading to
the hypothesis that BMAA causes neurodegeneration that may manifest
with features of amyotrophic lateral sclerosis, Parkinson’s disease, and
Alzheimer’s dementia. Recent evidence indicates that BMAA is produced
by most types of cyanobacteria, and that it may be associated with neurodegenerative
diseases elsewhere (Human Health Effects Workgroup Report