Transcript Microcystis Blooms Causes, Problems, and Solutions By Bernie Coates What is it? Microcystis is a blue-green algae (cyanobacteria) commonly found in nutrient rich freshwater.

Microcystis Blooms
Causes, Problems, and Solutions
By Bernie Coates
What is it?
Microcystis is a blue-green
algae (cyanobacteria)
commonly found in nutrient
rich freshwater. Its blooms
are being found more
frequently and its
associated toxins are cause
for worldwide concern.
Causes
Microcystis blooms are usually caused by eutrophication
(nutrient enrichment) of the water body. Typically the
limiting nutrient is phosphorous. Blooms can be
encouraged by:
 Fertilizer runoff from fields, golf courses, and urban lawns
 Untreated, or partially-treated, domestic sewage
 Liberation of phosphorous from the lake or pond bottom under
reducing conditions
 The presence of Microcystis can actually increase the liberation of
phosphorous from the sediments thereby accelerating bloom growth
(Xie, Xie, & Tang, 2000).
Some Microcystis Blooms
Photo from
Experimental
Lakes Area in
Manitoba, Canada
Unknown Pond
Lake Mokoan, Victoria, Australia
Balgavies Loch, Dundee, Scotland,
1981
Grandview Garden
Park, Beijing
Problems
Microcystis contain toxins known as microcystins.
These toxins can cause fish kills and in some instances
have resulted in human casualties.
There are several other cyanobacteria species that
produce microcystins including:
 Anabaena
 Oscillatoria
 Nostoc
 Hapalosiphon
 Anabaenopsis
 Microcystins are hepatotoxins.
 Acute toxicity is the main concern with
Microcystins. The compound attacks the
liver causing hemorrhaging and liver
failure.
 The threat to human health is of great
concern since long-term exposure to
relatively low doses could encourage the
development of liver tumors.
Occurrences
 In February 1996 sixty patients with kidney
failure died and 66 others were rendered ill in a
hemodialysis clinic in Caruaru, Brazil, when
untreated turbid water contaminated with
Microcystis was used for dialysis during a water
shortage.
Occurrences
 A large epidemic in Brazil involving human
deaths occurred in 1988. Over 2,000 residents
suffered from gastroenteritis over an 8-week
period, with 88 deaths. An epidemiologic
investigation implicated drinking water from a
reservoir, even water that had been boiled
before use. Infectious agents, metals or toxins
were not found; however, the cyanobacterium
genera Anabaena and Microcystis were found
in great quantities in untreated water from the
reservoir. Algal toxins were not assayed, but
the circumstantial evidence strongly implicated
the cyanobacteria as the cause.
Chemical Solutions
 Limit influx of nutrients to the water by more
efficient fertilizer application techniques.
 Dredging lakes and ponds where there are high
amounts of phosphorous tied up in the
sediments.
 Application of aluminum sulphate and copper
sulfate in combination (Hullebusch, Delutat,
Chazal, & Baudu, 2002) .
Non-chemical Solutions
 Non-chemical means of control was achieved using
barley straw extract made from decomposed barley
straw. Experiments produced a 10-fold decrease in
Chlorophyll a levels (Ball, Williams, Vincent, and
Robinson, 2001) .
 Ultraviolet (UV) radiation in small doses prior to
bloom development inhibits reproduction. Additionally,
UV increases the specific gravity of the cells thereby
limiting their ability to remain in suspension, which
effectively stops the Microcystis from photosynthesizing
(Alam, Otaki, Furumai, & Ohgaki, 2001).
Other Solutions
 Bank filtration
 Ozonation
 Reverse osmosis
 Activated carbon treatment
Acknowledgements
Xie, L.Q., Xie, P., & Tang, H. Enhancement of
dissolved phosphorous release from
sediment to lake water by Microcystis
blooms—an enclosure experiment in a
hyper-eutrophic, subtropical Chinese lake.
Environmental Pollution. 2003;12:391-399.
Hullebusch, E., Deluchat, V., Chazal, P., & Baudu,
M. Environmental impact of two successive
chemical treatments in a small shallow
eutrophied lake: Part I & II. Case of
aluminum sulphate. Environmental
Pollution. 2002;120:617-634.
Acknowledgements
Ball, A., Williams, M., Vincent, D., & Robinson, J.
Algal growth control by a barley straw extract.
Biosource Technology. 2001;77:177-181.
Alam, M., Otaki, M., Furumai, H., Ohgaki, S. Direct
and indirect inactivation of Microcystis
aeruginosa by uv-radiation. Wat. Res. No. 4.
2001;35:1008-1014.
And Now…For Something
Completely Different
Yukio Yamada
A Leader in Phycology in Japan:
Considered to be the founder of
modern Japanese phycology
Yamada’s Background
Born in 1900 in Kyoto Japan
Entered Daiichi High School in 1918
In 1921, Yamada entered the Botanical
Institute of the Faculty of Science at the
Imperial University of Tokyo
Professor Bunzo Hayata convinced
Yamada he should study algae
Positions Held
Professor of Taxonomic Botany for the Faculty
of Science at Hokkaido University in Sapporo
First director of the Institute of Algological
Research
Member of the University Senate and Dean of
the Faculty of Science at Hokkaido University
Founded and served as president of the
Japanese Society of Phycology
President of the International Phycological
Society
Primary Contributions
Detailed taxonomic, morphological and
floristic accounts of red, brown and green algae
from Japan
Described nearly 200 new taxa of marine algae
Floristic Studies of marine algae from Taiwan
Life history studies of various marine algae,
especially Chlorophyta
Mentor for almost 50 graduate students
Acknowledgement
Garbary, David J., and Michael J. Wynne, eds.
Prominent Phycologists of the 20th Century.
Hantsport, Nova Scotia: Lancelot Press
Ltd.,1996.