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• Can algae just be helpful in the
ecosystem, just be harmful, or can it be
both? Explain your answer.
A Bloom of a
“Different” Color
Using satellite imagery to
monitor coastal algae
Algal Blooms
Fish
Shrimp
Zooplankton
Marine Phytoplankton
• Marine algae form
the base of the
ocean food chain
• Coastal nutrient rich
waters support a
range of algal
species
• Population growth is
influenced by many
factors
What is our
interest in the
marine algae?
How do they
affect us?
National interest
Coccolithophore
Emiliania huxleyi
• Some species add
DMS (dimethyl
sulfide) to the
atmosphere
• Satellite algorithms
track pockets of high
cell counts
• Do the algal cells alter
the biogeochemical
nature of the area
over time?
National interest
cyanobacteria
Trichodesmium
• Important Nitrogen
fixer in the oceans
• Produces a
neurotoxin that can
be involved in fish
kills and human
illness
• Detection by Wide
Field-of-view Sensor
(SeaWiFS)
Harmful Algal Blooms
Many
different
algal species
are
responsible
for HAB’s
• The population of
algal cells can
increase rapidly
• Some algae produce
toxins that can
endanger marine
animals and humans
• > 5000 species
• < 5% are toxic
National interest
Dinoflagellate
Karenia brevis
May 25-Jun 1, 2003
• The water appears
“red” in color –
known as the red tide
• Neurotoxin
concentrates in
shellfish, but can be
released from algae
through wave action
• Fish kills, marine
mammals may die,
human concerns
National interest
Cells caught in Gulf Stream fingers
• Formation of
ECOHAB agency for
focused research on
Harmful Algal Blooms
• Provides greater
understanding of algal
cell transport,
conditions for blooms,
and toxicity
differences between
the species
Local Interest
• State agencies in
coastal zones monitor
the cell counts, notify
public of health
concerns
• Shellfish and fin
fishing may be
restricted
• Citizen awareness is
increased; action
groups are formed
Worldwide Effects of HAB’s
• Light penetration levels in water decrease
altering photosynthesis rate
• Algal blooms may be harmful to seagrass
and coral reef ecosystems and the
connected food webs
• Shellfish may accumulate algal toxins by
feeding on the toxic phytoplankton
resulting in fish kills, marine mammal
distress, human illness and possible death
Toxins and their Effects
• Compounds will bioconcentrate when ingested
at lower trophic levels (algal toxins or
phycotoxins are relatively chemically stable to
heat and cold)
• Can cause “lesions” on dermis of fish thus
providing a path for infection
• Produce symptoms that affect the nervous
system and/or intestinal distress;
some cardiovascular effects in
marine animals and humans
Types of HAB’s/Toxicity
•
•
•
•
•
•
•
Brown/red tide
Amnesic Shellfish Poisoning
Diarrhetic Shellfish Poisoning
Neurotoxic Shellfish Poisoning
Paralytic Shellfish Poisoning
Ciguatera Fish Poisoning
Harmful Cyanobacterial Blooms
What do you notice
about the incidents
of reported toxic
outbreaks?
How can the public
become more aware
of this problem?
Frequency of HAB events
Reasons for Increase in HAB’s
• Global climate change producing wider
ranges for some species
• Human contributions of increased
nutrients and pollution in coastal waters
• Subtle changes in local ecosystems that
may allow exotic species to thrive if
introduced
• A more comprehensive monitoring and
reporting system
Types of Toxicity
Ciquatera Fish Poisoning
• Pantropical distribution
• Toxins accumulate in reef
fish that may remain toxic
for as long as two years
• 50,000 plus victims
annually – many
unreported incidents
• Gastrointestinal and
neurological distress,
rarely fatal
• Gambierdiscus taxicus
Neurotoxic Shellfish Poison
• Less severe than CFP,
but similar toxic affects
• Often blooms discolor the
water and kill fish
• Causes respiratory
discomfort like allergies
when cells rupture
• Economic impact huge
when fisheries are closed
• Karenia brevis or
G.breve
Types of Toxicity
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•
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Paralytic Fish Poisoning
Concentrate in mackerel
on the food chain
PSP is caused by a
saxitoxin
Can cause death in
marine mammals and in
humans
World wide distribution –
species below is tropical
Pyrodinium bahamense
Diarrhetic Shellfish Poison
• Symptoms similar to
bacterial gastroenteritis
• Not fatal, recovery in
three days
• Algal cells found in all
coastal temperate waters
• Okadaic acid from
species below caused
problems in Japan
• Dinophysis sp.
Types of Toxicity
•
•
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Amnesic Shellfish Poison
First recognized in 1987
on Prince Edward Island
Caused 4 deaths and 100
acute cases from
ingestion of blue mussels
Neurotoxic domoic acid is
produced by the diatom
below
Careful monitoring during
bloom cycles – wide
distribution of this species
Nitzchia sp.
Can we
predict
when or
where the
next algal
bloom will
occur?
Watch for the HAB’s
Interactive
mapping on-line
to examine
satellite imagery
for SST, winds
and chlorophyll-a
http://www.csc.noaa.gov
/crs/habf/habmaps.html
Study proximity of shellfish beds and coastal
rivers to high algal cell counts
Predict bloom or not?
• Scientists agree that a combination of
factors seem to cause algae to “bloom” in
an area
• Satellite technology helps to focus on
global and local HAB problem spots
• Prediction capabilities have increased, so
the public can be informed earlier about
fishing restrictions and health concerns