HARMFUL ALGAL BLOOMS:

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HARMFUL ALGAL BLOOMS Nature or Nurture?
Guest Lecturer Clarissa Anderson 12 May 2007
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Global increase in reported incidence of algal
toxins
VanDolah, 2000
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Occurrence of Gymnodinium breve red tides on the
west coast of Florida (1878-1996), in months per
year.
VanDolah, 2000
(data, K. Steidenger)
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East Coast Harmful Algae

• Neurotoxic Shellfish Poisoning
• (NSP)
• Brevetoxin
• (can be aerosolized)
• alters voltage sensitivity of Na
• channels
• Unarmored Dinoflagellate

Karenia brevis (formerly Gymnodinium breve)
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East Coast Harmful Algae

• Ambush predator
• Produces a volatile toxin
• dangerous to humans
• Unusual non-photosynthetic,
• heterotrophic dinoflagellate

Pfiesteria piscicida
Pfiesteria Hysteria
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Coral Reefs of Florida, Puerto Rico
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East Coast Harmful Algae (Tropical Latitudes)

• Ciguatera Fish Poisoning (CFP)
• Ciguatoxins
• Biomagnifies up the food web

Gambierdiscus toxicus
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West Coast Harmful Algae

• Paralytic Shellfish Poisoning
• (PSP) -- 15 mortality rate!
• Saxitoxins -- inhibit Na
• channel conductance
• Chain-forming thecate
• dinoflagellates
• 10 species in 3 genera

e.g. Alexandrium spp.
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West Coast Harmful Algae

• Red-tide former
• Yessotoxin

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West Coast Harmful Algae

• Red-tide former
• Diarrhetic Shellfish Poisoning
• (DSP)
• Okadaic acid- inhibits protein
• phosphatases
• Unarmored dinoflagellate

Prorocentrum micans
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West Coast Harmful Algae

• Amnesic Shellfish Poisoning
• Domoic Acid binds to
• glutamate receptors
• Chain-forming pennate diatom
• 10 species in genus
• Pseudo-nitzschia

Pseudo-nitzschia australis
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Bioaccumulation of Domoic Acid in the Food Web
Pseudo-nitzschia spp. /Domoic Acid
Zooplankton
Planktivorous Fish
Pinnipeds, Cetaceans, Seabirds, Sharks (?)
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Horner et al, 1997
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Ekman
Pickett and Paduan, 2003
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1998
Trainer et al, 2000
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Trainer et al., 2000
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SANTA BARBARA CHANNEL, MAY 2003
SeaWiFS Chlorophyll
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SANTA BARBARA CHANNEL, MAY 2003
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Anderson et al. 2006
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Anderson et al. 2006
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Anderson et al. 2006
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Anderson et al. 2006
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Anderson et al. 2006
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Anderson et al. 2006
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What factors potentially drive domoic acid
production by Pseudo-nitzschia?
Si supply rate? Si-limitation?
P-limitation?

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Mesoscale Cyclonic (Counterclockwise) Eddy in the
SBC
HF Radar (CODAR) Surface Currents
Anderson et al. 2006
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Anderson et al. 2006
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Cyclonic Eddy
Cellular Domoic Acid (pg cell-1)
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Fate and Transport of Toxins in Eddy
Latitude (oN)
SeaWiFS May 28, 2003
Longitude (oW)
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Pseudo-nitzschia spp. Abundance
Cells L-1
Anderson et al., in prep
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Particulate Domoic Acid
Cellular Domoic Acid
Anderson et al., in prep
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MODIS Aqua Chlorophyll
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Mapping in Space and Time
hang
offshore
7 6 5 4 3 2 1
10 6.0 4.0 2.0 0.0 -2.0 -4.0 -6.0
Plumes and Blooms Station
1998 1999 2000 2001 2002 2003
Large Spring Blooms Dominated by
Pseudo-nitzschia spp.
inshore
GLOBAL CLIMATE CHANGE?
Anderson et al., submitted
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