Effects of Algal Blooms on Marine Mammals

1
Effects of Algal Blooms on Marine Mammals

• Jessica Crance

2
Reasons for algal blooms

• Upwelling
• Seasonal
• Environmental factors
• Global warming and increased water temperatures
• Increase in waste dumped into oceans

3
Toxin production

• Diatoms
• Domoic acid
• Dinoflagellates
• Neurotoxins
• Exponential increase in amount of toxins present
  in water

4
Ingestion of toxins

• Zooplankton prey on phytoplankton
• Copepods, protists, small arthropods
• Larger animals prey on zooplankton
• Fish, birds, large mammals
• Filter feeders ingest toxins in water column
• Bivalves harvested and sold on market
• Bioaccumulation in higher trophic levels

5
Effects of toxins

• Humans Shellfish Poisoning
• Amnesiatic SP, Paralytic SP, Diarrhetic SP
• Birds Go crazy, fly into windows, attack humans
• Marine animals behavioral effects unknown
• Large scale die-offs in cetaceans, sharks, sea
  lions, manatees, etc

6
Current research

• Determining vectors and species affected
• Krill as a major vector for Domoic acid
• Pseudo-nitzschia in Monterey Bay, CA
• Euphausiids primary consumers
• Main diet of squid, baleen whales, birds

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Manatee mass mortality

• Spring 1996 in surrounding Florida waters
• Over 200 manatees dead in a few weeks
• Corresponding algal bloom of Gymnodinium breve -
  produces brevetoxin
• High affinity binding to neural receptors in
  brains of mammals causing death

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Effects on humans

• Bivalve consumption
• Large game fish caught and sold for human
  consumption
• High toxin levels due to bioaccumulation
• Increase in bloom number increases risk

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How to deal with blooms

• New study using coagulants
• Remove algae from water column
• Only in calm waters, not for coastal waters
• Decrease effects of global warming
• Decrease amount of waste dumped into oceans
• Possible relocation of animals until bloom clears
• New buoys determine toxin levels and current
  direction and speed

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Conclusion

• Algal blooms a part of nature, but
• Harmful effects of blooms can be reduced
• New research and technology
• Changing human actions
• Dont eat raw seafood!!

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References

• Baden, DG., Trainer, VL. 1999 High affinity
  binding of red tide neurotoxins to marine
  mammal brains. Aquatic toxicology, 46 (2)
  139-148.
• Bargu, et al. 2002. Krill a potential vector
  for Domoic acid in marine food webs. Marine
  Ecology - Progress Series, 237 209-216.
• Beaulieu, et al. 2005. Using clay to control
  harmful algal blooms deposition and
  resuspension of clay/algal flocs. Harmful Algae,
  4 (1) 123-138.
• Pitcher, GC., Calder, D. 2000. Harmful algal
  blooms of the southern Benguela current a
  review and appraisal of monitoring from 1989 to
  1997. South African Journal of Marine Science,
  22 255-271.