Effects of Algal Blooms on Marine Mammals Jessica Crance

Reasons for algal blooms Upwelling Upwelling –Seasonal –Environmental factors Global warming and increased water temperatures Global warming and increased water temperatures Increase in waste dumped into oceans Increase in waste dumped into oceans

Toxin production Diatoms Diatoms –Domoic acid Dinoflagellates Dinoflagellates –Neurotoxins Exponential increase in amount of toxins present in water Exponential increase in amount of toxins present in water

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

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

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

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

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

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

Conclusion Algal blooms a part of nature, but… Algal blooms a part of nature, but… Harmful effects of blooms can be reduced Harmful effects of blooms can be reduced –New research and technology –Changing human actions –Don’t eat raw seafood!!

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