Toxic Algae: A Review Plus Notes on Prymnesium parvumJacob Butler

Overview• Algal communities and diversity• Trends in succession• Algal toxins and toxin production• Allelopathy and allelochemicals• Toxic algae found in AZ• Consequences of toxicity• Prymnesium parvum notes and research

Algal Communities and Diversity• Often quite diverse• Many factors affect succession• Temperature, pH, light, nutrient avaliability

• Seasonal trends, but not always

Deviations From Succession Patterns• Atypical weather• Pollutants• Excess nutrients

And…

Algal Toxins and Succession• Inhibit growth of some taxa, eliminate others• Aids in succession to dominant status• Can cause formation of blooms

• Because of the advantage provided, toxic secondary metabolite production seen many algae

• Unintentional consequences• Toxicity to humans, other organisms• Taste, odor, aesthetic issues

Allelopathy• Any positive or negative

effect on growth or development of biological, agricultural systems

• Frequent occurrence in aquatic ecosystems• Ease of transmission• Low cost

• Chemical warfare among algal species

Allelochemicals

Allelochemicals Continued From Legrand et al. 2003 (42)

Only the beginning…• Many algal toxins difficult to detect, let alone

quantify• Production of toxins highly variable• Exact mechanisms, triggers largely unknown

• Results of toxin production en masse often all that is seen.

Fish Kills

Toxic Algae in the Salt River Reservoirs• Anabaena• Cylindrospermopsis• Aphanizomenon• Lyngbya• Microcystis aeruginosa• Prymnesium parvum

Capable of producing Anatoxin-A, Saxitoxin, Cylindrospermopsin, Microcystin, Prymnesins

Consequences of Algal Toxins• Human health and water quality issues• Neurotoxicity• Hepatotoxicity• Tastes, odors• Collection in reservoirs, canals

• Environmental costs and alteration

Environmental Alteration• Corbicula die offs

• Filter feeders gone, bloom susceptibility

• Food web dynamics

• Less, different species recover

Prymnesium Parvum• Growth and toxicity of P.

parvum likely effected by other algae present in system• Cyanobacteria, Dinoflagellates

most resistant• Likely others follow suit

Interactions and Connectivity

Understanding Toxic Algae

• Secondary metabolites of P. parvum (prymnesins), vs those produced by others (Cyanobacteria, Dinoflagellates, etc)

• Tied to competition with one another, plus environmental factors

Connecting the Dots• Seasonal monitoring

• Documentation of assemblage shifts• Generation of history/database for comparison• Detection of algal toxins

•Site specificity• No succession model works everywhere• Observation of potentially toxic/allelopathic algae

• Notes on conditions and assemblage present in field before blooms and toxic events invaluable

• Inferences for laboratory studies

Research• Laboratory experiments critical to identify and validate

triggers and allelopathic interactions among algal species• Highly complex, even when limited in number of species

cultured• Possible to find strains which are non-toxic, but suppress

growth or toxin production of undesirables•Findings may be used to guide management actions in affected or vulnerable water bodies.

Conclusion• Algal toxins are potent and capable of massive

impacts to both environments and our quality of life

• Allelopathy in phytoplankton is complex, but with diligent and thorough research it can be understood in much greater detail

Questions?