Microcystin:The Freshwater Killer

By: Nubia Cervantes and Noah Craney

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Introduction• Significant increase in the awareness of the

interactions between terrestrial and marine ecosystems (positive and negative)

• Microcystin is one of these negative interactions.

• It has been proven to be deadly in sea otters which is why they will be the target species of this project.

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Microcystin: What is it and where does it comes from?• Microcystin is a planktonic, colonial,

cyanobacterium (Vanderploeg, H. A. et al. 2001)

• Microcystin is produced when large, toxic algal blooms in freshwater environments are washed downstream and into the marine environment

(Miller, M. A. et al. 2010)

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Questions

1) Characterize spatial and temporal dispersion of microcystin.

A) How far does microcystin extend into the Pacific Ocean?

B) How long will it take for the bacteria to reach the ocean?

2) Is the vector for microcystin the water itself or the invertebrates that otters prey on?

Two Hypotheses About DispersalA)• Microcystin will not

extend more than 5 kilometers into the Pacific Ocean at a level of 400 micrograms/liter.

• Currents and upwelling will disturb the bacteria.

B)• Microcystin floats in

the current.

• This means that the bacteria should reach the ocean within a day or two of the bloom.

Two Hypotheses About the VectorInvertebrates as the Vector• Toxin is absorbed by the

algae which are pushed downstream into the ocean.

• Shellfish, and other invertebrates, then feed on the algae that carries microcystin.

• The sea otters eat shellfish and are then intoxicated with high levels of microcystin.

Water as the Vector• The water itself is carrying

the toxins into the ocean. As otters swim and feed in the water, some is eventually swallowed.

• This could lead to an accumulation of microcystin in a sea otter just because it lives in the ocean.

Methods1) Collect water (at 1ft, 5ft, 10ft, and 15ft) and

invertebrate samples from Pinto Lake, Corralitos Creek, the Pajaro River, and the Pacific Ocean.

- Use the SPATT (Solid Phase Adsorption Toxin Tracking) method to test this water for blooms. This was proven effective in Miller’s study of microcystin in Pinto Lake.

(MacKenzie L. et al. 2010)

2) Factor in the current by sampling water and invertebrates north and south of the Pajaro River.

3) Conduct targeted sampling of sea otters on every other day using the method from (Wild and Ames 1974)

o Take samples of the liver tissues, blood, and stomach contents and test them for microcystin.

-Use the ELISA method and the protein phosphatase inhibition assay (Bressie et al. 2011)

4) Repeat this entire process multiple times over a five year period.

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Methods

Results (Spatial and Temporal)•The microcystin did as predicted and was less than 400 micrograms/liter at the 5 kilometer mark.

•The microcystin reached the ocean within the first day, and reached potentially dangerous levels for marine mammals very quickly.

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Microcystin Dispersal into the Ocean

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Meters from the Mouth of the Pajaro River

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Levels of Microcystin in Sea Otters

WATER AS THE VECTORINVERTEBRATES AS THE VECTOR

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Results (invertebrates)

• Otters that are found to be feeding in or around the mouth of the Pajaro River would have high concentrations of microcystin. Depending on the strength of this concentration, the otters will suffer from severe liver problems or will be found dead.

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Results (Water)•Any otter that was captured in the area should show high levels of microcystin in its liver and blood however, the otters won’t show much in their stomach content samplings.

•This will only increase as time increases so a steady upward trend of infection should be present.

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Results (Both)

•It is possible that both water and invertebrates are vectors for microcystin. In this case, all otters should show some level of infection after the first few days…however, these levels will be extremely high in the stomach as well as blood and liver.

LIVER BLOOD STOMACH

Microcystin Levels in Sea Otter

WATER AS THE VECTORINVERTEBRATES AS THE VECTORBOTH ARE VECTORS

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Why is this important?

• Otters and humans are the main consumers of shellfish which means that humans have the risk of being intoxicated.

• Microcystin can cause reproductive harm and in most cases death.

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References• Vanderploeg H.A.; Liebig J.R.; Carmichael W.W.; Agy M.A.; Johengen T.H.;

Fahnenstiel G.L.; Nalepa T.F. Canadian Journal of Fisheries and Aquatic Sciences, Volume 58, Number 6, June 2001 , pp. 1208-1221(14)

• Miller MA, Kudela RM, Mekebri A, Crane D, Oates SC, et al. (2010) Evidence for a Novel Marine Harmful Algal Bloom: Cyanotoxin (Microcystin) Transfer from Land to Sea Otters. PLoS ONE 5(9): e12576. doi:10.1371/journal.pone.0012576

• Wild, Paul W. and Ames, Jack A. (1974) A report on the sea otter, Enhydra lutris L., in California. Long Beach, CA, California Department of Fish and Game, (Marine Resources Technical Report, 20)

• Bressi, J.D. ; Kashian D; Pothoven S. (September 23, 2011) Evalutation od the Hazard of Microcystis Blooms for Human Health through Fish Comsumption http://www.glerl.noaa.gov/res/Task_rpts/2005/aislandrum05/1.html#top

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We would like to thank many people for their help in putting this presentation together. Chief among these are:

•Robin Dunkin: Our TA and our main advisor in this project.•Shawn Noren: Our professor and the one who taught us so much about marine mammals.•Jen Rodgers: The best teacher fellow ever, who guided us through every academic step of Cosmos.•Walter Heady: Our secondary professor who enkindled our love for ecology, especially in the freshwater environment.•D.J. Stoll and Jimena Garcia: our two amazing RAs who made sure we stayed on track and made Cluster 3 all that it is.

Thanks Everyone!!!

Acknowledgements

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QUESTIONS?

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