This document discusses the harmful algal bloom toxin microcystin, which is produced in freshwater environments and transported downstream into the marine environment, where it poses a threat to sea otters. The authors propose studying the dispersion of microcystin in the ocean and whether it enters otters' systems through the water itself or by being absorbed by the invertebrates they eat. They will test water and animal samples for microcystin levels to investigate how far into the ocean the toxin travels and whether it accumulates more in otters exposed through their food or environment. The results could help understand microcystin's impacts and the risks to both marine life and humans who consume shellfish.

1. Microcystin:
The Freshwater Killer
By: Nubia Cervantes and Noah Craney
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2. 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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3. 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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4. 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?

5. Two Hypotheses About Dispersal
A)
• 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.

6. Two Hypotheses About the Vector
Invertebrates 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.

7. Methods
1) 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.

9. Methods
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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10. 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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11. 1000
900
800
700
600
500
400
300
200
100
0
Microcystin Dispersal into the Ocean
500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500 10000
Micrograms of Microcystin/L of Water
Meters from the Mouth of the Pajaro River
1ft
5ft
10ft
15ft
Bressie et al. 2011

12. 1 3 5 7 9 11 13 15 17 19
Micrograms of Microcystin/L of Water
Levels of Microcystin in Sea Otters
WATER AS THE VECTOR
INVERTEBRATES AS THE VECTOR
Days

13. 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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14. 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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15. 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.

16. LIVER BLOOD STOMACH
Relative Amounts of Microcystin in Different Sites
Microcystin Levels in Sea Otter
WATER AS THE VECTOR
INVERTEBRATES AS THE VECTOR
BOTH ARE VECTORS

17. 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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18. 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
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19. Acknowledgements
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!!!

20. QUESTIONS?
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