1. Jellyfish or plastic bag?
Alex Smith
a deadly guessing game

2. Background research leatherbacks primary food source is jellyfish
leatherbacks are nearsighted
previous research looked at differentiation of objects by sea turtles based on luminance, flexibility and translucency
turtles tend to prefer items that are less bright, more flexible, and more translucent
rely primarily on visual cues when foraging, even when presented with chemical cues as well
leatherbacks forage for jellyfish near Nova Scotia and New Foundland even if they nest in the Guianas (northeastern south america: french guinea, guyana, suriname, and part of venezuela)
eat the white cannonball jellyfish and sea wasps and stinging pink nettles
had the turtles choose food ad examined stomach contents

3. background research Cont’d
plastic can cause intestinal compaction or tearing, digestive suppression, and exposure to chemical toxicants
juvenile turtles have been shown to have more than a third of their diet as plastic debris
americans use 100 million plastic bags each year and only 0.6% are recycled
DDT AND PCB

4. BAckground Research Cont’d
sea turtle cornea refractive index is same as the refractive index of seawater
see color in shorter wavelengths
have the visual acuity of other benthic shallow water marine species
leatherbacks have more open peripherals than the more shallow water species, like loggerheads and greens
nm—blue to ultraviolet
avoided the blue bait
oil droplets in the cones of the eye help discriminate between wavelengths

5. Null hypothesis
There will be no significant difference between light readings of jellyfish and plastic bags after light has passed through and reflected off of the object.
decided to test balloons later in the experiment

6. methods
Collect cannonball jellyfish (Stomolophus meleagris), plastic bags, and balloons from the beach
Freeze jellyfish to preserve them
Build the light apparatus (closed light system so only light comes from or through test objects)
Place object over the plexiglass hole in the bottom of the bucket and shine a light through it
Read the amount of light (lux) coming through with a light meter in the top
radiometric unit watts per square meter
measures the perceived power of light, not the total power of electromagnetic variation

7. Methods Cont’d
Place PVC pipe in the top of the bucket and shine a light through the pipe into the bucket, reflecting the light off of the object
Take a light reading of the albedo of the test object with the light meter.
Use unpaired T-tests to test for a significant difference between jellyfish and bags/balloons

8. The light containment apparatus
This isolated the light that shone through and off of the objects for the light meter measurements.
didn't end up filling with water bc too hard to measure with light meter
Transmittance
Luminance/Reflectivity

9. Results (all bags) Transmittance analysis—statistically significant
P<0.0001
degrees of freedom=24
std error=19.915
Luminance analysis— NOT statistically significant
P=0.1574
degrees of freedom=24
std error=0.104

10. Results (Bhi bags) Luminance analysis—statistically significant
Transmittance analysis—statistically significant
P<0.0001
degrees of freedom=20
std error=9.676
Luminance analysis—statistically significant
P=0.0014
degrees of freedom=20
std error=0.072

11. Results (other bags) Transmittance analysis—statistically significant
P=0.0049
degrees of freedom=16
std error=16.859
Luminance analysis— NOT statistically significant
P=0.6214
degrees of freedom=16
std error=0.152

12. Results (balloons) Luminance analysis—statistically significant
Transmittance analysis—statistically significant
P=0.0025
degrees of freedom=16
std error=32.109
Luminance analysis—statistically significant
P=0.0026
degrees of freedom=17
std error=0.127

13. had trouble making error bars,balloonandjellyfishdevationsdonotactuallyoverlap

14. you can see that the readings took place on different scales of lux

15. https://prezi.com/dmdqpyt_eupt/polymers-and-the-environment/
Discussion
The transmittance readings showed that jellyfish and the pollution let in different amounts of light (were not similar)
The luminance readings for bags from BHI and for balloons were very different
The luminance readings for all bags and the bags that were not from BHI are similar to jellyfish readings

16. conclusion
Luminance is the most important reading because of how turtles forage.
Bald Head Island bags may be of least concern compared to other plastic bags.
Balloons are not a large concern.
Overall plastic bags are still a concern for turtle conservation.
The experiment did not provide enough evidence or test enough variables to say that bags are easily mistaken or not conclusively.
turtles eat laterally
color of bald head bags are all white and seem to be least similar
bags were new and hadn’t been bleached by the salt water from extended exposure
would have liked to have used a spectrophotometer, but budget and complexity restraints

17. Plastic bags don’t taste good!
Plastic bags don’t taste good!

18. Works Cited
Carr, A. (1980). Some Problems of Sea Turtle Ecology. American Zoology, 20,
Rudloe, J. (1979). Time of the Turtle. New York, NY: Truman Talley Books.
Schuyler, Q., Wilcox, C., et al. (2014). Mistaken Identity? Visual similarity of marine debris to natural prey items of sea turtles. BMC Ecology, 14(14).
Donnelly, M. (2009). Plastics-at-Sea Catastrophe. Sea Turtle Conservancy Newsletter: Velador. (4).
Bartol, S. M. and Musick, J. A. (2003). The Biology of Sea Turtles, Vol. 2. London:CRC Press.
Young, M., Salmon, M., et al. (2012). Visual Wavelength discrimination by the loggerhead turtle, Caretta caretta. The Biological Bulletin, 222 (1).
any questions?