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PLASTICS IN MARINE
ENVIRONMENTS
By: Theophilos Collins
MEM Duke University
[email protected]
Objective:
 Comprehension: Students will
understand that plastic exists in the
ocean in tiny fragments, and that
scientists are studying these plastic
fragments.
 Application: Students apply this
knowledge by recreating the
procedures researchers use to collect
and quantify ocean plastic debris
while evaluating those methods.
 Synthesis: Students formulate their
own questions and design an
experiment to address those
questions.
Grade: 9-10
Time: One 50 minute class
Setting: In classroom
Key Terms: Marine Debris, North Atlantic
Subtropical Gyre, Neuston, Ocean Plastic,
Hypothesis, Error, Bias
Materials Needed:
Cut up pieces of plastic, varying colors.
Lots of small bits of white and colored paper to
make the different tow samples.
At least five tweezers to grab plastic pieces.
Large map of North Atlantic Ocean, Sargasso
Sea, and Eastern U.S. This could be projected
on a smart board or some other electronic
display as well.
Red, orange, yellow, and blue markers to mark
on the map. Or a way to mark up the electronic
map with red, orange, yellow, and blue marks.
Lecture
Activity 1
Activity 2
• Clip introduces students to marine plastics as a problem
• How do we quantify and measure this problem? Show
another video clip. Review and outline collection methods as
a class
• Instructor leads students through an example before
students split into groups to work more independently
• Students in groups perform experiment, answer questions
on the process, make calculations
• As a class, create a map showing the results of their work.
Students make a hypothesis about what would happen if
they extended their work and did it many more times.
• Compare class hypothesis to the 22 year dataset.
• Pose some follow-up questions and investigations to this
research. Instructor helps class think through an example.
• Students break into groups again and design an experiment
to address a follow-up question
Lecture: Measuring Plastics in the
Ocean
This part is meant to show students how
researchers study plastics in ocean
environments.
Introduce ocean plastic debris through a clip:
https://www.youtube.com/watch?v=lA_CM4txdx
k

There is a lot of plastic in the oceans. We have
to study its effects, and how it has been
changing over time. But it would also be a good
idea to know how big the problem is. How
much is out there, and where? Are some places
worse than others?

The most straightforward way to find out how
much plastic is in the ocean is to directly
measure and count pieces. That’s what these
scientists are doing: filtering water from
different places in the ocean and counting all
the pieces of plastic they find.
Introduce collection and measurement
methods
https://www.youtube.com/watch?v=kZGJTdbdvO
4
Review and outline the process as a class
1. Need a boat with a net. Remember the
woman in the video said their net was 1 m
wide. The mesh size on the net is 0.33 mm,
so it catches anything larger than 0.33 mm.
2. Drop net in the water, and tow alongside the
boat. They sail at 2 nautical miles/hr for 0.5
hours. What is the tow distance?
3. Strain the water out of the jar at the end of
the net by filtering through another 0.33
mm filter. Now we only have the solid
items we caught in our net. What would be
the smallest size item we would find?
4. Pick through the items found in the tow,
identify pieces of plastic, and set aside in a
labeled jar.
Calculation Example Done Together
Place a dark red marker at 300N, 400W on the
map. Here, these scientists caught 1069 pieces of
plastic! 1
Lead the class through calculating area
concentration of plastic (# pieces/km2). The
process is shown on the answer key sheet.
 1 group has 19 pieces of plastic, an example
of a sample from SE of New England.
 1 group has 37 pieces, an example of a
sample taken from about 300N, 650W (in
the Sargasso Sea)
 1 group has 27 pieces, another example from
the Sargasso Sea/North Atlantic
Subtropical Gyre.
Class Review
After no more than 20 minutes, start discussing
as a class. Quickly review calculations. Answer key
is attached. Thought questions meant to get
students thinking about the scientific method, to
view this experiment and method with a critical
eye and think about differences between error
and bias.

On the large map, place markers where each
sample came from, and have the markers
color-coded by concentration. Blue for North
Carolina and Gulf of Maine samples with only a
few samples, yellow for the intermediate New
England sample, orange and red for the two
Sargasso Sea samples.
o Based on our limited sampling, where
does it look like most of this microplastic
debris is concentrated? This is our
hypothesis.

We know wind makes waves on the sea. The
waves can mix up the pieces of plastic so
they’re not all at the surface, they’ll get down
to a few meters below the surface. However,
this is VERY dependent on wind speeds.
o In average wind conditions at sea,
about 54% of plastic pieces CAN (but
not necessarily WILL) remain below the
surface of the water where our net
collected.3 So even those 1069 pieces
could have been only 46% of the entire
amount of plastic that was really there
at that sample site!
o How much plastic was there actually?
(1069/0.46, which is 2324 pieces)
o Recalculate concentration.
o But since now we’re looking at a depth
dimension, let’s now calculate
#pieces/volume (L). Assume that at our
wind speeds all of the plastic at our site
is in the first 0.4 m below the surface.
Activity 1: Recreate collecting
methods in groups
Students recreate the experiment in
groups
Organize students in groups. They perform
experiment
Split into groups of 4-5. Explain how you did the
first three steps for them and are now handing
each group a sample containing a bunch of items,
some of which are little bits of plastic. Explain that
each sample came from a different place and
reflects actual data collected by the same
scientists we watched earlier.2
Have some variety of size of plastic, and a variety
of colors. Have students fill out their worksheet.
Each worksheet has specific latitude and longitude
coordinates for the instructor to match with their
homemade samples.
 1 group has 3 pieces of plastic in their
sample. This is an example of samples
taken from North Carolina waters.
 1 group has 4 pieces in their sample, and
example of samples taken from the Gulf of
Maine
Lucky for us we have a net with a mouth
1 m wide and 0.4 m tall! Calculations
done on instructor’s answer sheet.




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
Are the data from your samples enough to
determine a pattern in the North Atlantic? How
could you make a stronger case for our
hypothesis about a pattern in the North
Atlantic? Need more samples!!!
These scientists have been doing exactly what
you did, but they’ve been doing it since 1986!
So they have a lot of samples by now, and their
map looks like Figure 1.
o Does their map reinforce our hypothesis
about where most of plastic is?
There are lots of ways using math to “color in”
the rest of the areas we didn’t sample. A
process called interpolating.
o Example of interpolating: Two data
points a certain distance apart. You can
say that the point directly in the middle
of them would be the average of the
two.
One way of interpolating yields Figure 2. Note
that this is an example of a mathematical
model.
o Does this image agree with our
hypothesis? What do you notice about
this picture?
It turns out that the wind driven surface
currents in the Atlantic form a ring around the
basin, and all of those currents converge in the
center of the basin. This area of convergence is
called the North Atlantic Subtropical Gyre.
(Show Figure 3. If wanted, can briefly explain
the basic takeaways of the image.)
The same features exist in the South Atlantic
and in the North and South Pacific and Indian
Ocean. So if that’s where all the water is
converging, that means it will also be where all
the plastic will converge!
Activity 2: Follow-Up
Investigations
As a class, come up with follow-up
questions to this study and design
experiments to address those questions.
Class analyzes a follow-up question together
 Let’s look at some basic questions and think
them through.
o A piece of plastic will have a given total
surface area and volume. What will
happen to the total measurable surface
area once a piece of plastic starts to
break apart.
Lead students through creating Figure 4, but
there’s no need to show this figure. A brief
conceptual overview is below.
 As each particle breaks into more and more
particles, see an exponential increase in
number of fragments. With this increase in
fragments comes an exponential increase
in TOTAL surface area. Note that the
surface area of each piece shrinks, but the
total combined surface area increases.
Five key takeaways
1. Most of the plastic in the ocean are little bits
the size of a fingernail and smaller.
2. There’s plastic everywhere in the ocean, like
confetti, with some patches/regions in
higher concentration than other regions.
3. Ocean currents transport plastics, so the
areas of higher concentrations are
associated with the center of subtropical
ocean gyres, where currents converge.
4. Both field research and mathematical
models of ocean circulation back up these
conclusions.
5. Researchers are using direct ways to
measure quantities of plastic in the ocean.
6. Direct methods don’t necessarily mean easy,
or without error or bias.
Assignment: Students come up with their
questions and design experiments
Other questions might come up. A homework
assignment can be to devote time to creating their
own experiments to all test the same question, or
have each group work on different ones. Examples
of questions are below. Supplementary
information in appendix will address these
questions for the instructor to help them guide
students.
1. What animals will eat plastic?
2. How long does it take for pieces to get to the
gyre?
3. Can we trace where certain plastics came
from?
4. How small do the plastic pieces get, and how
fast do they break apart?
5. What are some consequences of many smaller
pieces of plastic?
6. If plastic trash disposal is theoretically
increasing, do we see an increase in the
amounts of ocean plastic over the past 30
years?
7. Does plastic ever disappear? Does anything
break it down completely?
The groups design their own experiment to
address their research question. They should hand
in a written product with answers to the following
questions:
1. What will your basic “experiment” or
process look like and what is it testing? Is it
testing a hypothesis or is it
exploratory/descriptive?
2. What will your methods be?
3. What is your hypothesis? Part of your
hypothesis should include a graph showing
some sort of relationship along with an
explanation for this proposed relationship
(Like we just did in class).
4. What would a result supporting your
hypothesis look like?
5. What would a result that doesn’t back up
your hypothesis look like?
6. Could something else be observed?
7. What could be a source of error in your
methods?
8. What could be a source of bias?
Sea Education
Association’s set of
data showing
concentration of
plastics at every
sample site of theirs
since 1986. The black
stars indicate locations
with measured
concentrations greater
than 200,000/km2
while the
concentration at the
green star measured
26 million pieces/km2
4
Figure 1
Figure 2
Interpolated surface
from datapoints above.
The black line shows
the approximate
location of the 2cm/s
surface current, a
general boundary of
the North Atlantic
Subtropical Gyre.5
Image of currents in the North Atlantic, including the Subtropical Gyre bounded by the Gulf Stream, North Atlantic Drift,
Canary Current, North Equatorial Current, and Antilles Current. 67
Figure 3
Image above shows a PURELY HYPOTHETICAL breakdown over time of different plastic items8
Figure 4
Collectors:
Date:
Time:
Latitude: 300N
Longitude: 650W
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters.
Plastic Count:
Plastic concentration (#pieces/km2)
Thought Questions
1. If we sampled once and didn’t find any plastic, does that mean it isn’t there? Justify your answer in at
least one complete sentence
2. What other information would be good to have for your sample site before putting the net in the
water?
3. Describe your success in identifying and picking out pieces? Were any pieces easier to identify than
others? Why or why not?
4. Can you identify any sources of error in this process? How well did it work? What challenges did you
have?
5. Bias:
a) What are some sources of bias?
b) Does something get systematically cut out of our analysis that could be important?
c) Could our methods actually interfere with or influence what results we get?
Collectors:
Date:
Time:
Latitude: 290N
Longitude: 600W
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters.
Plastic Count:
Plastic concentration (#pieces/km2)
Thought Questions
1) If we sampled once and didn’t find any plastic, does that mean it isn’t there? Justify your answer in at
least one complete sentence.
2) What other information would be good to have for your sample site before putting the net in the water?
3) Describe your success in identifying and picking out pieces? Were any pieces easier to identify than
others? Why or why not?
4) Can you identify any sources of error in this process? How well did it work? What challenges did you
have?
5) Bias:
a) What are some sources of bias?
b) Does something get systematically cut out of our analysis that could be important?
c) Could our methods actually interfere with or influence what results we get?
Collectors:
Date:
Time:
Latitude: 420N
Longitude: 650W
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters.
Plastic Count:
Plastic concentration (#pieces/km2)
Thought Questions
1. If we sampled once and didn’t find any plastic, does that mean it isn’t there? Justify your answer in at
least one complete sentence
2. What other information would be good to have for your sample site before putting the net in the
water?
3. Describe your success in identifying and picking out pieces? Were any pieces easier to identify than
others? Why or why not?
4. Can you identify any sources of error in this process? How well did it work? What challenges did you
have?
5. Bias:
a) What are some sources of bias?
b) Does something get systematically cut out of our analysis that could be important?
c) Could our methods actually interfere with or influence what results we get?
Collectors:
Date:
Time:
Latitude: 320N
Longitude: 780W
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters.
Plastic Count:
Plastic concentration (#pieces/km2)
Thought Questions
1. If we sampled once and didn’t find any plastic, does that mean it isn’t there? Justify your answer in at
least one complete sentence.
2. What other information would be good to have for your sample site before putting the net in the
water?
3. Describe your success in identifying and picking out pieces? Were any pieces easier to identify than
others? Why or why not?
4. Can you identify any sources of error in this process? How well did it work? What challenges did you
have?
5. Bias
a) What are some sources of bias?
b) Does something get systematically cut out of our analysis that could be important?
c) Could our methods actually interfere with or influence what results we get?
Collectors:
Date:
Time:
Latitude: 390N
Longitude: 680W
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters.
Plastic Count:
Plastic concentration (#pieces/km2)
Thought Questions
1. If we sampled once and didn’t find any plastic, does that mean it isn’t there? Justify your answer in at
least one complete sentence.
2. What other information would be good to have for your sample site before putting the net in the
water?
3. Describe your success in identifying and picking out pieces. Were any pieces easier to identify than
others? Why or why not?
4. Can you identify any sources of error in this process? How well did it work? What challenges did you
have?
5. Bias
a) What are some sources of bias?
b) Does something get systematically cut out of our analysis that could be important?
c) Could our methods actually interfere with or influence what results we get?
ANSWER KEY:
Collectors:
Date:
Time:
Positions: The ones at 300N (sample NASG-1) and 290N (NASG-2) are in the North Atlantic Subtropical
Gyre. The one at 320N is off the coast of NC (sample NC). Sample at 420N is from the Gulf of Maine (GOM).
The sample from 390N is just SE of New England on the fishing grounds (NEF).
Tow Distance : 1 nautical mile (6,076 ft). Convert to meters. 1852 m
Plastic Count: NASG-1: 37 pieces. NASG-2: 30 pieces. NC: 3 pieces. GOM: 4 pieces. NEF: 19 pieces
Plastic concentration (#pieces/km2): Example with 1069 pieces to do together with class: We’re
calculating # of pieces/tow area in km2. The tow area is the length of the tow in meters multiplied by the
width of the net.
1069 𝑝𝑖𝑒𝑐𝑒𝑠
1069 𝑝𝑖𝑒𝑐𝑒𝑠
1069 𝑝𝑖𝑒𝑐𝑒𝑠
577,213 𝑝𝑖𝑒𝑐𝑒𝑠
=
=
=
2
1,852 𝑚 ∗ 1 𝑚 1.852 𝑘𝑚 ∗ 0.001 𝑘𝑚 0.001852 𝑘𝑚
1 𝑘𝑚2
Thought Questions
1. If we sampled once and didn’t find any plastic, does that mean it isn’t there? No. We could have just
not picked up any of the pieces of plastic. Wind could have mixed it below the sea surface.
2. What other information would be good to have for your sample site before putting the net in the
water? Environmental conditions like wind, sea state (wave height).
3. Describe your success in identifying and picking out pieces. Were any easier to identify than others?
Why or why not? More pieces take more time and are harder! Colors are easier to see, larger pieces
easier to see.
4. Can you identify any sources of error in this method? How well did it work? What challenges did you
have? We could have missed a piece. Harder to count at night or in different light conditions.
5. Bias
a) What are some sources of bias? Our own eyes. It’s easier to see certain colors and sizes.
b) Do certain sizes of plastic pieces get systematically cut out of our analysis that could be
important? We don’t catch plastic pieces smaller than 0.33mm, but that doesn’t mean they’re not
there. What’s the smallest size we can see with our naked eye?
c) Could our methods actually interfere with or influence what results we get? Were we “good” at
looking for plastic only because we were told to look for it- has it been in the oceans in large
concentrations for a long time but we’re just now getting good at looking for it so it seems like
there’s more?
One way to calculate #pieces/volume (L) on the example given in class.
2324 𝑝𝑖𝑒𝑐𝑒𝑠
2324 𝑝𝑖𝑒𝑐𝑒𝑠
3,137,149,028
1𝑥10−12 𝑘𝑚3
=
=
∗
(
)
1.852 𝑘𝑚 ∗ 0.001 𝑘𝑚 ∗ 0.0004 𝑘𝑚
7.408𝑥10−7 𝑘𝑚3
1 𝑘𝑚3
1𝐿
0.003 𝑝𝑖𝑒𝑐𝑒𝑠
3 𝑝𝑖𝑒𝑐𝑒𝑠
=
=
𝐿
1000 𝐿
The volume of water we towed through in km3 was the tow distance (1.852 km) multiplied by the
width of the net (1 m = 0.001 km) and the depth of our net (0.4 m = 0.0004 km). We find out how
many pieces this amounts to per 1 km3, and then convert from km3 to L.
SUPPLEMENTARY INFORMATION FOR INSTRUCTORS
Learn About Marine Debris
“The Great Pacific Garbage Patch”?
 The idea of a huge island of trash “twice the size of Texas” swirling around in the middle of the Pacific
Ocean in some sort of current vortex isn’t correct. It doesn’t accurately represent the issue of marine
debris.
 There are certainly large pieces of plastic that float around. But most plastic at sea is the size of your
fingernails and smaller. One usually can’t see them from the deck of a ship, and we certainly can’t see
these “patches” from space.
 Think of it as confetti mixed in the water, and in some places this “confetti soup” is more concentrated than
in other places
What is Marine Debris?
 Solid, man-made material
 Persists in the marine environment. Lasts for some amount of time.
What are some examples of Marine Debris?
 Trash bags, soda cans, food cans, wood, paper products, glass bottles, plastic bottles.
 Plastic is the big one! Scientists estimate that about 60%-80% of all marine debris is plastic!
Image at right of pile of trash. 9
What Does Marine Debris Look Like?
People think that marine debris looks like this
picture at right. And near land, yes it can look like
this. But in the ocean, plastic debris looks like this
lower picture.
All of these little pieces of plastic are called
“microplastics”.
 Image at lower right of little plastic pieces.10
 Some of these pieces are smooth round
pieces called “nurdules” which are what
plastic looks like before they get melted
and reshaped into products that we all
use. Others are fragments have broken
down from other larger pieces.
Image directly below of model. 11
Where Are These Microplastics Coming
From? What are the sources?
LAND:
Litter and waste
On beaches, in rivers, from street/drainage outflows
and runoff
Catastrophic Events
Hurricanes and Floods
OCEAN:
Ships and at-sea work platforms (like oil rigs, etc)
Accidental or intentional dumping, lost cargo, fishing
gear, recreational equipment, oceanographic research
tools
 It is likely that the majority of plastic
pollution in the ocean comes from land.
Where Does It All Go?
We know that these pieces of plastic can get
transported from land to the ocean. And we
know that once they’re in the ocean, they can
break into even tinier pieces. But here’s
another question.
 Once plastic debris gets to the ocean, will
it stay in the same place in the ocean? If you
dropped a bunch of bits of plastic in the ocean
from a beach in North Carolina, would they
stay near that same beach?
Important to communicate that the ocean is
always moving. Waves go in and out, the wind
blows things everywhere, and many times the
water goes where the wind blows. So since the
water is carrying that plastic, we can
hypothesize that those pieces of plastic
entering the ocean from North Carolina
beaches will get transported wherever the
ocean water goes.
Let’s assume we did a really terrible thing, and
dropped thousands of microplastic debris off of
the NC coast. Imagine we could track each
little piece.
 After one month, where do you think
those little pieces will be? Will they all be in the
same place?
 Picture shows the timeline results of a
mathematical model a bunch of scientists
developed to track plastic debris in the ocean.
They have computer models that simulate how
ocean water moves, and they can place imaginary pieces of plastic into the system and see how it
responds.
 The areas of higher concentrations are in green, orange, and red.
 Find the east coast of the U.S, and the Atlantic Ocean. Where does it look like our pieces ended up? In
the green and yellow patch.
 This is only a prediction. We need data to back this up. That’s what SEA scientists are doing.
Global Ocean Surface Currents
We have many models which show microplastics transportation is influenced strongly by global ocean
currents. This section reviews global surface currents, how they develop and why they form “gyres”.
Remember two basic concepts driving this whole thing: The way the sun shines on the Earth to provide
energy and the way the Earth turns dictate the formation of ocean surface currents and of ocean gyres.
1. The Sun shines on the Earth.


But a ray of light hitting the Equator heats a little surface very efficiently while a ray of light hitting an
area near the north pole hits a much larger surface.
So the equatorial regions should heat up more efficiently and be warmer than the poles. We know
this- most of the hottest places in the world are closest to the equator.
2. Air and water distribute heat.



We also know that air (and water) at the equator is much warmer than air and water at the poles.
But they are not going stay in one place!
The warm air will spread out from equator to poles, trying to warm the cold part of the world.
The first thing this hot air at the equator will do is rise and move away from the equator.
3. Development of pressure regions causes wind.
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



Hot air rising causes a generally lower pressure system around the equator.
But as air rises and moves away from the equator, it cools which causes it to get denser and sink!
Results in a high pressure system around 30N and 30S. This is what’s called a Hadley Cell.
Some of this air escapes the Hadley Cell, then flows along the surface of the Earth north (trying to
get towards the poles still), and another similar cell forms between 30N and 60N. Called a Ferrell
Cell.
Some air escapes the Ferrell Cell and forms another circulation unit called a Polar Cell.
Look back at the Hadley Cell. See the H and L pressure systems. Imagine the high pressure as a
mound of air and the low pressure as a small valley
Which way will air want to flow-“up the hill” from L to H or “down the hill” from H to L? Air will want to
flow from H to L pressure, “downhill” from the mid-latitudes to the equator.
This is wind! It’s the result of air flow between areas of H pressure and L pressure, the result of
imbalance of the heating of the Earth!
Image above of Circulation Cells and prevailing surface winds affected by Coriolis. 12
4. The Earth turns, which affects how air and water move on the surface of the Earth.
 Take a large ball. Have a marked point at the “equator” and one near a “pole”. Rotate the globe once
counterclockwise- this is one day. Which point “traveled” farther-the one at the equator or the one at the
pole? The one near the equator. It covered a longer distance in the same amount of time.
 This means that an object thrown at the equator will have a faster Eastward velocity (to the right, facing
north) than an object at a point near the poles (or even the mid-latitudes).
 So an object moving from the equator towards the pole with that Eastward velocity will not appear to
move in a straight line. It will seem to bend to the right in the Northern Hemisphere and to the left in the
Southern Hemisphere. Note that this motion isn’t the result of an actual force pushing or pulling it. This
is because there is no actual force acting on it-the object is moving in a straight line. It is only from
inside our rotational frame of reference that we can see this “bend”. This is the Coriolis Effect.
 Why is this important? Because when air masses flow from the equator to the poles, the Coriolis Effect
affects them. We “see” this in the “bottom” of the Hadley, Ferrel, and Polar cells.
 Air will consistently move from ~30N towards the equator, and it will, predicted by the Coriolis Effect,
bend right. Hence the NE tradewinds, some of the most consistent, predictable prevailing winds on
Earth
 Air moves water. People have shown experimentally and can predict very well with mathematical models
that when air blows in a certain direction along water for great distances, water will flow 90 degrees to
the right of the wind direction. This is called Ekman transport.
5. Ocean Surface Currents Form as a result of Coriolis Force, Ekman Transport, and Pressure
Gradients. They form Gyres!





Ekman transport of water resulting from the NE trades and prevailing westerlies causes water to pile up in
the center of the ocean basin.
Water pressure is higher in center at top of pile, and lower at the edges.
Water will fall down the pile going from H to L pressure, and then get deflected to the right in the Northern
Hemisphere by Coriolis “Force”.
Surface currents develop as a result, the balance of coriolis force and pressure gradients.
Examples in North Atlantic are the Gulf Stream, North Atlantic Current, Canary Current, and North Atlantic
Equatorial Current. Inside these currents is that pile of water in the area of water convergence called the
North Atlantic Subtropical Gyre.
Image at left of ocean gyre forming as a result of
surface winds13
Image above of gyres in the major world’s oceans. 14
Image of how coriolis deflection and
pressure gradients affect water flow around a gyre. 15
REFERENCES/ENDNOTES
Lavender-Law, K., Moret-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E., Hafner, J., Reddy, C. M., “Plastic
Accumulation in the North Atlantic Subtropical Gyre,” 329 Science p. 1186.
2 Lavender-Law, K., Moret-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E., Hafner, J., Reddy, C. M., “Plastic
Accumulation in the North Atlantic Subtropical Gyre,” 329 Science p. 1186.
3 Kulkulka, T., Proskurowski, G., Moret-Ferguson, S., Meyer, D.W., Lavender Law, K., “The effect of wind mixing on the vertical
distribution of buoyant plastic debris” 39 L07601 Geophysical Research Letters, (2012),
4 Lavender-Law, K., Moret-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E., Hafner, J., Reddy, C. M., “Plastic
Accumulation in the North Atlantic Subtropical Gyre,” 329 Science p. 1186.
5 Lavender-Law, K., Moret-Ferguson, S., Maximenko, N.A., Proskurowski, G., Peacock, E., Hafner, J., Reddy, C. M., “Plastic
Accumulation in the North Atlantic Subtropical Gyre,” 329 Science p. 1186.
6 http://en.wikipedia.org/wiki/North_Atlantic_Gyre#mediaviewer/File:North_Atlantic_Gyre.png
7 http://en.wikipedia.org/wiki/North_Atlantic_Gyre#mediaviewer/File:North_Atlantic_Gyre.png
8 Figure courtesy of R. Thompson
9 juiceonline.com
10 Image courtesy of Sea Education Association
11 International Pacific Research Center. (2008). Newsletter of the International Pacific Research Center. Tracking Ocean Debris.
Retrieved from http://iprc.soest.hawaii.edu/newsletters/iprc_climate_vol8_no2.pdf. p.16
12 Townsend, D. (2012) Oceanography and Marine Biology. An Introduction to Marine Science. Sunderland, MA: Sinauer
Associates. p. 169.
13 Townsend, D. (2012) Oceanography and Marine Biology. An Introduction to Marine Science. Sunderland, MA: Sinauer
Associates. p. 181.
14 Townsend, D. (2012) Oceanography and Marine Biology. An Introduction to Marine Science. Sunderland, MA: Sinauer
Associates. p. 182.
15 Pinet, P.R. (1992). Oceanography. An Introduction to Planet Oceanus. St. Paul: West Publishing Company. p.172.
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