North Atlantic Gyre and

Microplastics

By: Katie Todoroff

Circulation

Sub-tropical Convergence Zone

Concentration of Plastics Sewage, tourism, fishing,

waste from ships and boats

9,064 tons of plastic debris

Gyre has surface area of 3,625,753 km^2

25,000 pieces of plastic/km^2

Highest concentrations observed in the Sargasso Sea

• Garbage Patches located beneath High Pressure Systems

• Weak winds

Estimation and Modeling

Use trajectories of drifting buoys to estimate the rate and location of aggregation

Consistent with observations of garbage and defragmented plastic

Neuston nets used to collect samplesBottom Trawling Nets also used on the seafloor

Entanglement and Ingestion

Microplastics

Undergo photo-oxidative degradation Happens faster on land and ocean surface, extremely slow process

at abyssal depths due to lack of UV-rays and colder temperatures Most are not visible to the naked-eye Once surface is degraded, further broken down by stresses in the

ocean such as turbulence

Microplastics

Persistent Organic Pollutants (POPs)- occur universally in the oceans via runoff

POPs are hydrophobic, dissolved in the microplastics and concentrated there

Become bioavailable to organisms

Implications to the Marine Food Web

Can deliver toxins across trophic levelsAll types of plankton susceptible- foundation of

the marine food webNo significant studies yet that quantify the

outcomes 1-L plastic water bottle will photo-degrade into

enough small pieces to pout once piece on every mile of beach in the world