by: katie todoroff. circulation sub-tropical convergence zone
TRANSCRIPT
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 samples
Bottom 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 levels
All types of plankton susceptible- foundation of the marine food web
No 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