Before revision: Boundary currents are ocean currents with dynamics determined by the presence of a coastline, and fall into two distinct categories: Eastern boundary currents are relatively shallow, broad and slow-flowing .
After revision: The world's largest ocean gyresBoundary currentsBoundary currents are ocean currents with dynamics determined by the presence of a coastline, and fall into two distinct categories: Eastern boundary currents are relatively shallow, broad and slow-flowing .