Great Lakes Areas of Concern rivers, and oceans causing pollution and buildup of sediment. Nonpoint source pollution is said to be the most problematic and hardest to reverse of the types of pollution because it is so hard to regulate and pinpoint where it originates. Many experts agree that nonpoint source pollution is the biggest concern facing the Great Lakes. With the increase of urbanization, a toll has been taken on the lakes in these areas. Lakes that once had stable ecosystems with the appropriate amount of plant life are now full of massive amounts of plants and algae that have been fed by excess
Great Lakes steamships, they were called "steamboats"—the same term used on the Mississippi. The ships also have a distinctive design (see Lake freighter). Ships that primarily trade on the lakes are known as "lakers". Foreign boats are known as "salties". One of the more common sights on the lakes has been since about 1950 the 1,000‑by‑105-foot (305-by-32-meter), self-unloader. This is a laker with a conveyor belt system that can unload itself by swinging a crane over the side. Today, the Great Lakes fleet is much smaller in numbers than it once was because of the increased use of overland freight, and a