Marine debris is a persistent pollution problem of global problem. Marine debris is a threat to wildlife, navigation safety, and is a factor affecting the economy and human health, particularly in poor countries in coastal regions. According to NOAA sources, approximately 1.4 billion pounds of trash per year ends up in the world’s oceans. The major components involve floating consumer plastic objects (including plastic bottles and caps, cigarette butts and lighters, and plastic bags), and these materials decay very slowly, if at all. Other materials include metals, rubber, paper, textiles, construction materials, and glass. The entire world’s oceans are impacted by solid wastes transported by currents. Large portions of the ocean in the center of the large gyres have become floating garbage patches where floating debris is accumulating.
Trash comes from many sources, mostly by careless acts that release trash into storm drains and eventually drain into coastal waterways. Some trash material blown into the by the wind. Much of it comes from coastal recreation and shoreline activities. In impoverished regions, garbage is intentionally dumped at sea. Fishing nets, hooks, lines, abandoned vessels are lost, drifting at sea. Trash washes up on beaches, accumulates on the seafloor, or drifts practically endlessly as sea. Trash is very harmful to wildlife. Small objects that are swallowed cannot be digested, often injuring or killing sea life. Bags, lines, and nets entangle animals, leading to starvation or strangulation.
Garbage patches are regions in the world's oceans where downwelling waters in the middle of ocean gyre region cause floating garbage to accumulate (discussed in Ocean Circulation, Chapter 9).
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