Causes:

Land based causes: Most of marine debris sources are land-based.  Beach and shore pollution are primary factors of marine debris.  Any pollution accumulated on land can be swept out to sea and lost in the ocean.  Even pollution off the shore can be transferred to the ocean.  Litter in streets can be swept into storm drains by rain.  The storm drains can then transfer the debris to another water source or directly to the ocean.  Lastly, natural disasters such as tsunamis, floods, hurricanes, and mudslides can inflict serious damage.  The immense amounts of debris caused by these natural events can be deposited into the ocean.

Ocean-based causes: The other primary sources of marine debris are ocean-based.  Fishing gear and nets from commercial fishing vessels as well as recreational boats can be lost at sea.  These nets continue to “fish” once in the ocean, unintentionally trapping and killing marine animals.  Offshore drills and platforms may also lose gear or equipment to the sea.  Some of these materials are plastic drill pipe thread protectors, storage drums, and hard hats.  Lastly, debris from huge commercial vessels can pose a serious threat.  Cargo can be dumped into the ocean because of rough seas.  This can cause massive amounts of pollution to enter the water.

Whether land or ocean based, the main type of marine debris is plastic.  Research has estimated that 60%-80% of all marine debris is made up of plastics.  Plastic takes almost forever to decompose, so it remains in the oceans, breaking up into smaller and smaller pieces.  Along with plastics, marine debris can also be composed of metal, glass, and rubber.  The following is a list of some common forms of marine debris:

·      Domestic products: plastic bags, Styrofoam cups, plastic bottles, balloons

·      Industrial products: plastic sheeting, resin pellets, hard hats

·      Fishing products: nets, traps, lines

·      Abandoned and derelict vessels