80% of trash in the ocean is from land-based sources, including individuals, industry and improper waste management/infrastructure. Only 20% is the result of ocean-based sources, such as the fishing, shipping, and cruise ship industries. The ocean has enough trash to cover every foot of coastline around the world with five full trash bags of plastic…compounding every year.
There are 5 gyres where trash accumulates in the ocean. One known as the Pacific garbage patch that is larger than most countries. More than a million seabirds and 100,000 marine mammals are killed annually from plastic and other solid waste in our oceans.
Over 8 million metric tons of plastic wash into the ocean every year. At this rate, their will be more plastic than fish by 2050. See plastic pollution in the ocean
More than 700,000 synthetic microfibers are washed into our waterways from laundry
70 percent of the ocean trash sinks where it cannot be seen causing incredible damage to marine life on the ocean floor. This trash is much more difficult to clean up
Toxic greenhouse gas emissions can be washed into the ocean from the air and cause ocean acidification. This may result in marine life like coral and mussels to bleach and die along with the creatures that depend on them for survival. See Air Pollution
The noise pollution from high-intensity sonar and air guns military , oil exploration, and shipping activity can cause ear damage to seals, dolphins, whales and other cetaceans causing whale strandings. Noise can also harm jellyfish and anemones and destroy the food source of turtles, sharks and other marine animals. NRDC
Nutrient pollution also can cause huge algae blooms which rob the ocean of oxygen and cause massive fish kills and dead zones in the ocean. Areas that lack oxygen are called hypoxic zones. The number of hypoxic dead zones are growing at an alarming rate from 174 in 2004 to 405 in 2008. See Non point source pollution…UNESCO
OIL and other TOXIC CHEMICALS
Oil spills can be devastating to marine ecosystems. Yet, only 12percent of the oil in the ocean comes from oil spills. 3x as much oil and other toxins come from runoff from roads, driveways, and other parking lots which washes through the drains into waterways and is carried to the ocean. See Point Source and Non Point Source Pollution
Untreated sewage from improperly maintained septic and sanitation systems can leach off into the water ways. Some areas that do not have proper sanitation equipment can cause terrible health issues for wildlife and people. https://wwf.panda.org/our_work/our_focus/oceans_practice/problems/pollution/
HUMAN HEALTH ISSUES
Pollution can find its way back into the human population and cause health issues like reproductive problems, nervous system damage, kidney damage, and digestive issues such as diarrhea