Ocean pollution arrives through a number of additional outlets such as sewage, industrial and agricultural runoff, garbage dumping, and chemical spills. Pesticide and fertilizer runoff are creating huge dead zones — oxygen-depleted areas where many marine species struggle to survive. The world’s largest dead zone, located in the Gulf of Mexico, is roughly the size of Connecticut.
Climate change effects like warming water temperature, higher carbon dioxide levels, and changes in salinity, rainfall and sea level will likely increase the occurrence of HABs, or Harmful Algal Blooms. The introduction of nutrients from water pollution fuels the growth of algal blooms, which reduce oxygen in the area, suffocating aquatic animals - this is called eutrophication.
The majority of water pollution is nonpoint source pollution. While point source pollution can be traced to specific sources, such as wastewater, chemical or oil spills, and illegal dumping from specific facilities, nonpoint source pollution consists of land runoff, precipitation, drainage and seepage. This can make water pollution difficult to regulate.
Water pollution in oceans, rivers, and lakes can seep into groundwater, and affect aquatic ecosystems.
Plastics, another major water pollutant entering the ocean, is on the rise: every year, Every year, 11 million metric tons of plastics enter our ocean on top of the estimated 200 million metric tons that currently circulate our marine environments.
Widespread use of plastics, outside of the military, did not occur until after World War II. The ensuing rapid growth in plastics production was and continues to be extraordinary, surpassing most other man-made materials. Its largest market is packaging, an application whose growth was accelerated by a global shift from reusable to single-use containers. As a result, the share of plastics in municipal solid waste (by mass) increased from less than 1% in 1960 to, according to the EPA, more than 12.2% by 2018.
The problem with plastic is that it never fully decomposes, but as it degrades, it emits greenhouse gases. These microplastics disrupt the food chain and kill ocean life.
To address the plastic epidemic Boyan Slat, at age 18, founded the Ocean Cleanup to remove plastic from the Great Pacific Garbage Patch, the largest accumulation of ocean plastic in the world. As of April 2024, the Ocean Cleanup has removed 345,000 kilograms of plastic from the patch - a third of a percent of the total mass of plastic. For sea turtles around the Great Pacific Garbage Patch, plastics can be up to 74% of their diet. Through bioaccumulation, the plastics consumed by animals make their way up the entire food chain, affecting the health of whole ecosystems.
CREDIT: NOAA
