Government and independent scientists believe nutrient runoff is the main cause of the dead zone.  Pollutants such as nitrogen and phosphorus flow into the gulf of Mexico by way of the Mississippi River and its tributaries.

For many, the ethanol industry and the government’s 2005 Renewable Fuel Standard carry a lot of the blame.  Since the governments introduction of the Renewable Fuel Standard in 2005, acreage of U.S. land to farm corn and soy beans has grown by 16.8 million and over 1.2 million acres of grassland has been lost.

Flooding in 2015 and earlier this year washed away tremendous amounts of pollutants that had accumulated on land during the prolonged drought. The sources of much of these nutrients were cornfields, 40% of which are dedicated to producing ethanol, which fuel companies are compelled by Congress to blend with gasoline.

NOAA officials estimate the Dead Zone costs the nation’s seafood and tourism industries $82 million a year. And it likely will get worse, scientists believe. The gulf produces about 40 percent of the nation’s seafood, which includes offshore species such as shrimp and red snapper. And Louisiana is second in seafood production to Alaska, according to The Nature Conservancy.

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We already know that eating fish comes with risks of ingesting metals like mercury and lead, or pesticides like DDT. Scientists don’t currently know whether or what amount of plastics in fish poses a threat to human safety. They do know, however, that plastics are associated with a cocktail of chemicals, some of which are carcinogenic, and some of which disrupt our hormone system. Once they enter the ocean, plastics can also become a sponge for other contaminants like pesticides and industrial chemicals.

According to PHY ORGS the researchers emphasize that the debris are found in the animals’ guts. That suggests people are likely to ingest the debris only if the animal is eaten whole, like sardines and anchovies. The team is still studying whether chemicals in the material can transfer into the meat.

The presence of tiny plastic particles, or microplastics, is a growing problem worldwide. A team of scientists estimated that eight million metric tons of plastic waste enters the world’s oceans each year, and predicted that that number will increase over the next decade.

Reducing plastics in the ocean will require a concerted, multi-pronged effort and interventions might include banning plastic microbeads in personal care products, working with big plastic producers to search for alternative materials, or even possibly putting fiber filters on washing machines.

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The reef supports a wide diversity of life including many endangered species, some of which are unique to the Great Barrier Reef.  More than 1,500 fish species call the reef home, including the clownfish like Nemo from the Disney movie, Finding Nemo.  There are six species of sea turtles, 30 species of dolphins, porpoises, and whales; including the humpback whale.  There are species of sea grass, coral, birds, sea snakes, mollusk, sea horses and frogs   that all call the Great Barrier Reef home.

Tropical cyclones, which can produce extremely powerful winds and torrential rain, can also produce high waves and storm surges which can damage the Great Barrier Reef.  However, most of the environmental threats to the reef are manmade.  Pollution, shipping accidents, oil spills, and climate change have all resulted in the loss of more than two-thirds of the reefs coral since 1985.

Pollution and declining water quality are a couple of key threats faced by the Great Barrier Reef.  In 2009 a pesticide monitoring program collected samples at eleven sites; at least two pesticides were detected at every site.  Diuron, atrazine, and metolachlor exceeded Australian and New Zealand water quality guidelines at eight sites.

Over 90% of this pollution comes from farm runoff which is caused by over grazing, excessive fertilizer and pesticide use.  The runoff problem is exacerbated by the loss of coastal wetlands which are necessary to act as filters for the toxins and to help trap the sediment.  The declines in water quality and pesticide pollution have made the reef less resilient to climate change.

The Great Barrier Reef Marine Park was created in 1975 to help manage the reef in a sustainable manner.  Their goal is reduce non-point sources of pollution and it specifically targets nutrients, pesticides and sediment that make their way into the reef due to agricultural activities.  The Center for Biological Diversity is also hoping to protect the reef; they filed a petition with the National Marine Fisheries Service to protect clownfish under the Endangered Species Act.

While there is no evidence that the clownfish population is in decline, the concern is the deteriorating health of the coral reefs.  A critical element of the Endangered Species Act is protecting species’ natural habitats as opposed to merely protecting the population.  The loss of the clownfish’s habitat is a long-term threat to the species which has prompted environmentalists to begin seeking protection now.

The Great Barrier Reef is Australia’s best documented case of contamination of an ecosystem by pesticides.  The Australian government put in place a three-month moratorium on diuron.  The ban covered the season, which began in December, when soil run-off is at its greatest.  Spraying has resumed, but with restrictions; spraying is not allowed if about two inches of rain is expected within three days of application or if the land has a slope greater than 3%.  Some believe it is a good start to saving the Great Barrier Reef while others feel it is too little of an effort.