Dead Zones Stretch Along Oregon Coast and Gulf of Mexico, Study Finds | Oceans
Scientists recently surveyed the bottom of the Gulf of Mexico around Louisiana and Texas and found a larger than average area of oxygen-depleted water – a “dead zone” where nothing can live.
National Oceanographic and Atmospheric Administration (NOAA) scientists announced their discoveries this week: About 4 million acres of habitat in the Gulf are unusable for fish and bottom-dwelling species. The researchers had estimated a smaller dead zone this year, predicting an area of medium size.
“The distribution of the low dissolved oxygen level was unusual this summer,” Nancy Rabalais, a Louisiana State University professor who led the study, said in a statement. “The low oxygen conditions were very close to shore with many observations showing an almost complete lack of oxygen.”
But the Gulf is not the only coastal region to experience dead zones this summer.
The waters off Oregon have had hypoxic zones every year since 2002. But it was also a record year in Oregon: the dead zone appeared earlier this year than in the past. 35 years.
Dead zones develop when fertilizers and nutrients from farmland flow into oceans or lakes, creating a windfall of algae that eventually dies and decomposes. As the algae decompose, it depletes the waters of oxygen, suffocating the species that live in the area.
Studies show that fish in hypoxic waters change what they eat, which affects what people can catch. Dead zones also make commercially important species like shrimp less available in the gulf and kills fish and crabs off the Pacific coast in the northwest.
Fertilizer pollution has caused an estimated $ 2.4 billion in damage to fisheries and marine habitat each year since 1980, the Union of Concerned Scientists said in a study released last summer.
In Oregon, the global climate crisis is compounding the problem: warmer waters retain less oxygen than cold waters, promoting the growth of dead zones. Additionally, as more carbon is absorbed into the oceans, the waters become more acidic, making it more difficult for creatures like crustaceans and crabs to grow their shells.
It all amounts to “a double whammy of the atmosphere and the ocean,” NOAA researcher Richard Feely told the Washington Post.
This year, crab fishermen described finding the carcasses of hundreds of Dungeness crabs along the Washington and Oregon coasts.
In 2001, a task force made up of state and federal agencies set a goal of keeping the five-year dead zone average at no more than 1,900 square miles. This summer’s dead zone is about three times the size of that. NOAA has also created a tool – Runoff Risk Prediction – to help farmers apply fertilizer at optimal times to ensure they stay on the fields, in hopes of limiting nutrient runoff to the soil. Gulf.
Some say these actions do not go far enough. “Without a large and focused effort to reduce nitrogen runoff from farms and ranching operations, Gulf Coast communities will continue to bear the costs of the dead zone,” said Rebecca Boehm, food program economist and environment of the Union of Concerned Scientists. in a report.
“The dead zone has not diminished significantly over the past 30 years, and we are no closer to the targets set by the Hypoxia Task Force. Policymakers need to rethink their strategy, or we are. will be back here next year with the same bad news. “