Each spring and summer, a sizable “dead zone” appears in the Gulf of Mexico, the Chesapeake Bay and other bodies of water around the world – large areas lacking the oxygen needed to support fish and other aquatic forms of life. This summer’s flooding in the Midwest has made it worse. How does this happen? And what are we doing to address it?
You may have heard of “dead zones”, a term used for areas in large bodies of water where marine life cannot be sustained because of rampant algae growth. To some ardent critics of animal agriculture, these dead zones can be traced to overdependence on animals as a cornerstone component of the modern global food system.
Agriculture and, in particular, production of beef and dairy cattle, as well as the corn and soybeans grown to feed the animals, are the primary targets under attack. Essentially, almost all U.S. crops feed into the Mississippi River Basin. But there is little, if any, attention called to the other sources of the troublesome run-off that causes massive algae growth.
So how do these dead zones occur? And is agriculture really to blame for these problem areas? And, most importantly, what is being done to bring life back to these dead zones?
How are Dead Zones created?
Dead zones occur from too much nitrogen and phosphorus in the water, most in the form of run-off from use and misuse of fertilizers, inadequate wastewater control, improperly managed animal wastes, and plain old natural phenomena, such as the heavy rains and flooding that plagued major parts of the United States earlier this year.
Hypoxia is the scientific term for having too little oxygen to support life. In a hypoxic zone, animal life simply suffocates and dies. Hypoxia occurs when excess nutrients such as nitrogen and phosphorus stimulate the growth of algae, which sinks and decomposes in water. The decomposition process consumes the oxygen needed by other marine life – impairing gestation, compromising egg production, or simply suffocating much of the life in the water.
Dead zones emerge from a complex web of sources:
Where do Dead Zones exist?
Currently, there are approximately 405 dead zones around the world and in different bodies of water, but mostly along coastlines. The Arabian Sea is currently the largest one with a continual lack of oxygen preventing marine life from growing.
The Baltic Sea dead zone is also massive, at more than 23,000 square miles and stretching from Poland to Finland. Smaller hypoxic areas have emerged in Lake Erie and oceanic conditions off the shores of California and Oregon are currently being monitored for a possible return of a Pacific dead zone.
NOAA scientists are forecasting this summer’s Gulf of Mexico hypoxic zone or ‘dead zone’ to be approximately 7,829 square miles or roughly the size of the land mass of Massachusetts.
National Oceanic and Atmospheric Administration’s June 10, 2019 Media Release
The second largest dead zone is the northern Gulf of Mexico. Some industry experts estimate that the Gulf of Mexico supplies 72 percent of U.S. harvested shrimp, 66 percent of harvested oysters and 16 percent of commercial fish. So a dead zone here not only leads to a meaningful loss of shrimp, crabs, oysters, fish, and other marine life, but also disrupts a large commercial industry that provides products in high demand by food consumers. The same situation is also happening in the Chesapeake Bay, where 500 million pounds of seafood are harvested each year, primarily oysters, blue crabs, and striped bass.
Waterways feeding the Dead Zones
The challenge in addressing the dead zone problem isn’t just the multiplicity of sources behind the problem. It’s also the sheer physical size of the area involved.
Waterways such as the Gulf of Mexico, the Chesapeake Bay, and U.S. Great Lakes draw water from an enormous network of sources. Potential pollutants can come not just from areas immediately adjacent to the dead zone, but also from potentially huge areas where run-off may occur.
For example, the Gulf of Mexico is fed by the Mississippi River basin – an area that encompasses 33 major river systems, more than 200 estuaries, and drains 41% of the contiguous United States. About four out of five acres used to produce corn and soybeans in this country are within it, as is more than half of all U.S. agricultural land, with an estimated annual production value of close to $100 billion. Such a vast drainage area shows just how important extensive flooding – like that seen across huge swatches of the Midwest this spring — can be in the creation of a dead zone.
Farming solutions to curb Dead Zone formation
Broad communities of scientists, environmentalists, farmers, ranchers, and others are joining together to tackle the problem – with the encouraging results that merit a continued mutual effort to protect one of the natural resources critical to a sustainable global food system.
In the world of agriculture, there are aggressive educational efforts to commit to responsible crop and herd management. Many farmers are employing technology to help reduce run-off through chemical and nutrient over-application, such as:
Precision agriculture combined with “micro nutrient” technology that fosters the application of the precisely correct type and amount of nutrients, herbicides, and pesticides
Genetic engineered crops also help reduce the amount of agricultural chemicals
Sound conservation practices such as no-tilling, proper crop rotation, and use of cover crops
Ranchers and dairy farmers are also proactively managing animal waste to help reduce run-off and revitalize these dead zones.
In fact, nearly nine out of every 10 farmers and ranchers recently surveyed by the industry’s National Cattleman’s Beef Association say they manage manure and waste in a proper manner that safeguards air and water.
Innovative programs developed by producers have helped find environmentally responsible uses for surplus manure, such as:
Expanded use of sanitized and pelletized manure for use in organic farming
Distribution arrangements with gardening and landscaping enterprises interested in expanded use of non-chemical fertilizers
“Spread the wealth” by finding available surplus storage and composting opportunities for “black gold,” as ranchers often call manure
The Environmental Protection Agency is facing lawsuits from environmental groups to speed their updating of wastewater guidelines for animal processing facilities, and public pressure on these companies is growing
Working together for real results
Despite what ag critics may say, there are multiple sources contributing to the problem. Many of the golf courses, housing developments, and other urban development areas that were previously undeveloped are now inadvertently contributing to the rising risks of run-off, and ultimately the growth of the occurrence and size of dead zones.
On the municipal wastewater front, state and federal agencies report an expansion in the number of municipal water management authorities monitoring nitrogen and phosphorus levels in their facilities, and perhaps more important, in establishing limits for each element in discharge levels.
On an even-broader scale, several task forces have been created to find long-term solutions to the management of U.S. dead zones. For example, the Mississippi River/Gulf of Mexico Hypoxia Task Force includes representatives of agencies from almost all states along the Mississippi, from Louisiana to Minnesota, as well as federal agencies such as the U.S. Army Corps of Engineers, the Departments of Agriculture, Commerce and Interior, the Environmental Protection Agency and the National Tribal Water Council.
Their goal is to reduce the size of the Gulf dead zone to 5,000 square kilometers (roughly 1,900 square miles) by 2035, with an interim goal of a 20 percent reduction in nitrogen and phosphorus loading by 2025. We have already seen significant progress in achieving its goals.
The Bottom Line:
Dead zones pose a challenge, not just to providing the fish and other marine foods that play an important role in feeding the world, but also to how we grow all the other foods consumers want and need. There is no single cause for the hypoxic activity and solving the problem will demand a collaborative effort. We’re making progress, but we have a lot more to do together to turn dead zones into a dead issue.