The Dead Zone: A year-round nightmare

By: Kristina Alexander / Published: Oct 26,  2017

For Halloween this year, consider dressing as The Dead Zone. You'll need a costume the size of New Jersey and the ability to suck all the oxygen from around you. You won't be the life of the party, but you'll be pretty scary.

This summer's Dead Zone – the area in the Gulf of Mexico where hypoxia is so extreme, all sea life dies – was anticipated to be the largest in history. It did not disappoint.

In August, the National Oceanic and Atmospheric Administration (NOAA) declared it to be 8,776 sq. miles, some 47 sq. miles larger than the Garden State. It's caused by excess nutrients from agricultural and developed land being flushed down the Mississippi River. Those nutrients, which concentrate at the mouth of the Mississippi, are part of an unnatural version of a normal biological cycle where nutrients feed algae, which grows and dies.

In the nightmare version happening each summer, massive quantities of nutrients lead to gargantuan algal blooms, and when that biomass dies, it takes all the oxygen in the water for decomposition, meaning there is no oxygen for the creatures that live there. The term is eutrophication or hypoxia. Without oxygen in an area so great, the loss is enormous. Sea life of all kinds die. The Dead Zone is too big for many to swim out of. Even those not killed outright are affected, with a NOAA study finding that shrimp in the Gulf don't grow as big. If a three-day red snapper season seems brief, consider how much longer it could be if fish weren't killed off each year unnecessarily.

The greatest dead zone is in the Gulf because it's at the mouth of the largest river in North America, but smaller dead zones occur throughout the United States. They are all caused by excess nutrients used as fertilizer on crops and lawns; and excess nitrogen caused by livestock, septic overflows and pet waste.

The 2017 Dead Zone is the largest ever (Credit: NOAA).
The 2017 Dead Zone is the largest ever (Credit: NOAA).

While Gulf anglers feel the brunt, and ranchers and farmers could make big changes, residents throughout the country can help, not just folks on the coast. Lawn fertilizer is a big contributor of excess nutrients in U.S. waters. Bags of fertilizer have three numbers on them, such as 30-10-3, giving the composition of the three key ingredients: nitrogen (N), phosphorus (P), and potassium (K). Both nitrogen and phosphorus are contributing nutrients to the Dead Zone. Hardware and big box stores sell grass fertilizer with a zero in the middle of that formula, such as 30-0-3, meaning the fertilizer contains no phosphorus. As phosphorus promotes root growth, and most soils are not phosphorus-deficient, home gardeners with established lawns don't need this ingredient to have a pretty yard.

As of 2012, 11 states had banned phosphorus in fertilizer, but no more have joined since then. Unfortunately for the Gulf, most of those 11 states are not in the Mississippi watershed (Illinois, Minnesota, and Wisconsin being the exceptions). New York State, for example, passed a Nutrient Runoff Law banning the use of phosphorus-containing fertilizer because "more than 100 water bodies in New York State cannot be used for drinking, fishing, or swimming because they contain too much phosphorus."

If your state does not want to address this problem, try a more local solution. In response to hypoxia conditions in east central Florida, Volusia County (think Daytona Beach), bans the application of nitrogen and phosphorus to lawns and landscape plants between June 1st and September 30th each year. If your county resists adopting such a plan, try your neighborhood, or your golf course, or your own yard.

If you're not willing to give up fertilizer altogether, there are ways to make using fertilizer less harmful.

  1. Use a slow-release nitrogen formula, such as water-insoluble nitrogen. This is less likely to burn brown spots on your turf, and less likely to leach out and contaminate the water instead of doing its job.
  2. Stop using fertilizer when grass is dormant, typically from mid-November until March. The grass doesn't absorb nutrients then, meaning you're washing your fertilizer and your money to sea.
  3. Add calcium instead of N-P-K fertilizer to help your yard.
  4. When you spread the fertilizer, try not to get any on pavement, and sweep it to the turf if you do (rather than hosing it off). All of those grains on the driveway will flush right to sea if you don't.
  5. You can also clean up after your dog. Pet waste is a nutrient-rich contaminant you don't want on your shoe or in your water.


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