Diving into the Dead Zone


Did you know that there is currently an area the size of New Jersey in the Gulf of Mexico that can be deadly to fish and other marine animals? What’s worse is that this area, known as a dead zone, shows up every summer and this year it is bigger than it has ever been.

The dead zone is actually a hypoxic area, or an area with low oxygen content. Hypoxic waters typically have dissolved oxygen concentrations of less than 2-3 ppm. The cause of these hypoxic areas is typically an excess of nutrients, namely nitrogen and phosphorus. These excess nutrients in water can promote the growth of harmful algal blooms. An overgrowth of algae in the water can lead to a variety of problems. One problem is that some types of algal blooms can produce dangerous toxins that are capable of causing sickness and, in severe cases, death to humans and animals. Another problem comes when these algal blooms begin to die off. As algae dies and decomposes it absorbs oxygen from the surrounding water and leads to areas of low oxygen. The lack of oxygen forces fish out of the hypoxic areas, but the less mobile species, such as young fish and shellfish, are often times killed during the process. This inability to support life is the reason these areas are known as dead zones.

The largest dead zone in the U.S. and one of the largest in the world, is the one located in the Gulf of Mexico. Scientist first began mapping the zone in 1985. Over the last 5 years, the average size of the dead zone was approximately 5,806 square miles. However, in 2017, the zone was measured to be an alarming 8,776 square miles, the largest recording ever. The primary cause for this specific dead zone is runoff from the Mississippi River. The watershed of the Mississippi River is the fourth largest watershed in the world, covering about 40% of the lower 48 states. With this huge watershed, comes a huge amount of pollution in the form of nutrient runoff. A large portion of this nutrient runoff comes from the use of fertilizers for agriculture in the upper midwest. All of these excess nutrients then work their way down the Mississippi and are then dumped into the Gulf of Mexico. The reason for the spike in size of the Gulf dead zone is directly tied to an increase in rainfall in the midwest this year.

Map showing the size and location of the 2017 dead zone in the Gulf of Mexico.

Knowing that we, as humans, are contributing to the size of the dead zone, the question becomes what can we do to reduce our impact. In 1997, the EPA created the Hypoxia Task Force (HTF) to address the problem that is the Gulf of Mexico dead zone. The primary goal of this task force is to reduce the size of the gulf hypoxic zone to 1,950 square miles by 2035. In order to meet this goal, the HTF agreed on an interim target to obtain a 20% reduction in the nutrient load being discharged into the Gulf of Mexico by the year 2025. In addition to the actions being made at the federal and state levels, individuals can also find ways to reduce their impact. Firstly, we can cut down on the use of fertilizers on farms, lawns and gardens. If fertilizers are necessary, it is important to use them at the appropriate times to limit the amount that can enter our waterways. Other ways to reduce the impact is to use phosphate free cleaning products, have septic tanks inspected on a regular basis, and clean up pet waste. Overall one of the biggest keys to achieving the goal of a smaller dead zone is to raise awareness of it. The majority of people are not even aware of the issue, but just because we can’t see the dead zone, doesn’t mean that we will not feel the harsh impact that it has on our environment.








12 thoughts on “Diving into the Dead Zone

  1. This is another example of how complicated and interconnected the environment is. Agriculture in Iowa can cause uninhabitable regions in the ocean a thousand miles away. I knew about dead zones but didn’t know there was one in the U.S., especially not one that big. I’ve read that these are not irreversible though. The Black Sea had a huge one in the 90s but has been repaired after a large increase in fertilizer costs. For potential solutions, it will be difficult to balance any regulation or fertilizer cost adjustments with the strong need of our U.S. agriculture industry. There will need to be an agreement and big remediation effort somewhere down the road because this is certainly not a sustainable system.


  2. Great read! As you mentioned, I was unaware of the dead zone in the Gulf of Mexico. I agree 100% that the first step has got to be achieving awareness! How are people going to care about something if they don’t know about it? If we could show consumers that they are contributing to the dead zone by buying goods from the areas effecting the Mississippi River, I feel like that would be an eye opener. Maybe it would also be beneficial if states contributing to the runoff in the river could take responsibility by implementing regulations at the state level. Through our course work in the environmental engineering major, I have become extremely interested in constructed wetlands. Maybe CWs would be a good tool for tackling some of the runoff issues along the river.


  3. I really enjoyed reading this article. I really liked the point about the best way to fight the dead zone is to raise the awareness of it. Just as the book mentioned one of the major issues of all the environmental problems is the lack of public knowledge on whats actually happening. With the public’s knowledge and hopefully support of these environmental issues maybe we can actually get something accomplished.


  4. Awareness on issues like these is important but I often feel like in the U.S. that unless it is done well, that it has little impact. The reality is that Americans are busy – between work, family, exercise, personal time, netflix & social media, – many don’t care to spend time on investigating the how to not contribute to the dead zone through food consumption. I find that unless the food may be harming their kids somehow, they would rather be on Facebook, making money, or attending the next yoga class – being environmental responsible tends to creep down on the list. Awareness needs to be quick, easily understandable, relatable, solution oriented, but also intellectually informative at the same time. Too lengthy and informative, than no one will care to learn but too surface level and people will not take it seriously.

    Maybe its just because I live in a region that tends to not be leading on this stuff – but these are just my observations!


  5. I had no idea that these “dead zones” even existed in the gulf. I was aware of low DO in freshwater but I was not aware that it also existed in saltwater. It’s great that there is a task force assigned to reducing the size of the dead zone. However, it will be hard to prevent or even reduce fertilizer nutrients from entering the waterways altogether. Agriculture is a major part of the economy for those midwest states and it will be difficult for them to reduce fertilizer use which boosts the production of their crops. This seems to be a very complex problem and I will be very interested in the progression of this problem and the solutions that will be applied to it.


  6. I have heard of dead zones before, but I had no idea how such a large area was impacted by this dead zone. I have barely heard anything in the media about this dead zone which goes to show you that this is another major problematic event that is shoved off to the side. You can see from the data that the deadzone in increasing each year and if we don’t approach this with caution and find a solution quick then it could end up being disastrous for all marine life which will inevitably affect us in the long run.


    1. I was not aware of the existence of dead zones. After reading the npr article linked at the end of your post I believe that it will take government influence to help this problem. The article references a smaller dead zone in the Chesapeake Bay in 2010. The government implemented limits on the amounts of nutrient pollutants entering the water and it did make the dead zone smaller. Fast forward a few years later and the overall pollution is lower and wildlife is starting to recover.


  7. I really enjoyed this article. Being from New Orleans I have heard a lot about the dead zone (I was going to write about it next week!!) and the destruction that it can have. I think the best way to address this issue is to inform the people up the Mississippi River, especially farmers, about this issue. Like you said, the main cause of it is from the pesticides and fertilizer that is used along the Mississippi River that then runoffs into it and down into the Gulf of Mexico. If we can cap the issue at the beginning we will have the best chance to stop this.


  8. I am not sure how I had never seen this, but as I was reading this article, my mind began to run and I quickly jumped to the conclusion that all fertilizers must be eliminated. Clearly, this is not in anyway a feasible solution. We need the fertilizer to grow crops and keep our food supply for lack of a better word supplying. Where do we draw the line? When does the benefits provided by fertilizers get out-weighed by the negative impacts like the dead zone? Is there another way to protect our food other than fertilizers? Is there a way to capture the excess fertilizing nutrients before they’re in the waterways and causing complications?


  9. It is honestly sad as what we’re doing to the world. This issue of dead zones is directly affected by us humans. These fertilizers are extremely harmful to the algae ecosystem. This is one reason I could argue for GMOs as we could modify our agricultural to the point that we wouldn’t need these disruptive fertilizers.


  10. Considering that the task force was created in 1997 yet we have seen a growth in the size of the dead zone, we can infer that something isn’t working. I realize that that the tasks forces goal had a deadline of 2025 and it’s only 2017, but in 20 years of them making changes, they seemed to be unable to even cause a minor shrinkage in the dead zone. In fact, from what this article says, it is bigger than it has ever been before. That says one of two things to me: either the damage has been done and there is nothing we can do impede the growth of algae, or the policies the task force put into place to stop the growth are inadequate at best. I think there needs to be a serious re-evaluation on what is going into that water from all sources.


  11. It seems like when you wonder what other ways humans could alter our environment, something else pops up. Our environment is very fragile and interconnected. This is also a good example of why we should start paying attention to runoff. No matter what it is or where runoff is coming from, the sum of it all can have dire consequences.


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