Background
Two years ago, during my freshman year at the University of Illinois, I was enrolled in ACES 101, which is required for all freshmen in the College of ACES. In that class, one assignment tasked us with interviewing an industry professional and presenting our findings. My group chose to interview Gary Johnson, a Supervisory Hydrologist with the United States Geological Survey, or USGS. During our interview, he brought up a phenomenon called “Gulf Hypoxia”. Prior to that conversation, I had not really heard of hypoxia and did not realize the implications it has on our society and our economy. Two years later, I have had the privilege to learn more and more about runoff, nutrient loss, and hypoxia through classes such as NRES 201 and ABE 199. However, what motivated me to choose the Gulf Hypoxia issue for my research paper was something that Dr. Kalita recently said in class. His discussion on the sheer lack of knowledge and awareness of the global water crisis by many US citizens is astounding. By looking more in depth at hypoxia in the United States (especially in the Gulf of Mexico), I hope to shed a light on the hypoxia and eutrophication issues that are facing US citizens from all walks of life, while also listing and exploring the ideas for how we can adapt and deter the growth of the hypoxic zones in the future.
Introduction
According to the Environmental Protection Agency (EPA), Hypoxia is a dead zone in a body of water that is caused by excess nutrients and algal decomposition which consumes a large amount of oxygen from the water (EPA, April 2017). Hypoxia is a form of eutrophication, or an area of water that has been oversaturated with nutrients (World Resources Institute, 2013). For Americans, Hypoxia is the most clearly present in the Gulf of Mexico, where nitrification, or high levels or nitrogen, are present. According to a September 2013 report by the World Resources Institute, hypoxia has grown from 10 documented cases in 1960 to over 160 cases in 2007.
Hypoxia can have many long-term negative effects on the environment, economy, and livelihood of those who live on the coast. Nutrient loss and runoff from fertilizers can lead to hypoxia, or dead zones, and costly, long term effects to the environment. This paper will serve to explore how hypoxia levels reached their current height, while also explaining how reduction strategies and changes in practices affect farmers, consumers, and our society. Additionally, current and future solutions and their feasibilities will be discussed, as the goal is to slow down the growth of the hypoxic zones that already exist, like the one in the Gulf of Mexico. It is also important to consider what could happen if the proposed solutions fail or if the issue of hypoxia remains unchecked. The potential implications of water-related issues such as hypoxia makes it important for stakeholders and producers to be aware of.
Contributing Factors
According to a 2014 MDPI report, Nitrogen and Phosphorus runoff has the potential to cause algal blooms and murky waters for many years to come in these bodies of water (Withers, Neal, et. al., 2014). These symptoms serve as the pre-cursor to true hypoxia and the destruction of coastal ecosystems. The hypoxic dead zone in the Gulf of Mexico forms every spring and is most prevalent during the warmer months. This is due to the melting of snow and thawing of rivers and streams in the upper Midwest, as well as the application of fertilizers by farmers during this time. Additionally, April and May tend to be a somewhat rainy season, which results in a greater amount of runoff and loss of nutrients to streams and rivers such as the Mississippi River. Rainfall plays a major role in the amount of nutrient loss that happens each year. In years with heavy rainfall, the amount of sediment that is washed away increases.
There are many factors that lead to severe levels of hypoxia like those seen in the Gulf of Mexico. According to the World Resources Institute, the most common responses are agricultural sources, urban and industrial sources, and fossil fuel sources. It is important to note that many different factors have led to high hypoxic levels on the coastlines. Often, the finger is pointed at farmers as the sole cause of hypoxia. While farmers are not free of blame, there are certainly other factors that contribute to increasing hypoxic levels. Below, Figure 1 shows the wealth of inputs that lead to nutrient runoff, eutrophication, and ultimately, hypoxia.
According to a Springer Link report published in Feb 2015, worldwide agricultural production has tripled over the past 50 years (Sharpley, Bergström, et. al., 2015). This means that agriculture has not only become much more efficient, but also more complex thanks to advancements in fertilizer. This all cycles back to nutrient loss which is a major issue facing agriculture. Agricultural nutrient loss occurs when fertilizer that was applied to fields runs off into bodies of water. The true loss of nutrients entails losing key nitrates and phosphates that play a major role in maximizing crop yields (Sharpley, Bergström, et. al., 2015). Nutrients are sometimes over-applied by farmers because that has been their historical practice. Even if the field is saturated with nutrients, the marginal cost of adding more fertilizer is low enough that farmers continue to apply it to their fields. In Figure 2 below, there are two graphs. The graph on the left shows the increase in agricultural use of Nitrogen by farmers worldwide (Food and Agriculture Organization, 2018). The graph on the right shows total nutrient application for agricultural use for Nitrogen, Phosphate (P2O5), and Potassium/Potash (K2O). Both graphs serve to illustrate that nutrient application, and in some cases, over-application, has been trending upward for much of the past fifteen years.
Figure 2
Source: Data from FAOstat Database
Fertilizer and nutrient application by farmers can come in several forms, whether it is applied synthetically through fertilizers, or naturally through animal waste products such as manure. Manure is a major culprit when it comes to over application of nutrients. As livestock production continues to increase and farms get bigger, producers are left with more and more waste products. As a result, farmers could be more likely to over-apply manure on their fields, which leaves an excess amount of nutrients that can be washed away and into streams and rivers (World Resources Institute, 2013). Fortunately, state specific manure-management plans are required by the EPA and help larger operations reduced the amount of over-application of manure that takes place.
In the fall of 2016, Gary Johnson from the USGS provided his opinion on the current hypoxia situation and his outlook for hypoxia in the future. Mr. Johnson attributed gulf hypoxia primarily to agricultural runoff, which he speculated could lead to greater restrictions on the use of chemicals by farmers in the future. (Johnson, 2016).
Another major contributor to hypoxia in coastal areas is runoff and leaching from urban and consumer areas. An analysis and comparison of the runoff coefficients for agricultural land and urban land provides quite a bit of insight into how nutrient loss could occur in a city. For example, a flat city business area has a runoff coefficient of 0.80, while flat cultivated land (clay and loam), has a runoff coefficient of 0.50 (ODOT 2014). The full runoff coefficient table can be seen in Figure 3.
Several conclusions can be drawn from these data. Even though “nutrient loss” and “urban areas” are not commonly associated with each other, the higher runoff coefficients mean that it is that much easier for even small quantities of excess nutrients to be washed away by rainfalls. Smoothly paved roads in urban are very conducive to water flow. In major coastal cities or areas with a river that leads to a larger body of water, excessive nutrient loss is certainly not out of the question. Other sources of nutrient loss in non-agricultural settings include leaching from septic tanks that are below ground (World Resources Institute, 2013). According to the World Resources Institute, “the most prevalent urban source of nutrient pollution is human sewage…sewage is estimated to contribute to 12 percent of the riverine nitrogen input in the United States.” Another factor that is causing nutrient pollution in the Gulf of Mexico and other hypoxia-ridden zones is aquaculture. Because of the high density of the fish in these operations, unusually high amounts of nitrogen and phosphorus are present. According to the 2005 report on aquaculture and its effects on an ecosystem, over 42 kilograms of nitrogen waste and 7 kilograms of phosphorus waste are produced for every ton of fish in an aquaculture operation (Strain and Hargrave, 2005).
In addition to agricultural and urban factors leading to eutrophication, the World Resources Institute names several other factors that are leading to continued contamination. Some less obvious factors that are leading to hypoxia and eutrophication are the worldwide booming population, as well as economic growth and success. As more and more countries move into the modern world and adopt new technologies and practices, they become more likely to attempt to optimize their agricultural gains, as well. This leads to the application of synthetic fertilizers for nutrient maximization, and eventually, nutrient oversaturation. The growth of the global population has also caused significant effects in terms of eutrophication of coastal waters. More people demand more food; however, they also need more land, energy, and entertainment. In order to provide all of these things, fossil fuels are burned, leading to further pollution of the atmosphere and excessive nutrient introduction to the water cycle.
The factors that lead to nutrient loss and hypoxia can come from a variety of different sources. The large amount of agricultural production that takes place in the Midwest, as well as the amount of urban areas and cities on the Mississippi River, work to create a perfect storm for nutrient transportation to the Gulf of Mexico. At right, Figure 4 shows the annual size of the dead zone in the Gulf of Mexico for every year since 1985, with the exception of 1988, 1989, and 2016. In nearly every year, the size of the dead zone has been well above the goal, and has seen a resurgence in growth in recent years (Conners, 2017). In 2012, the dead zone is significantly smaller, which is the result of the extreme drought that occurred that year. This is further evidence of the impact rainfall has on nutrient loss and erosion.
Proposed Solutions
The Mississippi River/Gulf of Mexico Watershed Nutrient Task Force was founded in 1997 in order to learn more about the hypoxia and eutrophication issues that were taking place in the Gulf of Mexico (United States EPA, April 2017). The task force released action plans in 2001 and 2008, but since then, have been relatively quiet, according to an April 2017 United States EPA article. In their 2008 action plan, the task force set out to develop and enforce new nutrient loss reduction strategies for states and watersheds that were identified as major hypoxic contributors (United States EPA, April 2017).
Figure 5 at left shows which watersheds are the most detrimental to the ecosystem in the Gulf of Mexico (United States EPA, January 2018). From this figure, it is clear that the majority of the efforts of the task force are focused on the Midwest and watersheds on or near the Mississippi River.
Many states in the Midwest have adopted their own nutrient loss reduction strategies; Illinois is one such state. A July 2015 pamphlet from the Illinois EPA states, “The Illinois Nutrient Loss Reduction Strategy lays out a comprehensive suite of best management practices for reducing loads from wastewater treatment plants and urban and agricultural runoff…along with water quality standards currently being developed, these practices will help the state achieve its ultimate goal of reducing phosphorus and nitrate loads by 45 percent.”
The benefit of a solution like the Illinois Nutrient Loss Reduction Strategy is that allows farmers to self-regulate in order to decrease nutrient loss and runoff. Farmers have an incentive to self-regulate—they do not want to pollute, nor do they want to lose key nutrients. Lost nutrients would mean that the fertilizer that they paid for would be gone, which would be costly to them and would also reduce their yields. The 2015 Springer Link report suggests using cover crops, which are crops that are planted after the harvest of the main crop. The planting of these crops help reduce erosion, which in turn reduces fertilizer runoff (Sharpley, Bergström,et. al., 2015). Farmers can also use slow release fertilizers, which are created specifically to cause less runoff and environmental effects. The Illinois Nutrient Loss Reduction Strategy does not require new regulations or changes, but instead allows farmers to collaborate and address the issue as a group.
Other current efforts to stop nutrient loss and hypoxia include potential government regulations on fertilizer use, or planting trees and using other landscape elements to reduce runoff. However, government regulations could be ineffective because they are not necessarily best for both farmers and the environment. If the government were to impose a nationwide quota for how much fertilizer can be applied per acre, farmers could be forced to change their farming practices; practices they have perfected and optimized over the course of many years. Farmers only have about 50 crop years in their lifetime to perfect their practices. Governmental meddling would tear down years of adaption and optimization by the farmers. Furthermore, the 2014 MDPI report states that to effectively carry out a policy like this, extensive research would need to be done (Withers, Neal, et. al., 2014). This would be extremely costly and would be time consuming; furthermore, the report states that it is likely that their conclusions would suggest practices very similar to what the farmers were already doing (Withers, Neal, et. al., 2014).
According to a January 2014 report by Schoumans, Chardon, et. al., another potential solution is using natural structures to reduce runoff and nutrient loss, by redirecting the water flow from fields. This solution is inefficient because it is time consuming and would not provide immediate change to this issue. In order to effectively stop runoff, a major landscape renovation would have to occur near highly erosive fields all around the nation. In addition to being expensive, this project would take an extensive amount of time to complete. The time lost while waiting for this prevention technique to start working would result in further contamination of the Gulf of Mexico. Time is of the essence, and wasting time waiting for trees to grow or for tile or other erosion control projects to be completed would not necessarily be an efficient use of time to solve this problem. The 2014 Schoumans, Chardon, et. al. report states that cross-contamination could occur as a result of changing water flow. This means that while some nutrients would be redirected to stay out of the Gulf of Mexico, other nutrients could be brought into the field that would have detrimental effects on yields and crop efficiency, which could lead to production and pollution issues in the future.
Similar to using natural structures to stop erosion, another nutrient loss reduction strategy is terracing fields, like what was displayed on the NRCS field trip. Utilizing this strategy helps control erosion and reduce sediment loss, according to a video from the USDA (Science Education Resource, 2018). However, this practice is very time-consuming and expensive, as a total renovation of the field must take place in order to set it up for terracing. Tons upon tons of earth must be moved, and the field must be maintained in order to keep it from resorting back to a hilly, eroded field. Terracing could be appropriate in extremely hilly areas, but is not necessarily a strategy that can be applied very frequently.
Economic Effects
There is little debate that hypoxia and eutrophication of coastal waters is an issue. In spite of this, there are still many people that are completely unaware of the negative implications of growing dead zones on society. In addition to harmful environmental effects and potential changes of practices for farmers, this phenomenon has begun to lead to economic effects as well. According to a study done by researchers at Duke University, one of the biggest economic issues associated with hypoxia is the fluctuation in price and market disturbance that is taking place for shrimp (Smith, Ogeland, et. al., 2017). Because of the low oxygen levels associated with hypoxia, more and more fish are dying off, forcing fishermen to change their fishing tactics or even move to different locations in hopes of bringing in more fish. The January 2017 Duke study focused on how seasonal runoff, which is largely attributed to agriculture, has an effect on the prices. Martin Smith, who oversaw the study, commented, “Because fishermen are catching more small shrimp and fewer large ones during these months, the price of small shrimp goes down and the price of large ones goes up.” (Smith, Ogeland, et. al., 2017)
A report from Iowa State University touched on the economic implications of a “regime shift”, or total change in the makeup of an ecosystem (Iowa State University, 2008). The results of this change run deeper than a potential loss of species. The snowball effect that the loss of several species and the eventual destruction of an entire ecosystem would have on those who live near the gulf would be very notable. When there are no longer fish living in a certain area of the Gulf of Mexico, fishermen will be forced to pack up and move somewhere else. This would lead to economic downturn in their cities, due to a decreasing population and loss of industry. More and more people would find themselves out of a job, driving poverty rates up and changing the entire makeup of the town. At a larger level, a decrease in availability of fish in the Gulf of Mexico drives up the prices of seafood all around the country due to the shortage of fish. The United States would then have to look to other countries for seafood products, thus increasing imports which would likely come at a higher price. These effects stem solely from unchecked hypoxia and eutrophication.
Not only does hypoxia affect industrial and professional fishermen, it would have an impact on tourism as well. With the dead zone in the Gulf of Mexico growing larger each year, there are less fish available for recreational fishing trips, a common tourist attraction. While it is unlikely that the lack of a fishing trip would be enough to totally deter a family from visiting an area on the Gulf of Mexico, it is possible that the vacation would be shortened by one day, which is one less day for them to spend money and help support the local economy.
While there is no way to know how exactly how severe the effects of hypoxia in coastal waters will be in the future, it remains important to attempt to reduce the dead zones so that the damage to coastal communities can be minimized. Although these cities are not extremely large, they are an important production hub for seafood in the United States.
Conclusion
Hypoxia in the Gulf of Mexico is a complex issue, due to all of the factors that have led to its current state. The tangential effects that are felt in the Gulf come from a variety of backgrounds—everyone from farmers, to construction workers, to everyday citizens have some sort of effect on the ever-growing dead zone. If there are so many inputs that are causing hypoxia, why has there not been any real improvement in decreasing the scope of the dead zone? The practices that have been suggested and developed by farmers, task forces, and economists are generally favorable, however, many are also long-term projects. Even if they had total buy-in from everyone that was contributing to the dead zone, there still would not be an overnight improvement. Patience and trust in the end results of the projects is essential if long-term improvements are to be made.
The good news is that there is increasing awareness of the gravity of the situation. The EPA, USGS, and other groups have been tracking this issue for quite some time, and they have likely played a role in slowing the growth of the dead zone. As technology continues to improve, it is possible that scientists will be able to finally isolate and put a stop to the major contributors of excess nutrients to the Gulf of Mexico. If changes do not take place and the hypoxic zone in the Gulf of Mexico continues to grow, the damage to the coastal ecosystems and economy will be irreparable. It is important for producers and consumers alike to see the bigger picture and take any steps that they can to help reduce nutrient loss, and eventually, the dead zone in the Gulf of Mexico.