Stopping Algae Growth
Mark Robinson
Professor Zen Dochterman
Writ 150
4 December 2021
Reducing Toxic Algae Blooms in Lacamas Lake with Cover Crops
With eighty degree weather and partly cloudy skies, it is the perfect day to relax in the water. This is the weather that residents of Southern Washington experience daily during the summer. People flock to the nearest lakes and rivers to escape the heat and have a relaxing day. In the small town of Camas, Washington, Lacamas Lake is one of these lakes. To me and many other Camas residents, Lacamas Lake is our main source of entertainment during the summer, with families flooding the banks to boat, wakeboard, swim, and fly off rope swings. Memories of this are some of the fondest of my childhood. However, due to toxic algae blooms in Lacamas Lake, the memories are all but a sore dream to me and the rest of the residents of Camas, Washington. Instead of people, the banks are now littered with bold signs warning visitors of the toxicity of algae blooms which can cause liver damage. One of my friends walked his dog on a trail by the lake during the algae blooms; unfortunately, his dog drank some of the lake water and passed away a couple days later. This algae growth must be stopped, so the lake can be used again. The main cause of this algae growth is nitrogen runoff from farms, which acts as nutrients for algae to flourish. By looking at the European Union’s (EU) implementation of cover crops to stop global warming and nutrient runoff, we can see how this implementation would help prevent algae growth as it would stop the main cause for algae. With this in mind, I propose that farms in Camas, Washington utilize cover crops in order to reduce algae growth.
To understand how to tackle the root problem of algae blooms, it is necessary to know how the whole system of the lake works and where it receives its nutrients and water. The area around Lacamas Lake is what is known as a watershed. The watershed is a 67 square mile area where all the water in this area feeds into the lake(Moyer). Essentially, when it rains, water accumulates onto the ground and enters small creeks and streams. These small creeks and streams run downhill and feed into larger rivers and these rivers feed into the lake which is at the lowest point of the watershed. It is quite simple, gravity pulls all the water to the lowest point which is the lake. As a result of this, the lake then accumulates all the nutrients that the water picked up within this huge area. There are many nutrients and toxins that the water can pickup that are harmful, but for this paper I will focus on nitrogen and phosphorus runoff because it is what algae feeds off of.
Nitrogen and phosphorus are important nutrients that are needed in aquatic ecosystems, so that plants can thrive and act as food sources for marine life. Nitrogen is necessary for protein synthesis, and phosphorus for DNA and RNA transfer (Conley et al. 1014). But, excess of these two nutrients can create the perfect setting for algae to grow. This is because in most circumstances there is not enough nutrients for algae to grow as other aquatic life consumes it, but once there is too much then it can grow at an uncontrollable rate.
Once algae starts growing, it creates a feedback loop which means that algae helps in the creation of more algae leading to a nasty cycle of endless algae. Algae thrives in warm water. When they grow, they expand and become thicker thus absorbing more sunlight leading to warmer water (Denchak and Sturm). Additionally, algae likes to feed off of carbon dioxide in the air so when they die they decompose and release carbon again into the water which provides fuel for even more algae to grow. It is quite apparent that these algae blooms can be difficult to remove once they have begun, as they are almost unstoppable. More algae leads to even more algae, so how can we stop them? We must stop the source of excess nitrogen and phosphorus so that these algae blooms can’t keep reproducing.
So where exactly are excess nutrients coming from? As one could probably infer it comes from the watershed, but where specifically? In the Lamas Lake watershed, 35% of the land is forested, 20% is owned by the public, 25% is used for agricultural purposes and 16% of the land is developed for residential use while the rest is under private ownership (Moyer). The two main sources of nitrogen and phosphorus are from the agricultural land and the residential area. Runoff from residential areas is due to recreational use of detergents and herbicides. Whereas runoff from agricultural areas is largely due to the immense use of fertilizers along with manure from animals. While the residents of Camas have came up with solutions to tackle the residential area, they have failed in tackling agricultural runoff which is arguably the greatest contributor to nutrient runoff as it constitutes for a larger percent of the land.
The residents of Camas started by fixing a nearby biofilter. This biofilter was meant to reduce runoff but had the opposite effect. Phosphorus levels had been measured to enter the bio filter at 145 micrograms per liter and leave at 976 micrograms per liter (Ley). This biofilter was making the condition of nutrient runoff worse as it significantly increased the amount of nutrients in the runoff. With this in mind, the city of Camas seeked to fix the biofilter. They plan to remove all the overgrown brush and begin putting in new plants that are healthy. Once the biofilter is cleaned it should reduce the total amounts of phosphorus entering the lake, thus reducing algae growth. But, fixing the biofilter will not solve the root cause of the algae.
What I mean by this, is that in 2007 phosphorus was only measured at 30 to 50 micrograms per liter, and in just 14 years these phosphorus levels had almost quadrupled (Ley). Residents are using more and more compounds that contain phosphorus, whether in the form of phosphates in detergent, fertilizer for their lawn, or more. So, then what can be done? It is quite simple, consumers must be aware of what they are buying and using and how it affects their environment. This can be done by buying phosphate free detergents and shampoo and being conscious of what products one buys. Now, onto solving the more impactful source of nutrient runoff that has been ignored, agriculture.
As I said earlier, agriculture takes up a larger area than residential areas but has largely been ignored by the city of Camas when looking at reducing nutrient runoff into Lacamas Lake. So what can be done to stop these farms from creating so much runoff? While it is true that these farms in the Lacamas Lake Watershed could reduce their fertilizer and herbicide use just as residential consumers could, they most likely wouldn’t unless there is an incentive. This could be done through tax cuts on farms that use less fertilizer, or subsidies for fertilizers that contain less nutrients. But, would either of these solutions really work? Most likely it would upset farmers as they would not see a reason behind this change. One solution that has not been implemented by farmers in Camas but is being used globally, specifically in the EU to prevent nutrient runoff and global warming, is using cover crops (Smit et al). Cover crops are a plant placed in the soil in rotation with regular crops in order to increase the retention of the soil. Farmers in Camas don’t use cover crops as they believe they reduce profits since they replace cash crops during a growing season. But, this is a misconceived notion as the reduction of runoff from cover crops is an economic incentive for them to implement them on their farms. What I mean by this is they can cutdown on costs as cover crops increase nutrient retention in soil which can result in surplus of crops and less fertlizer use. This means increased profits.
Cover crops would be an effective solution to stopping algae growth in Lacamas Lake since they reduce nitrogen runoff which is the direct cause of algae growth. In a study on cover crop effectiveness, it showed that “On average, [cover crops] CCs can reduce runoff by 50% relative to fields without CCs” (Blanco-Canqui 1634). This means there is less nutrient runoff as simply there is less water to carry the nutrients away. This not only is beneficial in reducing nutrient runoff, but it also benefits farmers as less nutrient runoff means more nutrients retained in the soil, so they don’t have to use as much fertilizer. Cover crops also directly solve the problem of nitrogen runoff. It was reported that cover crops reduce nitrate leeching by “18 to 95% with an average of 53%” (1635). A reduction in runoff of nitrogen from farms would go a long way in reducing algae growth because nitrogen is one of the key ingredients algae needs to grow. Also, reduction in nitrate leeching means that the soil retains the nutrients. As a result of this, farmers’ crops will be healthier since they are grown in richer soil. This means better crops and less fertilizer use as the crops are already getting their necessary nutrients. But, this is not a problem-free solution, the ability of cover crops to be effective is largely dependent on biomass.
With this in mind, farmers should specifically use a mixture of cover crops called Hairy vetch-cereal rye, because it can produce “63 and 21% more biomass compared with Hairy Vetch and Cereal Rye monocultures, respectively” (Thapa et al. 1197). Hairy Vetch and Cereal Rye are considered the best cover crops, but this mixture performs even better than the two alone. As a result of maximizing biomass by using this mixture, maximum prevention of nitrogen and water runoff will occur. This will mean less algae growth in Lacamas Lake and increased yield for farmers followed by less fertilizer use which results in positive profit. Ultimately, the implementation of this cover crop would benefit the lake and farmers as there would be a decrease in nitrogen runoff which would result in less algae and the cost of farmers to grow their plants would decrease as less fertilizer would be necessary.
The problem with algae blooms is not only a problem in Camas Washington. It is a global problem that is becoming more and more widespread. We can take our example of Lacamas Lake to shed light on the bigger problem surrounding algae and nutrient runoff. In the case of Camas, Washington the problem with algae is not nearly as grand as algae growth elsewhere. In Washington the main problem with the algae growth is that it inhibited recreational use. The thing is, with most algae growth elsewhere the problem is even more pressing, it can have drastic effects on thousands of people if the water is used for drinking and it can destroy ecosystems as algae creates hypoxic zones where fish and aquatic life can’t breathe. For example, in 2014 there was algae in Lake Erie, and a “do not drink” order had to be put in place since it contaminated the whole water which affected more than 500,000 people and resulted in more than 100 being sick (Denchak and Sturm). The solution I suggested, cover crops, can be implemented to stop algae growth at Lake Erie, and many other locations around the world so that everyone can have fresh water and use their lakes.
Works Cited
Blanco‐Canqui, Humberto. “Cover Crops and Water Quality.” Agronomy Journal, vol. 110, no. 5, 1 Sept. 2018, pp. 1633–164, https://doi.org/10.2134/agronj2018.02.0077. Accessed 22 November 2021.
Conley, Daniel J., et al. “Controlling Eutrophication: Nitrogen and Phosphorus.” American Association for the Advancement of Science, vol. 323, no. 5917, 20 Feb. 2009, pp. 1014–15, http://www.jstor.org/stable/20403108. Accessed 22 November 2021.
Denchak, Melissa, and Melanie Sturm. “Freshwater Harmful Algal Blooms 101.” NRDC, 24 Sept. 2020, https://www.nrdc.org/stories/freshwater-harmful-algal-blooms-101. Accessed 22 November 2021.
Ley, John. “Lacamas and Round Lake Toxic Algae Warning Issued.” ClarkCountyToday.com, 14 Aug. 2021, https://www.clarkcountytoday.com/news/lacamas-and-round-lake-toxic-algae-warning-issued/. Accessed 22 November 2021.
Moyer, Kelly. “There Is Concern All Three Lakes Will Continue to Degrade.” Camas-Washougal Post-Record, 22 Apr. 2021, https://www.camaspostrecord.com/news/2021/apr/22/there-is-concern-all-three-lakes-will-continue-to-degrade/. Accessed 22 November 2021.
Smit, Bert, et. al. “Adoption of Cover Crops for Climate Change Mitigation in the EU.” JRC Publications Repository, 2019, https://publications.jrc.ec.europa.eu/repository/handle/JRC116730. Accessed 22 November 2021.
Thapa, Resham, et al. “Biomass Production and Nitrogen Accumulation by Hairy Vetch–Cereal Rye Mixtures: A Meta‐Analysis.” Agronomy Journal, vol. 110, no. 4, 1 July 2018, pp. 1197–1208, https://doi.org/10.2134/agronj2017.09.0544. Accessed 22 November 2021.
