Integrated Human Practices

Utah Lake is very large, yet not very deep. Shallow lakes are much more vulnerable to eutrophication, oxygen depletion due to excess growth of plants and microorganisms, than deep-water bodies because of the limited nutrient load capacity of their ecosystems. The sources of excess nutrients in Utah Lake are water treatment plant effluent, ranching and farming run-off, trace metals from mining, and urban pollution. When the lake accumulates high concentrations of phosphate and nitrogen compounds, in conjunction with hot summer temperatures, cyanobacteria grow exponentially, causing harmful algal blooms (HABs).

To understand the significance of the issues, the UVU iGEM team spoke with a number of Utah Lake experts from government and academia, described below. We assured ourselves that our project is important to numerous stakeholders, most importantly, the local community who would like to fish and recreate there, but will not because of the unpleasantness of the lake. The cyanobacteria that make up the majority of the bloom population produce neurotoxins that cause illness in people and animals that come in contact with them. When the blooms prevent sunlight from penetrating the lake, photosynthesis ceases and blooms die. This results in toxin release and unsafe water conditions, and increased nutrient liberation, leading to more cyanobacterial growth.

In our meeting with Dr. Bonner and Dr. Daly from the Utah Division of Water Quality and Utah Lake Authority, they provided a substantial amount of background information on the factors contributing to HABs in Utah Lake and the hydrology of the system. Of particular importance was the information about the source of excess nutrients and the current wastewater treatment plant functions and the plans to upgrade the treatment plants in the near future to address excess phosphorus and nitrogen entering the lake from their facilities.

South Davis Wastewater Treatment Plant met with us and told us they were able to effectively remove and convert ammonia (NH3), but they struggled with other nitrogen-based molecules, so we reaffirmed our focus on building a pathway to convert the other nitrogen-based molecules to dinitrogen gas. Due to the difficulties with handling nitrogen-based molecules, the treatment plants are focusing their efforts on phosphorus.

In 2015, Utah state agencies set the standard for phosphorus to be below 1 mg/L by January 2020 for all water treatment plant effluents; however, all the facilities in Utah County requested extra time and the deadline was pushed to 2025. There has been some progress to meet the standard by the new deadline. Nitrogen, however, is more difficult and expensive to treat and remove. Since the treatment plants are focused on phosphorus removal, Drs. Bonner and Daly suggested we do something with stormwater runoff for parking lots and agriculture, such as engineering wetlands, since they are also major contributors to the surplus nitrogen and phosphorus that bypass wastewater treatment plants. While these could be future applications of our work, there is simply not enough time in the iGEM engineering cycle to create and test that application.

A UVU Microbiology faculty member, Dr. Lauren Brooks, was a guest speaker during our scheduled class time to teach us about the nitrogen cycle in prokaryotes and how it applies to our project. She also has expertise in aquatic microbes and is currently collaborating with NASA on an astrobiology project. Through class discussion we decided to change our approach on handling nitrogen. Last year’s team attempted to insert 3 genes involved in converting nitrate to nitrate and ultimately to dinitrogen gas (N2). We know that Chlamydomonas reinhardtii (Chlamy) expresses the genes in the pathway that convert nitrate to nitrous oxide (N2O) very effectively and efficiently and realized we could simplify our engineered machine by only adding the nosZ gene to complete the conversion of nitrous oxide to dinitrogen gas rather than the genes for each step of the pathway. We also incorporated the use of an ammonia uptake mutant (amt4-) to increase our chances of engineered Chlamydomonas using nitrates and not ammonia as their nitrogen source, thereby increasing their conversion into harmless nitrogen gas.

Dr. Ben Abbot, a BYU professor of Environmental Sciences and Sustainability, and Dr. Weihong Wong, a UVU professor of Earth Sciences, each described their research on the nutrient levels in Utah Lake and the ecology of the lake. Dr. Wong discussed with us the sources of nutrient loading and shared her data on phosphorus and nitrogen accumulation in the lake. Through our discussions with Dr. Abbott, we decided our project addressing Utah Lake eutrophication by removing excess nutrients was a very valid approach.

To investigate solutions that are already being implemented, our team met with Dr. Kevin Shurtleff, a Chemistry Professor at UVU, who built a “flotation filtration barge” with students that cleans sections of Utah Lake covered in the biggest HABs. They filter the lake water through cellulose filters, collect the algae-bound cellulose in presses, and release the cleaned water back into the lake. Dr. Shurtleff gave our team a tour of the boat and showed us how the filtration and processing system works.

Although the filtration barge works well, it is a treatment, not a preventative measure. Our project aims to prevent the blooms from reaching an exponential growth phase and is much less expensive than maintaining and running a boat. During the summer the student employees drive it for 8-hour shifts, twice a day, 6 days a week, every week for 4 months. It takes 15 days to clean a square mile and costs over $120,000 every season.

After asking Dr. Shurtleff questions during the boat tour, we realized that we need to test solid surfaces for attachment of our engineered Chlamy that would work best as a tertiary treatment at the water treatment facility. He also discussed how often we might need to change out the Chlamy-embedded solid surface, and how to potentially store the phosphorous-loaded Chlamy for future use by other industries.

Another problem leading to HABs has been described by Dr. Eddy Cadet from UVU Earth Sciences Department. Carp were introduced to Utah Lake in the late 19th century as a food source, decimating the lake’s ecosystem. Only 3 of the 13 native species of fish still exist in the lake but are struggling to survive with the fast-growing carp. The bottom-dwelling carp have consumed and destroyed the native aquatic plants that stabilize the soil, eliminating safe hiding places for the native June Sucker fish, and stirring up the phosphorous-containing sediment, thereby promoting HABs.

One way to eliminate carp is to capture and sell them as food; however, the state warns against eating too much Utah Lake carp as they accumulate heavy metals from mining runoff, dangerous PCBs, and carcinogens. Another step toward preventing algal blooms besides the one we are creating, is to use synthetic biology to introduce genetically engineered carp that cannot reproduce, thus eventually limiting or eliminating them from Utah Lake. Dr. Cadet has already expressed interest in this endeavor as a collaboration with us.

After meeting with many stakeholders, we realized just how complex the situation is. While there are many groups working to restore Utah Lake, there are also competing pressures that make its restoration difficult, and this impacts many individuals who live and/work near the lake. Our hope is that our Bloom Buster chlamy will eventually be one component of the solution to this many-faceted problem.

Our genetically engineered Chlamydomonas used as a tertiary water treatment to reduce nutrients flowing into the lake will be a viable product on its own, but also proof of concept for expanded use with the farming and ranching community. These efforts should inspire future researchers, entrepreneurs, and the community to become more invested in the health of the lake. This should hopefully lead to informed policy makers who can provide the resources to restore Utah Lake back to a desirable destination.

For more informaiton on our outreach see Education & Inclusivity pages!