## 3 Results and Discussion
### Future Field Studies  
As the cell density and microcstin concentration within this particular cyanoHAB were comparatively low, additional field studies with the CyanoSTUN(tm) should be conducted in surface waters experiencing more severe cyanoHABs to validate performance under more challenging conditions. It may also be advantageous to conduct future field studies in the morning when many species of planktonic cyanobacteria accumulate at the surface after consuming a significant portion of their reserve carbohydrates during the dark, and form floating scums [3]. Future field studies should examine the effects of the CyanoSTUN UV-C treatment on additional cyanotoxins, including cylindrospermopsin, saxitoxin, and anatoxin-a, as there is little data on methods to control these toxins. Additionally, future studies should measure the CyanoSTUN's impact on zooplankton and other small aquatic organisms. While the CyanoSTUN's design restricts all UV-C radiation to the control volume of its reactor, thereby preventing off-target ecological effects from occurring in the surrounding water, it is still possible that off-target effects will occur  
Figure 8: Total non-cyanobacterial cell density (cells/mL) over a 5-day period post-field trial. The “Day 5 Rear (45 mJ/cm2)” sample was compromised during transport to UF/IFAS and could not be analyzed. inside the reactor should non-target organisms pass through the 0.5-inch diameter holes of the CyanoSTUN's bow-mounted screen. Due to funding constraints, zooplankton and other small aquatic organisms could not be monitored in this study, but they are expected to experience some effects from UV-C exposure should they enter the reactor. For example, zooplankton are known to be susceptible to DNA damage from UV-B radiation ([PERSON] and [PERSON], 2009), and because UV-C is more reactive than UV-B and also absorbed by DNA, UV-C may be more harmful to zooplankton than UV-B. Thus, exposure to the UV-C from the CyanoSTUN treatment may adversely impact behavioral responses, fecundity, and, at a sufficient dose, cause increased mortality of zooplankton, among other possible adverse effects. However, [PERSON] and [PERSON] (2009) note that some zooplankton are less affected by UV radiation either due to possessing photoprotective compounds that prevent UV damage or having the capability to repair UV damage through photoenzymatic repair, so the precise impacts of the CyanoSTUN on zooplankton and other small aquatic organisms cannot be discerned without further study ([PERSON] and [PERSON], 2018). Scalability of UV-C is a key advantage of the technology. In terms of treatment scale for the current CyanoSTUN design, our modeling in UV Calc Premium software 2023 showed that the CyanoSTUN can treat a HAB with a surface area of 4.05 \(\times\) 10\({}^{3}\) m\({}^{2}\) (1 acre) to 12.7 cm depth (5 in.) in 11.9 h at a UV dose of 20 mJ/cm\({}^{2}\) assuming a bloom UVT of 50% and 9.13 h assuming a bloom UVT of 60% ([PERSON] and [PERSON], 2018). Currently, the CyanoSTUN vessel is designed with one wastewater-grade UV reactor because the chassis vessel is small (4.14 m in length); however, the treatment capability of the CyanoSTUN scales linearly with each additional reactor. For example, a vessel equipped with two of the Trojan UV3000 PTP reactors used here could treat the same area as our study in either half the time or with double the UV-C dose, or it could provide equivalent treatment to this study but in surface waters with lower UVTs than the approximately 50% encountered in Lake Cochituate. Adding UV-C reactors to the underside of pontoon- or catamaran-style hulls (i.e., two hulls connected by a platform) is straightforward but does require longer vessels with higher weight capacities (e.g., barges) as the number of reactors increases.