The shrinking availability of arable land and freshwater resources for conventional agriculture demands the development of alternative feedstock sources for human and animal nutrition. The mass production of photosynthetic marine microalgae on non-arable land using alternative water resources is a vital aspect of building a resilient and secure food system. Marine microalgae provide an alternative sustainable source of high-value proteins and essential omega-3 fatty acids (Moomaw et al. 2017). Nannochloropsis is a genus of marine microalgae, composed of a few predominantly marine species (including N. oceanica) with high industrial potential. These microalgae accumulate large amounts of omega-3 long-chain polyunsaturated fatty acid (LC-PUFA) eicosapentaenoic acid (EPA, 20:5n-3) in their membrane lipids. ROS protective mechanisms are an interesting candidate for study due to the central role that ROS plays as a feedback system on the photosynthetic apparatus. The photosynthetic apparatus proliferates large amounts of ROS in high light, especially when combined with other environmental stress. Here I will show how Rose bengal (a singlet oxygen photosensitizer) was used as part of a strain selection program for enhanced growth of N. oceanica in high-light environments.