Global seafood demand (including wild capture and farmed aquaculture) has increased from roughly 100 million tonnes per year to nearly 200 million tonnes per year since 1990. To meet this need, the global farmed aquaculture industry has increased 527% since 1990 [FAO, 2018]. As a result, there is a significant need to supply sustainable feed ingredients for the global aquaculture industry, leading to investigations of using marine microalgae to replace plant-based ingredients (corn, soy, wheat, and potato) and fish-based ingredients (fishmeal and fish oil). Marine microalgae have the potential to r educe the environmental impact of feed production with respect to land use, freshwater consumption, greenhouse gas emissions, and global fishery sustainability . However, c onventional micro algae production uses a large amount of fossil-fuel electricity and requires liquefied carbon dioxide that is bubbled into cultivation ponds. P rior analysis indicates that the cost and greenhouse gas impact of marine microalgae can be around $700 /t and 3.7 kg CO2e/kg, respectively [Beal, 2018], as compared to those for corn/soy, which are roughly $200/t and 0.4 kg CO2e/kg (see Table 1). In this study , we compare the conventional model of Beal, 2018 (CONV) with a scenario that replaces fossil-fueled electricity with solar electricity and liquified CO2 with Direct Air Capture (DAC) of atmospheric CO2 directly into high-pH cultivation ponds (DAC-SOL), which is a technique that has been developed by Global Algae Innovations (see Figure 1) . The DAC-SOL scenario assumes productivity of 18 g/m2-d as compared to 23 g/m2-d for CONV [Beal, 2018].
Preliminary results indicate that the DAC-SOL approach can generate algal biomass at roughly half the cost of fishmeal and reduce the GHG impact to be less than terrestrial plant-based ingredients and fish-based ingredients. In addition, using solar power and DAC allows for much greater flexibility in siting algal biomass facilities independent of the power grid or sources of CO2.