Microalgae can produce lipids, but nitrogen starvation reduces their efficiency. Researchers studied adding nitrogen at night to improve lipid productivity in Nannochloropsis gaditana. They found that adding nitrogen increased photosynthetic activity, biomass, and TAG production after 7 days of nitrogen starvation. However, the maximum TAG yield on light was highest after 3 days of nitrogen starvation. The added nitrogen was mainly used for protein production, and a small amount for chlorophyll a. Nightly nitrogen additions improved photosystem II yield, biomass, and TAG production in nitrogen-starved N. gaditana.