Understanding the effects of environmental stressors on photosynthetic organisms is crucial for predicting their responses to climate change. In this work we utilized advanced phenotyping techniques to investigate how temperature and light gradients affect non-photochemical quenching (NPQ) in microalgae.
The research introduces the "Phenoplate" method, which simultaneously assesses the impact of temperature and light gradients on marine microalgae's NPQ responses under chemical stress. Rapid light curves were employed to measure the photoprotective mechanisms of Tetraselmis sp., Thalassiosira pseudonana, and Nannochloropsis oceanica across a temperature gradient and varying phosphate levels. The results revealed that photoprotective mechanisms were highly efficient at lower temperatures, while higher temperatures negatively impacted the relaxation of photoprotection in Tetraselmis sp. Unique NPQ signatures were observed in Thalassiosira pseudonana and Nannochloropsis oceanica, indicating species-specific responses to temperature and light interactions [Herdean et al., 2022].
Additionally, the work maps the temperature dependency of NPQ in Chlorella vulgaris using the same Phenoplate technique. It demonstrated that fast-relaxing NPQ (qE) follows an inverse normal distribution with respect to temperature and is insensitive to prior temperature acclimation. A slow-relaxing NPQ component displayed a normal distribution similar to quantum yield (Y(II)), peaking at higher temperatures. These findings highlight the strong temperature dependency of photosynthetic processes even in conditions where temperature changes at short time scales (minutes). Furthermore, our findings highlight that the impact of temperature in PAM measurements may have been underestimated and suggest that results from experiments performed “room temperature” may be misleading [2].
This research underscores the importance of considering multiple environmental factors simultaneously to understand the complex responses of photosynthetic organisms.