Differential metabolomic shifts in jellyfish tissues exposed to artificial light spectra

This study aimed to determine how different light spectra affect the growth and metabolism of the upside-down jellyfish, Cassiopea andromeda, which relies on symbiotic algae for energy. Jellyfish were reared for 60 days under seven light conditions-red, yellow, white, blue, green, ultraviolet (UV), or complete darkness-while monitoring survival, growth, and metabolic changes. White, blue, and green lights yielded the highest growth and 100% survival. By contrast, red and yellow light produced moderate growth, whereas UV or darkness caused severely stunted growth and high mortality. Untargeted metabolomic profiling (UHPLC-MS/MS) detected ~380 metabolites, with amino acids and fatty acids comprising the major metabolite classes. Different spectra induced distinct metabolic profiles: bell tissues under white and blue/green light showed broader metabolic shifts (e.g., upregulated osmolyte and amino acid pathways), while tentacle tissues maintained more stable profiles enriched in unsaturated fatty acid metabolism. These findings demonstrate that light spectrum significantly shapes jellyfish physiology and metabolism, advancing our understanding of cnidarian photobiology. Optimizing spectral exposure (e.g., using green or blue light) could enhance jellyfish health in aquaculture and inform strategies to mitigate jellyfish blooms under artificial lighting conditions.