Targeting zero waste: when jellyfish become circular

Human food security and the sustainability of food production systems are among the main concerns together with the consequences of climate change, pushing towards food systems based on the principles of the circular economy. An ideal circular food system uses neglected resources, implements processes with low environmental impact, and is able to use byproducts for further uses. In this framework, we suggest to use non-edible jellyfish or byproducts of jellyfish food processes, as sources of organic and inorganic components in regenerative agriculture. Indeed, marine-derived fertilizers can help to mitigate the negative impact of chemical fertilizers on the environment. To test jellyfish biomasses as potential organic fertilizer, we used in vitro cultures of Arabidopsis thaliana as a model plant grown under laboratory conditions. We tested seed germination and seedling growth in the presence of MS-medium or agar only, supplemented or not with different concentrations of dried Rhizostoma pulmo jellyfish. The jellyfish supplement was able in a dose-dependent manner, to improve performance (i.e., germination, Vigor Index) as compared to the controls. Interesting results were obtained in absence of MS-medium, in which the control seeds (agar and seawater) were not able to germinate and grow, while in presence of jellyfish supplement the seeds were able to germinate and the seedlings to develop almost normally. The supplement of jellyfish, directly or somehow processed, could replace traditional agricultural practices to protect and restore natural ecosystems, contributing to improving the edaphic quality of poor soils and fertilizing crops known for their tolerance/resistance to salt stress.