Chronic exposure of the model organism Aurelia coerulea (Scyphozoa, Cnidaria) to “first generation” artificial sweeteners

Artificial sweeteners (ASs) are low-calories additives which utilization has increased in the last decades, reaching an economic revenue of ca. 26 billion US dollars in 2024. Through direct discharge or inadequate treatment of wastewater, they can spread in soil and reach the marine environment. Although the concrete risk of pollution deriving from these substances, their influence on coastal benthic communities is still unknown. We tested the effects of two ASs (aspartame and saccharin) through a chronic toxicity test on the cnidarian model species Aurelia coerulea polyps. We exposed polyps to a solution of aspartame and saccharine with filtered seawater (100 mg/l according to the REACH legislation for xenobiotics (Regulation 1272, Supplement No. 1, 2008), and measured their health status, asexual reproduction, somatic growth and mortality rates at 3-days intervals for ca. 60 days. Spectrophotometric analysis showed the degradation of aspartame, while saccharine remained unvaried indicating stability in water solution. Saccharin induced a moderate slowdown of growth, not impacting reproduction and health, while aspartame affected polyps by arresting growth, asexual reproduction, and triggering regression process. Afterwards, a full regeneration was reported with registered values similar to control group, suggesting acclimatization. Even though no mortality was observed, a delay in budding and growth rates could result in a carry-over effect on ephyrae production and adult populations. Since polyps are recognized as primary responsible driving jellyfish outbreaks, their altered physiological processes could affect the population dynamics of planktonic life-stages and consequently the trophic relationships of the habitat both at small and large scale.