Synergistic effects of UVA and UVB radiation on Moon Jellyfish proliferation and potential coping mechanisms

REU Fellow: Lauren Johnson, Trinity University

Mentor: Dr. Laura Treible

Ultraviolet radiation (UVR) consists of high-energy wavelengths that negatively affect marine organisms through general reduction in growth and structural changes in DNA. Stratospheric ozone controls surface UVR levels, but levels have altered because of anthropogenic influences on atmospheric composition (e.g. ozone-depleting substances). Jellyfish are considered robust to environmental stressors, which may explain localized increases in jellyfish blooms that negatively impact coastal communities. Early life stages of jellyfish control adult populations, and are essential to jellyfish bloom formation. This study exposed Aurelia aurita polyps to artificial UVA and UVB (isolated and combined) to determine effects on reproduction and potential coping mechanisms. Polyps reproduced when exposed to short term (~7-9 days) isolated UVB, but long-term exposure limited reproduction and overall health. When exposed to both UVB and UVA, polyps experienced 100% mortality. Thus, the total amount of energy received is potentially more important than wavelength, and studies that only examine UVB underestimate the full effect of UVR. Additionally, A. aurita polyps do not appear to have chemical (e.g. pigments) or behavioral (e.g. movement) mechanisms to combat UVR exposure, suggesting that the planula larvae stage must be important for settlement away from UVR to establish the success of the polyp stage.