UV induces reactive oxygen species, damages sperm, and impairs fertilisation in the sea urchin Anthocidaris crassispina

We demonstrated that environmentally relevant levels of UVA and UVB can reduce sperm motility (UVA: by 38-58%; UVB: by 42-85%; P < 0.05) and subsequently fertilisation success (UVA: by 38-72%; UVB: by 91-98%; P < 0.05) of urchins (Anthocidaris crassispina) in a dose-dependent manner, implicating that recruitment of urchin populations might be reduced by UVR (ultraviolet radiation) prevailing in their natural habitats. Concomitantly, reactive oxygen species (ROS) production was enhanced by UVA and UVB in a dose-dependent manner (UVA: by 1.3-fold; UVB: by 6.6-7.3-fold; P < 0.05), and the increase in ROS resulted in an increase in lipid peroxidation (LPO) in urchin sperm (UVA: by 4.2-7.2-fold; UVB: by 2.3-2.7-fold; P < 0.05). This study demonstrated that ROS production and oxidative damages enhanced by UVR may account for the observed declines in sperm motility and fertilisation, and suggests that levels of UVR prevailing in the environment may pose a significant threat to the reproductive success of natural populations of urchins spawning in shallow waters.