Assessment of the Impact of Increased Solar-Ultraviolet Radiation of Seagress

An early concern in the planning of the Space Shuttle Program was the loss of atmospheric ozone due to repeated Shuttle flights and a resultant increase in penetrant ultraviolet radiation. Our research group has examined the effects of an increase in this radiation (UV-B, 290- 315 nm) on three marine angiosperms (Halophila engelmannii Aschers, Halodule wrightii Aschers, and Syringodium filiforme Kutz) important to shallow marine and estuarine ecosystems. The photosynthetic tolerance of each seagrass to UV-B and mechanisms which might prevent or reverse damage were investigated. The data show little effect by current environmental levels of UV-B and suggest the capacity to adapt to an increased UV-B flux by various mechanisms in the different species: photorepair, flavonoid synthesis, chloroplast clumping, and epiphytic shielding