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[A-5.2 Effccts of Enhanced UV-B on Marine Zooplankton]

[Contact Person]

Hiroaki Saito
Researcher
Fisheries Oceanography Division, Hokkaido National Fisheries Research
Institute, Fisheries Agency
l16 Katsura-koi, Kushiro, Hokkaido 085, Japan
Tel: +81-154-91-9136 Fax: +81-154-91-9355
E-mail: hsaito@hnf.affrc.go.jp

[Total Budget for FY1993-1995]

38,417,000 Yen (FY1995; 13,517,000 Yen)

[Abstract]

　The Influence of enhanced UV-B radiation was investigated with vertical migratory and neustonic copepods. The hatching success of the boreal vertical migrator Paracalanas sp. decreased anti-sigmoidally with UV-B dose. The vulnerability of eggs to UV-B was dependent on the developmental stages of eggs. When the UV-B dose was same, the damage was severer for eggs exposed at lower UV-B dose rate for longer periods than those at higher dose rate for shorter period. Hatching success of a temperate vertical migrator Calanus sinicus was also decreased by the present-level solar UV-B radiation. On the other hand, no influence of solar UV-B radiation was observed for neustons. Carotenoid and mycosporine-like amino acids contents of the neustons were 4 to 17 times higher than those of the vertical migrator. These indicate that neustons can escape from lethal damages of UV-B using UV-B absorbing compounds. The present study suggests that enhanced UV-B radiation due to the ozone depletion would cause significant damages to vertical migrators, which would further imply that the marine ecosystem would be perturbed through productivity, species composition, species interaction of zooplankton.

[Key Words]

UV-B, ozone depletion, zooplankton, copepod, neuston, vertical migration