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9,313,000 Yen
Effects of enhanced UVB radiation on survival, grazing and growth rates were investigated for copepods and smaller zooplankters such as ciliates. Also, the effects on the Interaction between phytoplankton production and microzooplankton grazing were investigated using dilution culture Most vulnerable developmental stage of copepod was egg, which lacks swimming ability and contains less pigment. Tow distinct groups were observed in the copepods for their vulnerability for UVB radiation Neustonic copepods were less vulnerable, in contrast, water-column dwelling copepods were vulnerable than formers. The most vulnerable zooplankter was tintinnid ciliate Favella taraikaensis, they could not survive under the radiation of 1.1kJm-2d-1 Results of dilution culture suggested that negative effects on phytoplankton production and zooplankton grazing were same level, or slightly higher effects on zooplankton in average. The magnitude of the effect were different between on phytoplankton and zooplankton depending on season. Microscopic examination suggested that naked ciliates, the most dominant taxa in the ocean, were always the most vulnerable in the microzooplankton community
These results suggests that both phytoplankton and zooplankton are likely suffered by enhanced UVB radiation, and zooplankton, especially microzooplankton were relatively more vulnerable than phytoplankton Then the balance between phyioplankton production and zooplankton grazing will be most likely disrupted by enhanced UVB radiation.
UVB, ozone-depletion, phytoplankton, zooplankton, interrelationship, copepods, protozoans, dilution method