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INTERACTIONS BETWEEN NUTRITIONAL STATUS AND LONG-TERM RESPONSES TO ULTRAVIOLET-B RADIATION STRESS IN A MARINE DIATOM
Citation:
Behrenfeld, M., H. II, AND L. Small. INTERACTIONS BETWEEN NUTRITIONAL STATUS AND LONG-TERM RESPONSES TO ULTRAVIOLET-B RADIATION STRESS IN A MARINE DIATOM. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/425.
Description:
Influences of nutrition status on the photoinhibitory effects of ultraviolet-B radiation (UVBR:290 to 320nm)on the specific growth rates (Uobs )and biomass of Phaeodactylum tricornutum were determined using nutrient-replete batch cultures and nutrient-limited continuous cultures. . tricornutum cultures were exposed to UVBR doses representative of current mid-latitude and ozone-depletion intensities. pecific growth rates and biomass were inhibited from 2 to 16% by UVBR during nutrient-replete growth. owever, no effect of UVBR on g,b, or biomass was detectable when nutrient limitation exceeded the potential for limitation by UVBR. hus, a competitive interaction appears to occur between macronutrient stress and UVBR stress, such that Uobs and biomass will be determined by the most limiting factor. ur results suggest that measurable decreases in phytoplankton Uobs and biomass for UVBR are most likely in nutrient-rich areas of the ocean, while these parameters may not be appropriate for measuring UVBR stress in regions of nutrient limitation.