The influence of UV-B radiation on the reproductive cells of the intertidal macroalga, Enteromorpha intestinalis.
The relative sensitivity of the reproductive cells of the seaweed Enteromorpha intestinalis to UV-B was assessed by measuring in vivo chlorophyll fluorescence (F(v) variable fluorescence), germination success and growth rates. Zoospores (the asexual reproductive cells) exhibit up to a 6 fold higher sensitivity to UV-B exposure than the mature thalli (measured as chlorophyll fluorescence, F(v)), and differences in growth rates were also found. Consistent patterns emerged throughout these experiments in variable fluorescence, germination success and growth rates, indicating a greater sensitivity in the sexual reproductive phase of the life cycle compared with the asexual phase. Inhibition of germination success (up to 50%) and growth rates (up to 16.4%) of settled gametes and zoospores after 1-h exposures to elevated levels of UV-B (equivalent to 27 and 31% ozone depletion) showed that damage to the reproductive cells was irreversible. In conclusion, the ecological significance of elevated UV-B exposure in the marine environment may be seriously under-estimated if effects on the early lifestages of algae are not considered.
Cordi
B
B
Plymouth Environmental Research Centre, University of Plymouth, Drake Circus, PL4 8AA, Plymouth, UK. britt.cordi@envtran.camcnty.gov.uk
Donkin
M E
ME
Peloquin
J
J
Price
D N
DN
Depledge
M H
MH
D002734:Chlorophyll / Q000032:analysis / Q000096:biosynthesis; D000460:Chlorophyta / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects*; D004463:Ecology; D005470:Fluorometry; D012044:Regression Analysis; D014466:Ultraviolet Rays / Q000009:adverse effects*; D006113:United Kingdom
D002734:Chlorophyll