This paper deals with the photosynthetic effects of a range of heavy metals
on the seagrass Halophila ovalis. In this study, the photosynthetic respon
se of laboratory-cultured II. ovalis to four heavy metals (Cu, Cd, Pb, Zn)
was investigated. The results indicated clearly that chlorophyll a fluoresc
ence was effective in monitoring the onset and development of stress, and o
ccasional recovery, of H. avails when exposed to a wide range of heavy meta
ls. Heavy metals in concentrations from 1 to 10 mg litre(-1) produced sever
al acute toxic responses. They had a variety of effects on the photosynthet
ic processes of this seagrass, with Cu and Zn having substantially greater
effects than Pb and Cd. Quantum yield was the most sensitive measure of the
photosynthetic processes affected by all heavy metals tested. With some ex
ceptions, photosynthetic pigment content generally confirmed the chlorophyl
l a fluorescence responses. (C) 1998 Elsevier Science Ltd. All rights reser
ved.