Abstract: Gracilaria lemaneiformis was exposed to 0, 25, 50, 100, 250 and 500 μ g·L-1 of Cu2+ to study its physiological responses to Cu2+ st ress. When the Cu2+ concentration was ≥50 μg·L-1, the relative gr owth rate (RGR) of G. lemaneiformis decreased significantly, and the optimal quantum yield (Fv/Fm), the maximum relative electron transfer rate (r ETRmax), and the relative electron transfer efficiency (α) exhibited th e same variation trend, compared with the control. With the increase of Cu2+  concentration, the maximum net photosynthetic rate (Pmax) and l ight saturation point (LSP) decreased significantly, light compensation poin t (LCP) had a significant increase, while chlorophyll a, carotenoid, and phy cobiliprotein contents decreased after an initial increase. When the Cu2+ concentration reached 500 μg·L-1, the chlorophyll a, carotenoid, and phy cobiliprotein contents decreased significantly. It was suggested that G. leman eiformis could tolerate low concentration Cu2+ stress, but its physiolog ical activities were inhibited markedly when exposed to ≥50 μg·L-1 of C u2+.

Key words: eddy covariance, snow  evaporation, latent heat, diurnal variation, meteorological factor.