The Effect of Salinity Changes upon the Physiology of Eulittoral Green Macroalgae from Antarctica and Southern Chile. I. Cell Viability, Growth, Photosynthesis and Dark Respiration

Abstract

Summary The salinity tolerance of the eulittoral green macroalgae Ulothrix implexa , Ulothrix subflaccida , Enteromorpha bulbosa and Acrosiphonia arcta from Antarctica was determined. Cell viability, growth, photosynthesis and dark respiration were used as criteria. A Subantarctic-cold temperate Ulva rigida from southern Chile was also included in this study. Cells of U. implexa , E. bulbosa and A. arcta showed considerably broader salinity tolerance than cells of U. subflaccida and U. rigida . All investigated species grew well under a wide range of salt treatments. With the exception of U. implexa , growth rates of all other species were inhibited at the lowest salinity tested. After incubation under extreme hypersaline conditions all species responded with a strong reduction in growth. The photosynthesis and dark respiration responses were similar to those of growth. These very plastic physiological properties under different salinities are similar between Antarctic and temperate plants. The successful spreading of green macroalgae in the eulittoral zone of all continents including cold Antarctica and cold-temperate southern Chile may thus be explained.