PARENT SESSION
Poster Session 4: Marine Ecology
Monday, August 8, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

The role of cryoprotectants in the freezing tolerances of two competing species of red algae.

Harris, Jonathan^*,1, Logan, Barry¹, ¹ Biology Department, Brunswick, ME, USA

ABSTRACT- In the rocky intertidal zone of the coast of Maine, red algae must cope with frequent desiccation and freezing stress. Mastocarpus stellatus and Chondrus Crispus are taxonomically and morphologically similar species of intertidal algae with differing stress tolerances. M. stellatus exhibits greater stress tolerance and is able to inhabit more stressful, higher zones of the intertidal. Differential accumulation of antioxidants between species was proposed as an explanation for observed stress tolerances. However, a recent study cast doubt on this hypothesis [Lohrmann et al. (2004) Biol Bull. 207: 225]. We examined seasonal changes in the tissue content of recognized cryopotectant compounds, including mannitol, glycine betaine, and proline. M. stellatus and C. crispus collected in September both possessed measurable free proline. Although both species exhibited marked increases in free proline content in winter; the extent of this increase was greater in M. stellatus. The possible role proline plays in the greater stress tolerance of M. stellatus is discussed.

Key words: Cryprotectants, Red Algae, Proline, Intertidal zone