Seasonal acclimation of antioxidants in two co-occuring red algae with differing cold tolerances
by Nissa Leigh Lohrmann
Matocarpus stellatus (tufted red weed) and Chondrus crispus (Irish moss) are taxonomically, ecologically, and morphologically similar intertidal red macroalgae that co-occur along the Northern Atlantic coast. M. stellatus is reported to be more winter-tolerant than C. crispus, and it has been hypothesized that this is due to higher levels of antioxidant activity in M. stellatus. In this study, Ms. Lohrmann performed a seasonal comparison of four antioxidants, superoxide dismutase, ascorbate peroxidase, gutathione reductase, and ascorbate, between M. stellatus and C. crispus. She sought to determine whether M. stellatus and C. crispus acclimate to colder temperatures by upregulating levels of these antioxidants, whether M. stellatus had higher levels of these antioxidants in winter, and whether differences in photosynthentic capacities reinforced trends in antioxidant levels. She found that both species increased their antioxidant activity in response to cold temperatures. However, Ms. Lohrmann did not find consistently higher levels of antioxidants in M. stellatus in the winter, indicating that differences in winter tolerance cannot be explained by differing antioxidant levels. She also found no difference in photosynthesis between species during months tested, reinforcing the lack of differences seen in antioxidant activity.