Climate change has caused a rapid increase in ocean acidification and sea surface temperature. As anthropogenic effects continue, marine ecosystems must cope with continued shifts in ocean properties. Already, marine organisms have shown evidence of stress-induced responses through the form of bleaching, which is the loss of photosynthetic pigment. Research has largely focused on the bleaching of coral and calcified macroalgae which are more susceptible to changes in carbonate chemistry; however, the ecological importance of fleshy macroalgae necessitates further research as calcified macroalgal responses to climate change may not be representative of other forms of algae. In this study, we subject Porphyra lanceolata and Mastocarpus papillatus, intertidal fleshy macroalga of the Rhodophyta phylum, to the projected effects of climate change by manipulating water temperature and pH. We also investigated how the morphological structures of P. lanceolata and M. papillatus may play a role in mitigating bleaching. We eliminated overall morphology by excising small portions of algae and comparing these excised samples to intact samples. We found that an increase in temperature and a decrease in pH did not affect the amount of bleaching in both species. We also found that Intact samples of P. lanceolata showed a lower amount of bleaching as compared to excised samples while there was no difference in the amount of bleaching between intact and excised samples of M. papillatus. The ruffled, foliose morphology of P. lanceolata may help prevent bleaching while the simple, bladed morphology of M. papillatus may not. These functional morphological differences may give insight into how different species of algae can combat the effects of climate change on a morphological level.
Fadler D., Fontao A., Verduzco-Villanueva X. & Zhang X., in press. Mastocarpus papillatus and Porphyra lanceolata differ in stress-induced bleaching depending on morphological factors. University of California. Article.
