Higher temperatures may mean more productive seaweed in some locations

We all know that plants and animals have optimal climates for growth and reproduction. As our planet is experiencing rising temperatures both in and out of the water, it is important to understand how vital species will react to the warmer weather.

One of these species is a macroalga called Fucus gardneri. This seaweed is important in the intertidal ecosystem on the west coast of North America because it provides necessary habitat and food for many rocky shore residents. However, rising seawater temperatures may affect the photosynthetic productivity of this foundational species.

Nicholas Colvard, a graduate student in Brian Helmuth’s lab, researched the effects of increased seawater temperature and irradiance, or sun exposure, on photosynthesis in F. gardneri at Friday Harbor, WA. This research, which recently appeared in the Journal of Experimental Marine Biology and Ecology, shows that plants at this site may not be operating at maximum levels yet, and that an increase in temperature and sunlight may actually cause net photosynthesis to increase.

Furthermore, Colvard et al. went on to model the effect of tidal cycles on the net photosynthesis outputs and found that when the algae was submersed during peak irradiance, photosynthesis peaked. They suggest that the ultimate effects of temperature increases may also depend on tidal cycles as well, and emphasizes why responses to climate change can appear to be so variable among locations.