Intertidal Macroalgae and the Threat of Global Warming
Clark, J.S., Poore, A.G.B., Ralph, P.J. and Doblin, M.A. 2013. Potential for adaptation in response to thermal stress in an intertidal macroalga. Journal of Phycology 49: 630-639.
In their study of the subject, Clark et al. used "a quantitative genetic breeding design to establish whether there is a heritable variation in thermal sensitivity in two populations of a habitat-forming intertidal macroalga, Hormosira banksii (Turner) Descaisne," wherein "gametes from multiple parents were mixed and growth and photosynthetic performance were measured in the resulting embryos, which were incubated under control and elevated temperatures (20°C and 28°C)."
The four researchers report "significant interactions between male genotype and temperature in one population indicated the presence of genetic variation in thermal sensitivity," such that "selection for more tolerant genotypes thus has the ability to result in the evolution of increased thermal tolerance." In addition, they found "genetic correlations between embryos grown in the two temperatures were positive, indicating that those genotypes that performed well in elevated temperature also performed well in control temperature."
Clark et al. write, in the concluding paragraph of their paper, their "finding of genetic variation in thermal tolerance of H. banksii embryos suggests resilience to thermal stresses." But they nevertheless warn "the persistence of populations will also depend on tolerance to other environmental stressors and anthropogenic disturbance," such as trampling by visitors to the rocky shore (Keough and Quinn (1998) and sewage discharge (Doblin and Clayton (1995).
Doblin, M.A. and Clayton, M.N. 1995. Effects of secondarily treated sewage effluent on the early life-history stages of two species of brown macroalgae: Hormosira banksii and Durvillaea potatorum. Marine Biology 122: 689-698.
Harley, C.D.G., Hughes, A.R., Hultgren, K.M., Miner, B.G., Sorte, C.J.B., Thornber, C.S., Rodriguez, L.F., Tomanek, L. and Williams, S.L. 2006. The impacts of climate change in coastal marine systems. Ecology Letters 9: 228-241.
Keough, M.J. and Quinn, G.P. 1998. Effects of periodic disturbances from trampling on rocky intertidal algal beds. Ecological Applications 8: 141-161.
Lima, F.P., Ribeiro, P.A., Hawkins, S.J. and Santos, A.M. 2007. Do distributional shifts of northern and southern species of algae match the warming pattern? Global Change Biology 13: 2592-2604.