How does rising atmospheric CO2 affect marine organisms?

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How Well Equipped to Tolerate Climate Change Are Octocorals

Paper Reviewed
Madeira, C., Madeira, D., Vinagre, C. and Diniz, M. 2015. Octocorals in a changing environment: Seasonal response of stress biomarkers in natural populations of Veretillum cynomorium. Journal of Sea Research 103: 120-128.

Madeira et al. (2015) begin the introduction to their paper by noting that "the intertidal habitat is one of the harshest zones for marine biota to inhabit," citing the findings of Menge and Branch (2001) and while further noting that the organisms found there "are exposed to environmental conditions with steep gradients (Tomanek and Helmuth, 2002) such as temperature, ultraviolet radiation and salinity that can lead to cellular damage or death."

To further explore this situation, the four Portuguese researchers collected a large number of octocorals in the spring and summer of 2013 from a pristine sandy intertidal shore in Troia, Setubal, Portugal, during midday at low tide, when temperatures were normally at their daily extreme warmth, while simultaneously recording air temperature, intertidal water temperature, salinity and pH. And back at the laboratory, they analyzed the activities of several antioxidant defense enzymes and other biomarkers, along with total octocoral protein content. And what did they thereby learn?

In the words of Madeira et al., "this species is able to withstand low tide conditions in warmer temperatures without evidence of thermal or oxidative stress." And they also state that as observed by McClanahan et al. (2007), corals that experience the greatest temperature variability -- at higher latitudes, as in this study -- are also "the corals most capable of surviving in challenging conditions," while noting that "V. cynomorium seems to fall into this category." Consequently, they go on to predict that "this species is likely to be quite resilient," or to even "thrive under future climate warming conditions."

McClanahan, T.R., Atweberhan, M., Ruiz-Sebastian, C., Graham, N.A.J., Wilson, S., Bruggemann, J.H. and Guillaume, M.M.M. 2007. Predictability of coral bleaching from synoptic satellite and in situ temperature observations. Coral Reefs 26: 695-701.

Menge, B.A. and Branch, G.M. 2001. Rocky intertidal communities. In: Bertness, M.D., Gaines, S.D. and Hay, M.E. (Eds.), Marine Community Ecology. Sinauer Associates, Sunderland, Massachusetts, USA, pp. 221-251.

Tomanek, L. and Helmuth, B. 2002. Physiological ecology of rocky intertidal organisms: a synergy of concepts. Integrative and Comparative Biology 42: 771-775.

Posted 18 January 2016