How does rising atmospheric CO2 affect marine organisms?

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Cystoseira tamariscifolia -- A Brown Macroalgae that Benefits from Ocean Carbonation

Paper Reviewed
Celis-Plá, P.S.M., Martínez, B., Korbee, N., Hall-Spencer, J.M. and Figueroa, F.L. 2017. Ecophysiological responses to elevated CO2 and temperature in Cystoseira tamariscifolia (Phaeophyceae). Climatic Change 142: 67-81.

Noting that rising atmospheric CO2 concentrations increase the amount of dissolved inorganic carbon available in seawater, Celis-Plá et al. (2017) set out to determine whether such ocean carbonation would benefit a large brown macroalgae (Cystoseira tamariscifolia). And thus they performed a controlled laboratory experiment on this species, not only at two different pCO2 levels (corresponding to ambient and reduced pH values of ~8.25 and 7.88, respectively), but also at two temperature (~20 and 24°C) and nutrient levels (oligotrophic and ultraoligotrophic, corresponding to N/P ratios of 20: and 5:1, respectively) over a period of 28 days, in order to see how the macroalgae might respond to projections of future climate change.

In the words of the authors, the results of their experiment revealed that (1) "elevated pCO2 was beneficial to the brown macroalgae C. tamariscifolia, (2) "algae collected in ultra- and oligotrophic waters were able to acclimate to increased dissolved inorganic carbon and temperature, (3) acidification combined with an increase in temperature had beneficial effects on brown algal growth rates, [4] photosynthetic production, [5] antioxidant activity, and [6] photoprotection." Thus, it would appear there is a promising future in store for this important macroalgae that plays a key role in coastal Mediterranean communities.

Posted 15 August 2017