How does rising atmospheric CO2 affect marine organisms?

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Effects of Elevated CO2 on Phenolics in Perennial Grasses
Castells, E., Roumet, C., Penuelas, J. and Roy, J.  2002.  Intraspecific variability of phenolic concentrations and their responses to elevated CO2 in two mediterranean perennial grasses.  Environmental and Experimental Botany 47: 205-216.

What was done
The authors grew 14 genotypes of two Mediterranean perennial grass species (Dactylis glomerata and Bromus erectus) in glasshouses receiving atmospheric CO2 concentrations of 350 and 700 ppm to determine if elevated CO2 impacts phenolic production in a genotypic-dependent manner in these species.

What was learned
Atmospheric CO2 enrichment increased total phenolic compound concentrations in Dactylis and Bromus by 15 and 87%, respectively.  Moreover, there were no significant CO2 x genotype interactions in either of these species.

What it means
As the air's CO2 content rises, these two perennial grasses will likely exhibit greater resistance to herbivory, due to CO2-induced increases in tissue phenolic concentrations.  In addition, because there were no significant CO2 x genotype interactions, it is unlikely that elevated CO2 will act as a selective agent among genotypes in these species.  Thus, genotypic diversity within these species is likely to persist with future increases in the air's CO2 concentration.

Reviewed 8 May 2002