How does rising atmospheric CO2 affect marine organisms?

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Effects of Elevated CO2 on Dry Mass Partitioning in Three Species
Reference
Gunn, S., Bailey, S.J. and Farrar, J.F.  1999.  Partitioning of dry mass and leaf area within plants of three species grown at elevated CO2Functional Ecology 13: 3-11.

What was done
Dactylis glomerata, Bellis perennis, and Trifolium repens were grown hydroponically in controlled-environment chambers receiving atmospheric CO2 concentrations of 350 and 700 ppm for up to 50 days to determine the effects of elevated CO2 on growth and dry matter partitioning in these species.

What was learned
Whereas elevated CO2 increased total dry mass of Trifolium repens and Bellis perennis by more than 100%, it only increased total dry mass of Dactylis glomerata by 23%.  Although shoot to root ratios were higher in CO2-enriched plants, closer analyses revealed that CO2 alone had only a minor affect on dry matter partitioning when plant size was taken into consideration.

What it means
As the atmospheric CO2 concentration continues to increase, it is likely that all three of these species will exhibit increased rates of photosynthesis and biomass production.  Although elevated CO2 had little effect dry mass partitioning in this experiment, which was probably due to the hydroponic environment of the plant root systems, it is likely that these plants may indeed exhibit greater partitioning of dry mass to roots when grown in soil systems resembling those in which they commonly exist.


Reviewed 15 November 1999