How does rising atmospheric CO2 affect marine organisms?

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The Growth Response of Eucalyptus Plantlets to Elevated CO2
Kirdmanee, C., Kitaya, Y. and Kozai, T.  1995.  Effects of CO2 enrichment and supporting material in vitro on photoautotrophic growth of Eucalyptus plantlets in vitro and ex vitroIn Vitro Cellular and Developmental Biology - Plant 31: 144-149.

What was done
The authors removed actively growing shoots of Eucalyptus camaldulensis and grew them for six weeks in near-sterile environments at atmospheric CO2 concentrations of 400 and 1200 ppm, while using different supporting media.  Thereafter, the plantlets were moved to a greenhouse for an additional four weeks of growth under ambient CO2 concentrations.

What was learned
After the first six weeks of the study, the plantlets grown in air of elevated CO2 concentration exhibited an average net photosynthetic rate across all media treatments that was 26% greater than that displayed by plantlets grown in air of 400 ppm CO2.  This phenomenon lead to a 23% increase in CO2-enriched plantlet total dry weight across all media treatments.  In addition, after the final four weeks of growth in air maintained at 400 ppm CO2, the plantlets that were previously exposed to air of 1200 ppm CO2 displayed survival percentages that were 13% greater than those of plantlets previously grown in ambient air.

What it means
As the air's CO2 content continues to rise, Eucalyptus plantlets - and perhaps recently germinated seedlings - will probably display enhanced rates of photosynthesis and biomass production.  Thus, young Eucalyptus trees will likely sequester ever more carbon within their woody tissues as time progresses.

Reviewed 14 August 2002