How does rising atmospheric CO2 affect marine organisms?

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Strawberry Fields Forever
Bunce, J.A.  2001.  Seasonal patterns of photosynthetic response and acclimation to elevated carbon dioxide in field-grown strawberry.  Photosynthesis Research 68: 237-245.

What was done
Strawberry (Fragaria x ananassa Duchesne cv. Honeoye) plants were grown in the field in open-top chambers receiving atmospheric CO2 concentrations of 350, 650, and 950 ppm for two years to study the effects of elevated CO2 on photosynthesis in this important agricultural crop.  Measurements were made on a weekly basis to evaluate the temperature dependence of photosynthetic stimulation resulting from the two levels of atmospheric CO2 enrichment.

What was learned
Surprisingly, elevated CO2 increased photosynthetic rates to an even greater extent than predicted by kinetic models based on the characteristics of the enzyme rubisco at all temperatures.  Although photosynthetic acclimation was apparent in two-thirds of the measurements made during the course of the experiment, plants grown at 650 and 950 ppm CO2 still exhibited average photosynthetic rates that were 77 and 106% greater, respectively, than those displayed by control plants exposed to ambient air.  In addition, when soil water potentials were measured during several "dry summer days," as the author described them, an increasingly greater amount of soil moisture was indicated for each step increase in the air's CO2 concentration.

What it means
As the CO2 concentration of the atmosphere increases, strawberry plants will exhibit enhanced rates of photosynthesis, regardless of seasonal air temperature, which should lead to increased biomass and fruit production.  In addition, strawberry plants should fare better under conditions of water stress than they do now.  In fact, the outlook for the little red fruit is so good, we can hardly keep ourselves from singing about it.

Reviewed 9 January 2002