How does rising atmospheric CO2 affect marine organisms?

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Photosynthetic and Growth Responses of Field-grown Potato to Elevated CO2
Sicher, R.C. and Bunce, J.A.  1999.  Photosynthetic enhancement and conductance to water vapor of field-grown Solanum tuberosum (L.) in response to CO2 enrichment.  Photosynthesis Research 62: 155-163.

What was done
Potato (Solanum tuberosum) plants were grown in open-top chambers for three sequential growing seasons at atmospheric CO2 concentrations of 350, 530, and 700 ppm to determine the effects of elevated CO2 on photosynthesis and growth in this important agricultural crop species.

What was learned
Averaged over the three-year investigation, elevated CO2 increased net photosynthetic rates by 28 and 49% in plants grown at 530 and 700 ppm, in spite of the fact that the plants experienced photosynthetic acclimation, as indicated by 13 and 21% reductions in total rubisco activity.  However, atmospheric CO2 enrichment did not significantly affect leaf chlorophyll a and b contents, total soluble leaf protein content, leaf rubisco content, or initial rubisco activity.  The additional carbohydrates produced by plants grown in CO2-enriched environments were utilized to increase tuber number and dry weight, which rose by 14 and 9%, respectively, for plants grown at 530 ppm and by 44 and 40% for plants grown at 700 ppm.

What it means
As the CO2 content of the air continues to rise, it is likely that potato plants will exhibit enhanced rates of photosynthesis, thereby leading to increased tuber yield in the form of greater tuber numbers and dry weights.  Thus, one can expect greater yields from this important agronomic crop as the atmospheric CO2 concentration increases.

Reviewed 2 August 2000