How does rising atmospheric CO2 affect marine organisms?

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Growth Response of Cuphea to Ultrahigh CO2 Concentrations
Tisserat, B., Vaughn, S.F. and Berhow, M.A. 2008. Ultrahigh CO2 levels enhance cuphea growth and morphogenesis. Industrial Crops and Products 27: 133-135.

Cuphea, in the words of the authors, "is an annual native species which produces an oil seed that is high in saturated, medium-chain triacylglycerols and can be used for making detergents, surfactants, lubricants, and other products."

What was done
Three types of well-watered two-week-old Cuphea viscosissima x C. lanceolata L. (McCoy GT #1, Morton GT #1 and Morris heavy) seedlings were grown within 162-L transparent containers maintained for 30 days at atmospheric CO2 concentrations of either 350, 1500, 3000, 10000 or 30000 ppm CO2, after which time they were harvested and assessed for a number of measures of growth.

What was learned
Tisserat et al. report that the "fresh weight of seedlings, leaves per seedling, roots per seedling, and seedling length in cuphea Morris heavy seedlings increased 607%, 184%, 784% and 175%, respectively, after 30-day exposure to 10,000 ppm CO2 over those obtained from seedlings grown on ambient [350 ppm] CO2 levels," with a leveling off of growth stimulation between 10,000 and 30,000 ppm CO2, while they further note that the other two cuphea varieties "showed similar response trends."

What it means
The three USDA Agricultural Research Service scientists say their data suggest that "ultrahigh CO2 treatments may be effective for enhancing cuphea growth and benefit breeding treatments." In addition, their data indicate that huge increases in the air's CO2 concentration can lead to huge increases in plant growth and development, as is also demonstrated by the many other journal reviews we have archived under the heading of Growth Response to Very High CO2 Concentrations in our Subject Index.

Reviewed 2 July 2008