How does rising atmospheric CO2 affect marine organisms?

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Real-World CO2-Induced Growth Enhancements of Oak and Pine Trees in Missouri, USA
Voelker, S.L., Muzika, R.-M., Guyette, R.P. and Stambaugh, M.C. 2006. Historical CO2 growth enhancement declines with age in Quercus and Pinus. Ecological Monographs 76: 549-564.

What was done
Working with two species of oak (Quercus velutina Lam. and Quercus coccinea Muench.) and one of pine (Pinus echinata Mill.) in the Ozark Mountains of Missouri, USA, the authors cross-dated a large number of increment cores and aligned the ring-width data by pith date for accurate age-constant assessments of growth over the past 150 years, thereby circumventing "changes in growth trend associated with differences in physiological functioning during development, as well as the need for statistical detrending that removes an unknown degree of long-term environmental signal, the so-called segment length curse that applies to standard dendrochronological investigations." In addition, they similarly analyzed previously acquired data for P. echinata stretching back in time to nearly AD 1600.

What was learned
Voelker et al. report that since 1850 the stem growth of the three species has risen "coincidently with increases in atmospheric CO2," such that the overall trend in ring-width in recent years is "nearly two times that" experienced prior to 1850. In addition, they note that the "long-term increases in radial growth appear unrelated to historical disturbance levels for the region, to long-term changes in relevant climatic variables, or to productivity of sites sampled."

What it means
The four Department of Forestry researchers from the University of Missouri suggest that as the atmosphere's CO2 concentration continues to rise, aided by continued nitrogen deposition, it will likely "stimulate further increases in the rates of stand development and carbon storage," and that "some tree species historically selected against [our italics] in the uplands of this system (Acer rubrum L. or Acer saccharum Marsh.) could compete more effectively."

Reviewed 7 March 2007