This view may be biased by a neglect of the effects of the plants themselves on the water chemistry. In the June issue of Ecology Letters , Schippers, Lürling and Scheffer of the Wageningen University show that, if this effect is included, productivity may double due to a doubling of the atmospheric carbon dioxide concentration.
In practice productivity increase will usually be less, however, under nutrient rich conditions, doubling of atmospheric carbon dioxide may result in a productivity increase up to 40% in saltwater species and up to 50% in freshwater species.
These results indicate that the carbon uptake by fresh- and saltwater systems may increase more than expected, and that nuisance algal blooms may be aggravated at elevated atmospheric carbon dioxide concentrations.
Ecology Letters