Increase of atmospheric CO₂ promotes phytoplankton productivity

Abstract

It is usually thought that unlike terrestrial plants, phytoplankton will not show a significant response to an increase of atmospheric CO 2 . Here we suggest that this view may be biased by a neglect of the effects of carbon (C) assimilation on the pH and the dissociation of the C species. We show that under eutrophic conditions, productivity may double as a result of doubling of the atmospheric CO 2 concentration. Although in practice productivity increase will usually be less, we still predict a productivity increase of up to 40% in marine species with a low affinity for bicarbonate. In eutrophic freshwater systems doubling of atmospheric CO 2 may result in an increase of the productivity of more than 50%. Freshwaters with low alkalinity appeared to be very sensitive to atmospheric CO 2 elevation. Our results suggest that the aquatic C sink may increase more than expected, and that nuisance phytoplankton blooms may be aggravated at elevated atmospheric CO 2 concentrations.

Long-term culture at elevated atmospheric CO2fails to evoke specific adaptation in seven freshwater phytoplankton species

“…Our findings are consistent with previous reports that CO 2 availability can limit phytoplankton productivity in a wide range of conditions, including nutrientreplete freshwater cultures [16] and nutrient-poor oceans [15].…”

“…This assumption is challenged by the presence of inducible carbon concentration mechanisms (CCMs), which increase the local concentration of CO 2 around RuBisCo in the chloroplast when the external concentration is low [14]. Moreover, there is a growing body of evidence that enrichment with CO 2 increases productivity in a diversity of aquatic systems [15][16][17]. We are gaining a growing understanding of the growth response of phytoplankton to CO 2 , including the effect of nutrient availability and the physiological mechanism underlying it [18,19].…”

Differential effects of ocean acidification on growth and photosynthesis among phylotypes of Symbiodinium (Dinophyceae)

“…The use of an asterisk above the data indicates statistical differences between the two treatments for each phylotype. (4) 412 (15) 53 (5) 81 233 (6) 417 (7) 71 (4) plankton species has been demonstrated to be carbon Zondervan et al 2002;Schippers et al 2004). Similarly, a .…”

“…Algal photosynthesis is directly dependent on the concentration of CO 2 at the site of carbon fixation and, as such, it has been suggested that OA could have significant implications for marine primary productivity (Rost et al 2008). For example, the productivity of certain species of marine phytoplankton has been predicted to increase by up to 40% if atmospheric pCO 2 were to double (Schippers et al 2004).…”

Genetic diversity of inorganic carbon uptake systems causes variation in CO2 response of the cyanobacterium Microcystis

“…Similarly, the evolutionary loss of bicA in several Microcystis strains might be explained by natural selection during periods of low C i availability. Conversely, rising atmospheric CO 2 concentrations may enhance the C i availability in lakes, alleviating cyanobacterial blooms from carbon limitation (Schippers et al, 2004). This would disfavor high-affinity C i uptake systems (Collins et al, 2006), whereas strains with bicA will have a selective advantage in a high-CO 2 world.…”