Protistology 2 (2) 76–84 (2001) Abundances of protozoa in soil of laboratory-grown wheat plants cultivated under low and high atmospheric
CO2concentrations
O. Roger Anderson and Kevin L. Griffin
Biology, Lamont-Doherty Earth Observatory of Columbia University, Palisades, U.S.A
Summary
With increasing evidence of elevated carbon dioxide in the atmosphere, there is considerable interest in the effects of this
atmospheric change on aquatic and terrestrial biota. There is, however, little information on the effects of elevated atmospheric CO2 on terrestrial protozoa even though other research studies have shown an increase in density of soil-dwelling metazoa due
to enhanced plant productivity and increased root exudates. We examined densities of protozoa in rhizosphere soil of wheat plants grown under
experimentally controlled CO2 treatments. The mean density of protozoa (number g-1 soil) in rhizosphere samples of wheat plants grown in environmental controlled chambers was c. 17,000 g-1 for elevated CO2 concentrations (750 μmol 1-1)
and 10,900 g-1 for plants grown at near ambient CO2 concentrations
(365 μmol 1-1). The statistically significant (p < 0.01) increased density of total protozoa in the rhizosphere
of plants grown in elevated CO2 atmospheres provides additional evidence of enhanced soil microbial
activity in response to elevated atmospheric CO2 concentrations. The increased mineralizing activity of the
proliferated protists may enhance plant nutrient recovery and help support the increased growth observed in elevated CO2
environments. Key words: atmospheric CO2 enrichment, ciliates, flagellates,
gymnamoebae, protists, rhizosphere communities, soil fertility
|