Does atmospheric CO2 concentration influence soil nitrifying bacteria and their activity?
Saman Bowatte A B, R. Andrew Carran A, Paul C. D. Newton A, Phil Theobald A A AgResearch (Grasslands), Private Bag 11008, Palmerston North 4442, New Zealand. B Corresponding author. Email: saman.bowatte@agresearch.co.nz Abstract Ammonia oxidising bacteria (AOB) are important soil microorganisms that carry out the first step in nitrification, the oxidation of ammonia to nitrite. In this paper we investigated the impact of long-term elevated CO2 on soil nitrification and soil AOB community composition. Soil samples were taken from Hakanoa natural CO2 springs, Kamo, Northland, New Zealand. This site has been exposed to elevated CO2 for several decades. Soils were collected from different points near to CO2-emitting vents where the CO2 concentration at canopy height had been characterised. Nitrification activity was measured using a short-term nitrification assay, and AOB community composition was characterised using polymerase chain reaction and denaturing gradient gel electrophoresis (DG
