Nitrogen storage (communication arising): UV-B radiation and soil microbial communities

Top of page Stark and Hart question our finding1 that increased UV-B irradiation affects the biomass C:N ratio of Arctic soil microbial communities. Our data for microbial carbon biomass (Cmic; 1.0–3.1 mg per g soil) and nitrogen (Nmic; 0.1–0.3 mg per g soil) fall within the range presented by Stark and Hart (0.2–3.9 and 0.04–0.28 mg per g soil for Cmic and Nmic, respectively)2, but the C:N ratios in the control plots are greater than those for both similar3, 4 and contrasting soil types2. However, we do not agree that this invalidates our conclusions.