Influence of environmental factors on the decomposition of penguin guano in Antarctica

Summary

The microbial activity of guano samples from an age sequence of penguin rookery sites and adjacent areas at Cape Bird, Antarctica, was examined. Field moist and artificially moistened samples were buried at the sites (4°C) and duplicate samples incubated in the hut (10°C). Samples were then frozen and transported to New Zealand. Gas from above the frozen samples was analysed for CO₂ using gas chromatography. The samples were thawed and further incubated at 25°C. Microbial activity in the guano depended on the degree of penguin influence and was low in the field moist samples from all sites incubated both ‘in situ’, in the hut and at 25°C. In contrast microbial activity was higher in samples with added water, and very high in guano incubated at 25°C. Under favourable moisture and temperature conditions there may be rapid breakdown of penguin guano, but averaged over a year the estimated annual loss of carbon is less than 0.5% of the total carbon present.