High carbon burial rates by small ponds in the landscape

Temperate ponds may be important sinks and sources of greenhouse gases but just how quickly ponds bury carbon (C) is poorly understood. We derived – to the best of our knowledge – the first organic carbon (OC) burial rates for small ponds of known age by digging out the whole sediment from ponds, and determined that the average C burial rate was 142 g m−2 yr−1, with a range of 79–247 g m−2 yr−1, depending on the ponds' vegetation. Burial rates in the ponds were 20–30 times higher than rates estimated for many other habitat types, such as woodlands or grasslands, and higher than those of other natural wetlands. Although small ponds occupy a very small proportion of the landscape as compared to these other habitats, their high OC burial rates result in comparable annual OC burial overall. Ponds are easy to create, can fit in with other land uses, and are a globally ubiquitous habitat. Our results indicate that ponds have the potential to be a very useful additional tool for mitigating C emissions.