High-resolution monitoring reveals dissolved oxygen dynamics in an Antarctic cryoconite hole

This study presents the first high-resolution dataset of dissolved oxygen (DO) measurements in an ice-lidded cryoconite hole on Canada Glacier, McMurdo Dry Valleys, Antarctica. Fibre optic DO minisensors were installed in a cryoconite hole prior to seasonal internal melting and hydrological connection to the subsurface drainage system. Oxygen air saturation in the cryoconite hole typically ranged from 50 to 80%, in broad agreement with previous single measurements, indicating net respiration (R). This is consistent with results of simple incubation experiments performed in the field. Simultaneous time series for electrical conductivity, water temperature, and DO over the four-week study period provide information regarding the connectivity of cryoconite holes with the near-surface drainage system. The main driver of the observed variations in DO is likely to be periodic melt-freeze cycles. We conclude that automated sensing techniques, such as those described here, when used in conjunction with physical measurements, have great potential for high-resolution monitoring of the factors that perturb biogeochemical processes in cryospheric surface aquatic ecosystems. Copyright  2011 John Wiley & Sons, Ltd.