Plumbing the depths - the waters of the Ross Sea

Extract

The first oceanographic measurements in the Ross Sea were made by its discoverer James Clark Ross, from the Erebus, on 18 January 1841. Since that time its continental shelf, seasonally ice free in most years, has proved a magnet to explorers and scientists, if not to fishermen and tourists. Nevertheless, our knowledge of this environment is rapidly being outpaced by our ignorance of its variability. For example, the Ross Sea contains two of the largest, most persistent polynyas on the Antarctic coastline, but its sea ice extent has increased over recent decades while its salinity has steadily declined. Are regional winds now stronger, the ocean circulation faster, and the ice thinner now than at the time of the IGY? Are its winter polynyas characterized more by upwelling driven by offshore winds, or downwelling due to brine release when sea ice is formed? How are polynya surface layers stabilized and iron-enriched, reportedly enhancing summer productivity, if the ice cover is blown away before it can melt in situ?