CHEMISTRY OF STREAMS OF SIGNY ISLAND, MARITIME ANTARCTIC - SOURCES OFMAJOR IONS

A general study of the streams of Signy Island, South Orkney Islands, was undertaken to identify the effects of catchment, distance from sou rce, and time on concentrations of dissolved ions. In the majority of cases catchment did not affect the chemistry of streams, although mari ne-derived ions were affected by distance from the sea. Na+, K+, Mg2+, Ca2+, Cl . and NH4+ were derived from the thawing of the winter snowp ack. NO3- was derived from areas of permanent ice. SiO44-, Ca2+, Mg2and CO32- were derived from crustal weathering. Although PO43- was als o derived from crustal weathering, it was released as a pulse related to the thawing of the soil.