14C anomaly of freshwater algae in Antarctic coastal ponds and lakes

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In order to clarify the credibility of ^<14>C dating of Antarctic freshwater algae, δ^<13>C values and ^<14>C concentrations of algae collected from some lakes and ponds in Antarctic coastal areas were analyzed. ^<14>C concentration was measured by Tandetron Accelerator Mass Spectrometry. The δ^<13>C values of algae from Antarctica are relatively higher than global values. The reason for the relatively high δ^<13>C values of Antarctic algae may be sought in the limited CO_2 (aq) supply for algae in lake water. ^<14>C concentrations of algae from ponds in the First Crater and Crater Hill near McMurdo Station on Ross Island, where glacial meltwater does not flow into the ponds, are close to the global level in the same year. On the other hand, the algae from Richardson Lake in the Mt. Riiser-Larsen area in Enderby Land, where glacial meltwater flows into the lake, apparently have low ^<14>C concentration, ca. 90% of the global level. These facts lead us to the conclusion that the ^<14>C anomaly is attributable to a DIC of relatively low ^<14>C concentration derived from glacial meltwater with older carbon. If such samples are used for ^<14>C dating, the age determination will be erroneous.
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