Penguin and skua in the maritime Antarctic have high salt loadings in the body due to almost exclusive diet consumption of marine invertebrates. How-ever, the storage and turn over of sodium and potassium in these animals are poorly investigated. Here we determined the concentration and microscopic distribution of the two elements in the bones of penguinandskua.The average concentrations of sodium and potassium in penguin bone were comparable with that inskua bone (0.18% and 0.82% for penguin bone; 0.19% and 0.76% for skua bone in dry weight). The ratios of sodium to calciumand potassium to calcium (0.0330 and 0.0075 for penguin, 0.0335 and 0.0082 for skuain average by weight) were some what higher than the reported ratiosforter restrial animals, indicating the semarine animals-bone enrichment of salt. The ratios of sodium to potassiumin average by weight were 6.75 and 4.65 for penguin and skua, respectively. This value is much lower compared with the bulk sea water ratio of about 27.0, implying that potassiumis favorable to residein the bone rather than sodium. Both sodium and potassium were found to significant correlation with the content of organic materials in bone based up on the intensity of native signal determined by electron paramagnetic resonance (EPR). It was estimated that almost all of potassiumis kept with in the organic phases, while about 30% of sodium sstoredin organic phases and the other 70% within mineral phase. Them icroscopic distributions of potassium in the cross-section and/or surface were revealed by synchrotron radiation X-ray fluore scence (SR-XRF) technique. The ratio of potassium to calcium based upon the SR-XRF intensity counter varied considerably from the surface to the interior, and on the surface the highest concentration of potassium was observed in the middle section with decreasing amounts toward the edge. This indirectly documented that exchange of potassium between fluid and bone organic phase may be occur.
Sodium and potassium in the bones of penguin and skuare vealed by EPR and SR-XRF technique