Estimation of uncertainty for massive Porites coral skeletal density

Abstract

Previous studies have not demonstrated the estimate errors in growth parameters (skeletal density, extension rate and calcification rate) for massive coral skeletons. In order to discuss the variability of coral skeletal growth, it is crucial for quantitative evaluation of the parameters with errors. We report the protocol of calculating errors as combined standard uncertainty for coral skeletal density (uρ SA) based on ISO/IEC Guide 98-3 (2008). We applied the non-destructive transparent X-ray 2-D imaging scanner, TATSCAN-X1, which enabled to quick and quantitative analysis of the uρ SA parameters with digital procedures. We analyzed the annual skeletal density for massive Porites coral collected from Ishigaki Island. The skeletal densities changed from 1.45 to 1.70 g/cm 3 and uρ SA were ca. 0.02 g/cm 3. Our results indicated that the uρ SA was derived from the combined effects of 78.5% from the standard uncertainty of deducing of analytical curve (u ln OD (Y)→ρ*t (X)) and 6.3% from that of the sample thickness error (ut SA).