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 ).

Influence of Land Development on Holocene Porites Coral Calcification at Nagura Bay, Ishigaki Island, Japan

“…For the corals collected from Nagura, periodical Sr/Ca calibrated the deposition timing of their skeleton. It was supposed that the high-density band was deposited in the winter season for the corals collected from Todoroki [50] . To correct the effects of the inverse square law and heel effect [51] , we used the CoreCal 2 program [50] .…”

“…It was supposed that the high-density band was deposited in the winter season for the corals collected from Todoroki [50] . To correct the effects of the inverse square law and heel effect [51] , we used the CoreCal 2 program [50] . An aluminum bar with the same thickness as the coral slab was included on each digital X-radiograph, placed along the X (horizontal) and Y (vertical) axes of the X-ray machine, as well as an aragonitic step wedge built of blocks cut from a shell of the giant clam Hippopus hippopus as standards for analyzing coral skeletal density.…”

“…The analyzed ODs were then converted to logarithmic ODs, which were used to calculate the skeletal density. The uncertainties of skeletal density were analyzed and all uncertainties were <0.05 g cm −3 (see [50] for details).…”

Influence of local industrial changes on reef coral calcification

“…The extension rates of the corals were determined by measuring the distance between Sr/Ca maxima (SST minima). The skeletal density (g/cm 3 ) was calculated using the CoreCal 2 program method 58 . The annual skeletal calcification rate (g × cm −2 /year) was obtained from pairs of extension rates and annual skeletal density.…”