Sea Surface Temperature Reconstruction using 3D X-ray Computed Tomography in Coral Cores from Baler, Aurora, Philippines: An Initial Study


Massive coral like the Porites spp are essential archives of past sea surface temperature (SST) records as they incorporate biological and geochemical tracers that reflect temperature variations in the marine environments. In this paper, 3D X-ray computed tomography (3DXCT) was used to reconstruct sea surface temperature (SST) from the gray values obtained from the coral cores. 3DXCT allows quick imaging of coral density bands with minimal to no sample preparations to extract relevant climate data gray values (GV); a measure of total x-ray absorption on the sample. The result states that GV profiles from the coral cores in Baler, Aurora were matched with the existing SST data (Optimally Interpolated SST). Comparisons also showed significant positive linear correlations. The finding strongly suggest that 3DXCT as relatively easy, quick non-destructive and precise method for SST reconstruction.


This paper represents a novel method to reconstruct Sea Surface Temperature (SST) using the 3DXCT analysis of Porites spp. coral cores from Baler, Aurora, Philippines. Traces of annual growth bands recorded in the skeleton of the massive coral was visualized using the 3DXCT. Obtaining the gray values of the data, it able to reconstruct the SST. The reconstructed SST data obtained from the 3DXCT analysis was compared to the existing grid-SST data from OISST of Reynolds et al., 2007 and Banson et al., 2016. Given the current limitation of available SST data sets, and the fact that long-lived coral record SST changes throughout lifetime as density variation in the coral skeletons, 3DXCT imaging method can be used to visualize annual density bands of corals for high-resolution SST reconstruction. This work demonstrated that this method can create high-resolution SST dataset from coral cores that augment and improve the current available datasets.


Coral coring using hydraulic drill system
Breaks after every dives


Mary Margareth T. Bauyon (Department of Science and Technology – Philippine Nuclear Research Institute (DOST-PNRI))
Remjohn Aron H. Magtaas (DOST-PNRI)
Sophia Jobien M. Limlingan (DOST-PNRI)
Arvin M. Jagonoy (DOST-PNRI)
Joseph Michael D. Racho (DOST-PNRI)
Jeff Darren G. Valdez (DOST-PNRI)
Araceli M. Monsada (Department of Science and Technology – Industrial Technology Development Institute Advanced Device and Materials Testing Laboratory (DOST-ITDI ADMATEL))
Aldrin Jan E. Tabuso (DOST-ITDI ADMATEL)
John Kenneth C. Valerio (DOST-ITDI ADMATEL)
Keanu Jershon S. Sarmiento (Marine Science Institute, University of the Philippines)
Edwin E. Dumalagan, Jr. (Marine Science Institute, University of the Philippines)
Fernando P. Siringan (Marine Science Institute, University of the Philippines)
Angel T. Bautista VII (DOST-PNRI)

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