DOI: 10.5061/dryad.6t1g1jx6q
title: Tomographic data of Trilobatus trilobus shells from central Atlantic core-top sediment samples

description: Understanding the controls behind the calcification and distribution of
 planktonic foraminifera in the modern ocean is important when using these
 organisms for paleoceanographic reconstructions. This study combines shell
 geochemistry, light microscopy, and X-ray micro-computed tomography to
 dissect various parameters of Trilobatus trilobus shells from surface
 sediments and explore the factors influencing their biometry. The goal is
 to understand which aspects of the marine environment are critical for the
 calcification and vertical distribution of this species. T. trilobus is
 found to produce larger, thinner and overall lighter shells in the
 equatorial regions compared to the subtropical gyre regions where the
 shells were up to 4% smaller, more than 60% thicker and approximately 45%
 heavier. The skeletal mass percentage together with other calcification
 metrics (shell weight, thickness) are found to depend primarily on ambient
 seawater salinity rather than carbonate chemistry. In line with their
 degree of calcification, based on geochemically reconstructed apparent
 calcification depths, this group of organisms is found shallower into the
 water column at the equator and the subtropical gyres, while its habitat
 deepens in between these regions at the extra-equatorial sites.
 Furthermore, it is demonstrated that T. trilobus, in the (central)
 Atlantic, occupies a density layer slightly below the salinity maximum
 isopycnal at various depths, presumably by adjusting its shell properties.
description: High-resolution X-ray tomographic data of shells of planktonic
 foraminifera species <em>Trilobatus trilobus</em> from samples
 VM27-261, VM19-308, VM16-206, VM23-112, VM22-26, RC13-189, RC13-188,
 RC24-10, RC24-11, RC24-16, RC24-17, VM22-175, RC16-77, RC16-36, RC08-19,
 RC08-23 from the central Atlantic Ocean. The specimens are from the
 300-355 μm sieve fraction and the average scanning resolution is ~1.2 μm.
 The exact voxel size and other scan info are included in each zip file.
 The analyses were performed using a GE/Phoenix v|tome|x s 240 CT scanner
 at the Geozentrum Nordbayern. The planktonic tests were fixed in a
 customized cylindrical container together with a calcite microcrystal that
 can be used to standardize the CT number (grey levels) of the scanned
 specimens. A high-resolution setting (voltage of 80 kV, current 80 μA,
 detector array size of 1024×1024, 1501 projections/360°, 2.5 s/projection)
 enabled the acquisition of 3D images with an isotropic pixel size. Phoenix
 datos|x 2.0 software was used to correct and reconstruct tomographic data
 that uses the general principle of Feldkamp cone beam algorithm to
 reconstruct image cross sections from the filtered back
 projections.
description: # Tomographic data of *Trilobatus trilobus* shells from central Atlantic
 core-top sediment samples
 [https://doi.org/10.5061/dryad.6t1g1jx6q](https://doi.org/10.5061/dryad.6t1g1jx6q) High-resolution X-ray tomographic data of *Trilobatus trilobus* planktonic foraminifera shells collected from the Lamont-Doherty Core Repository. Samples were sourced from cores VM27-261, VM19-308, VM16-206, VM23-112, VM22-26, RC13-189, RC13-188, RC24-10, RC24-11, RC24-16, RC24-17, VM22-175, RC16-77, RC16-36, RC08-19, RC08-23 from the central Atlantic Ocean. The specimens are from the 300-355 μm sieve fraction and the average scanning resolution is ~1.2 μm. The exact voxel size and other scan info are included in each zip file. The analyses were performed using a GE/Phoenix v|tome|x s 240 CT scanner at the Geozentrum Nordbayern. The planktonic tests were fixed in a customized cylindrical container with a calcite microcrystal that can be used to standardize the scanned specimens' CT number (grey levels). A high-resolution setting (voltage of 80 kV, current 80 μA, detector array size of 1024×1024, 1501 projections/360°, 2.5 s/projection) enabled the acquisition of 3D images with an isotropic pixel size. Phoenix datos|x 2.0 software was used to correct and reconstruct tomographic data using the Feldkamp cone-beam algorithm's general principle to reconstruct image cross-sections from the filtered back projections. ## Description of the data and file structure The compressed (*.rar) files contain the Feldkamp cone-beam reconstructed TIFF stacks and an associated *.pca file, which includes acquisition details and can be opened with any text editor. The naming convention for the main folders are: Sample (VM27-261, VM19-308, VM16-206, etc.,)-shell thickness and the number of files included in each folder.