Café Thorium

Motivation

²³⁴Th is one of the most actively used tracers in oceanography, specifically for particle “scavenging.” After 5 decades of extensive use of ²³⁴Th to understand natural aquatic processes, a unique repository of ²³⁴Th measurements has never been compiled and ²³⁴Th data remain scattered. Many ²³⁴Th depth profiles have been collected using a variety of sampling instruments using sampling and analytical strategies that have been progressing since its first sampling in 1967. We present here a global oceanic compilation of ²³⁴Th measurements that collects results since the first reported measurement of this tracer in the ocean 1969 gathered in a single open-access, long-term repository that can be updated.

Compilation description

The compilation is made of a total 223 datasets. It includes data compiled from over 5000 locations spanning all the oceans for total, dissolved and particulate ²³⁴Th concentrations, and POC:²³⁴Th ratios. 379 oceanographic expeditions and more than 56000 ²³⁴Th and 18000 238U data points have been compiled. Appropriate metadata have also been included along with other relevant parameters such as temperature and salinity when available. Data sources and methods information are also detailed along with valuable information for future analysis.

Data availability

The compilation has been an ongoing effort since 2018 and is now archived in the data repository PANGAEA® (http://www.pangaea.de), under the following DOI: https://doi.pangaea.de/10.1594/PANGAEA.918125.

Moreover, a manuscript that introduces the dataset along with informative and descriptive graphics is under review in Earth Systems Science Data and accessible at: https://essd.copernicus.org/preprints/essd-2021-259/#discussion.

Last, a dedicated web page - Sea of Thorium - is under development to i) grant free access to the compilation, allowing the researchers to search, filter, visualize and freely use existing 234Th data, and ii) encourage researchers to share their ²³⁴Th measurements and contribute to the compilation.

Contribute data!

This effort provides a valuable resource to better understand and quantify how the contemporary oceanic carbon uptake functions and how it will change in future that seeks to act as a coordinating umbrella to serve as a focal point for the ²³⁴Th community under the principles of openness and reproducibility.

We encourage authors to review or complement a dataset included in this compilation and contribute to its extension with new data. A template will eventually be available on the PANGAEA page but currently it can be downloaded HERE. Contact Elena Caballos Romero at eceballos@whoi.edu with any questions. Instructions to fill in this template are included in the template itself.