CoralHydro2k

Overview

The PAGES Ocean2k project used available coral δ¹⁸O and Sr/Ca records to reconstruct regional tropical sea surface temperature for the past centuries at annual resolution. Most of these records were based on δ¹⁸O analysed in coral skeletons, a variable that reflects a combination of both the temperature and the δ¹⁸O of the seawater (δ¹⁸O_sw) near the ocean surface. The coral Sr/Ca temperature proxy has the potential to decouple the temperature and δ¹⁸O_sw signals from coral δ¹⁸O records in order to deliver reconstructions of δ¹⁸O_sw, but only a handful of centuries-long δ¹⁸O_sw reconstructions currently exist.

We intend to foster the generation of new paired coral Sr/Ca and δ¹⁸O records as well as the dynamical interpretation of available records, in order to reconstruct the spatiotemporal δ¹⁸O_sw changes of the tropical to subtropical surface ocean on seasonal, interannual, and decadal to multidecadal time scales during the observational period back into the Little Ice Age.

We aim to identify the dynamical drivers of changes in δ¹⁸O_sw on these timescales, including atmospheric processes such as the precipitation-evaporation balance at the sea surface and the isotopic signature of precipitation, as well as oceanic processes such as the advection of surface currents and the upwelling of deeper water masses.

While some changes in the coral-based δ¹⁸O_sw reconstructions can be linked to changes in the surface freshwater balance related to ENSO extremes, the dynamical drivers of inferred lower-frequency changes in δ¹⁸O_sw remain unclear in most cases. In addition, we intend to move forward the careful assessment of the errors associated with the calculation of coral-based δ¹⁸O_sw reconstructions.

CoralHydro2k seawater δ¹⁸O database - July 2021

The group has finished building the CoralHydro2k Database: a global, actively-curated compilation of coral δ18O and Sr/Ca proxy records of tropical ocean hydrology and temperature for the Common Era. The database contains 54 paired Sr/Ca-δ18O records and 125 unpaired Sr/Ca or δ18O records, with 88% of these records providing data coverage from 1800 CE to present. A quality-controlled set of metadata with standardized vocabulary and units accompanies each record. The CoralHydro2k database tracks large-scale temperature and hydrological variability. As such, it is well-suited for investigations of past climate variability, comparisons with climate model simulations including isotope-enabled models – and application in paleo-data assimilation projects.

The CoralHydro2k database will be publicly archived at https://lipdverse.org and on the NOAA National Center for Environmental Information’s Paleoclimate data service, with serializations in MATLAB, R, Python, and LiPD. In addition, the group has started an effort to compile and curate seawater δ18O data into a centralized, publicly available and actively maintained database, in order to address needs arising from new instrumentation and growing environmental modeling.

This activity is supported by a PAGES Data Stewardship Scholarship. The crowdsourcing efforts included calls to the community via various channels for “hidden” data, the establishment of a submission portal (https://fsu.qualtrics.com/jfe/form/SV_094ofPIJKM5KNyC), and a video tutorial assisting the data submission process. Drop-in "office hours" sessions were organized at the AGU Fall Meeting 2021. An article on the initiative is under review at Eos, titled, “Clues from the Sea - Paint a Picture of Earth's Water Cycle”.

This video walks potential survey respondents through the Qualtrics survey submission process. > Watch

If you don’t have data of your own, but know of a dataset that should be included in the database, please feel free to submit the DOI or citation via our Google Form: https://forms.gle/M263p7SM7mteQbrf9

Thoughts, comments, or questions about the survey? We value your opinion! Please direct all feedback to Andrea Moore: alm20emmy.fsu.edu (alm20em[at]my[dot]fsu[dot]edu)

New Science to Policy paper - July 2021

Project leader Thomas Felis was involved in the Science to Policy paper "Rebuilding Coral Reefs: A Decadal Grand Challenge" released during the 14th International Coral Reef Symposium in July 2021. This paper is from the International Coral Reef Society (ICRS) and Future Earth Coasts, with Thomas as a contributing author.
> Access the paper here

Learn more and participate

> CoralHydro2k scientific goals

> CoralHydro2k people

This group is open to anyone who is interested, and early-career researchers are encouraged to be involved.

- Subscribe to the CoralHydro2k mailing list here
- Subscribe to the 2k Network mailing list here
- Contact the project coordinators

Previous news

> Access a pdf presentation about CoralHydro2k, from the January 2018 2k Teleconference, here
> Read an interview with group leader Kim Cobb from 19 June 2018 by AAAS's Nathan Gilles here