Seminar: John Gunnell – Northeastern University, Marine Science Center

UNC-CH’s Department of Marine Sciences is proud to host a seminar by UNC alum (2016) John Gunnell, Ph.D. This event is scheduled for Wednesday, February 20th, at 3:35pm in room G201 on the ground floor of Murray Hall at the University of North Carolina at Chapel Hill. This seminar will also be broadcast live to both UNC’s Institute of Marine Sciences room 222 and online via Zoom (Meeting ID: 311-406-456).

Presenter Affiliation: Postdoctoral Research Associate; Marine Science Center, Northeastern University

Title:  Reconstructing warming throughout the Meso-American Barrier Reef System over the past century

Abstract: Tropical coral reef coverage has been cut in half by anthropogenic stressors over the past century. Thermal stress associated with global warming contributes to this historical decline in coral coverage, impairing coral growth rates and promoting mass bleaching events. Yet it is difficult to connect historical seawater temperatures with coral growth over the past century because reliable, spatially-integrated temperature measurements for tropical reef systems generally do not exist prior to satellite observations that commenced in the 1970s. We bridged this gap in regional climate records with a novel, multi-elemental paleothermometer archived in the skeleton of the massive scleractinian coral Siderastrea siderea. This method was applied to over 4000 annual growth bands stratified across 54 coral cores distributed throughout a roughly 8000 sq. km. section of the Meso-American Barrier Reef System (MBRS)—the second largest barrier reef in the world. The scope and scale of this endeavor allowed reconstruction of seawater temperatures across the entire reef system over the past century, which can be systematically compared to coral growth rates within the same coral cores over the same interval. This effort reveals the impact that past warming has had on coral growth throughout the MBRS over the past century and provides empirical support for predicting the impact of future warming on coral growth.