CAS- Climate: Assessing the potential of artificial upwelling to mitigate coral bleaching during heat waves

Bermuda Institute Of Ocean Sciences (Bios), Inc., St. George'S

Investigators

Abstract

Global warming is considered to be the most severe threat to coral reefs by causing heat stress events that lead to coral mass bleaching and reef degradation. This situation motivates the development of interventions that mitigate coral bleaching, such as artificial upwelling (AU). AU uplifts cool deep water to the surface. The overarching objective of this project is to provide improved understanding of how AU could be used for surface water cooling by identifying AU scenarios (depth, intensity) that mitigate coral bleaching effectively, while imposing minimal risk of unwanted side effects. The project will substantially improve understanding of how AU could be used to mitigate coral bleaching during thermal stress, by providing knowledge about the effects of different AU scenarios (different depths and lengths of AU pulses) on coral performance and on reef community structures. Investigating both short- and longer- term effects on coral performance and also assessing effects on community structures go beyond most manipulation studies that investigate organism-specific short-term responses. The resulting data set will be relevant not only for engineers, but also will provide critical knowledge for the coral reef ecology community about the coral’s ability to persist in a warming world. It is hypothesized that favorable results can be achieved by creating daily short-term thermal relief via pulsed AU (e.g., <5h/day) with waters from the mid- to lower photic zone (e.g., ~30-100 m). The immediate and lasting effects of AU on coral physiology during heat stress will be tested by (1) assessing the short-term physiological effects of pulsed AU treatments on heat-stressed corals, (2) assessing the long-term physiological effects of heat stress and pulsed AU experiments on coral recovery and thermal tolerance, and (3) testing the combined effects of pulsed AU experiments, variable temperature, and covarying environmental parameters on corals and coral reef communities. The project location at the Bermuda Institute of Ocean Sciences, Inc. (BIOS) is ideal due to its proximity to coral reefs and available research facilities that provide a highly suitable framework for near-natural manipulation studies, including the Bermuda Marine Mesocosm Facility supported by an NSF Facility grant. Students will be involved via existing BIOS-hosted intern programs, including an NSF-funded REU program. Undergraduate and graduate students will learn about the project in BIOS-run university courses. Public outreach will be attained in particular through the development of a new solitaire-like digital game called “EcoChains: Coral Futures”, where players will respond strategically to ocean warming, ocean acidification, sedimentation, outbreaks of crown-of-thorns starfish, and more in coral reefs. Furthermore, numerous visiting school and university groups will have the opportunity to observe the experimental setup and learn about the project. This project is co-funded by the CBET/ENG Environmental Sustainability program and the Biological Oceanography Program in the Division of Ocean Sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.