As the devastating impacts of global climate change and local anthropogenic stressors on shallow-water coral reefs are expected to rise, mesophotic coral ecosystems have increasingly been regarded as potential lifeboats for coral survival, providing a source of propagules to replenish shallower reefs. Yet, there is still limited knowledge of the capacity for coral larvae to adjust to light intensities that change with depth. This study elucidates the mechanisms underlying plasticity during early life stages of the coral Porites astreoides that enable survival across broad depth gradients. We examined physiological and morphological variations in larvae from shallow (8–10 m) and mesophotic (45 m) reefs in Bermuda, and evaluated differences in survival, settlement patterns and size among recruits depending on light conditions using a reciprocal ex situ transplantation experiment. Larvae released from mesophotic adults were found to have significantly lower respiration rates and were significantly larger than those derived from shallow adults, indicating higher content of energetic resources and suggesting a greater dispersal potential for mesophotic larvae compared to their shallow counterparts. Additionally, larvae released from mesophotic adults experienced higher settlement success and larger initial spat size compared to larvae from shallow adults, demonstrating a potential connection between parental origin, offspring quality, and recruitment success. Although both shallow and mesophotic larvae exhibited the capacity to survive and settle under reciprocal light conditions, all larvae had higher survival under mesophotic light conditions regardless of parental origin, suggesting that conditions experienced under low light may enable longer larval life, further extending the dispersal period. These results indicate that larvae from mesophotic Porites astreoides colonies are likely capable of reseeding shallow reefs in Bermuda, thereby supporting the Deep Reef Refugia Hypothesis.
Bibliographical noteFunding Information:
This project received funding from the United States National Science Foundation and United States – Israel Binational Science Foundation (NSF #1937770 to GG-G and BSF #2019653 to TM), a Grant-in-Aid award from BIOS, and the BIOS REU program from the National Science Foundation’s Diversity of Ocean Sciences (NSF #1757475).
We thank Alexander Hunter and the Bermuda Institute of Ocean Sciences, for facilitating technical SCUBA diving in Bermuda. We also thank Kevin Wong and Danielle Becker for their assistance with maintaining corals in the mesocosm and Hollie Putnam for use of the larval respiration set up and guidance with respiration data analysis. This work was conducted under permission from the Bermuda Government Department of Environment and Natural Resources permit #2019061407. Funding. This project received funding from the United States National Science Foundation and United States ? Israel Binational Science Foundation (NSF #1937770 to GG-G and BSF #2019653 to TM), a Grant-in-Aid award from BIOS, and the BIOS REU program from the National Science Foundation?s Diversity of Ocean Sciences (NSF #1757475).
© Copyright © 2021 Goodbody-Gringley, Scucchia, Ju, Chequer, Einbinder, Martinez, Nativ and Mass.
- coral larvae
ASJC Scopus subject areas
- Global and Planetary Change
- Aquatic Science
- Water Science and Technology
- Environmental Science (miscellaneous)
- Ocean Engineering