RRFB Plasticity and Epigenetics: Project Initiation and Overview

Since the 1980’s, Caribbean coral reefs have declined due to a variety of stressors including coral disease, nutrient pollution, overfishing, hurricanes, and warming temperatures.

If corals are unable to keep pace with the changing climate, many reefs are predicted to disappear within the next few decades. In addition to reducing sources of stress and enhancing coral populations through restoration, strategies to increase coral stress tolerance and resilience have become a recent focus within coral conservation research.

Epigenetics refers to changes in the function of genes, such as turning a certain gene “on” and another “off”, without changes to the DNA sequence. Epigenetic modifications, including DNA methylation, help organisms respond to environmental stress and can facilitate quick acclimation to changes in environmental conditions. However, there are still many unknowns about environmental epigenetics in reef building corals.

In collaboration with Reef Renewal Foundation Bonaire (RRFB), Ph.D. student Serena Hackerott has recently initiated a year-long study to assess connections between epigenetic modifications and coral performance across variations in environmental conditions. Serena will monitor the demographic and physiological performance and epigenetic DNA methylation of two endangered Caribbean corals, Acropora cervicornis (staghorn coral) and Acropora palmata (elkhorn coral) on four RRFB coral nursery sites on Bonaire, Caribbean Netherlands. The study sites were selected to cover a range of environmental conditions on Bonaire, including different distances to sources of runoff and nutrient pollution. Additionally, Serena will monitor these corals across different seasonal timepoints, including Bonaire’s rainy and dry seasons, as a “natural experiment” exposing corals to different water temperatures and nutrient levels. 

Within both of the two coral species, different genotypes or genetic “strains” are present at each of the study sites which will allow Serena to compare the genetic and epigenetic influence on coral performance. While coral restoration has recently focused on identifying strong coral genotypes, this study will provide insights into the additional effect of environmentally responsive epigenetic mechanisms on the performance of two important coral species. 

This work has been made possible by support from Reef Renewal Foundation Bonaire, FIU CREST-CAChE, FIU College of Arts and Sciences, FIU Center for Coastal Oceans Research, and FIU Tropics.

Over the past year, our lab and Reef Renewal Foundation Bonaire have collaborated to complete the first phase of a two-part project focused on exploring coral environmental memory and the role of epigenetic mechanisms in coral responses to environmental stress.

Coral Epigenetics in Bonaire

Bottom Time with Serena Hackerott

Serena is a PhD student at FIU’s Environmental Epigenetics Lab under the supervision of Dr. Jose Eirin-Lopez. As a graduate Research Assistant funded by FIU’s CREST-CAChE and NSF Rules of Life Programs, she is at the helm of this work, from fieldwork organization to lab experiments and analyses.

How did you become interested in the biology of corals?

As both of my parents are scuba divers, most of my childhood revolved around snorkeling and scuba diving on coral reefs around the world. Coral reefs became my home away from home and I knew from an early age that I would pursue a career focused on understanding these beautiful and complex ecosystems. However, due to the variety of threats they currently face, coral reefs have been declining and it is possible that they will disappear within the next few decades without action. An overarching goal of my career is therefore to pursue research that not only increases our knowledge of these ecosystems but also supports coral reef conservation. My scientific career began with an opportunity to volunteer in Dr. John Bruno’s Marine Ecology Lab as an undergraduate student at the University of North Carolina at Chapel Hill. After completing a B.S. Honors Thesis and M.S. Thesis with Dr. Bruno focused on impacts and mitigation of the Caribbean lionfish invasion, I taught marine science on Bonaire and the Marshall Islands to increase local marine conservation capacity. Since joining Dr. Jose Eirin-Lopez’s Environmental Epigenetics Lab in 2018, I have developed my Ph.D. research focusing on understanding coral responses to environmental stress, including the role of environmental epigenetics and stress memory. I am very excited for this opportunity to collaborate with Reef Renewal Foundation Bonaire, a local coral restoration NGO on Bonaire, for a large part of my dissertation work.

What is the most important contribution of this project to the assessment and recovery of coral reefs?

This project will track the performance of two critically endangered Caribbean coral species across variations in environmental conditions and will compare the effect of the coral genotype and epigenetic modifications on coral performance. One of the most important contributions of this project will be to provide insights on the role of epigenetics in helping corals respond to environmental stress. While coral restoration often focuses on propagating specific genotypes of corals, environmental epigenetics may also be an important factor to incorporate into coral restoration and conservation efforts.

Once this project is complete, what do you think would be the next step in coral research?

After this first year of the project has been completed, we have a second phase planned that will build on the coral performance, epigenetic, and environmental data collected during this first phase. Phase 2 of the project will further investigate coral environmental memory and evaluate the effect of coral nursery conditions on coral stress tolerance and performance after outplanting. In my opinion, coral environmental memory should also be explored in multiple coral restoration settings and tracked across years as well as generations to assess the potential long-term benefit for corals. In addition, the identification of molecular biomarkers of environmental memory and stress tolerance, such as certain epigenetic modifications, would help coral scientists and conservationist be able to identify more resilient corals.

How will this project impact your future scientific development?

This project will provide me with the opportunity to lead a multifaceted project including coordinating with international collaborations, planning and leading field expeditions, and training team members in both field and lab procedures. I am also excited for the new techniques I will learn throughout this project ranging from coral restoration methods to protocols to characterize coral performance and epigenetic modifications in the lab. Representing one chapter of my dissertation and providing critical baseline data for a second chapter, this project is also particularly important for my progress towards a doctorate degree.

In addition to further describing the role of epigenetic modification in coral responses to environmental stress, results from this project will also provide baseline data critical for the second phase of the study planned for 2021 that will explore coral environmental memory within coral restoration.