06/24/2025
By Irma Silva

The Kennedy College of Sciences, Department of Biological Sciences, invites to you attend a Ph.D. Dissertation Proposal Defense in Applied Biology by Brooke Sienkiewicz entitled: "Coral Resilience: The Interplay between Microbiome and Environment in a Changing Ocean."

Candidate: Brooke Sienkiewicz
Degree: Doctoral
Date: Tuesday, July 8
Time: noon to 3 p.m.
Location: Olsen 503 and via Zoom

Committee Members:

  • Sarah Gignoux-Wolfsohn, (Advisor) Assistant Professor, Biological Sciences, University of Massachusetts Lowell
  • Natalie Steinel, Associate Professor, Biological Sciences, University of Massachusetts Lowell
  • Matthew Sasaki, Assistant Professor, Biological Sciences, University of Massachusetts Lowell
  • Julia Brown, Senior Research Scientist, Bigelow Laboratory for Ocean Sciences

Title: Coral Resilience: The Interplay between Microbiome and Environment in a Changing Ocean

Abstract
Scleractinia, or stony corals, are vital foundation species in coral reef ecosystems that critically support marine biodiversity and global coastal economies. Corals function as a holobiont, consisting of the coral animal, its algal endosymbionts (Symbiodiniaceae), and a diverse microbial community that each play interdependent roles in host fitness, including nutrient cycling and immunity. Climate change stressors, such as rising temperatures and pollution, are exacerbating coral bleaching and disease, leading to a breakdown in these symbioses. While the role of algal symbionts in bleaching resistance is partially understood, the contribution of other microbiome members to holobiont resilience is understudied. Our research uses a natural experiment at Carrie Bow Cay, Belize where reefs experienced consecutive stressors: a Stony Coral Tissue Loss Disease (SCTLD) outbreak in ~2020 followed by a severe bleaching event in 2023. With prevalence of bleaching and SCTLD varying across host species and reefs, we hypothesize that microbiome composition and environmental factors influence bleaching and disease resistance. Aim 1 will analyze how reef location and host traits influence bleaching resilience using demographic monitoring data. Aim 2 will examine the relationship between water quality parameters and community-level bleaching resilience. Aim 3 will identify microbial biomarkers that contribute to SCTLD resistance using metagenomic comparisons of resistant and susceptible colonies. Aim 4 will examine the relationship between water quality and coral microbiomes and how this contributes to host resilience. These interconnected aims will advance our understanding of how environmental conditions and microbial communities shape coral holobiont resilience and can inform coral reef conservation strategies in an era of increasing environmental stress.