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Deciphering the mysterious relationship between coral and algae

February 27, 2023

New ASU lab to grow corals, shed light on underpinnings of coral bleaching

Across the world, once beautifully vibrant corals are turning ghostly white. 

In 2022, the Great Barrier Reef — the largest reef system in the world — was hit by its sixth mass bleaching event, severely bleaching 60% of the corals along hundreds of miles off the Australian coast. 

Over the last decade, as sea surface temperatures continue to rise, triggering physiological stress in corals, bleaching events have increased in frequency and intensity. Scientists are urgently working to find solutions to save this vulnerable resource, which is critical for preserving marine biodiversity, protecting coastlines and providing food for millions of people. 

Liza Roger, assistant professor in Arizona State University’s School of Molecular Sciences and an affiliate faculty in ASU’s School of Ocean Futures, is leading research to better understand coral bleaching and the phenomenon’s effect on the symbiotic relationship between coral and algae.

“With coral (research), one of the major things at the moment is their sensitivity to temperature,” said Roger, a marine scientist and geochemist. “We need to understand the dynamics of oxidative stressOxidative stress is part of the physiological stress response on corals better. We need to better understand the symbiosis with the algae that lives in their tissue.” 

Liza Roger

Coral and algae: A perfect match 

Corals and algae live in a mutually beneficial relationship with each other. Healthy corals are home to algae that photosynthesize, giving the coral energy and their bright color hues, while coral provide algae with shelter; both rely on each other for important nutrient exchanges for survival.

But as seawater temperatures rise, corals are hit with an onslaught of oxidative stress, causing algae to be expelled from coral tissue, leaving it transparent, showing the white underlying skeleton. 

It’s clear that the coral-algae symbiosis breaks down under these stressed conditions, but critical questions remain: How and why do these partners part ways, and who — the coral or algae — initiates the breakup? 

“We don’t know whether it's the host coral, or whether it's the algae partner, or whether it's both,” Roger said. “Is one poisoning the other? Are they poisoning each other? Is it just a mutual understanding that they've had enough of each other? You go your way, I go my way. We haven't figured that out yet.”

Roger is creating a new research lab at ASU that aims to bring together an interdisciplinary team of marine biologists, computer scientists, physicists and chemical engineers to better understand oxidative stress on corals and formulate conservation solutions. The one-of-a-kind lab will grow corals, in vitro and in vivo, and other marine organisms.

We’re trying to look at how they are handling this stress and understand it at the molecular level,” Roger said.

Hidden clues from other marine life 

Some clues about the breakdown of coral-algae symbiosis may already exist in other marine species. 

The upside down jellyfish Cassiopea, sea anemones and giant clams all have similar types of symbiotic relationships with algae as coral do, yet have different temperature thresholds.

Cassiopea live in tropical mangroves under warmer sea temperatures with low seawater flow and lower oxygen; sea anemones live in rocky pools with varying tides and drastic temperature and oxygen level fluctuations; and giant clams can live right beside a coral under the same stressful conditions, yet each in their own unique way manage to keep its symbiosis with algae. 

“These organisms are doing something that the coral is not managing to do,” Roger said. “So the idea is to look at those organisms and learn how they do it. Is it a pathway? Is it an enzyme? What is it? How can they do it? Then we can package that to give it to coral.”

For Roger, her work today examining oxidative stress on corals is the product of a lifelong fascination with the ocean and the organisms that live within it. 

“I knew how to pick up a crab without getting nipped before I knew how to tie my shoelaces,” said Roger, who grew up along the coastline of Normandy, France, playing in shallow rock pools at low tide with her family. 

From producing academic work in marine biology, coastal management and geochemistry, to a stint educating tourists on whale species and migration as a guide in Iceland, to introducing people to the vast life and world beneath the waves in Greece and Thailand as a scuba diving instructor, Roger’s affinity for the ocean only continued to grow with time.  

Today, Roger stays focused on the ocean and is driven to save the underwater spaces and its breath of biodiversity in which she is so intimately tied.  

“This is not just about spoiling your tourist destination. It's about the whole ocean and the whole ecosystem,” she said. “I always try to be very solution-oriented. I think that's something I've always had; finding the right type of problem is always the thing. This is a big deal.”

Roger is currently recruiting graduate students and postdocs for her new marine biochem research lab. To learn more, contact her at

Top photo: Coral colony on the Great Barrier Reef, Australia. Courtesy Liza Roger

David Rozul

Media Relations Officer , Media Relations and Strategic Communications


Celebrating cultural strengths to build resilience, self-esteem

Study looks to improve confidence in natural appearance

February 27, 2023

Nearly half of all teens have reported experiencing one or more forms of cyberbullying, with a majority reporting bullying centering around appearance or ethnic background. This appearance-based pressure can impact long-term self-esteem, confidence, physical and mental health.

A new study by Marisol Perez, professor of psychology and associate dean of graduate initiatives at Arizona State University, hopes to demonstrate the impact that strengths-based interventions can have on specific groups, such as the Hispanic/Latino community. Two dark-haired women smiling and looking at the camera. A new study by Marisol Perez, professor of psychology and associate dean of graduate initiatives at ASU, hopes to demonstrate the impact that strengths-based interventions can have on specific groups, such as the Hispanic/Latino community. Photo courtesy Omar Lopez/Unsplash Download Full Image

Currently, there are 35 million Latino youth in the United States and over 2.4 million Hispanic/Latinos reside in Arizona. With the support of the Dove Self-Esteem Project, Perez is launching “Celebrándome: Building self-confidence in Hispanic/Latinx Youth.” This project is expanding access to an evidence-based curriculum intended to improve beauty and appearance standards in Hispanic youth.

Perez previously launched initiatives for body positivity and hair positivity among African American youth.

Celebrandome (Celebrating Me) is a body confidence workshop that aims to increase children’s body satisfaction and self-esteem. The 60–90 minute workshop is implemented in person and is led by a facilitator in a group format with up to 15 children. The workshop involves having children think about the pressures they feel to change their appearance, ways to stop negative thoughts related to their bodies and ways to celebrate what our bodies allow us to do.

The curriculum is designed for teachers or any adult who's in charge of a youth group, such as Girl or Boy Scouts, coaches or community leaders. 

Eligible participants in the workshop will be compensated $100 to $150. To be eligible, children must be between 11 to 16 years old and identify as Hispanic, Latino or LatinxGender-neutral noun or adjective for a person from, or whose ancestors were from, a Spanish-speaking land or culture or from Latin America..

“This project is funded by the Dove Self-esteem Project, whose philanthropic mission is to increase the body confidence of all youth worldwide,” said Perez. “They hire researchers and experts in the field to create curriculum that is rigorously tested and then they disseminate it to everyone for free. What is awesome about this is that when we're done with the research, all of our materials will be available for free for anybody to use.”

Evidence has shown that young children are exposed to appearance-based pressures on a daily basis, through channels such as social media, television and in print advertisements, and it has been shown to impact self-esteem even as early as 5 years old. 

“What we find is that by age 5, kids start to report body dissatisfaction or a preoccupation with appearance concerns about their weight and their body size. By age 8 to 12, research shows that about 25% to 52% of youth report body dissatisfaction,” said Perez. “It's also associated at that age with starting to skip meals, with unhealthy dieting behaviors, low self-esteem and some depressive symptoms as well.”

To help combat these pressures, Perez and her lab also produced a library of resources for parents to help their young children navigate developing confidence in how they look. These activities range from as little as 20 minutes to fully integrated 60-minute discussions on how to create an action plan to deal with the pressures of social media influencers. 

“When kids are little, the mirror is a fun toy; however, we see that as kids age, the mirror changes over time to become something that's really coupled with body dissatisfaction, appearance, insecurities,” said Perez. “Our goal is to actually start teaching them young in schools with a curriculum that builds their confidence so that they don't start down this negative pathway. We want to have a future generation of youth that actually aren't worried about their looks and are more concentrated on skill-building — things that are essential for their life.”

The Body Image Research and Health Disparities (BIRHD) lab is looking for 200 Hispanic/Latino families with children between the ages of 11 to 16 years old. Interested participants or leaders can sign up using this link

Video courtesy the ASU Department of Psychology

Robert Ewing

Marketing and Communications Manager, Department of Psychology