Symbioses between animals and photosynthetic organisms occur widely in marine ecosystems, but they are particularly vulnerable to climate change because they depend on tightly coupled environmental conditions such as light, temperature, and oxygen availability. Climate-driven stress can disrupt the balance between host and photosynthetic partner, reducing benefits or turning the interaction costly. Dr. Ellie Laetz and her students investigate symbioses when exposed to environmental stressors including warming, deoxygenation, acidification and increased light in order to determine which symbioses are most vulnerable to environmental stress and which physiological processes underlie this vulnerability. Her work shows that warming and low-oxygen conditions can strongly alter the energetic and physiological benefits of photosynthesis, sometimes limiting or negating its advantages under stress. These findings highlight that photosymbioses are not inherently protective against climate change; instead, their persistence depends on environmental context, making them sensitive indicators of how climate stress reshapes biological interactions.
