Award: OCE-2128592

Nearly all the animals that inhabit the ocean are "cold-blooded" or ectothermic, meaning their body temperatures match the temperature of the ocean around them. This has important consequences for their physiology, and more broadly, for the way marine ecosystems function. When ectotherms warm up, their metabolism increases – meaning they breathe more rapidly and eat more just to stay alive. This is bad news for prey, since a warm predator is a hungry predator. But warming also enables prey species to crawl or swim away more quickly when being hunted. Thus, everything speeds up in a warmer environment. Energy flows more quickly from the sun to seaweeds (via photosynthesis), to herbivores, and then on up to the large predators at the top of the food chain. As a result, there are typically fewer prey, since predation intensity increases. 

The broad goal of this project was to understand the effects of temperature has on patterns and processes in coastal marine communities. Specifically, we measured the temperature dependence of herbivory and carnivory in rocky subtidal habitats of the Galápagos. We performed field experiments to measure the relative and interactive effects of temperature, herbivory, and nutrient flux on the productivity and standing biomass of benthic macroalgae. Additionally, we used in situ predation assays across spatial and temporal temperature gradients, as well as mesocosm experiments, to determine the relationship between ocean temperature and predation intensity. 

The primary findings of the study are:

1) Temperature plays a critical role in regulating predation intensity and prey biomass and abundance on the shallow subtidal rocky reefs of the Galápagos. 

2) The influence of temperature is based on multiple mechanisms, including its effects on the photosynthesis, growth, and survival of primary producers, as well as on predator metabolism and consumption rates. 

3) Although warming increases most biological and ecological rates, many species in this system become impaired at the highest temperatures. 

4) A diversity of responses to warming and other factors among species (called “ecological response diversity”) could help maintain critical ecosystem functions in a variable and changing environment.

5) Higher temperatures could alter the composition and structure of this iconic marine ecosystem. 

Our work in this iconic natural laboratory is helping marine ecologists better understand the role of temperature and how this and other ecosystems may function in the future as climate change warms the ocean. Other broader impacts of the project included student training and on-site outreach to tourists and the local community about ocean warming and some of the lesser-known species that inhabit the Galápagos. We also published 15 articles in peer-reviewed scientific journals and three PhD dissertations based on the core project science.  

 

Last Modified: 03/25/2026
Modified by: John F Bruno