This deep-sea animal takes recycling very seriously. 

The fragile pink sea urchin (Strongylocentrotus fragilis) is one of the most common neighbors MBARI encounters as we explore our blue backyard.

Sea urchins have a calcium carbonate test, or shell, covered in spines. As their name implies, the fragile pink sea urchin has a much thinner test than other urchin species.

Herds of fragile pink sea urchins roam the seafloor, shaping ecosystems through constant foraging, much like wildebeests grazing across African grasslands. These tiny grazers move across the soft sediment, munching on dead kelp and other organic material. With each nibble, they make nutrients and carbon available for other organisms on the seafloor and in the water column above. Upwelling draws cool, nutrient-rich water up from the depths to fuel pulses of productivity near shore, which means that these grazing Strongylocentrotus fragilis benefit coastal environments too. Large groups of these urchins can even create habitat for other seafloor animals, providing a safe place for small fishes and invertebrates to hide or maybe grab a bite to eat. 

Although they may be more delicate, Strongylocentrotus fragilis are resilient, thriving across a broad depth range. While they experience a variety of environmental conditions, some populations live at the extremes of their oxygen and temperature limits. Will a changing ocean push them over the edge?

MBARI researchers are studying how climate change and ocean acidification affect marine life. We have used our advanced technology to study the physiology of fragile pink sea urchins both in the lab and in the ocean. Our research has revealed that the ocean’s changing chemistry will weaken these urchins’ fragile tests even further, influence how successfully they can reproduce, and may even push populations out of their preferred habitats. 

A complex web of connections links animals within ocean ecosystems—predators and prey, competition for food or shelter, symbiotic partnerships, and more. When natural processes or human activities affect one species, their impact can reverberate across the whole web, ultimately affecting entire communities. Our everyday choices can have lasting ripples across the planet. What we do today shapes the ocean of tomorrow. Reducing our carbon footprint and speaking up about climate change can help safeguard the future of our ocean neighbors.