In this study, we tested how tiny marine organisms called foraminifera, key contributors to the carbon cycle, will respond to fine olivine particles in seawater. We used two species that have spines and sticky threads used to catch food, which might also make them more likely to interact with olivine particles.

At high olivine levels, all the foraminifera sank quickly, lost their spines, and some accidentally took in the particles, possibly mistaking them for food. A few survived for several days, but none recovered fully.

At lower olivine levels, the foraminifera also sank, and most lost their spines within two days. A few managed to regrow spines, but none continued to grow.

These early results suggest that spreading olivine in the ocean could harm foraminifera by affecting how they float, feed, and survive, raising concerns about potential side effects of this climate intervention approach.