The ocean stores an enormous amount of carbon and so plays an important role in regulating how much CO₂ stays in the atmosphere. When organisms die in the surface ocean, that organic matter starts sinking towards the bottom of the ocean. As this organic matter (particles) falls, bacteria break it down and turn it back into CO₂. Whether the breakdown occurs in the surface ocean or in the deep ocean has important implications because it determines the depth that the CO₂ is released. If a particle is degraded in the deep ocean, it effectively sequesters that CO₂ out of the atmosphere for hundreds to thousands of years. Previous work has focused on the impact of the number of sinking particles and their size. A recent study by Dr. Trang Thi Huyen Nguyen, a postdoctoral scholar in the Levine Lab, used experimental data from laboratory experiments on how individual bacteria interact with each other and with particles and incorporated these microscopic processes into a model to predict how fast organic carbon is degraded as it sinks. The study showed that these microscopic interactions and behavior of the bacteria can play an important role in setting the transfer of carbon into the deep oceans. This transfer is determined by which microbes are present, how many, and how they interact with the organic matter. The full study can be found in Nature Communications.