Carbon is the elemental building block for all living things. Over time, carbon moves through the land, air, and oceans in a process called the carbon cycle. Parts of the oceanic carbon cycle are still a mystery. How do tiny photosynthetic microbes and bacteria in the ocean affect the carbon cycle? Why does some carbon stay in the ocean for thousands of years while other carbon moves from the ocean to the air in just seconds or minutes? By combining new methods from chemistry, biology, and data management, we are investigating carbon dissolved in seawater. Eventually, we’d like to understand how bacteria in the ocean will react to our changing climate – will they help store more carbon safely in the ocean or will they speed climate change by adding more carbon to the atmosphere?