Program on the Environment

In my capstone internship I worked with NOAA at the NorthWest Fisheries Science Center (NWFSC) to research survival of Dungeness crab zoea under high alkalinity conditions. Zoea are in the early larval stages in the crab life cycle. At this stage, they are small, free-floating organisms with a shrimp-like appearance, distinguishable by two prominent spikes on top of its head and nose. While they may not resemble crabs yet, this developmental phase is critical to population health and ecosystem stability. This study investigates how increased alkalinity used in ocean alkalinity enhancement (OAE), a marine carbon dioxide removal (mCDR) strategy, impacts crab zoea survival. OAE is being explored as a method to mitigate ocean acidification by raising seawater pH levels, which are linked to carbon dioxide concentrations and global temperature. My team and I conducted a series of nine short-term exposure trials. Each trial consisted of a multi-day process beginning with zoea collection and seawater preparation. This is followed by controlled bubbling to adjust alkalinity levels. After plating the larvae in different treatment conditions, we observed their responses under a microscope over subsequent mortality observation days. These steps formed the core of my internship experience. My research focused on understanding the ecological consequences of mCDR and the possible ecosystem disruption. Some key takeaways include: (1) elevated alkalinity can significantly influence larval survival rates, (2) temperature variation and life cycle timing require careful seasonal deployment, and (3) understanding species-specific responses is essential for evaluating the environmental safety of carbon removal strategies.