Measuring carbon dioxide parameters in seawater is crucial for understanding the impacts carbon dioxide has in our oceans, but current methods require bulky, expensive equipment and technical expertise. This project will develop a small, portable device for measuring pH and total alkalinity in seawater using the spectrophotometric method (Dickson et al. 2007; Yao & Byrn, 1998). It will empower citizen scientists around the globe to contribute valuable data on the ocean's carbonate system.