This course will provide a basic introduction to physical, chemical, and biological properties of Earth's ocean. The course is divided into three parts that address various aspects of the marine carbon cycle, including carbon and tracer transport by the ocean circulation, carbonate chemistry, and fixation/respiration of carbon by biological processes. These parts are tied to three key questions that highlight the ocean's role in the global climate system: What processes contribute to changes in global and local sea level? How and where does the ocean exchange carbon dioxide with the atmosphere? Why is a warming climate associated with ocean acidification and what are the biological consequences? The course will also provide perspectives on how we observe and model the ocean and how these tools are used in climate predictions.