Field Trip, 2 credits, two weeks. Pre-requisite: OCE308. Estuaries and adjacent sea areas are the most active areas of sea-land interaction, and are areas where biogeochemical element cycles such as carbon, nitrogen, sulfur, and phosphorus are very active. Marine microorganisms account for more than 90% of the total marine organisms. They are the main drivers of the marine carbon and nitrogen cycle and the main maintainer of the balance of the marine ecosystem. This filed trip is arranged in Wanshan Island and Sanmen Island. Through theoretical teaching and practical practice, this course enables students to initially learn and use drones to collect marine samples, learn water sample collection and on-site measurement of relevant parameters in marine biochemistry, and understand marginal seas. Through this course students can develop the ability to process the data; at the same time, by overcoming the difficulties caused by various inconveniences in the filed, cultivate students' awareness of hard work and teamwork, and train students to solve problems.