In-situ surveying and sampling of ocean environments provides critical data for laboratory work and oceanographic research. However, sampling a time-varying ocean field is often time and resource limited-meaning that samples often miss the features of interest. This paper presents a modular autonomous multi-agent robotic system which has been developed to accommodate a variety of research activities. This paper demonstrates the complementary capabilities of the agents by simultaneously surveying a time-varying coastal environment and using that information to obtain a sparse but representative set of water samples. This autonomous system enables the elimination of redundant resources, thereby reducing the overall cost of at-sea sampling and improving sample quality.@en