Researchers from the Institute of Marine Systems at Tallinn University of Technology have discovered important short-term water movements occurring beneath the calm surface of the Gulf of Finland during the spring and summer periods. These movements have substantial impacts on the movement of heat, carbon, and nutrients in the seawater, directly affecting the health of the entire marine ecosystem. While large currents covering hundreds of kilometers are usually the focus, this research highlights significant mixing occurring at much smaller scales, specifically within the submesoscale range of hundreds of meters to a couple of kilometers. To reach this conclusion, the research team employed an autonomous underwater vehicle (AUV) to collect data from the depths over several weeks, which allowed them to observe previously hidden hydrodynamic dynamics. The AUV provided insights into how water masses were influenced by larger currents and how they smoothly interacted with the seabed's topography and differently temperatured water masses. This study represents a significant advance in understanding marine processes that take place on smaller scales, emphasizing the necessity of measuring these subtler dynamics. The implications of these findings extend beyond academic interest, as understanding these water movements can enhance predictions regarding marine health, help manage fish populations, and inform environmental protection efforts. By illuminating the complexities of water dynamics in the Baltic Sea, this research lays the groundwork for more effective conservation strategies in the region, showcasing the importance of technological advancements in marine research.