Melting dynamics of freely floating ice in calm waters.

Predicting floating ice dynamics remains a challenging problem with implications for Earth's climate. While gigantic icebergs have garnered worldwide attention, small ice bodies have been overlooked, and we still lack their mechanistic models. Aided by a real-time tracking, we unravel the transient processes of freely floating ice in calm waters-including the kinematics, phase transition, and surrounding fluid dynamics-that govern melting. Combining the heat transfer model and our experimental results, we develop and validate a theoretical model for the melt rate, identifying ice geometry and convective regime as key controls. Furthermore, the ice-driven convective volume flux is found to exceed the meltwater flux by orders of magnitude, underscoring the ecological relevance of floating ice; it not only supplies freshwater but also acts as a destabilizing buoyancy source that redistributes mass macroscopically. Our study provides a foundation for developing mechanistic parameterizations of icebergs and ice floes melting in climate models.