Floating ice cylinders
These two videos show the morphological changes that occur on ice cylinders that are left to melt floaing in a water tank. The left video is of an experiment where the water is fresh, the right one is one where the water is saline (about a third of the average ocean salinity). The videos are sped up, the melting takes about half an hour in real time.
The first notable difference is that the cylinder melting in fresh water capsizes, while the one in saline water does not.
The capsizing behaviour of the left cylinder can be explained by the erosion of the ice by the cold water that sinks around it. The different heat transfer between ice-air and ice-water makes such that the melting happens asymmetrically between the ice below water and the ice above water, and this corresponds to a repeated capsizing behaviour of the ice cylinder.
In the saline case, the cooled-down saline water meltwater tends to sink, while the fresh meltwater tends to float. The competition between these two effects creates a peculiar erosive effect, which produces a shape that is stable against capsizings.
Icebergs in fjords and oceans behave similarly to my laboratory ice cylinders, as the following video shows
More information and details can be found in the publication that corresponds to this resarch, currently hosted at https://arxiv.org/abs/2411.09620.