Complex sentence: A perturbation to the surface of hot salty water which finds itself surrounded by cold fresh water loses its heat more rapidly than its salinity the diffusion of heat is faster than of salt (just as unstirred coffee goes cold before sugar has diffused to the top).
Split into simpler sentences: A perturbation to the surface of hot salty water results in an element of hot salty water surrounded by cold fresh water. This element loses its heat more rapidly than its salinity because the diffusion of heat is faster than of salt (just as unstirred coffee goes cold before sugar has diffused to the top).